Source file src/net/http/request.go
1 // Copyright 2009 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 // HTTP Request reading and parsing. 6 7 package http 8 9 import ( 10 "bufio" 11 "bytes" 12 "context" 13 "crypto/tls" 14 "encoding/base64" 15 "errors" 16 "fmt" 17 "io" 18 "maps" 19 "mime" 20 "mime/multipart" 21 "net/http/httptrace" 22 "net/http/internal/ascii" 23 "net/textproto" 24 "net/url" 25 urlpkg "net/url" 26 "strconv" 27 "strings" 28 "sync" 29 _ "unsafe" // for linkname 30 31 "golang.org/x/net/http/httpguts" 32 "golang.org/x/net/idna" 33 ) 34 35 const ( 36 defaultMaxMemory = 32 << 20 // 32 MB 37 ) 38 39 // ErrMissingFile is returned by FormFile when the provided file field name 40 // is either not present in the request or not a file field. 41 var ErrMissingFile = errors.New("http: no such file") 42 43 // ProtocolError represents an HTTP protocol error. 44 // 45 // Deprecated: Not all errors in the http package related to protocol errors 46 // are of type ProtocolError. 47 type ProtocolError struct { 48 ErrorString string 49 } 50 51 func (pe *ProtocolError) Error() string { return pe.ErrorString } 52 53 // Is lets http.ErrNotSupported match errors.ErrUnsupported. 54 func (pe *ProtocolError) Is(err error) bool { 55 return pe == ErrNotSupported && err == errors.ErrUnsupported 56 } 57 58 var ( 59 // ErrNotSupported indicates that a feature is not supported. 60 // 61 // It is returned by ResponseController methods to indicate that 62 // the handler does not support the method, and by the Push method 63 // of Pusher implementations to indicate that HTTP/2 Push support 64 // is not available. 65 ErrNotSupported = &ProtocolError{"feature not supported"} 66 67 // Deprecated: ErrUnexpectedTrailer is no longer returned by 68 // anything in the net/http package. Callers should not 69 // compare errors against this variable. 70 ErrUnexpectedTrailer = &ProtocolError{"trailer header without chunked transfer encoding"} 71 72 // ErrMissingBoundary is returned by Request.MultipartReader when the 73 // request's Content-Type does not include a "boundary" parameter. 74 ErrMissingBoundary = &ProtocolError{"no multipart boundary param in Content-Type"} 75 76 // ErrNotMultipart is returned by Request.MultipartReader when the 77 // request's Content-Type is not multipart/form-data. 78 ErrNotMultipart = &ProtocolError{"request Content-Type isn't multipart/form-data"} 79 80 // Deprecated: ErrHeaderTooLong is no longer returned by 81 // anything in the net/http package. Callers should not 82 // compare errors against this variable. 83 ErrHeaderTooLong = &ProtocolError{"header too long"} 84 85 // Deprecated: ErrShortBody is no longer returned by 86 // anything in the net/http package. Callers should not 87 // compare errors against this variable. 88 ErrShortBody = &ProtocolError{"entity body too short"} 89 90 // Deprecated: ErrMissingContentLength is no longer returned by 91 // anything in the net/http package. Callers should not 92 // compare errors against this variable. 93 ErrMissingContentLength = &ProtocolError{"missing ContentLength in HEAD response"} 94 ) 95 96 func badStringError(what, val string) error { return fmt.Errorf("%s %q", what, val) } 97 98 // Headers that Request.Write handles itself and should be skipped. 99 var reqWriteExcludeHeader = map[string]bool{ 100 "Host": true, // not in Header map anyway 101 "User-Agent": true, 102 "Content-Length": true, 103 "Transfer-Encoding": true, 104 "Trailer": true, 105 } 106 107 // A Request represents an HTTP request received by a server 108 // or to be sent by a client. 109 // 110 // The field semantics differ slightly between client and server 111 // usage. In addition to the notes on the fields below, see the 112 // documentation for [Request.Write] and [RoundTripper]. 113 type Request struct { 114 // Method specifies the HTTP method (GET, POST, PUT, etc.). 115 // For client requests, an empty string means GET. 116 Method string 117 118 // URL specifies either the URI being requested (for server 119 // requests) or the URL to access (for client requests). 120 // 121 // For server requests, the URL is parsed from the URI 122 // supplied on the Request-Line as stored in RequestURI. For 123 // most requests, fields other than Path and RawQuery will be 124 // empty. (See RFC 7230, Section 5.3) 125 // 126 // For client requests, the URL's Host specifies the server to 127 // connect to, while the Request's Host field optionally 128 // specifies the Host header value to send in the HTTP 129 // request. 