http包

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"}})

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

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)
// ...

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

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))

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

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

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

const (
        StatusContinue           = 100 // RFC 7231, 6.2.1
        StatusSwitchingProtocols = 101 // RFC 7231, 6.2.2
        StatusProcessing         = 102 // RFC 2518, 10.1

        StatusOK                   = 200 // RFC 7231, 6.3.1
        StatusCreated              = 201 // RFC 7231, 6.3.2
        StatusAccepted             = 202 // RFC 7231, 6.3.3
        StatusNonAuthoritativeInfo = 203 // RFC 7231, 6.3.4
        StatusNoContent            = 204 // RFC 7231, 6.3.5
        StatusResetContent         = 205 // RFC 7231, 6.3.6
        StatusPartialContent       = 206 // RFC 7233, 4.1
        StatusMultiStatus          = 207 // RFC 4918, 11.1
        StatusAlreadyReported      = 208 // RFC 5842, 7.1
        StatusIMUsed               = 226 // RFC 3229, 10.4.1

        StatusMultipleChoices  = 300 // RFC 7231, 6.4.1
        StatusMovedPermanently = 301 // RFC 7231, 6.4.2
        StatusFound            = 302 // RFC 7231, 6.4.3
        StatusSeeOther         = 303 // RFC 7231, 6.4.4
        StatusNotModified      = 304 // RFC 7232, 4.1
        StatusUseProxy         = 305 // RFC 7231, 6.4.5

        StatusTemporaryRedirect = 307 // RFC 7231, 6.4.7
        StatusPermanentRedirect = 308 // RFC 7538, 3

        StatusBadRequest                   = 400 // RFC 7231, 6.5.1
        StatusUnauthorized                 = 401 // RFC 7235, 3.1
        StatusPaymentRequired              = 402 // RFC 7231, 6.5.2
        StatusForbidden                    = 403 // RFC 7231, 6.5.3
        StatusNotFound                     = 404 // RFC 7231, 6.5.4
        StatusMethodNotAllowed             = 405 // RFC 7231, 6.5.5
        StatusNotAcceptable                = 406 // RFC 7231, 6.5.6
        StatusProxyAuthRequired            = 407 // RFC 7235, 3.2
        StatusRequestTimeout               = 408 // RFC 7231, 6.5.7
        StatusConflict                     = 409 // RFC 7231, 6.5.8
        StatusGone                         = 410 // RFC 7231, 6.5.9
        StatusLengthRequired               = 411 // RFC 7231, 6.5.10
        StatusPreconditionFailed           = 412 // RFC 7232, 4.2
        StatusRequestEntityTooLarge        = 413 // RFC 7231, 6.5.11
        StatusRequestURITooLong            = 414 // RFC 7231, 6.5.12
        StatusUnsupportedMediaType         = 415 // RFC 7231, 6.5.13
        StatusRequestedRangeNotSatisfiable = 416 // RFC 7233, 4.4
        StatusExpectationFailed            = 417 // RFC 7231, 6.5.14
        StatusTeapot                       = 418 // RFC 7168, 2.3.3
        StatusUnprocessableEntity          = 422 // RFC 4918, 11.2
        StatusLocked                       = 423 // RFC 4918, 11.3
        StatusFailedDependency             = 424 // RFC 4918, 11.4
        StatusUpgradeRequired              = 426 // RFC 7231, 6.5.15
        StatusPreconditionRequired         = 428 // RFC 6585, 3
        StatusTooManyRequests              = 429 // RFC 6585, 4
        StatusRequestHeaderFieldsTooLarge  = 431 // RFC 6585, 5
        StatusUnavailableForLegalReasons   = 451 // RFC 7725, 3

        StatusInternalServerError           = 500 // RFC 7231, 6.6.1
        StatusNotImplemented                = 501 // RFC 7231, 6.6.2
        StatusBadGateway                    = 502 // RFC 7231, 6.6.3
        StatusServiceUnavailable            = 503 // RFC 7231, 6.6.4
        StatusGatewayTimeout                = 504 // RFC 7231, 6.6.5
        StatusHTTPVersionNotSupported       = 505 // RFC 7231, 6.6.6
        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
)

const DefaultMaxHeaderBytes = 1 << 20 // 1 MB

const DefaultMaxIdleConnsPerHost = 2

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

https://golang.org/pkg/net/http/#ResponseWriter
https://golang.org/pkg/net/http/#example_ResponseWriter_trailers

const TrailerPrefix = "Trailer:"

var (
        // 推送法返回 ErrNotSupported
        // 实现来指示 HTTP\/2 推送支持不是
        // 可用。
        ErrNotSupported = &ProtocolError{"feature not supported"}

