Go語言的 net/http 包中文說明
http包
import "net/http"
預覽 ?
Http包提供實現HTTP客戶端和服務端的方法與函數。
Get、Head、Post、PostForm配合使用實現HTTP請求:
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"}})
使用結束后,應該關閉客戶端的響應體:
resp, err := http.Get("http://example.com/")
if err != nil {
// handle error
}
defer resp.Body.Close()
body, err := ioutil.ReadAll(resp.Body)
為了控制HTTP客戶端的headers、重定向方案和其它設定,需要創建一個Client:
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)
為了控制代理、安全套接層設置、保持連接、壓縮和其它設定,需要創建一個Transport:
tr := &http.Transport{
TLSClientConfig: &tls.Config{RootCAs: pool},
DisableCompression: true,
}
client := &http.Client{Transport: tr}
resp, err := client.Get("https://example.com")
Client和Transport可以安全的進行多線程的并發,因此為了提高效率應該一次建立多次使用。
ListenAndServe根據提供的地址和handler創建一個HTTP Server。Handler通常是nil,nil表示使用DefaultServeMux。
可以使用Handle和HandleFunc給DefaultServeMux添加新的handler:
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))
更多的對服務端行為的控制需要通過創建Server來實現:
s := &http.Server{
Addr: ":8080",
Handler: myHandler,
ReadTimeout: 10 * time.Second,
WriteTimeout: 10 * time.Second,
MaxHeaderBytes: 1 << 20,
}
log.Fatal(s.ListenAndServe())
索引
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
func ListenAndServeTLS(addr string, certFile string, keyFile string, handler Handler) error
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, urlStr string, code int)
func Serve(l net.Listener, handler Handler) error
func ServeFile(w ResponseWriter, r *Request, name string)
func SetCookie(w ResponseWriter, cookie *Cookie)
func StatusText(code int) string
func (c *Client) Do(req *Request) (resp *Response, err error)
func (c *Client) Get(url string) (resp *Response, err error)
func (c *Client) Head(url string) (resp *Response, err error)
func (c *Client) Post(url string, bodyType string, body io.Reader) (resp *Response, err error)
func (c *Client) PostForm(url string, data url.Values) (resp *Response, err error)
func (c *Cookie) String() string
func (d Dir) Open(name string) (File, error)
func FileServer(root FileSystem) Handler
func NotFoundHandler() Handler
func RedirectHandler(url string, code int) Handler
func StripPrefix(prefix string, h Handler) Handler
func TimeoutHandler(h Handler, dt time.Duration, msg string) Handler
func (f HandlerFunc) ServeHTTP(w ResponseWriter, r *Request)
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
func (err *ProtocolError) Error() string
func NewRequest(method, urlStr string, body io.Reader) (*Request, error)
func ReadRequest(b *bufio.Reader) (req *Request, err error)
func (r *Request) AddCookie(c *Cookie)
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() (err 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) Write(w io.Writer) error
func (r *Request) WriteProxy(w io.Writer) error
func Get(url string) (resp *Response, err error)
func Head(url string) (resp *Response, err error)
func Post(url string, bodyType 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) (resp *Response, err 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
func NewFileTransport(fs FileSystem) RoundTripper
func (mux *ServeMux) Handle(pattern string, handler Handler)
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)
func (srv *Server) ListenAndServe() error
func (srv *Server) ListenAndServeTLS(certFile, keyFile string) error
func (srv *Server) Serve(l net.Listener) error
func (t *Transport) CloseIdleConnections()
func (t *Transport) RegisterProtocol(scheme string, rt RoundTripper)
func (t *Transport) RoundTrip(req *Request) (resp *Response, err error)
Examples
Package files