130 URL *url.URL 131 132 // The protocol version for incoming server requests. 133 // 134 // For client requests, these fields are ignored. The HTTP 135 // client code always uses either HTTP/1.1 or HTTP/2. 136 // See the docs on Transport for details. 137 Proto string // "HTTP/1.0" 138 ProtoMajor int // 1 139 ProtoMinor int // 0 140 141 // Header contains the request header fields either received 142 // by the server or to be sent by the client. 143 // 144 // If a server received a request with header lines, 145 // 146 // Host: example.com 147 // accept-encoding: gzip, deflate 148 // Accept-Language: en-us 149 // fOO: Bar 150 // foo: two 151 // 152 // then 153 // 154 // Header = map[string][]string{ 155 // "Accept-Encoding": {"gzip, deflate"}, 156 // "Accept-Language": {"en-us"}, 157 // "Foo": {"Bar", "two"}, 158 // } 159 // 160 // For incoming requests, the Host header is promoted to the 161 // Request.Host field and removed from the Header map. 162 // 163 // HTTP defines that header names are case-insensitive. The 164 // request parser implements this by using CanonicalHeaderKey, 165 // making the first character and any characters following a 166 // hyphen uppercase and the rest lowercase. 167 // 168 // For client requests, certain headers such as Content-Length 169 // and Connection are automatically written when needed and 170 // values in Header may be ignored. See the documentation 171 // for the Request.Write method. 172 Header Header 173 174 // Body is the request's body. 175 // 176 // For client requests, a nil body means the request has no 177 // body, such as a GET request. The HTTP Client's Transport 178 // is responsible for calling the Close method. 179 // 180 // For server requests, the Request Body is always non-nil 181 // but will return EOF immediately when no body is present. 182 // The Server will close the request body. The ServeHTTP 183 // Handler does not need to. 184 // 185 // Body must allow Read to be called concurrently with Close. 186 // In particular, calling Close should unblock a Read waiting 187 // for input. 188 Body io.ReadCloser 189 190 // GetBody defines an optional func to return a new copy of 191 // Body. It is used for client requests when a redirect requires 192 // reading the body more than once. Use of GetBody still 193 // requires setting Body. 194 // 195 // For server requests, it is unused. 196 GetBody func() (io.ReadCloser, error) 197 198 // ContentLength records the length of the associated content. 199 // The value -1 indicates that the length is unknown. 200 // Values >= 0 indicate that the given number of bytes may 201 // be read from Body. 202 // 203 // For client requests, a value of 0 with a non-nil Body is 204 // also treated as unknown. 205 ContentLength int64 206 207 // TransferEncoding lists the transfer encodings from outermost to 208 // innermost. An empty list denotes the "identity" encoding. 209 // TransferEncoding can usually be ignored; chunked encoding is 210 // automatically added and removed as necessary when sending and 211 // receiving requests. 212 TransferEncoding []string 213 214 // Close indicates whether to close the connection after 215 // replying to this request (for servers) or after sending this 216 // request and reading its response (for clients). 217 // 218 // For server requests, the HTTP server handles this automatically 219 // and this field is not needed by Handlers. 220 // 221 // For client requests, setting this field prevents re-use of 222 // TCP connections between requests to the same hosts, as if 223 // Transport.DisableKeepAlives were set. 224 Close bool 225 226 // For server requests, Host specifies the host on which the 227 // URL is sought. For HTTP/1 (per RFC 7230, section 5.4), this 228 // is either the value of the "Host" header or the host name 229 // given in the URL itself. For HTTP/2, it is the value of the 230 // ":authority" pseudo-header field. 231 // It may be of the form "host:port". For international domain 232 // names, Host may be in Punycode or Unicode form. Use 233 // golang.org/x/net/idna to convert it to either format if 234 // needed. 235 // To prevent DNS rebinding attacks, server Handlers should 236 // validate that the Host header has a value for which the 237 // Handler considers itself authoritative. The included 238 // ServeMux supports patterns registered to particular host 239 // names and thus protects its registered Handlers. 