        // ErrUnexpectedTrailer 由传输返回, 当服务器
        // 答复与拖车头, 但没有块答复。
        ErrUnexpectedTrailer = &ProtocolError{"trailer header without chunked transfer encoding"}

        // ErrMissingBoundary 是按请求返回的. MultipartReader 当
        // request's Content-Type does not include a "boundary" parameter.
        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.
        ErrNotMultipart = &ProtocolError{"request Content-Type isn't multipart/form-data"}

        // Deprecated: ErrHeaderTooLong is not used.
        ErrHeaderTooLong = &ProtocolError{"header too long"}
        // Deprecated: ErrShortBody is not used.
        ErrShortBody = &ProtocolError{"entity body too short"}
        // Deprecated: ErrMissingContentLength is not used.
        ErrMissingContentLength = &ProtocolError{"missing ContentLength in HEAD response"}
)

var (
        // ErrBodyNotAllowed is returned by ResponseWriter.Write calls
        // when the HTTP method or response code does not permit a
        // body.
        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 = 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 = errors.New("http: wrote more than the declared Content-Length")

        // Deprecated: ErrWriteAfterFlush is no longer used.
        ErrWriteAfterFlush = errors.New("unused")
)

var (
        // ServerContextKey 是一个上下文键。可用于 HTTP
        // 具有上下文的处理程序。WithValue 访问服务器,
        // 已启动处理程序。关联的值将为
        // 类型 * 服务器。
        ServerContextKey = &contextKey{"http-server"}

        // LocalAddrContextKey 是一个上下文键。可用于
        // 带有上下文的 HTTP 处理程序。WithValue 访问地址
        // 连接到达的本地地址。
        // 关联的值将为类型网。地址.
        LocalAddrContextKey = &contextKey{"local-addr"}
)

var DefaultClient = &Client{}

var DefaultServeMux = &defaultServeMux

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

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

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

var ErrLineTooLong = internal.ErrLineTooLong

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

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

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

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

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

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

var NoBody = noBody{}

func CanonicalHeaderKey(s string) string

func DetectContentType(data []byte) string

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

func Handle(pattern string, handler Handler)

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

func ListenAndServe(addr string, handler Handler) error

package main

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

// hello world, the web server
func HelloServer(w http.ResponseWriter, req *http.Request) {
	io.WriteString(w, "hello, world!\n")
}

func main() {
	http.HandleFunc("/hello", HelloServer)
	log.Fatal(http.ListenAndServe(":12345", nil))
}

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

import (
	"log"
	"net/http"
)

func handler(w http.ResponseWriter, req *http.Request) {
	w.Header().Set("Content-Type", "text/plain")
	w.Write([]byte("This is an example server.\n"))
}

func main() {
	http.HandleFunc("/", handler)
	log.Printf("About to listen on 10443. Go to https://127.0.0.1:10443/")
	err := http.ListenAndServeTLS(":10443", "cert.pem", "key.pem", nil)
	log.Fatal(err)
}

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

func NotFound(w ResponseWriter, r *Request)

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

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

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

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

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

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

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

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

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

func SetCookie(w ResponseWriter, cookie *Cookie)

func StatusText(code int) string

type Client struct {
        // Transport specifies the mechanism by which individual
        // HTTP requests are made.
        // If nil, DefaultTransport is used.
        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 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 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
        // using the Request.Cancel mechanism. Requests passed
        // to Client.Do may still set Request.Cancel; both will
        // cancel the request.
        //
        // For compatibility, the Client will also use the deprecated
        // CancelRequest method on Transport if found. New
        // RoundTripper implementations should use Request.Cancel
        // instead of implementing CancelRequest.
        Timeout time.Duration
}

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

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

301 (Moved Permanently)
302 (Found)
303 (See Other)
307 (Temporary Redirect)
308 (Permanent Redirect)

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

301 (Moved Permanently)
302 (Found)
303 (See Other)
307 (Temporary Redirect)
308 (Permanent Redirect)

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

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

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
}

type ConnState int

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 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

        // 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

        // StateHijacked represents a hijacked connection.
        // This is a terminal state. It does not transition to StateClosed.
        StateHijacked

