http

原文：https://pkg.go.dev/net/http@go1.23.0

Package http provides HTTP client and server implementations.

​ http包提供了 HTTP 客户端和服务端的实现。

Get, Head, Post, and PostForm make HTTP (or HTTPS) requests:

​ Get、Head、Post 和 PostForm 方法可用于发起 HTTP(或 HTTPS)请求：

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resp, err := http.Get("http://example.com/")
...
resp, err := http.Post("http://example.com/upload", "image/jpeg", &buf)
...
resp, err := http.PostForm("http://example.com/form",
	url.Values{"key": {"Value"}, "id": {"123"}})

The caller must close the response body when finished with it:

​ 在使用完响应后，客户端必须关闭响应主体：

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resp, err := http.Get("http://example.com/")
if err != nil {
	// 处理错误
}
defer resp.Body.Close()
body, err := io.ReadAll(resp.Body)
// ...

For control over HTTP client headers, redirect policy, and other settings, create a Client:

​ 为了控制 HTTP 客户端的标头、重定向策略和其他设置，可以创建一个 Client：

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client := &http.Client{
	CheckRedirect: redirectPolicyFunc,
}

resp, err := client.Get("http://example.com")
// ...

req, err := http.NewRequest("GET", "http://example.com", nil)
// ...
req.Header.Add("If-None-Match", `W/"wyzzy"`)
resp, err := client.Do(req)
// ...

For control over proxies, TLS configuration, keep-alives, compression, and other settings, create a Transport:

​ 为了控制代理、TLS 配置、保持连接、压缩和其他设置，可以创建一个 Transport：

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tr := &http.Transport{
	MaxIdleConns:       10,
	IdleConnTimeout:    30 * time.Second,
	DisableCompression: true,
}
client := &http.Client{Transport: tr}
resp, err := client.Get("https://example.com")

Clients and Transports are safe for concurrent use by multiple goroutines and for efficiency should only be created once and re-used.

​ Clients 和 Transports 可以被多个 goroutine 并发使用，并且为了效率应该只创建一次并重复使用。

ListenAndServe starts an HTTP server with a given address and handler. The handler is usually nil, which means to use DefaultServeMux. Handle and HandleFunc add handlers to DefaultServeMux:

​ ListenAndServe 方法可启动一个使用给定地址和处理程序的 HTTP 服务器。处理程序通常为 nil，这意味着使用 DefaultServeMux。Handle 和 HandleFunc 方法可将处理程序添加到 DefaultServeMux：

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http.Handle("/foo", fooHandler)

http.HandleFunc("/bar", func(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "Hello, %q", html.EscapeString(r.URL.Path))
})

log.Fatal(http.ListenAndServe(":8080", nil))

More control over the server’s behavior is available by creating a custom Server:

​ 通过创建自定义服务器可以获得更多对服务器行为的控制：

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s := &http.Server{
	Addr:           ":8080",
	Handler:        myHandler,
	ReadTimeout:    10 * time.Second,
	WriteTimeout:   10 * time.Second,
	MaxHeaderBytes: 1 << 20,
}
log.Fatal(s.ListenAndServe())

Starting with Go 1.6, the http package has transparent support for the HTTP/2 protocol when using HTTPS. Programs that must disable HTTP/2 can do so by setting Transport.TLSNextProto (for clients) or Server.TLSNextProto (for servers) to a non-nil, empty map. Alternatively, the following GODEBUG environment variables are currently supported:

​ 从 Go 1.6 开始，当使用 HTTPS 时，http 包对 HTTP/2 协议具有透明支持。必须禁用 HTTP/2 的程序可以通过将 Transport.TLSNextProto(用于客户端)或 Server.TLSNextProto(用于服务器)设置为non-nil的空映射来实现。或者，目前支持以下 GODEBUG 环境变量：

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GODEBUG=http2client=0  # disable HTTP/2 client support
GODEBUG=http2server=0  # disable HTTP/2 server support
GODEBUG=http2debug=1   # enable verbose HTTP/2 debug logs
GODEBUG=http2debug=2   # ... even more verbose, with frame dumps

The GODEBUG variables are not covered by Go’s API compatibility promise. Please report any issues before disabling HTTP/2 support: https://golang.org/s/http2bug

​ GODEBUG 变量不受 Go 的 API 兼容性承诺的保护。在禁用 HTTP/2 支持之前，请报告任何问题：https://golang.org/s/http2bug

The http package’s Transport and Server both automatically enable HTTP/2 support for simple configurations. To enable HTTP/2 for more complex configurations, to use lower-level HTTP/2 features, or to use a newer version of Go’s http2 package, import “golang.org/x/net/http2” directly and use its ConfigureTransport and/or ConfigureServer functions. Manually configuring HTTP/2 via the golang.org/x/net/http2 package takes precedence over the net/http package’s built-in HTTP/2 support.

​ http 包的 Transport 和 Server 都会自动为简单配置启用 HTTP/2 支持。为了启用更复杂的配置的 HTTP/2，使用更低级别的 HTTP/2 功能或使用 Go 的 http2 包的更新版本，请直接导入 “golang.org/x/net/http2” 并使用其 ConfigureTransport 和/或 ConfigureServer 函数。手动配置 HTTP/2 通过 golang.org/x/net/http2 包优先于 net/http 包内置的 HTTP/2 支持。

常量

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const (
	MethodGet     = "GET"
	MethodHead    = "HEAD"
	MethodPost    = "POST"
	MethodPut     = "PUT"
	MethodPatch   = "PATCH" // RFC 5789
	MethodDelete  = "DELETE"
	MethodConnect = "CONNECT"
	MethodOptions = "OPTIONS"
	MethodTrace   = "TRACE"
)

Common HTTP methods.

​ 常见的HTTP方法。

Unless otherwise noted, these are defined in RFC 7231 section 4.3.

​ 除非另有说明，这些方法定义在RFC 7231第4.3节中。

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const (
	StatusContinue           = 100 // RFC 9110, 15.2.1
	StatusSwitchingProtocols = 101 // RFC 9110, 15.2.2
	StatusProcessing         = 102 // RFC 2518, 10.1
	StatusEarlyHints         = 103 // RFC 8297

	StatusOK                   = 200 // RFC 9110, 15.3.1
	StatusCreated              = 201 // RFC 9110, 15.3.2
	StatusAccepted             = 202 // RFC 9110, 15.3.3
	StatusNonAuthoritativeInfo = 203 // RFC 9110, 15.3.4
	StatusNoContent            = 204 // RFC 9110, 15.3.5
	StatusResetContent         = 205 // RFC 9110, 15.3.6
	StatusPartialContent       = 206 // RFC 9110, 15.3.7
	StatusMultiStatus          = 207 // RFC 4918, 11.1
	StatusAlreadyReported      = 208 // RFC 5842, 7.1
	StatusIMUsed               = 226 // RFC 3229, 10.4.1

	StatusMultipleChoices  = 300 // RFC 9110, 15.4.1
	StatusMovedPermanently = 301 // RFC 9110, 15.4.2
	StatusFound            = 302 // RFC 9110, 15.4.3
	StatusSeeOther         = 303 // RFC 9110, 15.4.4
	StatusNotModified      = 304 // RFC 9110, 15.4.5
	StatusUseProxy         = 305 // RFC 9110, 15.4.6

	StatusTemporaryRedirect = 307 // RFC 9110, 15.4.8
	StatusPermanentRedirect = 308 // RFC 9110, 15.4.9

	StatusBadRequest                   = 400 // RFC 9110, 15.5.1
	StatusUnauthorized                 = 401 // RFC 9110, 15.5.2
	StatusPaymentRequired              = 402 // RFC 9110, 15.5.3
	StatusForbidden                    = 403 // RFC 9110, 15.5.4
	StatusNotFound                     = 404 // RFC 9110, 15.5.5
	StatusMethodNotAllowed             = 405 // RFC 9110, 15.5.6
	StatusNotAcceptable                = 406 // RFC 9110, 15.5.7
	StatusProxyAuthRequired            = 407 // RFC 9110, 15.5.8
	StatusRequestTimeout               = 408 // RFC 9110, 15.5.9
	StatusConflict                     = 409 // RFC 9110, 15.5.10
	StatusGone                         = 410 // RFC 9110, 15.5.11
	StatusLengthRequired               = 411 // RFC 9110, 15.5.12
	StatusPreconditionFailed           = 412 // RFC 9110, 15.5.13
	StatusRequestEntityTooLarge        = 413 // RFC 9110, 15.5.14
	StatusRequestURITooLong            = 414 // RFC 9110, 15.5.15
	StatusUnsupportedMediaType         = 415 // RFC 9110, 15.5.16
	StatusRequestedRangeNotSatisfiable = 416 // RFC 9110, 15.5.17
	StatusExpectationFailed            = 417 // RFC 9110, 15.5.18
	StatusTeapot                       = 418 // RFC 9110, 15.5.19 (Unused)
	StatusMisdirectedRequest           = 421 // RFC 9110, 15.5.20
	StatusUnprocessableEntity          = 422 // RFC 9110, 15.5.21
	StatusLocked                       = 423 // RFC 4918, 11.3
	StatusFailedDependency             = 424 // RFC 4918, 11.4
	StatusTooEarly                     = 425 // RFC 8470, 5.2.
	StatusUpgradeRequired              = 426 // RFC 9110, 15.5.22
	StatusPreconditionRequired         = 428 // RFC 6585, 3
	StatusTooManyRequests              = 429 // RFC 6585, 4
	StatusRequestHeaderFieldsTooLarge  = 431 // RFC 6585, 5
	StatusUnavailableForLegalReasons   = 451 // RFC 7725, 3

	StatusInternalServerError           = 500 // RFC 9110, 15.6.1
	StatusNotImplemented                = 501 // RFC 9110, 15.6.2
	StatusBadGateway                    = 502 // RFC 9110, 15.6.3
	StatusServiceUnavailable            = 503 // RFC 9110, 15.6.4
	StatusGatewayTimeout                = 504 // RFC 9110, 15.6.5
	StatusHTTPVersionNotSupported       = 505 // RFC 9110, 15.6.6
	StatusVariantAlsoNegotiates         = 506 // RFC 2295, 8.1
	StatusInsufficientStorage           = 507 // RFC 4918, 11.5
	StatusLoopDetected                  = 508 // RFC 5842, 7.2
	StatusNotExtended                   = 510 // RFC 2774, 7
	StatusNetworkAuthenticationRequired = 511 // RFC 6585, 6
)

HTTP status codes as registered with IANA. See: https://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml

​ HTTP状态码在IANA注册。请参见：https://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml

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const DefaultMaxHeaderBytes = 1 << 20 // 1 MB

DefaultMaxHeaderBytes is the maximum permitted size of the headers in an HTTP request. This can be overridden by setting Server.MaxHeaderBytes.

​ DefaultMaxHeaderBytes是HTTP请求中标头的最大允许大小。这可以通过设置Server.MaxHeaderBytes来覆盖。

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const DefaultMaxIdleConnsPerHost = 2

DefaultMaxIdleConnsPerHost is the default value of Transport’s MaxIdleConnsPerHost.

