package httputil

Import Path
	net/http/httputil (on go.dev)

Dependency Relation
	imports 16 packages, and imported by one package


Involved Source Files

	      dump.go
	
		Package httputil provides HTTP utility functions, complementing the
		more common ones in the net/http package.

	      persist.go
	      reverseproxy.go


Code Examples

	
		package main
		
		import (
			"fmt"
			"io"
			"log"
			"net/http"
			"net/http/httptest"
			"net/http/httputil"
			"strings"
		)
		
		func main() {
			ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				dump, err := httputil.DumpRequest(r, true)
				if err != nil {
					http.Error(w, fmt.Sprint(err), http.StatusInternalServerError)
					return
				}
		
				fmt.Fprintf(w, "%q", dump)
			}))
			defer ts.Close()
		
			const body = "Go is a general-purpose language designed with systems programming in mind."
			req, err := http.NewRequest("POST", ts.URL, strings.NewReader(body))
			if err != nil {
				log.Fatal(err)
			}
			req.Host = "www.example.org"
			resp, err := http.DefaultClient.Do(req)
			if err != nil {
				log.Fatal(err)
			}
			defer resp.Body.Close()
		
			b, err := io.ReadAll(resp.Body)
			if err != nil {
				log.Fatal(err)
			}
		
			fmt.Printf("%s", b)
		
		}

	
		package main
		
		import (
			"fmt"
			"log"
			"net/http"
			"net/http/httputil"
			"strings"
		)
		
		func main() {
			const body = "Go is a general-purpose language designed with systems programming in mind."
			req, err := http.NewRequest("PUT", "http://www.example.org", strings.NewReader(body))
			if err != nil {
				log.Fatal(err)
			}
		
			dump, err := httputil.DumpRequestOut(req, true)
			if err != nil {
				log.Fatal(err)
			}
		
			fmt.Printf("%q", dump)
		
		}

	
		package main
		
		import (
			"fmt"
			"log"
			"net/http"
			"net/http/httptest"
			"net/http/httputil"
		)
		
		func main() {
			const body = "Go is a general-purpose language designed with systems programming in mind."
			ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				w.Header().Set("Date", "Wed, 19 Jul 1972 19:00:00 GMT")
				fmt.Fprintln(w, body)
			}))
			defer ts.Close()
		
			resp, err := http.Get(ts.URL)
			if err != nil {
				log.Fatal(err)
			}
			defer resp.Body.Close()
		
			dump, err := httputil.DumpResponse(resp, true)
			if err != nil {
				log.Fatal(err)
			}
		
			fmt.Printf("%q", dump)
		
		}

	
		package main
		
		import (
			"fmt"
			"io"
			"log"
			"net/http"
			"net/http/httptest"
			"net/http/httputil"
			"net/url"
		)
		
		func main() {
			backendServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				fmt.Fprintln(w, "this call was relayed by the reverse proxy")
			}))
			defer backendServer.Close()
		
			rpURL, err := url.Parse(backendServer.URL)
			if err != nil {
				log.Fatal(err)
			}
			frontendProxy := httptest.NewServer(httputil.NewSingleHostReverseProxy(rpURL))
			defer frontendProxy.Close()
		
			resp, err := http.Get(frontendProxy.URL)
			if err != nil {
				log.Fatal(err)
			}
		
			b, err := io.ReadAll(resp.Body)
			if err != nil {
				log.Fatal(err)
			}
		
			fmt.Printf("%s", b)
		
		}




Package-Level Type Names (total 11, in which 4 are exported)


	/* sort exporteds by:  |  */
	
		A BufferPool is an interface for getting and returning temporary
		byte slices for use by io.CopyBuffer.

		
			( T) Get() []byte
			( T) Put([]byte)


	
		ClientConn is an artifact of Go's early HTTP implementation.
		It is low-level, old, and unused by Go's current HTTP stack.
		We should have deleted it before Go 1.