chunked.go client.go cookie.go doc.go filetransport.go fs.go header.go jar.go lex.go request.go response.go server.go sniff.go status.go transfer.go transport.go
常量
const (
StatusContinue = 100
StatusSwitchingProtocols = 101
StatusOK = 200
StatusCreated = 201
StatusAccepted = 202
StatusNonAuthoritativeInfo = 203
StatusNoContent = 204
StatusResetContent = 205
StatusPartialContent = 206
StatusMultipleChoices = 300
StatusMovedPermanently = 301
StatusFound = 302
StatusSeeOther = 303
StatusNotModified = 304
StatusUseProxy = 305
StatusTemporaryRedirect = 307
StatusBadRequest = 400
StatusUnauthorized = 401
StatusPaymentRequired = 402
StatusForbidden = 403
StatusNotFound = 404
StatusMethodNotAllowed = 405
StatusNotAcceptable = 406
StatusProxyAuthRequired = 407
StatusRequestTimeout = 408
StatusConflict = 409
StatusGone = 410
StatusLengthRequired = 411
StatusPreconditionFailed = 412
StatusRequestEntityTooLarge = 413
StatusRequestURITooLong = 414
StatusUnsupportedMediaType = 415
StatusRequestedRangeNotSatisfiable = 416
StatusExpectationFailed = 417
StatusTeapot = 418
StatusInternalServerError = 500
StatusNotImplemented = 501
StatusBadGateway = 502
StatusServiceUnavailable = 503
StatusGatewayTimeout = 504
StatusHTTPVersionNotSupported = 505
)
以上都是RFC 2616規定的HTTP狀態碼
const DefaultMaxHeaderBytes = 1 << 20 // 1 MB
DefaultMaxHeaderBytes是HTTP請求頭的最大允許值,可以通過設定Server.MaxHeaderBytes來重寫。
const DefaultMaxIdleConnsPerHost = 2
DefaultMaxIdleConnsPerHost是Transport默認的單位地址最大空閑連接值。
const TimeFormat = "Mon, 02 Jan 2006 15:04:05 GMT"
TimeFormat是使用時間的格式。當分析或者結合HTTP頭的時間數據時,用來分拆(Parse)和格式化(time.time.Format)時間。類似time.RFC1123但硬編碼為GMT作為時間域。
變量
var (
ErrHeaderTooLong = &ProtocolError{"header too long"}
ErrShortBody = &ProtocolError{"entity body too short"}
ErrNotSupported = &ProtocolError{"feature not supported"}
ErrUnexpectedTrailer = &ProtocolError{"trailer header without chunked transfer encoding"}
ErrMissingContentLength = &ProtocolError{"missing ContentLength in HEAD response"}
ErrNotMultipart = &ProtocolError{"request Content-Type isn't multipart/form-data"}
ErrMissingBoundary = &ProtocolError{"no multipart boundary param Content-Type"}
)
var (
ErrWriteAfterFlush = errors.New("Conn.Write called after Flush")
ErrBodyNotAllowed = errors.New("http: request method or response status code does not allow body")
ErrHijacked = errors.New("Conn has been hijacked")
ErrContentLength = errors.New("Conn.Write wrote more than the declared Content-Length")
)
HTTP服務端聲明的錯誤信息。
var DefaultClient = &Client{}
DefaultClient是默認的Client,供Get、Head、Post等操作使用。
var DefaultServeMux = NewServeMux()
DefaultServeMux是默認的ServeMux,供Server使用。
var ErrBodyReadAfterClose = errors.New("http: invalid Read on closed request Body")
當請求體被關閉后讀取它時,返回ErrBodyReadAfterClose。一般在某個HTTP handler執行了請求體的ResponseWriter的WriteHeader或Write方法后,再次讀取請求體時,就會導致這個錯誤。
var ErrHandlerTimeout = errors.New("http: Handler timeout")
當ResponseWriter的Write操作呼叫的handler發生超時后,就會返回ErrHandlerTimeout。
var ErrLineTooLong = errors.New("header line too long")
var ErrMissingFile = errors.New("http: no such file")
當提供的文件地址出現錯誤(不是文件地址或者文件不存在)時,FormFile函數將返回ErrMissingFile。
var ErrNoCookie = errors.New("http: named cookie not present")
var ErrNoLocation = errors.New("http: no Location header in response")
func CanonicalHeaderKey
func CanonicalHeaderKey(s string) string
CanonicalHeaderKey返回字符串s的標準格式。函數將單詞的首字母和連字符后的首字母轉為大寫,其余都轉為小寫。例如,"accept-encoding"的標準版是"Accept-Encoding"。
func DetectContentType
func DetectContentType(data []byte) string
DetectContentType使用http://mimesniff.spec.whatwg.org/ 描述的算法來確定給定數據的內容類型(Content-Type)。它最多評估開始的512字節。本函數一定會返回有效的多用途互聯網郵件擴展(MIME)類型:如果函數無法確定明確的類型,它返回"application/octet-stream"。