​ DefaultMaxIdleConnsPerHost是Transport的MaxIdleConnsPerHost的默认值。

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const TimeFormat = "Mon, 02 Jan 2006 15:04:05 GMT"

TimeFormat is the time format to use when generating times in HTTP headers. It is like time.RFC1123 but hard-codes GMT as the time zone. The time being formatted must be in UTC for Format to generate the correct format.

​ TimeFormat是生成HTTP标头中时间时要使用的时间格式。它类似于time.RFC1123，但将GMT硬编码为时区。要格式化的时间必须在UTC中，Format才能生成正确的格式。

For parsing this time format, see ParseTime.

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const TrailerPrefix = "Trailer:"

TrailerPrefix is a magic prefix for ResponseWriter.Header map keys that, if present, signals that the map entry is actually for the response trailers, and not the response headers. The prefix is stripped after the ServeHTTP call finishes and the values are sent in the trailers.

​ TrailerPrefix是ResponseWriter.Header映射键的魔术前缀，如果存在，则表示该映射条目实际上是响应trailer，而不是响应标头。 ServeHTTP调用完成后，将删除前缀并将值发送到trailers中。

This mechanism is intended only for trailers that are not known prior to the headers being written. If the set of trailers is fixed or known before the header is written, the normal Go trailers mechanism is preferred:

​ 该机制仅用于不在编写标头之前未知的trailers。如果trailers的集合是固定的或在编写标头之前已知，则首选常规的Go trailers机制：

> 原文：[https://pkg.go.dev/net/http#ResponseWriter](https://pkg.go.dev/net/http#ResponseWriter)
> 原文：[https://pkg.go.dev/net/http#example-ResponseWriter-Trailers](https://pkg.go.dev/net/http#example-ResponseWriter-Trailers)

变量

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var (
    // ErrNotSupported indicates that a feature is not supported.
	//
	// It is returned by ResponseController methods to indicate that
	// the handler does not support the method, and by the Push method
	// of Pusher implementations to indicate that HTTP/2 Push support
	// is not available.
	// ErrNotSupported 表示不支持某一特性。
	//
	// 它由 ResponseController 方法返回，表示处理程序不支持该方法，
	// 并且由 Pusher 实现的 Push 方法返回，表示不支持 HTTP/2 推送功能。
	ErrNotSupported = &ProtocolError{"feature not supported"}

    // Deprecated: ErrUnexpectedTrailer is no longer returned by
	// anything in the net/http package. Callers should not
	// compare errors against this variable.
	// 已弃用：ErrUnexpectedTrailer 
    // 不再由 net/http 包中的任何内容返回。
	// 调用者不应将错误与此变量进行比较。
	ErrUnexpectedTrailer = &ProtocolError{"trailer header without chunked transfer encoding"}

    // ErrMissingBoundary is returned by Request.MultipartReader when the
	// request's Content-Type does not include a "boundary" parameter.
	// 当请求的 Content-Type 不包含 "boundary" 参数时，
	// Request.MultipartReader 将返回 ErrMissingBoundary。
	ErrMissingBoundary = &ProtocolError{"no multipart boundary param in Content-Type"}

    // ErrNotMultipart is returned by Request.MultipartReader when the
	// request's Content-Type is not multipart/form-data.
	// 当请求的 Content-Type 不是 multipart/form-data 时，
	// Request.MultipartReader 将返回 ErrNotMultipart。
	ErrNotMultipart = &ProtocolError{"request Content-Type isn't multipart/form-data"}

    // Deprecated: ErrHeaderTooLong is no longer returned by
	// anything in the net/http package. Callers should not
	// compare errors against this variable.
	// 已弃用：ErrHeaderTooLong 不再由 net/http 包中的任何内容返回。
	// 调用者不应将错误与此变量进行比较。
	ErrHeaderTooLong = &ProtocolError{"header too long"}

    // Deprecated: ErrShortBody is no longer returned by
	// anything in the net/http package. Callers should not
	// compare errors against this variable.
	// 已弃用：ErrShortBody 不再由 net/http 包中的任何内容返回。
	// 调用者不应将错误与此变量进行比较。
	ErrShortBody = &ProtocolError{"entity body too short"}

    // Deprecated: ErrMissingContentLength is no longer returned by
	// anything in the net/http package. Callers should not
	// compare errors against this variable.
	// 已弃用：ErrMissingContentLength 
    // 不再由 net/http 包中的任何内容返回。
	// 调用者不应将错误与此变量进行比较。
	ErrMissingContentLength = &ProtocolError{"missing ContentLength in HEAD response"}
)

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var (
    // ErrBodyNotAllowed is returned by ResponseWriter.Write calls
	// when the HTTP method or response code does not permit a
	// body.
	// ErrBodyNotAllowed 在 ResponseWriter.Write 调用时，
    // 当 HTTP 方法或响应状态码不允许 body 时返回。
	ErrBodyNotAllowed = errors.New("http: request method or response status code does not allow body")

    // ErrHijacked is returned by ResponseWriter.Write calls when
	// the underlying connection has been hijacked using the
	// Hijacker interface. A zero-byte write on a hijacked
	// connection will return ErrHijacked without any other side
	// effects.
	// ErrHijacked 在 ResponseWriter.Write 调用时，
    // 当使用 Hijacker 接口劫持了底层连接时返回。
    // 在劫持的连接上进行零字节写操作会返回 ErrHijacked，没有其他副作用。
	ErrHijacked = errors.New("http: connection has been hijacked")

    // ErrContentLength is returned by ResponseWriter.Write calls
	// when a Handler set a Content-Length response header with a
	// declared size and then attempted to write more bytes than
	// declared.
	// ErrContentLength 在 ResponseWriter.Write 调用时，
    // 当处理程序设置了一个声明大小的 Content-Length 响应头
    // 并尝试写入比声明的更多字节时返回。
	ErrContentLength = errors.New("http: wrote more than the declared Content-Length")

    // Deprecated: ErrWriteAfterFlush is no longer returned by
	// anything in the net/http package. Callers should not
	// compare errors against this variable.
	// Deprecated: ErrWriteAfterFlush 
    // 不再由 net/http 包中的任何内容返回。
    // 调用方不应将错误与此变量进行比较。
	ErrWriteAfterFlush = errors.New("unused")
)

​ HTTP 服务器使用的错误。

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var (
    // ServerContextKey is a context key. It can be used in HTTP
	// handlers with Context.Value to access the server that
	// started the handler. The associated value will be of
	// type *Server.
	// ServerContextKey 是一个 context key。
    // 它可在 HTTP 处理程序中使用 Context.Value 
    // 来访问启动处理程序的服务器。相关的值的类型为 *Server。

	ServerContextKey = &contextKey{"http-server"}

    // LocalAddrContextKey is a context key. It can be used in
	// HTTP handlers with Context.Value to access the local
	// address the connection arrived on.
	// The associated value will be of type net.Addr.
	// LocalAddrContextKey 是一个 context key。
    // 它可在 HTTP 处理程序中使用 Context.Value 
    // 来访问连接到达的本地地址。相关的值的类型为 net.Addr。
	LocalAddrContextKey = &contextKey{"local-addr"}
)

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var DefaultClient = &Client{}

DefaultClient is the default Client and is used by Get, Head, and Post.

​ DefaultClient 是默认的 Client，并被 Get、Head 和 Post 使用。

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var DefaultServeMux = &defaultServeMux

DefaultServeMux is the default ServeMux used by Serve.

​ DefaultServeMux 是 Serve 使用的默认 ServeMux。

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var ErrAbortHandler = errors.New("net/http: abort Handler")

ErrAbortHandler is a sentinel panic value to abort a handler. While any panic from ServeHTTP aborts the response to the client, panicking with ErrAbortHandler also suppresses logging of a stack trace to the server’s error log.

​ ErrAbortHandler 是一个特殊的 panic 值，用于中止处理程序。虽然任何从 ServeHTTP 中发生的 panic 都会中止向客户端的响应，但是使用 ErrAbortHandler 发生 panic 还会阻止将堆栈跟踪记录到服务器的错误日志中。

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var ErrBodyReadAfterClose = errors.New("http: invalid Read on closed Body")

ErrBodyReadAfterClose is returned when reading a Request or Response Body after the body has been closed. This typically happens when the body is read after an HTTP Handler calls WriteHeader or Write on its ResponseWriter.

​ 当请求或响应主体关闭后继续读取主体时，返回 ErrBodyReadAfterClose。这通常发生在 HTTP 处理程序在其 ResponseWriter 上调用 WriteHeader 或 Write 后读取主体时。

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var ErrHandlerTimeout = errors.New("http: Handler timeout")

ErrHandlerTimeout is returned on ResponseWriter Write calls in handlers which have timed out.

​ 在处理超时的处理程序的 ResponseWriter Write 调用上返回 ErrHandlerTimeout。

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var ErrLineTooLong = internal.ErrLineTooLong

ErrLineTooLong is returned when reading request or response bodies with malformed chunked encoding.

​ 当使用格式错误的分块编码读取请求或响应主体时返回 ErrLineTooLong。

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var ErrMissingFile = errors.New("http: no such file")

ErrMissingFile is returned by FormFile when the provided file field name is either not present in the request or not a file field.

​ 当请求中提供的文件字段名称不存在或不是文件字段时，由 FormFile 返回 ErrMissingFile。

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var ErrNoCookie = errors.New("http: named cookie not present")

ErrNoCookie is returned by Request’s Cookie method when a cookie is not found.

​ 当找不到 cookie 时，Request 的 Cookie 方法会返回 ErrNoCookie。

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var ErrNoLocation = errors.New("http: no Location header in response")

ErrNoLocation is returned by Response’s Location method when no Location header is present.

​ 当响应中没有 Location 头时，Response 的 Location 方法会返回 ErrNoLocation。

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var ErrServerClosed = errors.New("http: Server closed")

ErrServerClosed is returned by the Server’s Serve, ServeTLS, ListenAndServe, and ListenAndServeTLS methods after a call to Shutdown or Close.

​ ErrServerClosed在Server的Serve、ServeTLS、ListenAndServe和ListenAndServeTLS方法调用Shutdown或Close后返回。

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var ErrSkipAltProtocol = errors.New("net/http: skip alternate protocol")

ErrSkipAltProtocol is a sentinel error value defined by Transport.RegisterProtocol.

​ ErrSkipAltProtocol是Transport.RegisterProtocol定义的标志性错误值。

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var ErrUseLastResponse = errors.New("net/http: use last response")

ErrUseLastResponse can be returned by Client.CheckRedirect hooks to control how redirects are processed. If returned, the next request is not sent and the most recent response is returned with its body unclosed.

​ 如果Client.CheckRedirect钩子返回ErrUseLastResponse，则可以控制如何处理重定向。 如果返回此值，则不会发送下一个请求，并使用其正文未关闭的最近响应返回。

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var NoBody = noBody{}

NoBody is an io.ReadCloser with no bytes. Read always returns EOF and Close always returns nil. It can be used in an outgoing client request to explicitly signal that a request has zero bytes. An alternative, however, is to simply set Request.Body to nil.

​ NoBody是一个没有字节的io.ReadCloser。Read始终返回EOF，Close始终返回nil。 它可以在传出的客户端请求中使用，以显式地表示请求没有字节。 但是，另一种方法是将Request.Body设置为nil。

函数

func CanonicalHeaderKey

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func CanonicalHeaderKey(s string) string

CanonicalHeaderKey returns the canonical format of the header key s. The canonicalization converts the first letter and any letter following a hyphen to upper case; the rest are converted to lowercase. For example, the canonical key for “accept-encoding” is “Accept-Encoding”. If s contains a space or invalid header field bytes, it is returned without modifications.