        // StateClosed represents a closed connection.
        // This is a terminal state. Hijacked connections do not
        // transition to StateClosed.
        StateClosed
)

func (c ConnState) String() string

type Cookie struct {
        Name  string
        Value string

        Path       string    // optional
        Domain     string    // optional
        Expires    time.Time // optional
        RawExpires string    // for reading cookies only

        // 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   int
        Secure   bool
        HttpOnly bool
        Raw      string
        Unparsed []string // Raw text of unparsed attribute-value pairs
}

func (c *Cookie) String() string

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(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(u *url.URL) []*Cookie
}

type Dir string

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

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

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

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

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

func FileServer(root FileSystem) Handler

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

package main

import (
	"log"
	"net/http"
)

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

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 NotFoundHandler() Handler

func RedirectHandler(url string, code int) Handler

func StripPrefix(prefix string, h Handler) Handler

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

type HandlerFunc func(ResponseWriter, *Request)

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

type Header map[string][]string

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

func (h Header) Del(key string)

func (h Header) Get(key string) string

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

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

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

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 should
        // not be used.
        Hijack() (net.Conn, *bufio.ReadWriter, error)
}

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 ProtocolError struct {
        ErrorString string
}

func (pe *ProtocolError) Error() string

type PushOptions struct {
        // Method specifies the HTTP method for the promised request.
        // If set, it must be "GET" or "HEAD". Empty means "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 Header
}

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 returns ErrNotSupported if the client has disabled push or if push
        // is not supported on the underlying connection.
        Push(target string, opts *PushOptions) error
}

type Request struct {
        // Method specifies the HTTP method (GET, POST, PUT, etc.).
        // For client requests an empty string means GET.
        Method string

        // URL specifies either the URI being requested (for server
        // requests) or the URL to access (for client requests).
        //
        // For server requests the URL is parsed from the URI
        // supplied on the Request-Line as stored in RequestURI.  For
        // most requests, fields other than Path and RawQuery will be
        // empty. (See RFC 2616, Section 5.1.2)
        //
        // For client requests, the URL's Host specifies the server to
        // connect to, while the Request's Host field optionally
        // specifies the Host header value to send in the HTTP
        // request.
        URL *url.URL

        // The protocol version for incoming server requests.
        //
        // For client requests these fields are ignored. The HTTP
        // client code always uses either HTTP/1.1 or HTTP/2.
        // See the docs on Transport for details.
        Proto      string // "HTTP/1.0"
        ProtoMajor int    // 1
        ProtoMinor int    // 0

        // Header contains the request header fields either received
        // by the server or to be sent by the client.
        //
        // If a server received a request with header lines,
        //
        //	Host: example.com
        //	accept-encoding: gzip, deflate
        //	Accept-Language: en-us
        //	fOO: Bar
        //	foo: two
        //
        // then
        //
        //	Header = map[string][]string{
        //		"Accept-Encoding": {"gzip, deflate"},
        //		"Accept-Language": {"en-us"},
        //		"Foo": {"Bar", "two"},
        //	}
        //
        // For incoming requests, the Host header is promoted to the
        // Request.Host field and removed from the Header map.
        //
        // HTTP defines that header names are case-insensitive. The
        // request parser implements this by using CanonicalHeaderKey,
        // making the first character and any characters following a
        // hyphen uppercase and the rest lowercase.
        //
        // For client requests, certain headers such as Content-Length
        // and Connection are automatically written when needed and
        // values in Header may be ignored. See the documentation
        // for the Request.Write method.
        Header Header

        // Body is the request's body.
        //
        // For client requests a nil body means the request has no
        // body, such as a GET request. The HTTP Client's Transport
        // is responsible for calling the Close method.
        //
        // For server requests the Request Body is always non-nil
        // but will return EOF immediately when no body is present.
        // The Server will close the request body. The ServeHTTP
        // Handler does not need to.
        Body io.ReadCloser

        // GetBody defines an optional func to return a new copy of
        // Body. It is used for client requests when a redirect requires
        // reading the body more than once. Use of GetBody still
        // requires setting Body.
        //
        // For server requests it is unused.
        GetBody func() (io.ReadCloser, error)

        // ContentLength records the length of the associated content.
        // The value -1 indicates that the length is unknown.
        // Values >= 0 indicate that the given number of bytes may
        // be read from Body.
        // For client requests, a value of 0 with a non-nil Body is
        // also treated as unknown.
        ContentLength int64

        // TransferEncoding lists the transfer encodings from outermost to
        // innermost. An empty list denotes the "identity" encoding.
        // TransferEncoding can usually be ignored; chunked encoding is
        // automatically added and removed as necessary when sending and
        // receiving requests.
        TransferEncoding []string