		Deprecated: Use Client or Transport in package net/http instead.

		
			
		
			
				Close calls Hijack and then also closes the underlying connection.

			
				Do is convenience method that writes a request and reads a response.

			
				Hijack detaches the ClientConn and returns the underlying connection as well
				as the read-side bufio which may have some left over data. Hijack may be
				called before the user or Read have signaled the end of the keep-alive
				logic. The user should not call Hijack while Read or Write is in progress.

			
				Pending returns the number of unanswered requests
				that have been sent on the connection.

			
				Read reads the next response from the wire. A valid response might be
				returned together with an ErrPersistEOF, which means that the remote
				requested that this be the last request serviced. Read can be called
				concurrently with Write, but not with another Read.

			
				Write writes a request. An ErrPersistEOF error is returned if the connection
				has been closed in an HTTP keep-alive sense. If req.Close equals true, the
				keep-alive connection is logically closed after this request and the opposing
				server is informed. An ErrUnexpectedEOF indicates the remote closed the
				underlying TCP connection, which is usually considered as graceful close.

		
			*T : io.Closer
		
			func NewClientConn(c net.Conn, r *bufio.Reader) *ClientConn
			func NewProxyClientConn(c net.Conn, r *bufio.Reader) *ClientConn


	
		ReverseProxy is an HTTP Handler that takes an incoming request and
		sends it to another server, proxying the response back to the
		client.

		ReverseProxy by default sets the client IP as the value of the
		X-Forwarded-For header.

		If an X-Forwarded-For header already exists, the client IP is
		appended to the existing values. As a special case, if the header
		exists in the Request.Header map but has a nil value (such as when
		set by the Director func), the X-Forwarded-For header is
		not modified.

		To prevent IP spoofing, be sure to delete any pre-existing
		X-Forwarded-For header coming from the client or
		an untrusted proxy.

		
			
				BufferPool optionally specifies a buffer pool to
				get byte slices for use by io.CopyBuffer when
				copying HTTP response bodies.

			
				Director must be a function which modifies
				the request into a new request to be sent
				using Transport. Its response is then copied
				back to the original client unmodified.
				Director must not access the provided Request
				after returning.

			
				ErrorHandler is an optional function that handles errors
				reaching the backend or errors from ModifyResponse.

				If nil, the default is to log the provided error and return
				a 502 Status Bad Gateway response.

			
				ErrorLog specifies an optional logger for errors
				that occur when attempting to proxy the request.
				If nil, logging is done via the log package's standard logger.

			
				FlushInterval specifies the flush interval
				to flush to the client while copying the
				response body.
				If zero, no periodic flushing is done.
				A negative value means to flush immediately
				after each write to the client.
				The FlushInterval is ignored when ReverseProxy
				recognizes a response as a streaming response, or
				if its ContentLength is -1; for such responses, writes
				are flushed to the client immediately.

			
				ModifyResponse is an optional function that modifies the
				Response from the backend. It is called if the backend
				returns a response at all, with any HTTP status code.
				If the backend is unreachable, the optional ErrorHandler is
				called without any call to ModifyResponse.

				If ModifyResponse returns an error, ErrorHandler is called
				with its error value. If ErrorHandler is nil, its default
				implementation is used.

			
				The transport used to perform proxy requests.
				If nil, http.DefaultTransport is used.

		
			(*T) ServeHTTP(rw http.ResponseWriter, req *http.Request)
			
		
			*T : net/http.Handler
		
			func NewSingleHostReverseProxy(target *url.URL) *ReverseProxy


	
		ServerConn is an artifact of Go's early HTTP implementation.
		It is low-level, old, and unused by Go's current HTTP stack.
		We should have deleted it before Go 1.

		Deprecated: Use the Server in package net/http instead.

		
			
		
			
				Close calls Hijack and then also closes the underlying connection.

