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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// HTTP Request reading and parsing.
package http
import (
"bufio"
"bytes"
"context"
"crypto/tls"
"encoding/base64"
"errors"
"fmt"
"io"
"io/ioutil"
"mime"
"mime/multipart"
"net"
"net/http/httptrace"
"net/textproto"
"net/url"
"strconv"
"strings"
"sync"
"golang.org/x/net/idna"
)
const (
defaultMaxMemory = 32 << 20 // 32 MB
)
// ErrMissingFile is returned by FormFile when the provided file field name
// is either not present in the request or not a file field.
var ErrMissingFile = errors.New("http: no such file")
// ProtocolError represents an HTTP protocol error.
//
// Deprecated: Not all errors in the http package related to protocol errors
// are of type ProtocolError.
type ProtocolError struct {
ErrorString string
}
func (pe *ProtocolError) Error() string { return pe.ErrorString }
var (
// ErrNotSupported is returned by the Push method of Pusher
// implementations to indicate that HTTP/2 Push support is not
// available.
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.
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.
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 no longer returned by
// anything in the net/http package. Callers should not
// compare errors against this variable.
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.
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.
ErrMissingContentLength = &ProtocolError{"missing ContentLength in HEAD response"}
)
type badStringError struct {
what string
str string
}
func (e *badStringError) Error() string { return fmt.Sprintf("%s %q", e.what, e.str) }
// Headers that Request.Write handles itself and should be skipped.
var reqWriteExcludeHeader = map[string]bool{
"Host": true, // not in Header map anyway
"User-Agent": true,
"Content-Length": true,
"Transfer-Encoding": true,
"Trailer": true,
}
// A Request represents an HTTP request received by a server
// or to be sent by a client.
//
// The field semantics differ slightly between client and server
// usage. In addition to the notes on the fields below, see the
// documentation for Request.Write and RoundTripper.
type Request struct {
// Method specifies the HTTP method (GET, POST, PUT, etc.).
// For client requests, an empty string means GET.
//
// Go's HTTP client does not support sending a request with
// the CONNECT method. See the documentation on Transport for
// details.
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 7230, Section 5.3)
//
// 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 7230, section 5.4, 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.
// To prevent DNS rebinding attacks, server Handlers should
// validate that the Host header has a value for which the
// Handler considers itself authoritative. The included
// ServeMux supports patterns registered to particular host
// names and thus protects its registered Handlers.
//
// 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 PATCH, 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 PATCH, POST
// 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-target of the
// Request-Line (RFC 7230, Section 3.1.1) 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: Set the Request's context with NewRequestWithContext
// 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
// ctx is either the client or server context. It should only
// be modified via copying the whole Request using WithContext.
// It is unexported to prevent people from using Context wrong
// and mutating the contexts held by callers of the same request.
ctx context.Context
}
// Context returns the request's context. To change the context, use
// WithContext.
//
// The returned context is always non-nil; it defaults to the
// background context.
//
// For outgoing client requests, the context controls cancellation.
//
// For incoming server requests, the context is canceled when the
// client's connection closes, the request is canceled (with HTTP/2),
// or when the ServeHTTP method returns.
func (r *Request) Context() context.Context {
if r.ctx != nil {
return r.ctx
}
return context.Background()
}
// WithContext returns a shallow copy of r with its context changed
// to ctx. The provided ctx must be non-nil.
//
// For outgoing client request, the context controls the entire
// lifetime of a request and its response: obtaining a connection,
// sending the request, and reading the response headers and body.
//
// To create a new request with a context, use NewRequestWithContext.
// To change the context of a request (such as an incoming) you then
// also want to modify to send back out, use Request.Clone. Between
// those two uses, it's rare to need WithContext.
func (r *Request) WithContext(ctx context.Context) *Request {
if ctx == nil {
panic("nil context")
}
r2 := new(Request)
*r2 = *r
r2.ctx = ctx
r2.URL = cloneURL(r.URL) // legacy behavior; TODO: try to remove. Issue 23544
return r2
}
// Clone returns a deep copy of r with its context changed to ctx.
// The provided ctx must be non-nil.