        // Close indicates whether to close the connection after
        // replying to this request (for servers) or after sending this
        // request and reading its response (for clients).
        //
        // For server requests, the HTTP server handles this automatically
        // and this field is not needed by Handlers.
        //
        // For client requests, setting this field prevents re-use of
        // TCP connections between requests to the same hosts, as if
        // Transport.DisableKeepAlives were set.
        Close bool

        // For server requests Host specifies the host on which the
        // URL is sought. Per RFC 2616, this is either the value of
        // the "Host" header or the host name given in the URL itself.
        // It may be of the form "host:port". For international domain
        // names, Host may be in Punycode or Unicode form. Use
        // golang.org/x/net/idna to convert it to either format if
        // needed.
        //
        // For client requests Host optionally overrides the Host
        // header to send. If empty, the Request.Write method uses
        // the value of URL.Host. Host may contain an international
        // domain name.
        Host string

        // Form contains the parsed form data, including both the URL
        // field's query parameters and the POST or PUT form data.
        // This field is only available after ParseForm is called.
        // The HTTP client ignores Form and uses Body instead.
        Form url.Values

        // PostForm contains the parsed form data from POST, PATCH,
        // or PUT body parameters.
        //
        // This field is only available after ParseForm is called.
        // The HTTP client ignores PostForm and uses Body instead.
        PostForm url.Values

        // MultipartForm is the parsed multipart form, including file uploads.
        // This field is only available after ParseMultipartForm is called.
        // The HTTP client ignores MultipartForm and uses Body instead.
        MultipartForm *multipart.Form

        // Trailer specifies additional headers that are sent after the request
        // body.
        //
        // For server requests the Trailer map initially contains only the
        // trailer keys, with nil values. (The client declares which trailers it
        // will later send.)  While the handler is reading from Body, it must
        // not reference Trailer. After reading from Body returns EOF, Trailer
        // can be read again and will contain non-nil values, if they were sent
        // by the client.
        //
        // For client requests Trailer must be initialized to a map containing
        // the trailer keys to later send. The values may be nil or their final
        // values. The ContentLength must be 0 or -1, to send a chunked request.
        // After the HTTP request is sent the map values can be updated while
        // the request body is read. Once the body returns EOF, the caller must
        // not mutate Trailer.
        //
        // Few HTTP clients, servers, or proxies support HTTP trailers.
        Trailer Header

        // RemoteAddr allows HTTP servers and other software to record
        // the network address that sent the request, usually for
        // logging. This field is not filled in by ReadRequest and
        // has no defined format. The HTTP server in this package
        // sets RemoteAddr to an "IP:port" address before invoking a
        // handler.
        // This field is ignored by the HTTP client.
        RemoteAddr string

        // RequestURI is the unmodified Request-URI of the
        // Request-Line (RFC 2616, Section 5.1) as sent by the client
        // to a server. Usually the URL field should be used instead.
        // It is an error to set this field in an HTTP client request.
        RequestURI string

        // TLS allows HTTP servers and other software to record
        // information about the TLS connection on which the request
        // was received. This field is not filled in by ReadRequest.
        // The HTTP server in this package sets the field for
        // TLS-enabled connections before invoking a handler;
        // otherwise it leaves the field nil.
        // This field is ignored by the HTTP client.
        TLS *tls.ConnectionState

        // Cancel is an optional channel whose closure indicates that the client
        // request should be regarded as canceled. Not all implementations of
        // RoundTripper may support Cancel.
        //
        // For server requests, this field is not applicable.
        //
        // Deprecated: Use the Context and WithContext methods
        // instead. If a Request's Cancel field and context are both
        // set, it is undefined whether Cancel is respected.
        Cancel <-chan struct{}

        // Response is the redirect response which caused this request
        // to be created. This field is only populated during client
        // redirects.
        Response *Response
        // contains filtered or unexported fields
}

func NewRequest(method, url string, body io.Reader) (*Request, error)

func ReadRequest(b *bufio.Reader) (*Request, error)

func (r *Request) AddCookie(c *Cookie)

func (r *Request) BasicAuth() (username, password string, ok bool)

func (r *Request) Context() context.Context

func (r *Request) Cookie(name string) (*Cookie, error)

func (r *Request) Cookies() []*Cookie

func (r *Request) FormFile(key string) (multipart.File, *multipart.FileHeader, error)

func (r *Request) FormValue(key string) string

func (r *Request) MultipartReader() (*multipart.Reader, error)