240 // 241 // For client requests, Host optionally overrides the Host 242 // header to send. If empty, the Request.Write method uses 243 // the value of URL.Host. Host may contain an international 244 // domain name. 245 Host string 246 247 // Form contains the parsed form data, including both the URL 248 // field's query parameters and the PATCH, POST, or PUT form data. 249 // This field is only available after ParseForm is called. 250 // The HTTP client ignores Form and uses Body instead. 251 Form url.Values 252 253 // PostForm contains the parsed form data from PATCH, POST 254 // or PUT body parameters. 255 // 256 // This field is only available after ParseForm is called. 257 // The HTTP client ignores PostForm and uses Body instead. 258 PostForm url.Values 259 260 // MultipartForm is the parsed multipart form, including file uploads. 261 // This field is only available after ParseMultipartForm is called. 262 // The HTTP client ignores MultipartForm and uses Body instead. 263 MultipartForm *multipart.Form 264 265 // Trailer specifies additional headers that are sent after the request 266 // body. 267 // 268 // For server requests, the Trailer map initially contains only the 269 // trailer keys, with nil values. (The client declares which trailers it 270 // will later send.) While the handler is reading from Body, it must 271 // not reference Trailer. After reading from Body returns EOF, Trailer 272 // can be read again and will contain non-nil values, if they were sent 273 // by the client. 274 // 275 // For client requests, Trailer must be initialized to a map containing 276 // the trailer keys to later send. The values may be nil or their final 277 // values. The ContentLength must be 0 or -1, to send a chunked request. 278 // After the HTTP request is sent the map values can be updated while 279 // the request body is read. Once the body returns EOF, the caller must 280 // not mutate Trailer. 281 // 282 // Few HTTP clients, servers, or proxies support HTTP trailers. 283 Trailer Header 284 285 // RemoteAddr allows HTTP servers and other software to record 286 // the network address that sent the request, usually for 287 // logging. This field is not filled in by ReadRequest and 288 // has no defined format. The HTTP server in this package 289 // sets RemoteAddr to an "IP:port" address before invoking a 290 // handler. 291 // This field is ignored by the HTTP client. 292 RemoteAddr string 293 294 // RequestURI is the unmodified request-target of the 295 // Request-Line (RFC 7230, Section 3.1.1) as sent by the client 296 // to a server. Usually the URL field should be used instead. 297 // It is an error to set this field in an HTTP client request. 298 RequestURI string 299 300 // TLS allows HTTP servers and other software to record 301 // information about the TLS connection on which the request 302 // was received. This field is not filled in by ReadRequest. 303 // The HTTP server in this package sets the field for 304 // TLS-enabled connections before invoking a handler; 305 // otherwise it leaves the field nil. 306 // This field is ignored by the HTTP client. 307 TLS *tls.ConnectionState 308 309 // Cancel is an optional channel whose closure indicates that the client 310 // request should be regarded as canceled. Not all implementations of 311 // RoundTripper may support Cancel. 312 // 313 // For server requests, this field is not applicable. 314 // 315 // Deprecated: Set the Request's context with NewRequestWithContext 316 // instead. If a Request's Cancel field and context are both 317 // set, it is undefined whether Cancel is respected. 318 Cancel <-chan struct{} 319 320 // Response is the redirect response which caused this request 321 // to be created. This field is only populated during client 322 // redirects. 323 Response *Response 324 325 // Pattern is the [ServeMux] pattern that matched the request. 326 // It is empty if the request was not matched against a pattern. 327 Pattern string 328 329 // ctx is either the client or server context. It should only 330 // be modified via copying the whole Request using Clone or WithContext. 331 // It is unexported to prevent people from using Context wrong 332 // and mutating the contexts held by callers of the same request. 333 ctx context.Context 334 335 // The following fields are for requests matched by ServeMux. 