func Error
func Error(w ResponseWriter, error string, code int)
Error函數向請求返回HTTP錯誤碼和詳細的錯誤信息。
func Handle
func Handle(pattern string, handler Handler)
Handle為DefaultServeMux中給定的模式(pattern)注冊反應器(handler)。ServeMux的說明文檔講解了pattern是如何工作的。
func HandleFunc
func HandleFunc(pattern string, handler func(ResponseWriter, *Request))
HandleFunc為DefaultServeMux中給定的模式(pattern)注冊反應函數(handler function)。
func ListenAndServe
func ListenAndServe(addr string, handler Handler) error
ListenAndServe監聽TCP網絡地址并且呼叫具有handler的Server對在進入連接發出的請求作出反應。Handler一般是nil,此時使用DefaultServeMux。
一個簡單的server例子:
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)
err := http.ListenAndServe(":12345", nil)
if err != nil {
log.Fatal("ListenAndServe: ", err)
}
}
func ListenAndServeTLS
func ListenAndServeTLS(addr string, certFile string, keyFile string, handler Handler) error
ListenAndServeTLS和ListenAndServe作用一致,但它要求HTTPS連接。此外,必須提供包含證書的文件和與服務臺(server)匹配的私鑰。如果證書是權威機構簽發的,則證書文件必須是服務臺證書緊跟CA證書的級聯。
一個簡單的server例子:
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)
if err != nil {
log.Fatal(err)
}
}
可以使用crypto/tls目錄下的generate_cert.go來生成cert.pem和key.pem。
func MaxBytesReader
func MaxBytesReader(w ResponseWriter, r io.ReadCloser, n int64) io.ReadCloser
MaxBytesReader類似于io.LimitReader但被設計用來限定接收的請求體的大小。不同于io.LimitReader,MaxBytesReader的返回值是一個ReadCloser,當讀取超過限制時會返回non-EOF錯誤并且當它的關閉方法調用時會關閉潛在的讀取者(函數/進程)。
MaxBytesReader保護客戶端避免偶然或者惡意發送的長數據請求導致的server資源的浪費。
func NotFound
func NotFound(w ResponseWriter, r *Request)
NotFound對請求返回一個HTTP 404 未發現資源的錯誤(寫入ResponseWriter)。
func ParseHTTPVersion
func ParseHTTPVersion(vers string) (major, minor int, ok bool)
ParseHTTPVersion函數分析并分解HTTP版本字符串。"HTTP/1.0"返回(1, 0, true)。
func ParseTime
func ParseTime(text string) (t time.Time, err error)
ParseTime嘗試HTTP/1.1支持的三種格式TimeFormat、time.RFC850、time.ANSIC的每一種來分解時間頭(例如 Date: header)。
func ProxyFromEnvironment
func ProxyFromEnvironment(req *Request) (*url.URL, error)
ProxyFromEnvironment根據環境變量$HTTP_PROXY和$NO_PROXY (或$http_proxy和$no_proxy)返回給定request的代理url。如果全局代理非法會返回錯誤。如果環境沒有設置代理或者設置的代理不能用于給出的request則返回空(nil)url和空錯誤碼。
func ProxyURL
func ProxyURL(fixedURL *url.URL) func(*Request) (*url.URL, error)
ProxyURL返回一個代理函數,這個代理函數(一般在Transport中使用)接受請求,并總是返回一個(代理后的)地址。
func Redirect
func Redirect(w ResponseWriter, r *Request, urlStr string, code int)
Redirect返回request一個與請求地址有關的重定向地址。
func Serve
func Serve(l net.Listener, handler Handler) error
Serve接受Listener l接收到的HTTP連接,并為每個連接創建一個新的線程。服務線程會讀取每一個請求,調用handler做出回應。Handler參數一般是nil,此時使用DefaultServeMux。
func ServeContent
func ServeContent(w ResponseWriter, req *Request, name string, modtime time.Time, content io.ReadSeeker)
ServeContent使用提供的ReadSeeker的內容反饋給請求。本函數相對io.Copy的主要優點是它可以較好的操作隨機請求、設定MIME類型,操作If-Modified-Since請求。
如果reponse的header的內容類型行未設定,本函數首先嘗試從name的文件擴展名進行推斷,如果失敗則讀取ReadSeeker的第一數據段發送給DetectContentType函數判斷。此外name參數是無用的,特定情況下它可以是空的并且從不會加入reponse中。
如果modtime參數非零,ServeContent會在response的header中包含一個包含該參數的Last-Modified行。如果request的header包含If-Modified-Since行,ServeContent使用modtime參數來確定使用應該發送全部內容。
content參數的Seek方法必須有效:ServeContent通過移位到結尾來確定content的大小。
如果呼叫者設定了w's ETag header,ServeContent將通過它,使用If-Range和If-None-Match(header中的參數行)來處理request。
注意:os.File包實現了io.ReadSeeker接口。
func ServeFile
func ServeFile(w ResponseWriter, r *Request, name string)
ServeFile對請求返回name參數指定的文件的內容。
func SetCookie
func SetCookie(w ResponseWriter, cookie *Cookie)
SetCookie給提供的ResponseWeriter的頭部添加cookie。
func StatusText
func StatusText(code int) string
StatusText返回HTTP狀態碼的文本信息,如果狀態碼未知返回空字符串。