func (r *Request) ParseForm() error

func (r *Request) ParseMultipartForm(maxMemory int64) error

func (r *Request) PostFormValue(key string) string

func (r *Request) ProtoAtLeast(major, minor int) bool

func (r *Request) Referer() string

func (r *Request) SetBasicAuth(username, password string)

func (r *Request) UserAgent() string

func (r *Request) WithContext(ctx context.Context) *Request

func (r *Request) Write(w io.Writer) error

Host
URL
Method (defaults to "GET")
Header
ContentLength
TransferEncoding
Body

func (r *Request) WriteProxy(w io.Writer) error

type Response struct {
        Status     string // e.g. "200 OK"
        StatusCode int    // e.g. 200
        Proto      string // e.g. "HTTP/1.0"
        ProtoMajor int    // e.g. 1
        ProtoMinor int    // e.g. 0

        // Header maps header keys to values. If the response had multiple
        // headers with the same key, they may be concatenated, with comma
        // delimiters.  (Section 4.2 of RFC 2616 requires that multiple headers
        // be semantically equivalent to a comma-delimited sequence.) When
        // Header values are duplicated by other fields in this struct (e.g.,
        // ContentLength, TransferEncoding, Trailer), the field values are
        // authoritative.
        //
        // Keys in the map are canonicalized (see CanonicalHeaderKey).
        Header Header

        // Body represents the response body.
        //
        // The http Client and Transport guarantee that Body is always
        // non-nil, even on responses without a body or responses with
        // a zero-length body. It is the caller's responsibility to
        // close Body. The default HTTP client's Transport does not
        // attempt to reuse HTTP/1.0 or HTTP/1.1 TCP connections
        // ("keep-alive") unless the Body is read to completion and is
        // closed.
        //
        // The Body is automatically dechunked if the server replied
        // with a "chunked" Transfer-Encoding.
        Body io.ReadCloser

        // ContentLength records the length of the associated content. The
        // value -1 indicates that the length is unknown. Unless Request.Method
        // is "HEAD", values >= 0 indicate that the given number of bytes may
        // be read from Body.
        ContentLength int64

        // Contains transfer encodings from outer-most to inner-most. Value is
        // nil, means that "identity" encoding is used.
        TransferEncoding []string

        // Close records whether the header directed that the connection be
        // closed after reading Body. The value is advice for clients: neither
        // ReadResponse nor Response.Write ever closes a connection.
        Close bool

        // Uncompressed reports whether the response was sent compressed but
        // was decompressed by the http package. When true, reading from
        // Body yields the uncompressed content instead of the compressed
        // content actually set from the server, ContentLength is set to -1,
        // and the "Content-Length" and "Content-Encoding" fields are deleted
        // from the responseHeader. To get the original response from
        // the server, set Transport.DisableCompression to true.
        Uncompressed bool

        // Trailer maps trailer keys to values in the same
        // format as Header.
        //
        // The Trailer initially contains only nil values, one for
        // each key specified in the server's "Trailer" header
        // value. Those values are not added to Header.
        //
        // Trailer must not be accessed concurrently with Read calls
        // on the Body.
        //
        // After Body.Read has returned io.EOF, Trailer will contain
        // any trailer values sent by the server.
        Trailer Header

        // Request is the request that was sent to obtain this Response.
        // Request's Body is nil (having already been consumed).
        // This is only populated for Client requests.
        Request *Request

        // TLS contains information about the TLS connection on which the
        // response was received. It is nil for unencrypted responses.
        // The pointer is shared between responses and should not be
        // modified.
        TLS *tls.ConnectionState
}

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

301 (Moved Permanently)
302 (Found)
303 (See Other)
307 (Temporary Redirect)
308 (Permanent Redirect)

package main

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

func main() {
	res, err := http.Get("http://www.google.com/robots.txt")
	if err != nil {
		log.Fatal(err)
	}
	robots, err := ioutil.ReadAll(res.Body)
	res.Body.Close()
	if err != nil {
		log.Fatal(err)
	}
	fmt.Printf("%s", robots)
}

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

301 (Moved Permanently)
302 (Found)
303 (See Other)
307 (Temporary Redirect)
308 (Permanent Redirect)