			
				Hijack detaches the ServerConn and returns the underlying connection as well
				as the read-side bufio which may have some left over data. Hijack may be
				called before Read has signaled the end of the keep-alive logic. The user
				should not call Hijack while Read or Write is in progress.

			
				Pending returns the number of unanswered requests
				that have been received on the connection.

			
				Read returns the next request on the wire. An ErrPersistEOF is returned if
				it is gracefully determined that there are no more requests (e.g. after the
				first request on an HTTP/1.0 connection, or after a Connection:close on a
				HTTP/1.1 connection).

			
				Write writes resp in response to req. To close the connection gracefully, set the
				Response.Close field to true. Write should be considered operational until
				it returns an error, regardless of any errors returned on the Read side.

		
			*T : io.Closer
		
			func NewServerConn(c net.Conn, r *bufio.Reader) *ServerConn


	


Package-Level Functions (total 18, in which 9 are exported)


	
		DumpRequest returns the given request in its HTTP/1.x wire
		representation. It should only be used by servers to debug client
		requests. The returned representation is an approximation only;
		some details of the initial request are lost while parsing it into
		an http.Request. In particular, the order and case of header field
		names are lost. The order of values in multi-valued headers is kept
		intact. HTTP/2 requests are dumped in HTTP/1.x form, not in their
		original binary representations.

		If body is true, DumpRequest also returns the body. To do so, it
		consumes req.Body and then replaces it with a new io.ReadCloser
		that yields the same bytes. If DumpRequest returns an error,
		the state of req is undefined.

		The documentation for http.Request.Write details which fields
		of req are included in the dump.


	
		DumpRequestOut is like DumpRequest but for outgoing client requests. It
		includes any headers that the standard http.Transport adds, such as
		User-Agent.


	
		DumpResponse is like DumpRequest but dumps a response.


	
		NewChunkedReader returns a new chunkedReader that translates the data read from r
		out of HTTP "chunked" format before returning it.
		The chunkedReader returns io.EOF when the final 0-length chunk is read.

		NewChunkedReader is not needed by normal applications. The http package
		automatically decodes chunking when reading response bodies.


	
		NewChunkedWriter returns a new chunkedWriter that translates writes into HTTP
		"chunked" format before writing them to w. Closing the returned chunkedWriter
		sends the final 0-length chunk that marks the end of the stream but does
		not send the final CRLF that appears after trailers; trailers and the last
		CRLF must be written separately.

		NewChunkedWriter is not needed by normal applications. The http
		package adds chunking automatically if handlers don't set a
		Content-Length header. Using NewChunkedWriter inside a handler
		would result in double chunking or chunking with a Content-Length
		length, both of which are wrong.


	
		NewClientConn is an artifact of Go's early HTTP implementation.
		It is low-level, old, and unused by Go's current HTTP stack.
		We should have deleted it before Go 1.

		Deprecated: Use the Client or Transport in package net/http instead.


	
		NewProxyClientConn is an artifact of Go's early HTTP implementation.
		It is low-level, old, and unused by Go's current HTTP stack.
		We should have deleted it before Go 1.

		Deprecated: Use the Client or Transport in package net/http instead.


	
		NewServerConn is an artifact of Go's early HTTP implementation.
		It is low-level, old, and unused by Go's current HTTP stack.
		We should have deleted it before Go 1.

		Deprecated: Use the Server in package net/http instead.


	
		NewSingleHostReverseProxy returns a new ReverseProxy that routes
		URLs to the scheme, host, and base path provided in target. If the
		target's path is "/base" and the incoming request was for "/dir",
		the target request will be for /base/dir.
		NewSingleHostReverseProxy does not rewrite the Host header.
		To rewrite Host headers, use ReverseProxy directly with a custom
		Director policy.


	


Package-Level Variables (total 10, in which 4 are exported)


	
		Deprecated: No longer used.


	
		ErrLineTooLong is returned when reading malformed chunked data
		with lines that are too long.


	
		Deprecated: No longer used.


	
		Deprecated: No longer used.