336 pat *pattern // the pattern that matched 337 matches []string // values for the matching wildcards in pat 338 otherValues map[string]string // for calls to SetPathValue that don't match a wildcard 339 } 340 341 // Context returns the request's context. To change the context, use 342 // [Request.Clone] or [Request.WithContext]. 343 // 344 // The returned context is always non-nil; it defaults to the 345 // background context. 346 // 347 // For outgoing client requests, the context controls cancellation. 348 // 349 // For incoming server requests, the context is canceled when the 350 // client's connection closes, the request is canceled (with HTTP/2), 351 // or when the ServeHTTP method returns. 352 func (r *Request) Context() context.Context { 353 if r.ctx != nil { 354 return r.ctx 355 } 356 return context.Background() 357 } 358 359 // WithContext returns a shallow copy of r with its context changed 360 // to ctx. The provided ctx must be non-nil. 361 // 362 // For outgoing client request, the context controls the entire 363 // lifetime of a request and its response: obtaining a connection, 364 // sending the request, and reading the response headers and body. 365 // 366 // To create a new request with a context, use [NewRequestWithContext]. 367 // To make a deep copy of a request with a new context, use [Request.Clone]. 368 func (r *Request) WithContext(ctx context.Context) *Request { 369 if ctx == nil { 370 panic("nil context") 371 } 372 r2 := new(Request) 373 *r2 = *r 374 r2.ctx = ctx 375 return r2 376 } 377 378 // Clone returns a deep copy of r with its context changed to ctx. 379 // The provided ctx must be non-nil. 380 // 381 // Clone only makes a shallow copy of the Body field. 382 // 383 // For an outgoing client request, the context controls the entire 384 // lifetime of a request and its response: obtaining a connection, 385 // sending the request, and reading the response headers and body. 386 func (r *Request) Clone(ctx context.Context) *Request { 387 if ctx == nil { 388 panic("nil context") 389 } 390 r2 := new(Request) 391 *r2 = *r 392 r2.ctx = ctx 393 r2.URL = cloneURL(r.URL) 394 r2.Header = r.Header.Clone() 395 r2.Trailer = r.Trailer.Clone() 396 if s := r.TransferEncoding; s != nil { 397 s2 := make([]string, len(s)) 398 copy(s2, s) 399 r2.TransferEncoding = s2 400 } 401 r2.Form = cloneURLValues(r.Form) 402 r2.PostForm = cloneURLValues(r.PostForm) 403 r2.MultipartForm = cloneMultipartForm(r.MultipartForm) 404 405 // Copy matches and otherValues. See issue 61410. 406 if s := r.matches; s != nil { 407 s2 := make([]string, len(s)) 408 copy(s2, s) 409 r2.matches = s2 410 } 411 r2.otherValues = maps.Clone(r.otherValues) 412 return r2 413 } 414 415 // ProtoAtLeast reports whether the HTTP protocol used 416 // in the request is at least major.minor. 417 func (r *Request) ProtoAtLeast(major, minor int) bool { 418 return r.ProtoMajor > major || 419 r.ProtoMajor == major && r.ProtoMinor >= minor 420 } 421 422 // UserAgent returns the client's User-Agent, if sent in the request. 423 func (r *Request) UserAgent() string { 424 return r.Header.Get("User-Agent") 425 } 426 427 // Cookies parses and returns the HTTP cookies sent with the request. 428 func (r *Request) Cookies() []*Cookie { 429 return readCookies(r.Header, "") 430 } 431 432 // CookiesNamed parses and returns the named HTTP cookies sent with the request 433 // or an empty slice if none matched. 434 func (r *Request) CookiesNamed(name string) []*Cookie { 435 if name == "" { 436 return []*Cookie{} 437 } 438 return readCookies(r.Header, name) 439 } 440 441 // ErrNoCookie is returned by Request's Cookie method when a cookie is not found. 442 var ErrNoCookie = errors.New("http: named cookie not present") 443 444 // Cookie returns the named cookie provided in the request or 445 // [ErrNoCookie] if not found. 446 // If multiple cookies match the given name, only one cookie will 447 // be returned. 448 func (r *Request) Cookie(name string) (*Cookie, error) { 449 if name == "" { 450 return nil, ErrNoCookie 451 } 452 for _, c := range readCookies(r.Header, name) { 453 return c, nil 454 } 455 return nil, ErrNoCookie 456 } 457 458 // AddCookie adds a cookie to the request. Per RFC 6265 section 5.4, 459 // AddCookie does not attach more than one [Cookie] header field. That 460 // means all cookies, if any, are written into the same line, 461 // separated by semicolon. 462 // AddCookie only sanitizes c's name and value, and does not sanitize 463 // a Cookie header already present in the request. 