​ CanonicalHeaderKey返回标头键s的规范格式。规范化将第一个字母和任何连字符后面的字母转换为大写字母；其余字母转换为小写字母。例如，“accept-encoding"的规范键是"Accept-Encoding”。如果s包含空格或无效的标头字段字节，则返回不带修改的s。

func DetectContentType

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func DetectContentType(data []byte) string

DetectContentType implements the algorithm described at https://mimesniff.spec.whatwg.org/ to determine the Content-Type of the given data. It considers at most the first 512 bytes of data. DetectContentType always returns a valid MIME type: if it cannot determine a more specific one, it returns “application/octet-stream”.

​ DetectContentType实现在https://mimesniff.spec.whatwg.org/上描述的算法，以确定给定数据的Content-Type。它最多考虑前512个字节的数据。DetectContentType始终返回有效的MIME类型：如果无法确定更具体的类型，则返回"application/octet-stream"。

func Error

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func Error(w ResponseWriter, error string, code int)

Error replies to the request with the specified error message and HTTP code. It does not otherwise end the request; the caller should ensure no further writes are done to w. The error message should be plain text.

​ Error使用指定的错误消息和HTTP代码回复请求。它不会以其他方式结束请求；调用者应确保不会对w进行进一步的写入。错误消息应为纯文本。

func Handle

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func Handle(pattern string, handler Handler)

Handle registers the handler for the given pattern in the DefaultServeMux. The documentation for ServeMux explains how patterns are matched.

​ Handle 在 DefaultServeMux 中为给定的 pattern 注册 handler。ServeMux 的文档解释了如何匹配 pattern。

Handle Example

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package main

import (
	"fmt"
	"log"
	"net/http"
	"sync"
)

type countHandler struct {
	mu sync.Mutex // guards n
	n  int
}

func (h *countHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	h.mu.Lock()
	defer h.mu.Unlock()
	h.n++
	fmt.Fprintf(w, "count is %d\n", h.n)
}

func main() {
	http.Handle("/count", new(countHandler))
	log.Fatal(http.ListenAndServe(":8080", nil))
}

func HandleFunc

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func HandleFunc(pattern string, handler func(ResponseWriter, *Request))

HandleFunc registers the handler function for the given pattern in the DefaultServeMux. The documentation for ServeMux explains how patterns are matched.

​ HandleFunc 在 DefaultServeMux 中为给定的 pattern 注册 handler function。ServeMux 的文档解释了如何匹配 pattern。

HandleFunc Example

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package main

import (
	"io"
	"log"
	"net/http"
)

func main() {
	h1 := func(w http.ResponseWriter, _ *http.Request) {
		io.WriteString(w, "Hello from a HandleFunc #1!\n")
	}
	h2 := func(w http.ResponseWriter, _ *http.Request) {
		io.WriteString(w, "Hello from a HandleFunc #2!\n")
	}

	http.HandleFunc("/", h1)
	http.HandleFunc("/endpoint", h2)

	log.Fatal(http.ListenAndServe(":8080", nil))
}

func ListenAndServe

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func ListenAndServe(addr string, handler Handler) error

ListenAndServe listens on the TCP network address addr and then calls Serve with handler to handle requests on incoming connections. Accepted connections are configured to enable TCP keep-alives.

​ ListenAndServe 监听 TCP 网络地址 addr，并在传入连接上调用 Serve 以处理请求。已接受的连接已配置为启用 TCP keep-alives。

The handler is typically nil, in which case the DefaultServeMux is used.

​ 通常 handler 是 nil，在这种情况下会使用 DefaultServeMux。

ListenAndServe always returns a non-nil error.

​ ListenAndServe 总是返回非 nil 错误。

ListenAndServe Example

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package main

import (
	"io"
	"log"
	"net/http"
)

func main() {
	// Hello world, the web server

	helloHandler := func(w http.ResponseWriter, req *http.Request) {
		io.WriteString(w, "Hello, world!\n")
	}

	http.HandleFunc("/hello", helloHandler)
	log.Fatal(http.ListenAndServe(":8080", nil))
}

func ListenAndServeTLS

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func ListenAndServeTLS(addr, certFile, keyFile string, handler Handler) error

ListenAndServeTLS acts identically to ListenAndServe, except that it expects HTTPS connections. Additionally, files containing a certificate and matching private key for the server must be provided. If the certificate is signed by a certificate authority, the certFile should be the concatenation of the server’s certificate, any intermediates, and the CA’s certificate.

​ ListenAndServeTLS 的行为与 ListenAndServe 相同，除了它预期 HTTPS 连接。另外，必须提供包含服务器证书和匹配私钥的文件。如果证书由证书颁发机构签署，则 certFile 应该是服务器证书、任何中间文件以及 CA 的证书的连接。

ListenAndServeTLS Example

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package main

import (
	"io"
	"log"
	"net/http"
)

func main() {
	http.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
		io.WriteString(w, "Hello, TLS!\n")
	})

	// One can use generate_cert.go in crypto/tls to generate cert.pem and key.pem.
	log.Printf("About to listen on 8443. Go to https://127.0.0.1:8443/")
	err := http.ListenAndServeTLS(":8443", "cert.pem", "key.pem", nil)
	log.Fatal(err)
}

func MaxBytesReader

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func MaxBytesReader(w ResponseWriter, r io.ReadCloser, n int64) io.ReadCloser

MaxBytesReader is similar to io.LimitReader but is intended for limiting the size of incoming request bodies. In contrast to io.LimitReader, MaxBytesReader’s result is a ReadCloser, returns a non-nil error of type *MaxBytesError for a Read beyond the limit, and closes the underlying reader when its Close method is called.

​ MaxBytesReader 类似于 io.LimitReader，但旨在限制传入请求主体的大小。与 io.LimitReader 不同，MaxBytesReader 的结果是一个 ReadCloser，在超出限制的情况下返回类型为 *MaxBytesError 的非 nil 错误，并在调用其 Close 方法时关闭底层读取器。

MaxBytesReader prevents clients from accidentally or maliciously sending a large request and wasting server resources. If possible, it tells the ResponseWriter to close the connection after the limit has been reached.

​ MaxBytesReader 防止客户端意外或恶意发送大型请求并浪费服务器资源。如果可能，它会告诉 ResponseWriter 在达到限制后关闭连接。

func NotFound

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func NotFound(w ResponseWriter, r *Request)

NotFound replies to the request with an HTTP 404 not found error.

​ NotFound 函数返回一个 HTTP 404 错误响应。

func ParseHTTPVersion

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func ParseHTTPVersion(vers string) (major, minor int, ok bool)

ParseHTTPVersion parses an HTTP version string according to RFC 7230, section 2.6. “HTTP/1.0” returns (1, 0, true). Note that strings without a minor version, such as “HTTP/2”, are not valid.

​ ParseHTTPVersion 函数按照 RFC 7230 第 2.6 节解析 HTTP 版本字符串。例如 “HTTP/1.0” 会返回 (1, 0, true)。请注意，不带次要版本号的字符串，例如 “HTTP/2”，是无效的。

func ParseTime <- go1.1

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func ParseTime(text string) (t time.Time, err error)

ParseTime parses a time header (such as the Date: header), trying each of the three formats allowed by HTTP/1.1: TimeFormat, time.RFC850, and time.ANSIC.

​ ParseTime 函数解析时间头(如 Date 头)，尝试 HTTP/1.1 所允许的三种格式：TimeFormat、time.RFC850 和 time.ANSIC。

func ProxyFromEnvironment

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func ProxyFromEnvironment(req *Request) (*url.URL, error)

ProxyFromEnvironment returns the URL of the proxy to use for a given request, as indicated by the environment variables HTTP_PROXY, HTTPS_PROXY and NO_PROXY (or the lowercase versions thereof). Requests use the proxy from the environment variable matching their scheme, unless excluded by NO_PROXY.

​ ProxyFromEnvironment 函数返回给定请求使用的代理 URL，该 URL 由环境变量 HTTP_PROXY、HTTPS_PROXY 和 NO_PROXY(或它们的小写形式)指示。请求使用与其方案匹配的环境变量中的代理，除非被 NO_PROXY 排除。

The environment values may be either a complete URL or a “host[:port]”, in which case the “http” scheme is assumed. The schemes “http”, “https”, and “socks5” are supported. An error is returned if the value is a different form.

​ 环境变量的值可以是完整的 URL，也可以是 “host[:port]” 形式，在这种情况下会假定为 “http” 方案。支持 “http”、“https” 和 “socks5” 方案。如果值是其他形式，则返回错误。

A nil URL and nil error are returned if no proxy is defined in the environment, or a proxy should not be used for the given request, as defined by NO_PROXY.

​ 如果环境中没有定义代理，或者请求不应使用代理，则返回 nil URL 和 nil 错误。

As a special case, if req.URL.Host is “localhost” (with or without a port number), then a nil URL and nil error will be returned.

​ 作为特例，如果 req.URL.Host 是 “localhost”(带或不带端口号)，则会返回 nil URL 和 nil 错误。

func ProxyURL

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func ProxyURL(fixedURL *url.URL) func(*Request) (*url.URL, error)

ProxyURL returns a proxy function (for use in a Transport) that always returns the same URL.

​ ProxyURL 函数返回一个代理函数(供 Transport 使用)，该函数始终返回相同的 URL。

func Redirect

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func Redirect(w ResponseWriter, r *Request, url string, code int)

Redirect replies to the request with a redirect to url, which may be a path relative to the request path.

​ Redirect 函数将请求重定向到 url，url 可以是相对于请求路径的路径。

The provided code should be in the 3xx range and is usually StatusMovedPermanently, StatusFound or StatusSeeOther.

​ 提供的 code 应该在 3xx 范围内，通常为 StatusMovedPermanently、StatusFound 或 StatusSeeOther。

If the Content-Type header has not been set, Redirect sets it to “text/html; charset=utf-8” and writes a small HTML body. Setting the Content-Type header to any value, including nil, disables that behavior.

​ 如果尚未设置 Content-Type 标头，则 Redirect 函数会将其设置为 “text/html; charset=utf-8” 并写入小的 HTML 主体。设置 Content-Type 标头为任何值(包括 nil)都会禁用该行为。

func Serve

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func Serve(l net.Listener, handler Handler) error

Serve accepts incoming HTTP connections on the listener l, creating a new service goroutine for each. The service goroutines read requests and then call handler to reply to them.

​ Serve 函数在监听器 l 上接受传入的 HTTP 连接，为每个连接创建一个新的服务协程。服务协程读取请求，然后调用 handler 进行响应。

The handler is typically nil, in which case the DefaultServeMux is used.

​ handler 通常为 nil，此时会使用 DefaultServeMux。

HTTP/2 support is only enabled if the Listener returns *tls.Conn connections and they were configured with “h2” in the TLS Config.NextProtos.

​ 只有当 Listener 返回 *tls.Conn 连接且它们在 TLS Config.NextProtos 中配置为 “h2” 时，才启用 HTTP/2 支持。

Serve always returns a non-nil error.