//
// For an outgoing client request, the context controls the entire
// lifetime of a request and its response: obtaining a connection,
// sending the request, and reading the response headers and body.
func (r *Request) Clone(ctx context.Context) *Request {
if ctx == nil {
panic("nil context")
}
r2 := new(Request)
*r2 = *r
r2.ctx = ctx
r2.URL = cloneURL(r.URL)
if r.Header != nil {
r2.Header = r.Header.Clone()
}
if r.Trailer != nil {
r2.Trailer = r.Trailer.Clone()
}
if s := r.TransferEncoding; s != nil {
s2 := make([]string, len(s))
copy(s2, s)
r2.TransferEncoding = s
}
r2.Form = cloneURLValues(r.Form)
r2.PostForm = cloneURLValues(r.PostForm)
r2.MultipartForm = cloneMultipartForm(r.MultipartForm)
return r2
}
// ProtoAtLeast reports whether the HTTP protocol used
// in the request is at least major.minor.
func (r *Request) ProtoAtLeast(major, minor int) bool {
return r.ProtoMajor > major ||
r.ProtoMajor == major && r.ProtoMinor >= minor
}
// UserAgent returns the client's User-Agent, if sent in the request.
func (r *Request) UserAgent() string {
return r.Header.Get("User-Agent")
}
// Cookies parses and returns the HTTP cookies sent with the request.
func (r *Request) Cookies() []*Cookie {
return readCookies(r.Header, "")
}
// ErrNoCookie is returned by Request's Cookie method when a cookie is not found.
var ErrNoCookie = errors.New("http: named cookie not present")
// Cookie returns the named cookie provided in the request or
// ErrNoCookie if not found.
// If multiple cookies match the given name, only one cookie will
// be returned.
func (r *Request) Cookie(name string) (*Cookie, error) {
for _, c := range readCookies(r.Header, name) {
return c, nil
}
return nil, ErrNoCookie
}
// AddCookie adds a cookie to the request. Per RFC 6265 section 5.4,
// AddCookie does not attach more than one Cookie header field. That
// means all cookies, if any, are written into the same line,
// separated by semicolon.
func (r *Request) AddCookie(c *Cookie) {
s := fmt.Sprintf("%s=%s", sanitizeCookieName(c.Name), sanitizeCookieValue(c.Value))
if c := r.Header.Get("Cookie"); c != "" {
r.Header.Set("Cookie", c+"; "+s)
} else {
r.Header.Set("Cookie", s)
}
}
// Referer returns the referring URL, if sent in the request.
//
// Referer is misspelled as in the request itself, a mistake from the
// earliest days of HTTP. This value can also be fetched from the
// Header map as Header["Referer"]; the benefit of making it available
// as a method is that the compiler can diagnose programs that use the
// alternate (correct English) spelling req.Referrer() but cannot
// diagnose programs that use Header["Referrer"].
func (r *Request) Referer() string {
return r.Header.Get("Referer")
}
// multipartByReader is a sentinel value.
// Its presence in Request.MultipartForm indicates that parsing of the request
// body has been handed off to a MultipartReader instead of ParseMultipartForm.
var multipartByReader = &multipart.Form{
Value: make(map[string][]string),
File: make(map[string][]*multipart.FileHeader),
}
// MultipartReader returns a MIME multipart reader if this is a
// multipart/form-data or a multipart/mixed POST request, else returns nil and an error.
// Use this function instead of ParseMultipartForm to
// process the request body as a stream.
func (r *Request) MultipartReader() (*multipart.Reader, error) {
if r.MultipartForm == multipartByReader {
return nil, errors.New("http: MultipartReader called twice")
}
if r.MultipartForm != nil {
return nil, errors.New("http: multipart handled by ParseMultipartForm")
}
r.MultipartForm = multipartByReader
return r.multipartReader(true)
}
func (r *Request) multipartReader(allowMixed bool) (*multipart.Reader, error) {
v := r.Header.Get("Content-Type")
if v == "" {
return nil, ErrNotMultipart
}
d, params, err := mime.ParseMediaType(v)
if err != nil || !(d == "multipart/form-data" || allowMixed && d == "multipart/mixed") {
return nil, ErrNotMultipart
}
boundary, ok := params["boundary"]
if !ok {
return nil, ErrMissingBoundary
}
return multipart.NewReader(r.Body, boundary), nil
}
// isH2Upgrade reports whether r represents the http2 "client preface"
// magic string.
func (r *Request) isH2Upgrade() bool {
return r.Method == "PRI" && len(r.Header) == 0 && r.URL.Path == "*" && r.Proto == "HTTP/2.0"
}
// Return value if nonempty, def otherwise.
func valueOrDefault(value, def string) string {
if value != "" {
return value
}
return def
}
// NOTE: This is not intended to reflect the actual Go version being used.
// It was changed at the time of Go 1.1 release because the former User-Agent
// had ended up on a blacklist for some intrusion detection systems.
// See https://codereview.appspot.com/7532043.
const defaultUserAgent = "Go-http-client/1.1"
// Write writes an HTTP/1.1 request, which is the header and body, in wire format.