464 func (r *Request) AddCookie(c *Cookie) { 465 s := fmt.Sprintf("%s=%s", sanitizeCookieName(c.Name), sanitizeCookieValue(c.Value, c.Quoted)) 466 if c := r.Header.Get("Cookie"); c != "" { 467 r.Header.Set("Cookie", c+"; "+s) 468 } else { 469 r.Header.Set("Cookie", s) 470 } 471 } 472 473 // Referer returns the referring URL, if sent in the request. 474 // 475 // Referer is misspelled as in the request itself, a mistake from the 476 // earliest days of HTTP. This value can also be fetched from the 477 // [Header] map as Header["Referer"]; the benefit of making it available 478 // as a method is that the compiler can diagnose programs that use the 479 // alternate (correct English) spelling req.Referrer() but cannot 480 // diagnose programs that use Header["Referrer"]. 481 func (r *Request) Referer() string { 482 return r.Header.Get("Referer") 483 } 484 485 // multipartByReader is a sentinel value. 486 // Its presence in Request.MultipartForm indicates that parsing of the request 487 // body has been handed off to a MultipartReader instead of ParseMultipartForm. 488 var multipartByReader = &multipart.Form{ 489 Value: make(map[string][]string), 490 File: make(map[string][]*multipart.FileHeader), 491 } 492 493 // MultipartReader returns a MIME multipart reader if this is a 494 // multipart/form-data or a multipart/mixed POST request, else returns nil and an error. 495 // Use this function instead of [Request.ParseMultipartForm] to 496 // process the request body as a stream. 497 func (r *Request) MultipartReader() (*multipart.Reader, error) { 498 if r.MultipartForm == multipartByReader { 499 return nil, errors.New("http: MultipartReader called twice") 500 } 501 if r.MultipartForm != nil { 502 return nil, errors.New("http: multipart handled by ParseMultipartForm") 503 } 504 r.MultipartForm = multipartByReader 505 return r.multipartReader(true) 506 } 507 508 func (r *Request) multipartReader(allowMixed bool) (*multipart.Reader, error) { 509 v := r.Header.Get("Content-Type") 510 if v == "" { 511 return nil, ErrNotMultipart 512 } 513 if r.Body == nil { 514 return nil, errors.New("missing form body") 515 } 516 d, params, err := mime.ParseMediaType(v) 517 if err != nil || !(d == "multipart/form-data" || allowMixed && d == "multipart/mixed") { 518 return nil, ErrNotMultipart 519 } 520 boundary, ok := params["boundary"] 521 if !ok { 522 return nil, ErrMissingBoundary 523 } 524 return multipart.NewReader(r.Body, boundary), nil 525 } 526 527 // isH2Upgrade reports whether r represents the http2 "client preface" 528 // magic string. 529 func (r *Request) isH2Upgrade() bool { 530 return r.Method == "PRI" && len(r.Header) == 0 && r.URL.Path == "*" && r.Proto == "HTTP/2.0" 531 } 532 533 // Return value if nonempty, def otherwise. 534 func valueOrDefault(value, def string) string { 535 if value != "" { 536 return value 537 } 538 return def 539 } 540 541 // NOTE: This is not intended to reflect the actual Go version being used. 542 // It was changed at the time of Go 1.1 release because the former User-Agent 543 // had ended up blocked by some intrusion detection systems. 544 // See https://codereview.appspot.com/7532043. 545 const defaultUserAgent = "Go-http-client/1.1" 546 547 // Write writes an HTTP/1.1 request, which is the header and body, in wire format. 548 // This method consults the following fields of the request: 549 // 550 // Host 551 // URL 552 // Method (defaults to "GET") 553 // Header 554 // ContentLength 555 // TransferEncoding 556 // Body 557 // 558 // If Body is present, Content-Length is <= 0 and [Request.TransferEncoding] 559 // hasn't been set to "identity", Write adds "Transfer-Encoding: 560 // chunked" to the header. Body is closed after it is sent. 561 func (r *Request) Write(w io.Writer) error { 562 return r.write(w, false, nil, nil) 563 } 564 565 // WriteProxy is like [Request.Write] but writes the request in the form 566 // expected by an HTTP proxy. In particular, [Request.WriteProxy] writes the 567 // initial Request-URI line of the request with an absolute URI, per 568 // section 5.3 of RFC 7230, including the scheme and host. 569 // In either case, WriteProxy also writes a Host header, using 570 // either r.Host or r.URL.Host. 571 func (r *Request) WriteProxy(w io.Writer) error { 572 return r.write(w, true, nil, nil) 573 } 574 575 // errMissingHost is returned by Write when there is no Host or URL present in 576 // the Request. 