​ Serve 函数始终返回非 nil 错误。

func ServeContent

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func ServeContent(w ResponseWriter, req *Request, name string, modtime time.Time, content io.ReadSeeker)

ServeContent replies to the request using the content in the provided ReadSeeker. The main benefit of ServeContent over io.Copy is that it handles Range requests properly, sets the MIME type, and handles If-Match, If-Unmodified-Since, If-None-Match, If-Modified-Since, and If-Range requests.

​ ServeContent 使用 io.ReadSeeker 中提供的内容回复请求。ServeContent 相对于 io.Copy 的主要好处在于正确处理范围请求、设置 MIME 类型以及处理 If-Match、If-Unmodified-Since、If-None-Match、If-Modified-Since 和 If-Range 请求。

If the response’s Content-Type header is not set, ServeContent first tries to deduce the type from name’s file extension and, if that fails, falls back to reading the first block of the content and passing it to DetectContentType. The name is otherwise unused; in particular it can be empty and is never sent in the response.

​ 如果响应的 Content-Type 头未设置，ServeContent 首先尝试从 name 的文件扩展名推断类型，如果失败，则返回到读取内容的第一个块并将其传递给 DetectContentType。否则，不使用 name；特别地，它可以为空，并且永远不会在响应中发送。

If modtime is not the zero time or Unix epoch, ServeContent includes it in a Last-Modified header in the response. If the request includes an If-Modified-Since header, ServeContent uses modtime to decide whether the content needs to be sent at all.

​ 如果 modtime 不是零时间或 Unix 纪元，则 ServeContent 在响应中包括一个 Last-Modified 头。如果请求包括一个 If-Modified-Since 头，则 ServeContent 使用 modtime 来决定是否需要发送内容。

The content’s Seek method must work: ServeContent uses a seek to the end of the content to determine its size.

​ 内容的 Seek 方法必须工作：ServeContent 使用 seek 到内容的末尾以确定其大小。

If the caller has set w’s ETag header formatted per RFC 7232, section 2.3, ServeContent uses it to handle requests using If-Match, If-None-Match, or If-Range.

​ 如果调用方按 RFC 7232，第 2.3 节格式化了 w 的 ETag 头，则 ServeContent 使用它来处理使用 If-Match、If-None-Match 或 If-Range 的请求。

Note that *os.File implements the io.ReadSeeker interface.

​ 请注意，*os.File 实现了 io.ReadSeeker 接口。

func ServeFile

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func ServeFile(w ResponseWriter, r *Request, name string)

ServeFile replies to the request with the contents of the named file or directory.

​ ServeFile 用指定的文件或目录的内容回复请求。

If the provided file or directory name is a relative path, it is interpreted relative to the current directory and may ascend to parent directories. If the provided name is constructed from user input, it should be sanitized before calling ServeFile.

​ 如果提供的文件或目录名是相对路径，则相对于当前目录进行解释，可能升到父目录。如果提供的名称由用户输入构造，则在调用 ServeFile 之前应进行清理。

As a precaution, ServeFile will reject requests where r.URL.Path contains a “..” path element; this protects against callers who might unsafely use filepath.Join on r.URL.Path without sanitizing it and then use that filepath.Join result as the name argument.

​ 作为一项预防措施，ServeFile 将拒绝 r.URL.Path 包含 “..” 路径元素的请求；这可保护免受可能会不安全地对 r.URL.Path 使用 filepath.Join 而未对其进行清理的调用者的侵害，并使用 filepath.Join 结果作为名称参数。

As another special case, ServeFile redirects any request where r.URL.Path ends in “/index.html” to the same path, without the final “index.html”. To avoid such redirects either modify the path or use ServeContent.

​ 作为另一个特殊情况，ServeFile 将任何以 “/index.html” 结尾的 r.URL.Path 的请求重定向到相同的路径，不包括最后的 “index.html”。为避免此类重定向，请修改路径或使用 ServeContent。

Outside of those two special cases, ServeFile does not use r.URL.Path for selecting the file or directory to serve; only the file or directory provided in the name argument is used.

​ 除了这两个特殊情况外，ServeFile 不使用 r.URL.Path 来选择要提供的文件或目录；只使用名称参数中提供的文件或目录。

func ServeFileFS <- go1.22.0

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func ServeFileFS(w ResponseWriter, r *Request, fsys fs.FS, name string)

ServeFileFS replies to the request with the contents of the named file or directory from the file system fsys. The files provided by fsys must implement io.Seeker.

​ ServeFileFS 使用文件系统 fsys 中指定文件或目录的内容来回复请求。fsys 提供的文件必须实现 io.Seeker 接口。

If the provided name is constructed from user input, it should be sanitized before calling ServeFileFS.

​ 如果提供的文件名是由用户输入生成的，在调用 ServeFileFS 之前应对其进行清理。

As a precaution, ServeFileFS will reject requests where r.URL.Path contains a “..” path element; this protects against callers who might unsafely use filepath.Join on r.URL.Path without sanitizing it and then use that filepath.Join result as the name argument.

​ 作为预防措施，ServeFileFS 将拒绝 r.URL.Path 中包含 “..” 路径元素的请求；这可以防止调用者在未清理 r.URL.Path 的情况下使用 filepath.Join 并将该 filepath.Join 结果作为 name 参数使用。

As another special case, ServeFileFS redirects any request where r.URL.Path ends in “/index.html” to the same path, without the final “index.html”. To avoid such redirects either modify the path or use ServeContent.

​ 作为另一种特殊情况，ServeFileFS 会将 r.URL.Path 以 “/index.html” 结尾的请求重定向到相同路径，但去掉最后的 “index.html”。要避免这种重定向，可以修改路径或使用 ServeContent。

Outside of those two special cases, ServeFileFS does not use r.URL.Path for selecting the file or directory to serve; only the file or directory provided in the name argument is used.

​ 除了这两种特殊情况之外，ServeFileFS 不会使用 r.URL.Path 来选择要提供的文件或目录；只会使用 name 参数中提供的文件或目录。

func ServeTLS <- go1.9

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func ServeTLS(l net.Listener, handler Handler, certFile, keyFile string) error

ServeTLS accepts incoming HTTPS connections on the listener l, creating a new service goroutine for each. The service goroutines read requests and then call handler to reply to them.

​ ServeTLS 函数在监听器 l 上接受传入的 HTTPS 连接，为每个连接创建一个新的服务协程。服务协程读取请求，然后调用处理程序来回复请求。

The handler is typically nil, in which case the DefaultServeMux is used.

​ 处理程序通常为 nil，此时将使用 DefaultServeMux。

Additionally, files containing a certificate and matching private key for the server must be provided. If the certificate is signed by a certificate authority, the certFile should be the concatenation of the server’s certificate, any intermediates, and the CA’s certificate.

​ 另外，必须提供包含服务器证书和匹配的私钥的文件。如果证书由证书颁发机构签名，则 certFile 应该是服务器证书、任何中间证书和 CA 证书的连接。

ServeTLS always returns a non-nil error.

​ ServeTLS 函数总是返回非 nil 的错误。

func SetCookie

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func SetCookie(w ResponseWriter, cookie *Cookie)

SetCookie adds a Set-Cookie header to the provided ResponseWriter’s headers. The provided cookie must have a valid Name. Invalid cookies may be silently dropped.

​ SetCookie 函数将 Set-Cookie 头添加到提供的 ResponseWriter 的头中。提供的 cookie 必须有一个有效的名称。无效的 cookie 可能会被静默丢弃。

func StatusText

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func StatusText(code int) string

StatusText returns a text for the HTTP status code. It returns the empty string if the code is unknown.

​ StatusText 函数返回 HTTP 状态码的文本。如果状态码未知，则返回空字符串。

类型

type Client

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type Client struct {
    // Transport specifies the mechanism by which individual
	// HTTP requests are made.
	// If nil, DefaultTransport is used.
	// Transport 指定单个 HTTP 请求的执行机制。
	// 如果为 nil，则使用 DefaultTransport。
	Transport RoundTripper

    // CheckRedirect specifies the policy for handling redirects.
	// If CheckRedirect is not nil, the client calls it before
	// following an HTTP redirect. The arguments req and via are
	// the upcoming request and the requests made already, oldest
	// first. If CheckRedirect returns an error, the Client's Get
	// method returns both the previous Response (with its Body
	// closed) and CheckRedirect's error (wrapped in a url.Error)
	// instead of issuing the Request req.
	// As a special case, if CheckRedirect returns ErrUseLastResponse,
	// then the most recent response is returned with its body
	// unclosed, along with a nil error.
	//
	// If CheckRedirect is nil, the Client uses its default policy,
	// which is to stop after 10 consecutive requests.
	// CheckRedirect 指定处理重定向的策略。
	// 如果 CheckRedirect 不为 nil，
    // 则客户端在跟随 HTTP 重定向之前调用它。
	// 参数 req 和 via 分别是即将到来的请求和已经发出的请求，
    // 最旧的请求在最前面。
	// 如果 CheckRedirect 返回一个错误，
    // 则 Get 方法返回之前的 Response(其 Body 已关闭)和 	
    // CheckRedirect 的错误(封装在 url.Error 中)，
    // 而不是发出请求 req。
	// 作为特殊情况，如果 CheckRedirect 返回 ErrUseLastResponse，
    // 则返回最近的 Response，并保持其 Body 未关闭，同时返回空错误。
	//
	// 如果 CheckRedirect 为 nil，则客户端使用其默认策略，
    // 即在连续 10 次请求后停止。
	CheckRedirect func(req *Request, via []*Request) error

    // Jar specifies the cookie jar.
	//
	// The Jar is used to insert relevant cookies into every
	// outbound Request and is updated with the cookie values
	// of every inbound Response. The Jar is consulted for every
	// redirect that the Client follows.
	//
	// If Jar is nil, cookies are only sent if they are explicitly
	// set on the Request.
	// Jar 指定 cookie 存储。
	//
	// Jar 用于在每个出站请求中插入相关的 cookies，
    // 并使用每个入站 Response 的 cookie 值进行更新。
    // Jar 用于处理客户端跟随的每个重定向。
	//
	// 如果 Jar 为 nil，则仅在请求上显式设置了 cookie 时才发送它们。
	Jar CookieJar

    // Timeout specifies a time limit for requests made by this
	// Client. The timeout includes connection time, any
	// redirects, and reading the response body. The timer remains
	// running after Get, Head, Post, or Do return and will
	// interrupt reading of the Response.Body.
	//
	// A Timeout of zero means no timeout.
	//
	// The Client cancels requests to the underlying Transport
	// as if the Request's Context ended.
	//
	// For compatibility, the Client will also use the deprecated
	// CancelRequest method on Transport if found. New
	// RoundTripper implementations should use the Request's Context
	// for cancellation instead of implementing CancelRequest.
	// Timeout 指定此客户端发出的请求的时间限制。
	// 超时包括连接时间、任何重定向和读取响应正文。
    // 定时器在 Get、Head、Post 或 Do 返回之后仍在运行，
    // 并将中断读取 Response.Body。
	//
	// Timeout 为零表示没有超时。
	//
	// 如同请求的 Context 结束一样，客户端会取消底层传输的请求。
	//
	// 为了兼容性，
    // 如果 Transport 中找到了废弃的 CancelRequest 方法，
    // 则客户端也会使用它。
    // 新的 RoundTripper 实现应使用请求的 Context 进行取消，
    // 而不是实现 CancelRequest。
	Timeout time.Duration
}

A Client is an HTTP client. Its zero value (DefaultClient) is a usable client that uses DefaultTransport.