// This method consults the following fields of the request:
// Host
// URL
// Method (defaults to "GET")
// Header
// ContentLength
// TransferEncoding
// Body
//
// If Body is present, Content-Length is <= 0 and TransferEncoding
// hasn't been set to "identity", Write adds "Transfer-Encoding:
// chunked" to the header. Body is closed after it is sent.
func (r *Request) Write(w io.Writer) error {
return r.write(w, false, nil, nil)
}
// WriteProxy is like Write but writes the request in the form
// expected by an HTTP proxy. In particular, WriteProxy writes the
// initial Request-URI line of the request with an absolute URI, per
// section 5.3 of RFC 7230, including the scheme and host.
// In either case, WriteProxy also writes a Host header, using
// either r.Host or r.URL.Host.
func (r *Request) WriteProxy(w io.Writer) error {
return r.write(w, true, nil, nil)
}
// errMissingHost is returned by Write when there is no Host or URL present in
// the Request.
var errMissingHost = errors.New("http: Request.Write on Request with no Host or URL set")
// extraHeaders may be nil
// waitForContinue may be nil
func (r *Request) write(w io.Writer, usingProxy bool, extraHeaders Header, waitForContinue func() bool) (err error) {
trace := httptrace.ContextClientTrace(r.Context())
if trace != nil && trace.WroteRequest != nil {
defer func() {
trace.WroteRequest(httptrace.WroteRequestInfo{
Err: err,
})
}()
}
// Find the target host. Prefer the Host: header, but if that
// is not given, use the host from the request URL.
//
// Clean the host, in case it arrives with unexpected stuff in it.
host := cleanHost(r.Host)
if host == "" {
if r.URL == nil {
return errMissingHost
}
host = cleanHost(r.URL.Host)
}
// According to RFC 6874, an HTTP client, proxy, or other
// intermediary must remove any IPv6 zone identifier attached
// to an outgoing URI.
host = removeZone(host)
ruri := r.URL.RequestURI()
if usingProxy && r.URL.Scheme != "" && r.URL.Opaque == "" {
ruri = r.URL.Scheme + "://" + host + ruri
} else if r.Method == "CONNECT" && r.URL.Path == "" {
// CONNECT requests normally give just the host and port, not a full URL.
ruri = host
if r.URL.Opaque != "" {
ruri = r.URL.Opaque
}
}
if stringContainsCTLByte(ruri) {
return errors.New("net/http: can't write control character in Request.URL")
}
// TODO: validate r.Method too? At least it's less likely to
// come from an attacker (more likely to be a constant in
// code).
// Wrap the writer in a bufio Writer if it's not already buffered.
// Don't always call NewWriter, as that forces a bytes.Buffer
// and other small bufio Writers to have a minimum 4k buffer
// size.
var bw *bufio.Writer
if _, ok := w.(io.ByteWriter); !ok {
bw = bufio.NewWriter(w)
w = bw
}
_, err = fmt.Fprintf(w, "%s %s HTTP/1.1\r\n", valueOrDefault(r.Method, "GET"), ruri)
if err != nil {
return err
}
// Header lines
_, err = fmt.Fprintf(w, "Host: %s\r\n", host)
if err != nil {
return err
}
if trace != nil && trace.WroteHeaderField != nil {
trace.WroteHeaderField("Host", []string{host})
}
// Use the defaultUserAgent unless the Header contains one, which
// may be blank to not send the header.
userAgent := defaultUserAgent
if r.Header.has("User-Agent") {
userAgent = r.Header.Get("User-Agent")
}
if userAgent != "" {
_, err = fmt.Fprintf(w, "User-Agent: %s\r\n", userAgent)
if err != nil {
return err
}
if trace != nil && trace.WroteHeaderField != nil {
trace.WroteHeaderField("User-Agent", []string{userAgent})
}
}
// Process Body,ContentLength,Close,Trailer
tw, err := newTransferWriter(r)
if err != nil {
return err
}
err = tw.writeHeader(w, trace)
if err != nil {
return err
}
err = r.Header.writeSubset(w, reqWriteExcludeHeader, trace)
if err != nil {
return err
}
if extraHeaders != nil {
err = extraHeaders.write(w, trace)
if err != nil {
return err
}
}
_, err = io.WriteString(w, "\r\n")
if err != nil {
return err
}
if trace != nil && trace.WroteHeaders != nil {
trace.WroteHeaders()
}
// Flush and wait for 100-continue if expected.
if waitForContinue != nil {
if bw, ok := w.(*bufio.Writer); ok {
err = bw.Flush()
if err != nil {
return err
}
}
if trace != nil && trace.Wait100Continue != nil {
trace.Wait100Continue()
}
if !waitForContinue() {
r.closeBody()
return nil
}
}
if bw, ok := w.(*bufio.Writer); ok && tw.FlushHeaders {
if err := bw.Flush(); err != nil {
return err
}
}
// Write body and trailer
err = tw.writeBody(w)
if err != nil {
if tw.bodyReadError == err {
err = requestBodyReadError{err}
}
return err
}
if bw != nil {
return bw.Flush()
}
return nil
}
// requestBodyReadError wraps an error from (*Request).write to indicate
// that the error came from a Read call on the Request.Body.