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

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

func ReadResponse(r *bufio.Reader, req *Request) (*Response, error)

func (r *Response) Cookies() []*Cookie

func (r *Response) Location() (*url.URL, error)

func (r *Response) ProtoAtLeast(major, minor int) bool

func (r *Response) Write(w io.Writer) error

StatusCode
ProtoMajor
ProtoMinor
Request.Method
TransferEncoding
Trailer
Body
ContentLength
Header, values for non-canonical keys will have unpredictable behavior

type ResponseWriter interface {
        // Header returns the header map that will be sent by
        // WriteHeader. The Header map also is the mechanism with which
        // Handlers can set HTTP trailers.
        //
        // Changing the header map after a call to WriteHeader (or
        // Write) has no effect unless the modified headers are
        // trailers.
        //
        // There are two ways to set Trailers. The preferred way is to
        // predeclare in the headers which trailers you will later
        // send by setting the "Trailer" header to the names of the
        // trailer keys which will come later. In this case, those
        // keys of the Header map are treated as if they were
        // trailers. See the example. The second way, for trailer
        // keys not known to the Handler until after the first Write,
        // is to prefix the Header map keys with the TrailerPrefix
        // constant value. See TrailerPrefix.
        //
        // To suppress implicit response headers (such as "Date"), set
        // their value to nil.
        Header() Header

        // Write writes the data to the connection as part of an HTTP reply.
        //
        // If WriteHeader has not yet been called, Write calls
        // WriteHeader(http.StatusOK) before writing the data. If the Header
        // does not contain a Content-Type line, Write adds a Content-Type set
        // to the result of passing the initial 512 bytes of written data to
        // DetectContentType.
        //
        // Depending on the HTTP protocol version and the client, calling
        // Write or WriteHeader may prevent future reads on the
        // Request.Body. For HTTP/1.x requests, handlers should read any
        // needed request body data before writing the response. Once the
        // headers have been flushed (due to either an explicit Flusher.Flush
        // call or writing enough data to trigger a flush), the request body
        // may be unavailable. For HTTP/2 requests, the Go HTTP server permits
        // handlers to continue to read the request body while concurrently
        // writing the response. However, such behavior may not be supported
        // by all HTTP/2 clients. Handlers should read before writing if
        // possible to maximize compatibility.
        Write([]byte) (int, error)

        // WriteHeader sends an HTTP response header with status code.
        // If WriteHeader is not called explicitly, the first call to Write
        // will trigger an implicit WriteHeader(http.StatusOK).
        // Thus explicit calls to WriteHeader are mainly used to
        // send error codes.
        WriteHeader(int)
}

package main

import (
	"io"
	"net/http"
)

func main() {
	mux := http.NewServeMux()
	mux.HandleFunc("/sendstrailers", func(w http.ResponseWriter, req *http.Request) {
		// Before any call to WriteHeader or Write, declare
		// the trailers you will set during the HTTP
		// response. These three headers are actually sent in
		// the trailer.
		w.Header().Set("Trailer", "AtEnd1, AtEnd2")
		w.Header().Add("Trailer", "AtEnd3")

		w.Header().Set("Content-Type", "text/plain; charset=utf-8") // normal header
		w.WriteHeader(http.StatusOK)

		w.Header().Set("AtEnd1", "value 1")
		io.WriteString(w, "This HTTP response has both headers before this text and trailers at the end.\n")
		w.Header().Set("AtEnd2", "value 2")
		w.Header().Set("AtEnd3", "value 3") // These will appear as trailers.
	})
}

type RoundTripper interface {
        // RoundTrip executes a single HTTP transaction, returning
        // a Response for the provided Request.
        //
        // RoundTrip should not attempt to interpret the response. In
        // particular, RoundTrip must return err == nil if it obtained
        // a response, regardless of the response's HTTP status code.
        // A non-nil err should be reserved for failure to obtain a
        // response. Similarly, RoundTrip should not attempt to
        // handle higher-level protocol details such as redirects,
        // authentication, or cookies.
        //
        // RoundTrip should not modify the request, except for
        // consuming and closing the Request's Body.
        //
        // RoundTrip must always close the body, including on errors,
        // but depending on the implementation may do so in a separate
        // goroutine even after RoundTrip returns. This means that
        // callers wanting to reuse the body for subsequent requests
        // must arrange to wait for the Close call before doing so.
        //
        // The Request's URL and Header fields must be initialized.
        RoundTrip(*Request) (*Response, error)
}

var DefaultTransport RoundTripper = &Transport{
        Proxy: ProxyFromEnvironment,
        DialContext: (&net.Dialer{
                Timeout:   30 * time.Second,
                KeepAlive: 30 * time.Second,
                DualStack: true,
        }).DialContext,
        MaxIdleConns:          100,
        IdleConnTimeout:       90 * time.Second,
        TLSHandshakeTimeout:   10 * time.Second,
        ExpectContinueTimeout: 1 * time.Second,
}

func NewFileTransport(fs FileSystem) RoundTripper

t := &http.Transport{}
t.RegisterProtocol("file", http.NewFileTransport(http.Dir("/")))
c := &http.Client{Transport: t}
res, err := c.Get("file:///etc/passwd")
...