​ 一个 Client 是一个 HTTP 客户端。它的零值(DefaultClient)是一个可用的客户端，它使用 DefaultTransport。

The Client’s Transport typically has internal state (cached TCP connections), so Clients should be reused instead of created as needed. Clients are safe for concurrent use by multiple goroutines.

​ Client 的 Transport 通常具有内部状态(缓存的 TCP 连接)，因此应该重复使用 Client，而不是按需创建。Client 可以被多个 goroutine 并发使用。

A Client is higher-level than a RoundTripper (such as Transport) and additionally handles HTTP details such as cookies and redirects.

​ Client 比 RoundTripper(如 Transport)更高级，还处理诸如 cookie 和重定向之类的 HTTP 细节。

When following redirects, the Client will forward all headers set on the initial Request except:

​ 在遵循重定向时，Client 将转发在初始请求上设置的所有标头，但除了以下情况：

• when forwarding sensitive headers like “Authorization”, “WWW-Authenticate”, and “Cookie” to untrusted targets. These headers will be ignored when following a redirect to a domain that is not a subdomain match or exact match of the initial domain. For example, a redirect from “foo.com” to either “foo.com” or “sub.foo.com” will forward the sensitive headers, but a redirect to “bar.com” will not.

• 将敏感标头(例如"Authorization"、“WWW-Authenticate"和"Cookie”)转发到不受信任的目标时。在重定向到与初始域不是子域匹配或精确匹配的域时，将忽略这些标头。例如，从"foo.com"重定向到"foo.com"或"sub.foo.com"将转发敏感标头，但是重定向到"bar.com"将不会。

• when forwarding the “Cookie” header with a non-nil cookie Jar. Since each redirect may mutate the state of the cookie jar, a redirect may possibly alter a cookie set in the initial request. When forwarding the “Cookie” header, any mutated cookies will be omitted, with the expectation that the Jar will insert those mutated cookies with the updated values (assuming the origin matches). If Jar is nil, the initial cookies are forwarded without change.

• 使用非空 cookie Jar 转发"Cookie"标头时。由于每个重定向可能会更改 cookie jar 的状态，重定向可能会更改在初始请求中设置的 cookie。在转发"Cookie"标头时，任何已更改的 cookie 都将被省略，预期 Jar 将使用更新后的值插入这些已更改的 cookie(假设原点匹配)。如果 Jar 为 nil，则初始 cookie 会不加更改地转发。

(*Client) CloseIdleConnections <- go1.12

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func (c *Client) CloseIdleConnections()

CloseIdleConnections closes any connections on its Transport which were previously connected from previous requests but are now sitting idle in a “keep-alive” state. It does not interrupt any connections currently in use.

​ CloseIdleConnections 关闭 Transport 上任何连接，这些连接先前从先前的请求连接，但现在处于"keep-alive"状态。它不会中断当前正在使用的任何连接。

If the Client’s Transport does not have a CloseIdleConnections method then this method does nothing.

​ 如果 Client 的 Transport 没有 CloseIdleConnections 方法，则此方法不执行任何操作。

(*Client) Do

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func (c *Client) Do(req *Request) (*Response, error)

Do sends an HTTP request and returns an HTTP response, following policy (such as redirects, cookies, auth) as configured on the client.

​ Do 发送 HTTP 请求并返回 HTTP 响应，遵循客户端配置的策略(例如重定向、cookie、身份验证)。

An error is returned if caused by client policy (such as CheckRedirect), or failure to speak HTTP (such as a network connectivity problem). A non-2xx status code doesn’t cause an error.

​ 如果由客户端策略(例如 CheckRedirect)或无法进行 HTTP 通信(例如网络连接问题)导致错误，则返回错误。非 2xx 状态码不会导致错误。

If the returned error is nil, the Response will contain a non-nil Body which the user is expected to close. If the Body is not both read to EOF and closed, the Client’s underlying RoundTripper (typically Transport) may not be able to re-use a persistent TCP connection to the server for a subsequent “keep-alive” request.

​ 如果返回的错误是 nil，那么 Response 将包含一个非 nil 的 Body，用户应该在读取完后关闭它。如果 Body 没有读取到 EOF 并且关闭，Client 的底层 RoundTripper(通常是 Transport)可能无法重用持久的 TCP 连接，用于后续的 “keep-alive” 请求。

The request Body, if non-nil, will be closed by the underlying Transport, even on errors.

​ 如果请求的 Body 非 nil，则在底层的 Transport 上即使发生错误，也会关闭它。

On error, any Response can be ignored. A non-nil Response with a non-nil error only occurs when CheckRedirect fails, and even then the returned Response.Body is already closed.

​ 在出现错误时，可以忽略任何 Response。当 CheckRedirect 失败时，非 nil 的 Response 和非 nil 的 error 仅会出现一次。即使出现这种情况，返回的 Response.Body 也已经关闭。

Generally Get, Post, or PostForm will be used instead of Do.

​ 通常会使用 Get、Post 或 PostForm 而不是 Do。

If the server replies with a redirect, the Client first uses the CheckRedirect function to determine whether the redirect should be followed. If permitted, a 301, 302, or 303 redirect causes subsequent requests to use HTTP method GET (or HEAD if the original request was HEAD), with no body. A 307 or 308 redirect preserves the original HTTP method and body, provided that the Request.GetBody function is defined. The NewRequest function automatically sets GetBody for common standard library body types.

​ 如果服务器回复重定向，则客户端首先使用 CheckRedirect 函数来确定是否应该跟随重定向。如果被允许，则 301、302 或 303 重定向会导致后续请求使用 HTTP 方法 GET(或 HEAD，如果原始请求是 HEAD)，而不使用 Body。307 或 308 重定向会保留原始的 HTTP 方法和 Body，前提是定义了 Request.GetBody 函数。NewRequest 函数会自动为常见的标准库 Body 类型设置 GetBody。

Any returned error will be of type *url.Error. The url.Error value’s Timeout method will report true if the request timed out.

​ 任何返回的错误都将是 *url.Error 类型。url.Error 值的 Timeout 方法将在请求超时时报告 true。

(*Client) Get

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func (c *Client) Get(url string) (resp *Response, err error)

Get issues a GET to the specified URL. If the response is one of the following redirect codes, Get follows the redirect after calling the Client’s CheckRedirect function:

​ Get 向指定的 URL 发送一个 GET 请求。如果响应是以下重定向代码之一，则 Get 在调用 Client 的 CheckRedirect 函数后跟随重定向：

301 (Moved Permanently)(永久移动)
302 (Found)(找到)
303 (See Other)(参见其他)
307 (Temporary Redirect)(临时重定向)
308 (Permanent Redirect)(永久重定向)

An error is returned if the Client’s CheckRedirect function fails or if there was an HTTP protocol error. A non-2xx response doesn’t cause an error. Any returned error will be of type *url.Error. The url.Error value’s Timeout method will report true if the request timed out.

​ 如果 Client 的 CheckRedirect 函数失败或存在 HTTP 协议错误，则返回错误。非 2xx 响应不会导致错误。任何返回的错误都将是 *url.Error 类型。url.Error 值的 Timeout 方法将在请求超时时报告 true。

When err is nil, resp always contains a non-nil resp.Body. Caller should close resp.Body when done reading from it.

​ 当 err 为 nil 时，resp 总是包含一个非 nil 的 resp.Body。在读取完它后，调用者应该关闭 resp.Body。

To make a request with custom headers, use NewRequest and Client.Do.

​ 要使用自定义标头发出请求，请使用 NewRequest 和 Client.Do。

To make a request with a specified context.Context, use NewRequestWithContext and Client.Do.

​ 要使用指定的 context.Context 发出请求，请使用 NewRequestWithContext 和 Client.Do。

(*Client) Head

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func (c *Client) Head(url string) (resp *Response, err error)

Head issues a HEAD to the specified URL. If the response is one of the following redirect codes, Head follows the redirect after calling the Client’s CheckRedirect function:

​ Head 向指定的 URL 发出一个 HEAD 请求。如果响应是以下重定向代码之一，则在调用 Client 的 CheckRedirect 函数后，Head 跟随重定向：

301 (Moved Permanently)(永久移动)
302 (Found)(找到)
303 (See Other)(参见其他)
307 (Temporary Redirect)(临时重定向)
308 (Permanent Redirect)(永久重定向)

To make a request with a specified context.Context, use NewRequestWithContext and Client.Do.

​ 使用NewRequestWithContext和Client.Do可以指定context.Context进行请求。

(*Client) Post

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func (c *Client) Post(url, contentType string, body io.Reader) (resp *Response, err error)

Post issues a POST to the specified URL.

​ Post向指定的URL发出POST请求。

Caller should close resp.Body when done reading from it.

​ 调用者在完成读取后应关闭resp.Body。

If the provided body is an io.Closer, it is closed after the request.

​ 如果提供的body是io.Closer，则在请求后关闭它。

To set custom headers, use NewRequest and Client.Do.

​ 要设置自定义标头，请使用NewRequest和Client.Do。

To make a request with a specified context.Context, use NewRequestWithContext and Client.Do.

​ 要使用指定的context.Context进行请求，请使用NewRequestWithContext和Client.Do。

See the Client.Do method documentation for details on how redirects are handled.

​ 有关如何处理重定向的详细信息，请参阅Client.Do方法文档。

(*Client) PostForm

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func (c *Client) PostForm(url string, data url.Values) (resp *Response, err error)

PostForm issues a POST to the specified URL, with data’s keys and values URL-encoded as the request body.

​ PostForm将数据的键和值作为请求正文进行URL编码，并向指定的URL发出POST请求。

The Content-Type header is set to application/x-www-form-urlencoded. To set other headers, use NewRequest and Client.Do.

​ Content-Type标头设置为application/x-www-form-urlencoded。要设置其他标头，请使用NewRequest和Client.Do。

When err is nil, resp always contains a non-nil resp.Body. Caller should close resp.Body when done reading from it.

​ 当err为nil时，resp始终包含非nil resp.Body。完成读取后，调用者应关闭resp.Body。

See the Client.Do method documentation for details on how redirects are handled.

​ 有关如何处理重定向的详细信息，请参阅Client.Do方法文档。

To make a request with a specified context.Context, use NewRequestWithContext and Client.Do.

​ 要使用指定的context.Context进行请求，请使用NewRequestWithContext和Client.Do。

type CloseNotifier <- DEPRECATED

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type CloseNotifier interface {
	// CloseNotify returns a channel that receives at most a
	// single value (true) when the client connection has gone
	// away.
	//
	// CloseNotify may wait to notify until Request.Body has been
	// fully read.
	//
	// After the Handler has returned, there is no guarantee
	// that the channel receives a value.
	//
	// If the protocol is HTTP/1.1 and CloseNotify is called while
	// processing an idempotent request (such a GET) while
	// HTTP/1.1 pipelining is in use, the arrival of a subsequent
	// pipelined request may cause a value to be sent on the
	// returned channel. In practice HTTP/1.1 pipelining is not
	// enabled in browsers and not seen often in the wild. If this
	// is a problem, use HTTP/2 or only use CloseNotify on methods
	// such as POST.
	CloseNotify() <-chan bool
}

The CloseNotifier interface is implemented by ResponseWriters which allow detecting when the underlying connection has gone away.