// This error type should not escape the net/http package to users.
type requestBodyReadError struct{ error }
func idnaASCII(v string) (string, error) {
// TODO: Consider removing this check after verifying performance is okay.
// Right now punycode verification, length checks, context checks, and the
// permissible character tests are all omitted. It also prevents the ToASCII
// call from salvaging an invalid IDN, when possible. As a result it may be
// possible to have two IDNs that appear identical to the user where the
// ASCII-only version causes an error downstream whereas the non-ASCII
// version does not.
// Note that for correct ASCII IDNs ToASCII will only do considerably more
// work, but it will not cause an allocation.
if isASCII(v) {
return v, nil
}
return idna.Lookup.ToASCII(v)
}
// cleanHost cleans up the host sent in request's Host header.
//
// It both strips anything after '/' or ' ', and puts the value
// into Punycode form, if necessary.
//
// Ideally we'd clean the Host header according to the spec:
// https://tools.ietf.org/html/rfc7230#section-5.4 (Host = uri-host [ ":" port ]")
// https://tools.ietf.org/html/rfc7230#section-2.7 (uri-host -> rfc3986's host)
// https://tools.ietf.org/html/rfc3986#section-3.2.2 (definition of host)
// But practically, what we are trying to avoid is the situation in
// issue 11206, where a malformed Host header used in the proxy context
// would create a bad request. So it is enough to just truncate at the
// first offending character.
func cleanHost(in string) string {
if i := strings.IndexAny(in, " /"); i != -1 {
in = in[:i]
}
host, port, err := net.SplitHostPort(in)
if err != nil { // input was just a host
a, err := idnaASCII(in)
if err != nil {
return in // garbage in, garbage out
}
return a
}
a, err := idnaASCII(host)
if err != nil {
return in // garbage in, garbage out
}
return net.JoinHostPort(a, port)
}
// removeZone removes IPv6 zone identifier from host.
// E.g., "[fe80::1%en0]:8080" to "[fe80::1]:8080"
func removeZone(host string) string {
if !strings.HasPrefix(host, "[") {
return host
}
i := strings.LastIndex(host, "]")
if i < 0 {
return host
}
j := strings.LastIndex(host[:i], "%")
if j < 0 {
return host
}
return host[:j] + host[i:]
}
// ParseHTTPVersion parses a HTTP version string.
// "HTTP/1.0" returns (1, 0, true).
func ParseHTTPVersion(vers string) (major, minor int, ok bool) {
const Big = 1000000 // arbitrary upper bound
switch vers {
case "HTTP/1.1":
return 1, 1, true
case "HTTP/1.0":
return 1, 0, true
}
if !strings.HasPrefix(vers, "HTTP/") {
return 0, 0, false
}
dot := strings.Index(vers, ".")
if dot < 0 {
return 0, 0, false
}
major, err := strconv.Atoi(vers[5:dot])
if err != nil || major < 0 || major > Big {
return 0, 0, false
}
minor, err = strconv.Atoi(vers[dot+1:])
if err != nil || minor < 0 || minor > Big {
return 0, 0, false
}
return major, minor, true
}
func validMethod(method string) bool {
/*
Method = "OPTIONS" ; Section 9.2
| "GET" ; Section 9.3
| "HEAD" ; Section 9.4
| "POST" ; Section 9.5
| "PUT" ; Section 9.6
| "DELETE" ; Section 9.7
| "TRACE" ; Section 9.8
| "CONNECT" ; Section 9.9
| extension-method
extension-method = token
token = 1*<any CHAR except CTLs or separators>
*/
return len(method) > 0 && strings.IndexFunc(method, isNotToken) == -1
}
// NewRequest wraps NewRequestWithContext using the background context.
func NewRequest(method, url string, body io.Reader) (*Request, error) {
return NewRequestWithContext(context.Background(), method, url, body)
}
// NewRequestWithContext returns a new Request given a method, URL, and
// optional body.
//
// If the provided body is also an io.Closer, the returned
// Request.Body is set to body and will be closed by the Client
// methods Do, Post, and PostForm, and Transport.RoundTrip.