type ServeMux struct {
        // contains filtered or unexported fields
}

func NewServeMux() *ServeMux

func (mux *ServeMux) Handle(pattern string, handler Handler)

mux := http.NewServeMux()
mux.Handle("/api/", apiHandler{})
mux.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
        // The "/" pattern matches everything, so we need to check
        // that we're at the root here.
        if req.URL.Path != "/" {
                http.NotFound(w, req)
                return
        }
        fmt.Fprintf(w, "Welcome to the home page!")
})

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

func (mux *ServeMux) Handler(r *Request) (h Handler, pattern string)

func (mux *ServeMux) ServeHTTP(w ResponseWriter, r *Request)

type Server struct {
        Addr      string      // TCP address to listen on, ":http" if empty
        Handler   Handler     // handler to invoke, http.DefaultServeMux if nil
        TLSConfig *tls.Config // optional TLS config, used by ServeTLS and ListenAndServeTLS

        // ReadTimeout is the maximum duration for reading the entire
        // request, including the body.
        //
        // Because ReadTimeout does not let Handlers make per-request
        // decisions on each request body's acceptable deadline or
        // upload rate, most users will prefer to use
        // ReadHeaderTimeout. It is valid to use them both.
        ReadTimeout time.Duration

        // ReadHeaderTimeout is the amount of time allowed to read
        // request headers. The connection's read deadline is reset
        // after reading the headers and the Handler can decide what
        // is considered too slow for the body.
        ReadHeaderTimeout time.Duration

        // WriteTimeout is the maximum duration before timing out
        // writes of the response. It is reset whenever a new
        // request's header is read. Like ReadTimeout, it does not
        // let Handlers make decisions on a per-request basis.
        WriteTimeout time.Duration

        // IdleTimeout is the maximum amount of time to wait for the
        // next request when keep-alives are enabled. If IdleTimeout
        // is zero, the value of ReadTimeout is used. If both are
        // zero, ReadHeaderTimeout is used.
        IdleTimeout time.Duration

        // MaxHeaderBytes controls the maximum number of bytes the
        // server will read parsing the request header's keys and
        // values, including the request line. It does not limit the
        // size of the request body.
        // If zero, DefaultMaxHeaderBytes is used.
        MaxHeaderBytes int

        // TLSNextProto optionally specifies a function to take over
        // ownership of the provided TLS connection when an NPN/ALPN
        // protocol upgrade has occurred. The map key is the protocol
        // name negotiated. The Handler argument should be used to
        // handle HTTP requests and will initialize the Request's TLS
        // and RemoteAddr if not already set. The connection is
        // automatically closed when the function returns.
        // If TLSNextProto is not nil, HTTP/2 support is not enabled
        // automatically.
        TLSNextProto map[string]func(*Server, *tls.Conn, Handler)

        // ConnState specifies an optional callback function that is
        // called when a client connection changes state. See the
        // ConnState type and associated constants for details.
        ConnState func(net.Conn, ConnState)

        // ErrorLog specifies an optional logger for errors accepting
        // connections and unexpected behavior from handlers.
        // If nil, logging goes to os.Stderr via the log package's
        // standard logger.
        ErrorLog *log.Logger
        // contains filtered or unexported fields
}

func (srv *Server) Close() error

func (srv *Server) ListenAndServe() error

func (srv *Server) ListenAndServeTLS(certFile, keyFile string) error

func (srv *Server) RegisterOnShutdown(f func())

func (srv *Server) Serve(l net.Listener) error

func (srv *Server) ServeTLS(l net.Listener, certFile, keyFile string) error

func (srv *Server) SetKeepAlivesEnabled(v bool)

func (srv *Server) Shutdown(ctx context.Context) error

type Transport struct {

        // Proxy specifies a function to return a proxy for a given
        // Request. If the function returns a non-nil error, the
        // request is aborted with the provided error.
        //
        // The proxy type is determined by the URL scheme. "http"
        // and "socks5" are supported. If the scheme is empty,
        // "http" is assumed.
        //
        // If Proxy is nil or returns a nil *URL, no proxy is used.
        Proxy func(*Request) (*url.URL, error)