This mechanism can be used to cancel long operations on the server if the client has disconnected before the response is ready.

Deprecated: the CloseNotifier interface predates Go’s context package. New code should use Request.Context instead.

type ConnState <- go1.3

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type ConnState int

A ConnState represents the state of a client connection to a server. It’s used by the optional Server.ConnState hook.

​ ConnState表示与服务器的客户端连接状态。它由可选的Server.ConnState钩子使用。

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const (
    // StateNew represents a new connection that is expected to
	// send a request immediately. Connections begin at this
	// state and then transition to either StateActive or
	// StateClosed.
	// StateNew 表示一个新的连接，该连接预计会立即发送请求。
    // 连接从此状态开始，然后转换为 StateActive 或 StateClosed。
	StateNew ConnState = iota

    // StateActive represents a connection that has read 1 or more
	// bytes of a request. The Server.ConnState hook for
	// StateActive fires before the request has entered a handler
	// and doesn't fire again until the request has been
	// handled. After the request is handled, the state
	// transitions to StateClosed, StateHijacked, or StateIdle.
	// For HTTP/2, StateActive fires on the transition from zero
	// to one active request, and only transitions away once all
	// active requests are complete. That means that ConnState
	// cannot be used to do per-request work; ConnState only notes
	// the overall state of the connection.
	// StateActive 表示已读取一个或多个请求字节的连接。
    // 对于 StateActive 的 Server.ConnState 钩子
    // 会在请求进入处理程序之前触发，
    // 然后在请求被处理之前不再触发。请求处理完成后，
    // 状态转换为 StateClosed、StateHijacked 或 StateIdle。
    // 对于 HTTP/2，StateActive 在从零到一个活动请求的转换时触发，
    // 并且仅在所有活动请求完成后再次转换。
    // 这意味着 ConnState 不能用于执行每个请求的工作；
    // ConnState 只记录连接的整体状态。
	StateActive

    // StateIdle represents a connection that has finished
	// handling a request and is in the keep-alive state, waiting
	// for a new request. Connections transition from StateIdle
	// to either StateActive or StateClosed.
	// StateIdle 表示已完成请求处理并处于保持活动状态的连接，
    // 等待新的请求。
    // 连接从 StateIdle 转换为 StateActive 或 StateClosed。
	StateIdle

    // StateHijacked represents a hijacked connection.
	// This is a terminal state. It does not transition to StateClosed.
	// StateHijacked 表示被劫持的连接。
    // 这是一个终止状态。它不会转换为 StateClosed。
	StateHijacked

    // StateClosed represents a closed connection.
	// This is a terminal state. Hijacked connections do not
	// transition to StateClosed.
	// StateClosed 表示已关闭的连接。
    // 这是一个终止状态。
    // 被劫持的连接不会转换为 StateClosed。
	StateClosed
)

(ConnState) String <- go1.3

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func (c ConnState) String() string

type Cookie

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type Cookie struct {
	Name  string
	Value string

	Path       string    // 可选
	Domain     string    // 可选
	Expires    time.Time // 可选
	RawExpires string    // 仅用于读取cookie

    // MaxAge=0 means no 'Max-Age' attribute specified.
	// MaxAge<0 means delete cookie now, equivalently 'Max-Age: 0'
	// MaxAge>0 means Max-Age attribute present and given in seconds
	// MaxAge=0 表示没有指定"Max-Age"属性。
	// MaxAge<0 表示立即删除 cookie，相当于"Max-Age: 0"
	// MaxAge>0 表示指定了以秒为单位的"Max-Age"属性
	MaxAge   int
	Secure   bool
	HttpOnly bool
	SameSite SameSite
	Raw      string
	Unparsed []string // 未解析的属性-值对的原始文本
}

A Cookie represents an HTTP cookie as sent in the Set-Cookie header of an HTTP response or the Cookie header of an HTTP request.

​ Cookie 表示 HTTP cookie，其在 HTTP 响应的 Set-Cookie 标头或 HTTP 请求的 Cookie 标头中发送。

See https://tools.ietf.org/html/rfc6265 for details.

​ 详见https://tools.ietf.org/html/rfc6265。

func ParseCookie <- go1.23.0

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func ParseCookie(line string) ([]*Cookie, error)

ParseCookie parses a Cookie header value and returns all the cookies which were set in it. Since the same cookie name can appear multiple times the returned Values can contain more than one value for a given key.

​ ParseCookie 解析一个 Cookie 头部的值，并返回其中设置的所有 Cookie。由于同一 Cookie 名称可能会出现多次，因此返回的值可能包含相同键的多个值。

func ParseSetCookie <- go1.23.0

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func ParseSetCookie(line string) (*Cookie, error)

ParseSetCookie parses a Set-Cookie header value and returns a cookie. It returns an error on syntax error.

​ ParseSetCookie 解析一个 Set-Cookie 头部的值并返回一个 Cookie。如果语法错误，它将返回错误。

(*Cookie) String

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func (c *Cookie) String() string

String returns the serialization of the cookie for use in a Cookie header (if only Name and Value are set) or a Set-Cookie response header (if other fields are set). If c is nil or c.Name is invalid, the empty string is returned.

​ String 返回 cookie 的序列化字符串，以用于 Cookie 标头(如果仅设置了 Name 和 Value)或 Set-Cookie 响应标头(如果设置了其他字段)。如果 c 为 nil 或 c.Name 无效，则返回空字符串。

(*Cookie) Valid <- go1.18

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func (c *Cookie) Valid() error

Valid reports whether the cookie is valid.

​ Valid 函数用于判断 cookie 是否有效。

type CookieJar

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type CookieJar interface {
    // SetCookies handles the receipt of the cookies in a reply for the
	// given URL.  It may or may not choose to save the cookies, depending
	// on the jar's policy and implementation.
	// SetCookies 处理收到的回复中的 cookie。
    // 根据 jar 的策略和实现，它可能会选择保存 cookie。
	SetCookies(u *url.URL, cookies []*Cookie)

    // Cookies returns the cookies to send in a request for the given URL.
	// It is up to the implementation to honor the standard cookie use
	// restrictions such as in RFC 6265.
	// Cookies 返回指定 URL 的请求中应发送的 cookie。
    // 实现必须遵守 RFC 6265 等标准 cookie 使用限制。
	Cookies(u *url.URL) []*Cookie
}

A CookieJar manages storage and use of cookies in HTTP requests.

​ CookieJar 管理 HTTP 请求中的 cookie 的存储和使用。

Implementations of CookieJar must be safe for concurrent use by multiple goroutines.

​ CookieJar 的实现必须支持多 goroutine 并发使用。

The net/http/cookiejar package provides a CookieJar implementation.

​ net/http/cookiejar 包提供了 CookieJar 的实现。

type Dir

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type Dir string

A Dir implements FileSystem using the native file system restricted to a specific directory tree.

​ Dir 类型使用本地文件系统来实现 FileSystem 接口，且仅限于特定的目录树。

While the FileSystem.Open method takes ‘/’-separated paths, a Dir’s string value is a filename on the native file system, not a URL, so it is separated by filepath.Separator, which isn’t necessarily ‘/’.

​ 尽管 FileSystem.Open 方法接收以 / 分隔的路径，但 Dir 的 string 值是本地文件系统上的文件名，而不是 URL，因此它由 filepath.Separator 分隔，不一定是 /。

Note that Dir could expose sensitive files and directories. Dir will follow symlinks pointing out of the directory tree, which can be especially dangerous if serving from a directory in which users are able to create arbitrary symlinks. Dir will also allow access to files and directories starting with a period, which could expose sensitive directories like .git or sensitive files like .htpasswd. To exclude files with a leading period, remove the files/directories from the server or create a custom FileSystem implementation.

​ 请注意，Dir 可能会暴露敏感文件和目录。Dir 将遵循指向目录树之外的符号链接，如果从用户可以创建任意符号链接的目录提供服务，这可能会特别危险。Dir 还将允许访问以句点开头的文件和目录，这可能会暴露像 .git 这样的敏感目录或像 .htpasswd 这样的敏感文件。要排除以句点开头的文件，请从服务器删除这些文件/目录，或者创建自定义 FileSystem 实现。

An empty Dir is treated as “.”.

​ 一个空的 Dir 被视为 “."。

(Dir) Open

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func (d Dir) Open(name string) (File, error)

Open implements FileSystem using os.Open, opening files for reading rooted and relative to the directory d.

​ Open 实现 FileSystem 接口，使用 os.Open 打开文件进行读取，根据目录 d 来确定其路径。

type File

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type File interface {
	io.Closer
	io.Reader
	io.Seeker
	Readdir(count int) ([]fs.FileInfo, error)
	Stat() (fs.FileInfo, error)
}

A File is returned by a FileSystem’s Open method and can be served by the FileServer implementation.

​ 该接口的 Open 方法返回一个 File，可由 FileServer 实现进行服务。

The methods should behave the same as those on an *os.File.

​ 该接口的方法应与 *os.File 上的方法表现相同。

type FileSystem

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type FileSystem interface {
	Open(name string) (File, error)
}

A FileSystem implements access to a collection of named files. The elements in a file path are separated by slash (’/’, U+002F) characters, regardless of host operating system convention. See the FileServer function to convert a FileSystem to a Handler.

​ FileSystem 实现对命名文件集合的访问。文件路径中的元素使用斜杠(’/’，U+002F)字符分隔，而不管主机操作系统惯例如何。请参见 FileServer 函数，将 FileSystem 转换为处理程序。

This interface predates the fs.FS interface, which can be used instead: the FS adapter function converts an fs.FS to a FileSystem.

​ 该接口早于 fs.FS 接口，可以使用 fs.FS 代替：FS 适配器函数将 fs.FS 转换为 FileSystem。

func FS <- go1.16

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func FS(fsys fs.FS) FileSystem

FS converts fsys to a FileSystem implementation, for use with FileServer and NewFileTransport. The files provided by fsys must implement io.Seeker.

​ FS 将 fsys 转换为 FileSystem 实现，供 FileServer 和 NewFileTransport 使用。由 fsys 提供的文件必须实现 io.Seeker。

type Flusher

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type Flusher interface {
	// Flush sends any buffered data to the client.
	Flush()
}

The Flusher interface is implemented by ResponseWriters that allow an HTTP handler to flush buffered data to the client.

​ Flusher 接口由 ResponseWriter 实现，允许 HTTP 处理程序将缓冲的数据刷新到客户端。

The default HTTP/1.x and HTTP/2 ResponseWriter implementations support Flusher, but ResponseWriter wrappers may not. Handlers should always test for this ability at runtime.

​ 默认的 HTTP/1.x 和 HTTP/2 ResponseWriter 实现支持 Flusher，但 ResponseWriter 包装器可能不支持。处理程序应始终在运行时测试此功能。

Note that even for ResponseWriters that support Flush, if the client is connected through an HTTP proxy, the buffered data may not reach the client until the response completes.