//
// NewRequestWithContext returns a Request suitable for use with
// Client.Do or Transport.RoundTrip. To create a request for use with
// testing a Server Handler, either use the NewRequest function in the
// net/http/httptest package, use ReadRequest, or manually update the
// Request fields. For an outgoing client request, the context
// controls the entire lifetime of a request and its response:
// obtaining a connection, sending the request, and reading the
// response headers and body. See the Request type's documentation for
// the difference between inbound and outbound request fields.
//
// If body is of type *bytes.Buffer, *bytes.Reader, or
// *strings.Reader, the returned request's ContentLength is set to its
// exact value (instead of -1), GetBody is populated (so 307 and 308
// redirects can replay the body), and Body is set to NoBody if the
// ContentLength is 0.
func NewRequestWithContext(ctx context.Context, method, url string, body io.Reader) (*Request, error) {
if method == "" {
// We document that "" means "GET" for Request.Method, and people have
// relied on that from NewRequest, so keep that working.
// We still enforce validMethod for non-empty methods.
method = "GET"
}
if !validMethod(method) {
return nil, fmt.Errorf("net/http: invalid method %q", method)
}
if ctx == nil {
return nil, errors.New("net/http: nil Context")
}
u, err := parseURL(url) // Just url.Parse (url is shadowed for godoc).
if err != nil {
return nil, err
}
rc, ok := body.(io.ReadCloser)
if !ok && body != nil {
rc = ioutil.NopCloser(body)
}
// The host's colon:port should be normalized. See Issue 14836.
u.Host = removeEmptyPort(u.Host)
req := &Request{
ctx: ctx,
Method: method,
URL: u,
Proto: "HTTP/1.1",
ProtoMajor: 1,
ProtoMinor: 1,
Header: make(Header),
Body: rc,
Host: u.Host,
}
if body != nil {
switch v := body.(type) {
case *bytes.Buffer:
req.ContentLength = int64(v.Len())
buf := v.Bytes()
req.GetBody = func() (io.ReadCloser, error) {
r := bytes.NewReader(buf)
return ioutil.NopCloser(r), nil
}
case *bytes.Reader:
req.ContentLength = int64(v.Len())
snapshot := *v
req.GetBody = func() (io.ReadCloser, error) {
r := snapshot
return ioutil.NopCloser(&r), nil
}
case *strings.Reader:
req.ContentLength = int64(v.Len())
snapshot := *v
req.GetBody = func() (io.ReadCloser, error) {
r := snapshot
return ioutil.NopCloser(&r), nil
}
default:
// This is where we'd set it to -1 (at least
// if body != NoBody) to mean unknown, but
// that broke people during the Go 1.8 testing
// period. People depend on it being 0 I
// guess. Maybe retry later. See Issue 18117.
}
// For client requests, Request.ContentLength of 0
// means either actually 0, or unknown. The only way
// to explicitly say that the ContentLength is zero is
// to set the Body to nil. But turns out too much code
// depends on NewRequest returning a non-nil Body,
// so we use a well-known ReadCloser variable instead
// and have the http package also treat that sentinel
// variable to mean explicitly zero.
if req.GetBody != nil && req.ContentLength == 0 {
req.Body = NoBody
req.GetBody = func() (io.ReadCloser, error) { return NoBody, nil }
}
}
return req, nil
}
// BasicAuth returns the username and password provided in the request's
// Authorization header, if the request uses HTTP Basic Authentication.
// See RFC 2617, Section 2.
func (r *Request) BasicAuth() (username, password string, ok bool) {
auth := r.Header.Get("Authorization")
if auth == "" {
return
}
return parseBasicAuth(auth)
}
// parseBasicAuth parses an HTTP Basic Authentication string.
// "Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==" returns ("Aladdin", "open sesame", true).
func parseBasicAuth(auth string) (username, password string, ok bool) {
const prefix = "Basic "
// Case insensitive prefix match. See Issue 22736.
if len(auth) < len(prefix) || !strings.EqualFold(auth[:len(prefix)], prefix) {
return
}
c, err := base64.StdEncoding.DecodeString(auth[len(prefix):])
if err != nil {
return
}
cs := string(c)
s := strings.IndexByte(cs, ':')
if s < 0 {
return
}
return cs[:s], cs[s+1:], true
}
// SetBasicAuth sets the request's Authorization header to use HTTP
// Basic Authentication with the provided username and password.
//
// With HTTP Basic Authentication the provided username and password
// are not encrypted.