        // DialContext specifies the dial function for creating unencrypted TCP connections.
        // If DialContext is nil (and the deprecated Dial below is also nil),
        // then the transport dials using package net.
        DialContext func(ctx context.Context, network, addr string) (net.Conn, error)

        // Dial specifies the dial function for creating unencrypted TCP connections.
        //
        // Deprecated: Use DialContext instead, which allows the transport
        // to cancel dials as soon as they are no longer needed.
        // If both are set, DialContext takes priority.
        Dial func(network, addr string) (net.Conn, error)

        // DialTLS specifies an optional dial function for creating
        // TLS connections for non-proxied HTTPS requests.
        //
        // If DialTLS is nil, Dial and TLSClientConfig are used.
        //
        // If DialTLS is set, the Dial hook is not used for HTTPS
        // requests and the TLSClientConfig and TLSHandshakeTimeout
        // are ignored. The returned net.Conn is assumed to already be
        // past the TLS handshake.
        DialTLS func(network, addr string) (net.Conn, error)

        // TLSClientConfig specifies the TLS configuration to use with
        // tls.Client.
        // If nil, the default configuration is used.
        // If non-nil, HTTP/2 support may not be enabled by default.
        TLSClientConfig *tls.Config

        // TLSHandshakeTimeout specifies the maximum amount of time waiting to
        // wait for a TLS handshake. Zero means no timeout.
        TLSHandshakeTimeout time.Duration

        // DisableKeepAlives, if true, prevents re-use of TCP connections
        // between different HTTP requests.
        DisableKeepAlives bool

        // DisableCompression, if true, prevents the Transport from
        // requesting compression with an "Accept-Encoding: gzip"
        // request header when the Request contains no existing
        // Accept-Encoding value. If the Transport requests gzip on
        // its own and gets a gzipped response, it's transparently
        // decoded in the Response.Body. However, if the user
        // explicitly requested gzip it is not automatically
        // uncompressed.
        DisableCompression bool

        // MaxIdleConns controls the maximum number of idle (keep-alive)
        // connections across all hosts. Zero means no limit.
        MaxIdleConns int

        // MaxIdleConnsPerHost, if non-zero, controls the maximum idle
        // (keep-alive) connections to keep per-host. If zero,
        // DefaultMaxIdleConnsPerHost is used.
        MaxIdleConnsPerHost int

        // IdleConnTimeout is the maximum amount of time an idle
        // (keep-alive) connection will remain idle before closing
        // itself.
        // Zero means no limit.
        IdleConnTimeout time.Duration

        // ResponseHeaderTimeout, if non-zero, specifies the amount of
        // time to wait for a server's response headers after fully
        // writing the request (including its body, if any). This
        // time does not include the time to read the response body.
        ResponseHeaderTimeout time.Duration

        // ExpectContinueTimeout, if non-zero, specifies the amount of
        // time to wait for a server's first response headers after fully
        // writing the request headers if the request has an
        // "Expect: 100-continue" header. Zero means no timeout and
        // causes the body to be sent immediately, without
        // waiting for the server to approve.
        // This time does not include the time to send the request header.
        ExpectContinueTimeout time.Duration

        // TLSNextProto specifies how the Transport switches to an
        // alternate protocol (such as HTTP/2) after a TLS NPN/ALPN
        // protocol negotiation. If Transport dials an TLS connection
        // with a non-empty protocol name and TLSNextProto contains a
        // map entry for that key (such as "h2"), then the func is
        // called with the request's authority (such as "example.com"
        // or "example.com:1234") and the TLS connection. The function
        // must return a RoundTripper that then handles the request.
        // If TLSNextProto is not nil, HTTP/2 support is not enabled
        // automatically.
        TLSNextProto map[string]func(authority string, c *tls.Conn) RoundTripper

        // ProxyConnectHeader optionally specifies headers to send to
        // proxies during CONNECT requests.
        ProxyConnectHeader Header

        // MaxResponseHeaderBytes specifies a limit on how many
        // response bytes are allowed in the server's response
        // header.
        //
        // Zero means to use a default limit.
        MaxResponseHeaderBytes int64
        // contains filtered or unexported fields
}

func (t *Transport) CancelRequest(req *Request)

func (t *Transport) CloseIdleConnections()

func (t *Transport) RegisterProtocol(scheme string, rt RoundTripper)

func (t *Transport) RoundTrip(req *Request) (*Response, error)