​ 请注意，即使对于支持 Flush 的 ResponseWriter，如果客户端通过 HTTP 代理连接，则缓冲的数据可能要等到响应完成后才能到达客户端。

type Handler

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type Handler interface {
	ServeHTTP(ResponseWriter, *Request)
}

A Handler responds to an HTTP request.

​ Handler 响应 HTTP 请求。

ServeHTTP should write reply headers and data to the ResponseWriter and then return. Returning signals that the request is finished; it is not valid to use the ResponseWriter or read from the Request.Body after or concurrently with the completion of the ServeHTTP call.

​ ServeHTTP 应将响应标头和数据写入 ResponseWriter，然后返回。返回信号表示请求已完成；在完成 ServeHTTP 调用之后或与之同时使用 ResponseWriter 或从 Request.Body 中读取是无效的。

Depending on the HTTP client software, HTTP protocol version, and any intermediaries between the client and the Go server, it may not be possible to read from the Request.Body after writing to the ResponseWriter. Cautious handlers should read the Request.Body first, and then reply.

​ 根据HTTP客户端软件、HTTP协议版本以及客户端和Go服务器之间的任何中介，可能无法在写入ResponseWriter之后从Request.Body中读取。谨慎的处理程序应该先读取Request.Body，然后再回复。

Except for reading the body, handlers should not modify the provided Request.

​ 除了读取body外，处理程序不应修改提供的Request。

If ServeHTTP panics, the server (the caller of ServeHTTP) assumes that the effect of the panic was isolated to the active request. It recovers the panic, logs a stack trace to the server error log, and either closes the network connection or sends an HTTP/2 RST_STREAM, depending on the HTTP protocol. To abort a handler so the client sees an interrupted response but the server doesn’t log an error, panic with the value ErrAbortHandler.

​ 如果ServeHTTP恐慌，服务器(ServeHTTP的调用者)假定恐慌的影响仅限于活动请求。它会恢复panic，将堆栈跟踪记录到服务器错误日志，并关闭网络连接或发送HTTP/2 RST_STREAM，具体取决于HTTP协议。为了中止处理程序，以便客户端看到中断的响应但服务器不记录错误，请使用值为ErrAbortHandler的panic。

func AllowQuerySemicolons <- go1.17

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func AllowQuerySemicolons(h Handler) Handler

AllowQuerySemicolons returns a handler that serves requests by converting any unescaped semicolons in the URL query to ampersands, and invoking the handler h.

​ AllowQuerySemicolons返回一个处理程序，它通过将URL查询中的任何未转义分号转换为”&“并调用处理程序h来为请求提供服务。

This restores the pre-Go 1.17 behavior of splitting query parameters on both semicolons and ampersands. (See golang.org/issue/25192). Note that this behavior doesn’t match that of many proxies, and the mismatch can lead to security issues.

​ 这恢复了分割查询参数的分号和”&“的Go 1.17之前的行为。(请参阅golang.org/issue/25192)。请注意，此行为与许多代理的行为不匹配，不匹配可能导致安全问题。

AllowQuerySemicolons should be invoked before Request.ParseForm is called.

​ 在调用Request.ParseForm之前，应调用AllowQuerySemicolons。

func FileServer

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func FileServer(root FileSystem) Handler

FileServer returns a handler that serves HTTP requests with the contents of the file system rooted at root.

​ FileServer返回一个处理程序，它使用以root为根的文件系统的内容为HTTP请求提供服务。

As a special case, the returned file server redirects any request ending in “/index.html” to the same path, without the final “index.html”.

​ 作为一个特殊情况，返回的文件服务器将以”/index.html"结尾的任何请求重定向到相同的路径，而不包括最后的"index.html"。

To use the operating system’s file system implementation, use http.Dir:

​ 要使用操作系统的文件系统实现，请使用http.Dir：

http.Handle("/", http.FileServer(http.Dir("/tmp")))

To use an fs.FS implementation, use http.FS to convert it:

​ 要使用fs.FS实现，请使用http.FS将其转换：

http.Handle("/", http.FileServer(http.FS(fsys)))

FileServer Example

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package main

import (
	"log"
	"net/http"
)

func main() {
	// Simple static webserver:
	log.Fatal(http.ListenAndServe(":8080", http.FileServer(http.Dir("/usr/share/doc"))))
}

FileServer Example (DotFileHiding)

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package main

import (
	"io/fs"
	"log"
	"net/http"
	"strings"
)

// containsDotFile reports whether name contains a path element starting with a period.
// The name is assumed to be a delimited by forward slashes, as guaranteed
// by the http.FileSystem interface.
func containsDotFile(name string) bool {
	parts := strings.Split(name, "/")
	for _, part := range parts {
		if strings.HasPrefix(part, ".") {
			return true
		}
	}
	return false
}

// dotFileHidingFile is the http.File use in dotFileHidingFileSystem.
// It is used to wrap the Readdir method of http.File so that we can
// remove files and directories that start with a period from its output.
type dotFileHidingFile struct {
	http.File
}

// Readdir is a wrapper around the Readdir method of the embedded File
// that filters out all files that start with a period in their name.
func (f dotFileHidingFile) Readdir(n int) (fis []fs.FileInfo, err error) {
	files, err := f.File.Readdir(n)
	for _, file := range files { // Filters out the dot files
		if !strings.HasPrefix(file.Name(), ".") {
			fis = append(fis, file)
		}
	}
	return
}

// dotFileHidingFileSystem is an http.FileSystem that hides
// hidden "dot files" from being served.
type dotFileHidingFileSystem struct {
	http.FileSystem
}

// Open is a wrapper around the Open method of the embedded FileSystem
// that serves a 403 permission error when name has a file or directory
// with whose name starts with a period in its path.
func (fsys dotFileHidingFileSystem) Open(name string) (http.File, error) {
	if containsDotFile(name) { // If dot file, return 403 response
		return nil, fs.ErrPermission
	}

	file, err := fsys.FileSystem.Open(name)
	if err != nil {
		return nil, err
	}
	return dotFileHidingFile{file}, err
}

func main() {
	fsys := dotFileHidingFileSystem{http.Dir(".")}
	http.Handle("/", http.FileServer(fsys))
	log.Fatal(http.ListenAndServe(":8080", nil))
}

FileServer Example (StripPrefix)

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package main

import (
	"net/http"
)

func main() {
	// To serve a directory on disk (/tmp) under an alternate URL
	// path (/tmpfiles/), use StripPrefix to modify the request
	// URL's path before the FileServer sees it:
	http.Handle("/tmpfiles/", http.StripPrefix("/tmpfiles/", http.FileServer(http.Dir("/tmp"))))
}

func FileServerFS <- go1.22.0

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func FileServerFS(root fs.FS) Handler

FileServerFS returns a handler that serves HTTP requests with the contents of the file system fsys. The files provided by fsys must implement io.Seeker.

​ FileServerFS 返回一个处理器，用于通过文件系统 fsys 的内容来处理 HTTP 请求。fsys 提供的文件必须实现 io.Seeker 接口。

As a special case, the returned file server redirects any request ending in “/index.html” to the same path, without the final “index.html”.

​ 作为一种特殊情况，返回的文件服务器会将任何以 “/index.html” 结尾的请求重定向到相同路径，但去掉最后的 “index.html”。

http.Handle("/", http.FileServerFS(fsys))

func MaxBytesHandler <- go1.18

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func MaxBytesHandler(h Handler, n int64) Handler

MaxBytesHandler returns a Handler that runs h with its ResponseWriter and Request.Body wrapped by a MaxBytesReader.

​ MaxBytesHandler返回一个处理程序，该处理程序使用其ResponseWriter和Request.Body包装了一个MaxBytesReader。

func NotFoundHandler

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func NotFoundHandler() Handler

NotFoundHandler returns a simple request handler that replies to each request with a “404 page not found” reply.

​ NotFoundHandler返回一个简单的请求处理程序，它回复每个请求的"404页面未找到"回复。

NotFoundHandler Example

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package main

import (
	"fmt"
	"log"
	"net/http"
)

func newPeopleHandler() http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		fmt.Fprintln(w, "This is the people handler.")
	})
}

func main() {
	mux := http.NewServeMux()

	// Create sample handler to returns 404
	mux.Handle("/resources", http.NotFoundHandler())

	// Create sample handler that returns 200
	mux.Handle("/resources/people/", newPeopleHandler())

	log.Fatal(http.ListenAndServe(":8080", mux))
}

func RedirectHandler

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func RedirectHandler(url string, code int) Handler

RedirectHandler returns a request handler that redirects each request it receives to the given url using the given status code.

​ RedirectHandler 函数返回一个请求处理程序，该程序会使用给定的状态码将收到的每个请求重定向到给定的URL。

The provided code should be in the 3xx range and is usually StatusMovedPermanently, StatusFound or StatusSeeOther.

​ 提供的状态码应该在 3xx 范围内，通常为 StatusMovedPermanently、StatusFound 或 StatusSeeOther。

func StripPrefix

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func StripPrefix(prefix string, h Handler) Handler

StripPrefix returns a handler that serves HTTP requests by removing the given prefix from the request URL’s Path (and RawPath if set) and invoking the handler h. StripPrefix handles a request for a path that doesn’t begin with prefix by replying with an HTTP 404 not found error. The prefix must match exactly: if the prefix in the request contains escaped characters the reply is also an HTTP 404 not found error.

​ StripPrefix 函数返回一个处理程序，它通过从请求 URL 的路径(如果设置，则为 RawPath)中删除给定前缀并调用处理程序 h 来服务 HTTP 请求。如果路径不以前缀开头，则 StripPrefix 会用 HTTP 404 未找到错误回复。前缀必须精确匹配：如果请求中的前缀包含转义字符，则回复也是 HTTP 404 未找到错误。

StripPrefix Example

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package main

import (
	"net/http"
)

func main() {
	// To serve a directory on disk (/tmp) under an alternate URL
	// path (/tmpfiles/), use StripPrefix to modify the request
	// URL's path before the FileServer sees it:
	http.Handle("/tmpfiles/", http.StripPrefix("/tmpfiles/", http.FileServer(http.Dir("/tmp"))))
}

func TimeoutHandler

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func TimeoutHandler(h Handler, dt time.Duration, msg string) Handler

TimeoutHandler returns a Handler that runs h with the given time limit.

​ TimeoutHandler 函数返回一个运行限时的处理程序。

The new Handler calls h.ServeHTTP to handle each request, but if a call runs for longer than its time limit, the handler responds with a 503 Service Unavailable error and the given message in its body. (If msg is empty, a suitable default message will be sent.) After such a timeout, writes by h to its ResponseWriter will return ErrHandlerTimeout.

​ 新的处理程序调用 h.ServeHTTP 来处理每个请求，但如果一个调用的运行时间超过其时间限制，则处理程序会使用一个 HTTP 503 Service Unavailable 错误并在其主体中给出给定的消息进行回复。 (如果 msg 为空，则将发送适当的默认消息。)在此类超时之后，h 对其 ResponseWriter 的写入将返回 ErrHandlerTimeout。

TimeoutHandler supports the Pusher interface but does not support the Hijacker or Flusher interfaces.