//
// Some protocols may impose additional requirements on pre-escaping the
// username and password. For instance, when used with OAuth2, both arguments
// must be URL encoded first with url.QueryEscape.
func (r *Request) SetBasicAuth(username, password string) {
r.Header.Set("Authorization", "Basic "+basicAuth(username, password))
}
// parseRequestLine parses "GET /foo HTTP/1.1" into its three parts.
func parseRequestLine(line string) (method, requestURI, proto string, ok bool) {
s1 := strings.Index(line, " ")
s2 := strings.Index(line[s1+1:], " ")
if s1 < 0 || s2 < 0 {
return
}
s2 += s1 + 1
return line[:s1], line[s1+1 : s2], line[s2+1:], true
}
var textprotoReaderPool sync.Pool
func newTextprotoReader(br *bufio.Reader) *textproto.Reader {
if v := textprotoReaderPool.Get(); v != nil {
tr := v.(*textproto.Reader)
tr.R = br
return tr
}
return textproto.NewReader(br)
}
func putTextprotoReader(r *textproto.Reader) {
r.R = nil
textprotoReaderPool.Put(r)
}
// ReadRequest reads and parses an incoming request from b.
//
// ReadRequest is a low-level function and should only be used for
// specialized applications; most code should use the Server to read
// requests and handle them via the Handler interface. ReadRequest
// only supports HTTP/1.x requests. For HTTP/2, use golang.org/x/net/http2.
func ReadRequest(b *bufio.Reader) (*Request, error) {
return readRequest(b, deleteHostHeader)
}
// Constants for readRequest's deleteHostHeader parameter.
const (
deleteHostHeader = true
keepHostHeader = false
)
func readRequest(b *bufio.Reader, deleteHostHeader bool) (req *Request, err error) {
tp := newTextprotoReader(b)
req = new(Request)
// First line: GET /index.html HTTP/1.0
var s string
if s, err = tp.ReadLine(); err != nil {
return nil, err
}
defer func() {
putTextprotoReader(tp)
if err == io.EOF {
err = io.ErrUnexpectedEOF
}
}()
var ok bool
req.Method, req.RequestURI, req.Proto, ok = parseRequestLine(s)
if !ok {
return nil, &badStringError{"malformed HTTP request", s}
}
if !validMethod(req.Method) {
return nil, &badStringError{"invalid method", req.Method}
}
rawurl := req.RequestURI
if req.ProtoMajor, req.ProtoMinor, ok = ParseHTTPVersion(req.Proto); !ok {
return nil, &badStringError{"malformed HTTP version", req.Proto}
}
// CONNECT requests are used two different ways, and neither uses a full URL:
// The standard use is to tunnel HTTPS through an HTTP proxy.
// It looks like "CONNECT www.google.com:443 HTTP/1.1", and the parameter is
// just the authority section of a URL. This information should go in req.URL.Host.
//
// The net/rpc package also uses CONNECT, but there the parameter is a path
// that starts with a slash. It can be parsed with the regular URL parser,
// and the path will end up in req.URL.Path, where it needs to be in order for
// RPC to work.
justAuthority := req.Method == "CONNECT" && !strings.HasPrefix(rawurl, "/")
if justAuthority {
rawurl = "http://" + rawurl
}
if req.URL, err = url.ParseRequestURI(rawurl); err != nil {
return nil, err
}
if justAuthority {
// Strip the bogus "http://" back off.
req.URL.Scheme = ""
}
// Subsequent lines: Key: value.
mimeHeader, err := tp.ReadMIMEHeader()
if err != nil {
return nil, err
}
req.Header = Header(mimeHeader)
// RFC 7230, section 5.3: Must treat
// GET /index.html HTTP/1.1
// Host: www.google.com
// and
// GET http://www.google.com/index.html HTTP/1.1
// Host: doesntmatter
// the same. In the second case, any Host line is ignored.
req.Host = req.URL.Host
if req.Host == "" {
req.Host = req.Header.get("Host")
}
if deleteHostHeader {
delete(req.Header, "Host")
}
fixPragmaCacheControl(req.Header)
req.Close = shouldClose(req.ProtoMajor, req.ProtoMinor, req.Header, false)
err = readTransfer(req, b)
if err != nil {
return nil, err
}
if req.isH2Upgrade() {
// Because it's neither chunked, nor declared:
req.ContentLength = -1
// We want to give handlers a chance to hijack the
// connection, but we need to prevent the Server from
// dealing with the connection further if it's not
// hijacked. Set Close to ensure that:
req.Close = true
}
return req, nil
}
// 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-EOF error for a Read beyond the limit, and closes the
// underlying reader when its Close method is called.
//
// MaxBytesReader prevents clients from accidentally or maliciously
// sending a large request and wasting server resources.
func MaxBytesReader(w ResponseWriter, r io.ReadCloser, n int64) io.ReadCloser {
return &maxBytesReader{w: w, r: r, n: n}
}
type maxBytesReader struct {
w ResponseWriter
r io.ReadCloser // underlying reader
n int64 // max bytes remaining
err error // sticky error
}
func (l *maxBytesReader) Read(p []byte) (n int, err error) {
if l.err != nil {
return 0, l.err
}
if len(p) == 0 {
return 0, nil
}
// If they asked for a 32KB byte read but only 5 bytes are
// remaining, no need to read 32KB. 6 bytes will answer the
// question of the whether we hit the limit or go past it.
if int64(len(p)) > l.n+1 {
p = p[:l.n+1]
}
n, err = l.r.Read(p)
if int64(n) <= l.n {
l.n -= int64(n)
l.err = err
return n, err
}
n = int(l.n)
l.n = 0
// The server code and client code both use
// maxBytesReader. This "requestTooLarge" check is
// only used by the server code. To prevent binaries
// which only using the HTTP Client code (such as
// cmd/go) from also linking in the HTTP server, don't
// use a static type assertion to the server
// "*response" type. Check this interface instead:
type requestTooLarger interface {
requestTooLarge()
}
if res, ok := l.w.(requestTooLarger); ok {
res.requestTooLarge()
}
l.err = errors.New("http: request body too large")
return n, l.err
}
func (l *maxBytesReader) Close() error {
return l.r.Close()
}
func copyValues(dst, src url.Values) {
for k, vs := range src {
for _, value := range vs {
dst.Add(k, value)
}
}
}
func parsePostForm(r *Request) (vs url.Values, err error) {
if r.Body == nil {
err = errors.New("missing form body")
return
}
ct := r.Header.Get("Content-Type")
// RFC 7231, section 3.1.1.5 - empty type
// MAY be treated as application/octet-stream
if ct == "" {
ct = "application/octet-stream"
}
ct, _, err = mime.ParseMediaType(ct)
switch {
case ct == "application/x-www-form-urlencoded":
var reader io.Reader = r.Body
maxFormSize := int64(1<<63 - 1)
if _, ok := r.Body.(*maxBytesReader); !ok {
maxFormSize = int64(10 << 20) // 10 MB is a lot of text.
reader = io.LimitReader(r.Body, maxFormSize+1)
}
b, e := ioutil.ReadAll(reader)
if e != nil {
if err == nil {
err = e
}
break
}
if int64(len(b)) > maxFormSize {
err = errors.New("http: POST too large")
return
}
vs, e = url.ParseQuery(string(b))
if err == nil {
err = e
}
case ct == "multipart/form-data":
// handled by ParseMultipartForm (which is calling us, or should be)
// TODO(bradfitz): there are too many possible
// orders to call too many functions here.
// Clean this up and write more tests.
// request_test.go contains the start of this,
// in TestParseMultipartFormOrder and others.
}
return
}
// ParseForm populates r.Form and r.PostForm.
//
// For all requests, ParseForm parses the raw query from the URL and updates
// r.Form.
//
// For POST, PUT, and PATCH requests, it also parses the request body as a form
// and puts the results into both r.PostForm and r.Form. Request body parameters
// take precedence over URL query string values in r.Form.
//
// For other HTTP methods, or when the Content-Type is not
// application/x-www-form-urlencoded, the request Body is not read, and
// r.PostForm is initialized to a non-nil, empty value.
//
// If the request Body's size has not already been limited by MaxBytesReader,
// the size is capped at 10MB.
//
// ParseMultipartForm calls ParseForm automatically.
// ParseForm is idempotent.
func (r *Request) ParseForm() error {
var err error
if r.PostForm == nil {
if r.Method == "POST" || r.Method == "PUT" || r.Method == "PATCH" {
r.PostForm, err = parsePostForm(r)
}
if r.PostForm == nil {
r.PostForm = make(url.Values)
}
}
if r.Form == nil {
if len(r.PostForm) > 0 {
r.Form = make(url.Values)
copyValues(r.Form, r.PostForm)
}
var newValues url.Values
if r.URL != nil {
var e error
newValues, e = url.ParseQuery(r.URL.RawQuery)
if err == nil {
err = e
}
}
if newValues == nil {
newValues = make(url.Values)
}
if r.Form == nil {
r.Form = newValues
} else {
copyValues(r.Form, newValues)
}
}
return err
}
// ParseMultipartForm parses a request body as multipart/form-data.
// The whole request body is parsed and up to a total of maxMemory bytes of
// its file parts are stored in memory, with the remainder stored on
// disk in temporary files.
// ParseMultipartForm calls ParseForm if necessary.