​ TimeoutHandler 支持 Pusher 接口，但不支持 Hijacker 或 Flusher 接口。

type HandlerFunc

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type HandlerFunc func(ResponseWriter, *Request)

The HandlerFunc type is an adapter to allow the use of ordinary functions as HTTP handlers. If f is a function with the appropriate signature, HandlerFunc(f) is a Handler that calls f.

​ HandlerFunc 类型是一个适配器，允许使用普通函数作为 HTTP 处理程序。如果 f 是具有适当签名的函数，则 HandlerFunc(f) 是调用 f 的处理程序。

(HandlerFunc) ServeHTTP

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func (f HandlerFunc) ServeHTTP(w ResponseWriter, r *Request)

ServeHTTP calls f(w, r).

​ ServeHTTP 调用 f(w, r)。

type Header

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type Header map[string][]string

A Header represents the key-value pairs in an HTTP header.

​ Header 表示 HTTP 头中的键值对。

The keys should be in canonical form, as returned by CanonicalHeaderKey.

​ 键应该是规范化形式，即由 CanonicalHeaderKey函数返回的形式。

(Header) Add

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func (h Header) Add(key, value string)

Add adds the key, value pair to the header. It appends to any existing values associated with key. The key is case insensitive; it is canonicalized by CanonicalHeaderKey.

​ Add方法向 Header 中添加一个键值对，它会将值附加到与键相关联的任何现有值的末尾。键的大小写不敏感，因此会通过 CanonicalHeaderKey 进行规范化。

(Header) Clone <- go1.13

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func (h Header) Clone() Header

Clone returns a copy of h or nil if h is nil.

​ Clone方法返回 h 的一个副本，如果 h 为 nil，则返回 nil。

(Header) Del

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func (h Header) Del(key string)

Del deletes the values associated with key. The key is case insensitive; it is canonicalized by CanonicalHeaderKey.

​ Del方法删除与 key 关联的值。键的大小写不敏感，因此会通过 CanonicalHeaderKey函数进行规范化。

(Header) Get

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func (h Header) Get(key string) string

Get gets the first value associated with the given key. If there are no values associated with the key, Get returns “”. It is case insensitive; textproto.CanonicalMIMEHeaderKey is used to canonicalize the provided key. Get assumes that all keys are stored in canonical form. To use non-canonical keys, access the map directly.

​ Get方法获取与给定键关联的第一个值。如果没有与该键关联的值，则 Get 返回 “"。键的大小写不敏感，因此使用 textproto.CanonicalMIMEHeaderKey 来规范化提供的键。Get 假定所有键都以规范形式存储。要使用非规范键，请直接访问映射。

(Header) Set

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func (h Header) Set(key, value string)

Set sets the header entries associated with key to the single element value. It replaces any existing values associated with key. The key is case insensitive; it is canonicalized by textproto.CanonicalMIMEHeaderKey. To use non-canonical keys, assign to the map directly.

​ Set方法将与 key 关联的 header 条目设置为单个元素值。它将替换与 key 关联的任何现有值。键的大小写不敏感，因此会通过 textproto.CanonicalMIMEHeaderKey 进行规范化。要使用非规范键，请直接分配到映射中。

(Header) Values <- go1.14

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func (h Header) Values(key string) []string

Values returns all values associated with the given key. It is case insensitive; textproto.CanonicalMIMEHeaderKey is used to canonicalize the provided key. To use non-canonical keys, access the map directly. The returned slice is not a copy.

​ Values方法返回与给定键关联的所有值。键的大小写不敏感，因此使用 textproto.CanonicalMIMEHeaderKey 来规范化提供的键。要使用非规范键，请直接访问映射。返回的切片不是副本。

(Header) Write

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func (h Header) Write(w io.Writer) error

Write writes a header in wire format.

​ Write 方法以 wire format 写入 Header。

(Header) WriteSubset

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func (h Header) WriteSubset(w io.Writer, exclude map[string]bool) error

WriteSubset writes a header in wire format. If exclude is not nil, keys where exclude[key] == true are not written. Keys are not canonicalized before checking the exclude map.

​ WriteSubset 方法以 wire format 写入 Header。如果 exclude 不为 nil，则不会写入其中 exclude[key] == true 的键。写入之前不会对键进行规范化。

type Hijacker

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type Hijacker interface {
    // Hijack lets the caller take over the connection.
	// After a call to Hijack the HTTP server library
	// will not do anything else with the connection.
	//
	// It becomes the caller's responsibility to manage
	// and close the connection.
	//
	// The returned net.Conn may have read or write deadlines
	// already set, depending on the configuration of the
	// Server. It is the caller's responsibility to set
	// or clear those deadlines as needed.
	//
	// The returned bufio.Reader may contain unprocessed buffered
	// data from the client.
	//
	// After a call to Hijack, the original Request.Body must not
	// be used. The original Request's Context remains valid and
	// is not canceled until the Request's ServeHTTP method
	// returns.
	// Hijack允许调用方接管连接。
	// 调用Hijack后，HTTP服务器库将不会再对连接进行任何操作。
	//
	// 管理和关闭连接将成为调用方的责任。
	//
	// 返回的net.Conn可能已经设置了读取或写入期限，
    // 具体取决于服务器的配置。
    // 调用方有责任根据需要设置或清除这些期限。
    //
    // 返回的bufio.Reader可能包含来自客户端的未处理缓冲数据。
    //
    // 在调用Hijack后，原始Request.Body不能再使用。
    // 原始请求的上下文保持有效，直到请求的ServeHTTP方法返回为止。
	Hijack() (net.Conn, *bufio.ReadWriter, error)
}

The Hijacker interface is implemented by ResponseWriters that allow an HTTP handler to take over the connection.

​ Hijacker接口由允许HTTP处理程序接管连接的ResponseWriters实现。

The default ResponseWriter for HTTP/1.x connections supports Hijacker, but HTTP/2 connections intentionally do not. ResponseWriter wrappers may also not support Hijacker. Handlers should always test for this ability at runtime.

​ 默认的HTTP/1.x连接的ResponseWriter支持Hijacker，但是HTTP/2连接有意不支持它。 ResponseWriter包装器也可能不支持Hijacker。处理程序应始终在运行时测试此能力。

Example

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package main

import (
	"fmt"
	"log"
	"net/http"
)

func main() {
	http.HandleFunc("/hijack", func(w http.ResponseWriter, r *http.Request) {
		hj, ok := w.(http.Hijacker)
		if !ok {
			http.Error(w, "webserver doesn't support hijacking", http.StatusInternalServerError)
			return
		}
		conn, bufrw, err := hj.Hijack()
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		// Don't forget to close the connection:
		defer conn.Close()
		bufrw.WriteString("Now we're speaking raw TCP. Say hi: ")
		bufrw.Flush()
		s, err := bufrw.ReadString('\n')
		if err != nil {
			log.Printf("error reading string: %v", err)
			return
		}
		fmt.Fprintf(bufrw, "You said: %q\nBye.\n", s)
		bufrw.Flush()
	})
}

type MaxBytesError <- go1.19

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type MaxBytesError struct {
	Limit int64
}

MaxBytesError is returned by MaxBytesReader when its read limit is exceeded.

​ MaxBytesReader读取的字节数超过其读取限制时返回MaxBytesError。

(*MaxBytesError) Error <- go1.19

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func (e *MaxBytesError) Error() string

type ProtocolError <- DEPRECATED

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type ProtocolError struct {
	ErrorString string
}

ProtocolError represents an HTTP protocol error.

​ ProtocolError 表示一个 HTTP 协议错误。

Deprecated: Not all errors in the http package related to protocol errors are of type ProtocolError.

​ 已弃用：并非所有与协议错误相关的 http 包中的错误都属于 ProtocolError 类型。

(*ProtocolError) Error

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func (pe *ProtocolError) Error() string

(*ProtocolError) Is <-go1.21.0

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func (pe *ProtocolError) Is(err error) bool

Is lets http.ErrNotSupported match errors.ErrUnsupported.

​ Is 允许 http.ErrNotSupported 与 errors.ErrUnsupported 匹配。

type PushOptions <- go1.8

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type PushOptions struct {
    // Method specifies the HTTP method for the promised request.
	// If set, it must be "GET" or "HEAD". Empty means "GET".
	// Method指定承诺请求的HTTP方法。
    // 如果设置，则必须是"GET"或"HEAD"。空表示"GET"。
	Method string

    // Header specifies additional promised request headers. This cannot
	// include HTTP/2 pseudo header fields like ":path" and ":scheme",
	// which will be added automatically.
	// Header指定额外的承诺请求标头。
    // 这不能包括HTTP/2伪标头字段，如"：path"和"：scheme"，
    // 它们将自动添加。
	Header Header
}

PushOptions describes options for Pusher.Push.

type Pusher <- go1.8

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type Pusher interface {
    // Push initiates an HTTP/2 server push. This constructs a synthetic
	// request using the given target and options, serializes that request
	// into a PUSH_PROMISE frame, then dispatches that request using the
	// server's request handler. If opts is nil, default options are used.
	//
	// The target must either be an absolute path (like "/path") or an absolute
	// URL that contains a valid host and the same scheme as the parent request.
	// If the target is a path, it will inherit the scheme and host of the
	// parent request.
	//
	// The HTTP/2 spec disallows recursive pushes and cross-authority pushes.
	// Push may or may not detect these invalid pushes; however, invalid
	// pushes will be detected and canceled by conforming clients.
	//
	// Handlers that wish to push URL X should call Push before sending any
	// data that may trigger a request for URL X. This avoids a race where the
	// client issues requests for X before receiving the PUSH_PROMISE for X.
	//
	// Push will run in a separate goroutine making the order of arrival
	// non-deterministic. Any required synchronization needs to be implemented
	// by the caller.
	//
	// Push returns ErrNotSupported if the client has disabled push or if push
	// is not supported on the underlying connection.
	// Push启动HTTP/2服务器推送。
    // 这将使用给定的目标和选项构造合成请求，
    // 将该请求序列化为PUSH_PROMISE帧，
    // 然后使用服务器的请求处理程序分派该请求。
    // 如果opts为nil，则使用默认选项。
	//
	// 目标必须是绝对路径(如"/path")或
    // 包含有效主机和与父请求相同的方案的绝对URL。
    // 如果目标是路径，则会继承父请求的方案和主机。
	//
	// HTTP/2规范禁止递归推送和跨权威推送。
    // Push可以或可以不检测这些无效推送；
    // 但是，符合规范的客户端将检测并取消无效的推送。
	//
	// 希望推送URL X的处理程序应在发送可能触发
    // 对URL X的请求的任何数据之前调用Push。
    // 这避免了客户端在收到X的PUSH_PROMISE之前就发出X的请求的竞争条件。
	//
	// Push将在单独的goroutine中运行，使到达顺序是不确定的。
    // 任何必需的同步需要由调用者实现。
	//
	// 如果客户端禁用推送或底层连接不支持推送，
    // 则Push返回ErrNotSupported。
	Push(target string, opts *PushOptions) error
}

Pusher is the interface implemented by ResponseWriters that support HTTP/2 server push. For more background, see https://tools.ietf.org/html/rfc7540#section-8.2.

​ Pusher是ResponseWriters实现的接口，用于支持HTTP/2服务器推送。有关更多背景信息，请参见https://tools.ietf.org/html/rfc7540#section-8.2。

type Request

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