// After one call to ParseMultipartForm, subsequent calls have no effect.
func (r *Request) ParseMultipartForm(maxMemory int64) error {
if r.MultipartForm == multipartByReader {
return errors.New("http: multipart handled by MultipartReader")
}
if r.Form == nil {
err := r.ParseForm()
if err != nil {
return err
}
}
if r.MultipartForm != nil {
return nil
}
mr, err := r.multipartReader(false)
if err != nil {
return err
}
f, err := mr.ReadForm(maxMemory)
if err != nil {
return err
}
if r.PostForm == nil {
r.PostForm = make(url.Values)
}
for k, v := range f.Value {
r.Form[k] = append(r.Form[k], v...)
// r.PostForm should also be populated. See Issue 9305.
r.PostForm[k] = append(r.PostForm[k], v...)
}
r.MultipartForm = f
return nil
}
// FormValue returns the first value for the named component of the query.
// POST and PUT body parameters take precedence over URL query string values.
// FormValue calls ParseMultipartForm and ParseForm if necessary and ignores
// any errors returned by these functions.
// If key is not present, FormValue returns the empty string.
// To access multiple values of the same key, call ParseForm and
// then inspect Request.Form directly.
func (r *Request) FormValue(key string) string {
if r.Form == nil {
r.ParseMultipartForm(defaultMaxMemory)
}
if vs := r.Form[key]; len(vs) > 0 {
return vs[0]
}
return ""
}
// PostFormValue returns the first value for the named component of the POST,
// PATCH, or PUT request body. URL query parameters are ignored.
// PostFormValue calls ParseMultipartForm and ParseForm if necessary and ignores
// any errors returned by these functions.
// If key is not present, PostFormValue returns the empty string.
func (r *Request) PostFormValue(key string) string {
if r.PostForm == nil {
r.ParseMultipartForm(defaultMaxMemory)
}
if vs := r.PostForm[key]; len(vs) > 0 {
return vs[0]
}
return ""
}
// FormFile returns the first file for the provided form key.
// FormFile calls ParseMultipartForm and ParseForm if necessary.
func (r *Request) FormFile(key string) (multipart.File, *multipart.FileHeader, error) {
if r.MultipartForm == multipartByReader {
return nil, nil, errors.New("http: multipart handled by MultipartReader")
}
if r.MultipartForm == nil {
err := r.ParseMultipartForm(defaultMaxMemory)
if err != nil {
return nil, nil, err
}
}
if r.MultipartForm != nil && r.MultipartForm.File != nil {
if fhs := r.MultipartForm.File[key]; len(fhs) > 0 {
f, err := fhs[0].Open()
return f, fhs[0], err
}
}
return nil, nil, ErrMissingFile
}
func (r *Request) expectsContinue() bool {
return hasToken(r.Header.get("Expect"), "100-continue")
}
func (r *Request) wantsHttp10KeepAlive() bool {
if r.ProtoMajor != 1 || r.ProtoMinor != 0 {
return false
}
return hasToken(r.Header.get("Connection"), "keep-alive")
}
func (r *Request) wantsClose() bool {
if r.Close {
return true
}
return hasToken(r.Header.get("Connection"), "close")
}
func (r *Request) closeBody() {
if r.Body != nil {
r.Body.Close()
}
}
func (r *Request) isReplayable() bool {
if r.Body == nil || r.Body == NoBody || r.GetBody != nil {
switch valueOrDefault(r.Method, "GET") {
case "GET", "HEAD", "OPTIONS", "TRACE":
return true
}
// The Idempotency-Key, while non-standard, is widely used to
// mean a POST or other request is idempotent. See
// https://golang.org/issue/19943#issuecomment-421092421
if r.Header.has("Idempotency-Key") || r.Header.has("X-Idempotency-Key") {
return true
}
}
return false
}
// outgoingLength reports the Content-Length of this outgoing (Client) request.
// It maps 0 into -1 (unknown) when the Body is non-nil.
func (r *Request) outgoingLength() int64 {
if r.Body == nil || r.Body == NoBody {
return 0
}
if r.ContentLength != 0 {
return r.ContentLength
}
return -1
}
// requestMethodUsuallyLacksBody reports whether the given request
// method is one that typically does not involve a request body.
// This is used by the Transport (via
// transferWriter.shouldSendChunkedRequestBody) to determine whether
// we try to test-read a byte from a non-nil Request.Body when
// Request.outgoingLength() returns -1. See the comments in
// shouldSendChunkedRequestBody.
func requestMethodUsuallyLacksBody(method string) bool {
switch method {
case "GET", "HEAD", "DELETE", "OPTIONS", "PROPFIND", "SEARCH":
return true
}
return false
}
// requiresHTTP1 reports whether this request requires being sent on
// an HTTP/1 connection.
func (r *Request) requiresHTTP1() bool {
return hasToken(r.Header.Get("Connection"), "upgrade") &&
strings.EqualFold(r.Header.Get("Upgrade"), "websocket")
}
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