577 var errMissingHost = errors.New("http: Request.Write on Request with no Host or URL set") 578 579 // extraHeaders may be nil 580 // waitForContinue may be nil 581 // always closes body 582 func (r *Request) write(w io.Writer, usingProxy bool, extraHeaders Header, waitForContinue func() bool) (err error) { 583 trace := httptrace.ContextClientTrace(r.Context()) 584 if trace != nil && trace.WroteRequest != nil { 585 defer func() { 586 trace.WroteRequest(httptrace.WroteRequestInfo{ 587 Err: err, 588 }) 589 }() 590 } 591 closed := false 592 defer func() { 593 if closed { 594 return 595 } 596 if closeErr := r.closeBody(); closeErr != nil && err == nil { 597 err = closeErr 598 } 599 }() 600 601 // Find the target host. Prefer the Host: header, but if that 602 // is not given, use the host from the request URL. 603 // 604 // Clean the host, in case it arrives with unexpected stuff in it. 605 host := r.Host 606 if host == "" { 607 if r.URL == nil { 608 return errMissingHost 609 } 610 host = r.URL.Host 611 } 612 host, err = httpguts.PunycodeHostPort(host) 613 if err != nil { 614 return err 615 } 616 // Validate that the Host header is a valid header in general, 617 // but don't validate the host itself. This is sufficient to avoid 618 // header or request smuggling via the Host field. 619 // The server can (and will, if it's a net/http server) reject 620 // the request if it doesn't consider the host valid. 621 if !httpguts.ValidHostHeader(host) { 622 // Historically, we would truncate the Host header after '/' or ' '. 623 // Some users have relied on this truncation to convert a network 624 // address such as Unix domain socket path into a valid, ignored 625 // Host header (see https://go.dev/issue/61431). 626 // 627 // We don't preserve the truncation, because sending an altered 628 // header field opens a smuggling vector. Instead, zero out the 629 // Host header entirely if it isn't valid. (An empty Host is valid; 630 // see RFC 9112 Section 3.2.) 631 // 632 // Return an error if we're sending to a proxy, since the proxy 633 // probably can't do anything useful with an empty Host header. 634 if !usingProxy { 635 host = "" 636 } else { 637 return errors.New("http: invalid Host header") 638 } 639 } 640 641 // According to RFC 6874, an HTTP client, proxy, or other 642 // intermediary must remove any IPv6 zone identifier attached 643 // to an outgoing URI. 644 host = removeZone(host) 645 646 ruri := r.URL.RequestURI() 647 if usingProxy && r.URL.Scheme != "" && r.URL.Opaque == "" { 648 ruri = r.URL.Scheme + "://" + host + ruri 649 } else if r.Method == "CONNECT" && r.URL.Path == "" { 650 // CONNECT requests normally give just the host and port, not a full URL. 651 ruri = host 652 if r.URL.Opaque != "" { 653 ruri = r.URL.Opaque 654 } 655 } 656 if stringContainsCTLByte(ruri) { 657 return errors.New("net/http: can't write control character in Request.URL") 658 } 659 // TODO: validate r.Method too? At least it's less likely to 660 // come from an attacker (more likely to be a constant in 661 // code). 662 663 // Wrap the writer in a bufio Writer if it's not already buffered. 664 // Don't always call NewWriter, as that forces a bytes.Buffer 665 // and other small bufio Writers to have a minimum 4k buffer 666 // size. 667 var bw *bufio.Writer 668 if _, ok := w.(io.ByteWriter); !ok { 669 bw = bufio.NewWriter(w) 670 w = bw 671 } 672 673 _, err = fmt.Fprintf(w, "%s %s HTTP/1.1\r\n", valueOrDefault(r.Method, "GET"), ruri) 674 if err != nil { 675 return err 676 } 677 678 // Header lines 679 _, err = fmt.Fprintf(w, "Host: %s\r\n", host) 680 if err != nil { 681 return err 682 } 683 if trace != nil && trace.WroteHeaderField != nil { 684 trace.WroteHeaderField("Host", []string{host}) 685 } 686 687 // Use the defaultUserAgent unless the Header contains one, which 688 // may be blank to not send the header. 689 userAgent := defaultUserAgent 690 if r.Header.has("User-Agent") { 691 userAgent = r.Header.Get("User-Agent") 692 } 693 if userAgent != "" { 694 userAgent = headerNewlineToSpace.Replace(userAgent) 695 userAgent = textproto.TrimString(userAgent) 696 _, err = fmt.Fprintf(w, "User-Agent: %s\r\n", userAgent) 697 if err != nil { 698 return err 699 } 700 if trace != nil && trace.WroteHeaderField != nil { 701 trace.WroteHeaderField("User-Agent", []string{userAgent}) 702 } 703 } 704 705 // Process Body,ContentLength,Close,Trailer 706 tw, err := newTransferWriter(r) 707 if err != nil { 708 return err 709 } 710 err = tw.writeHeader(w, trace) 711 if err != nil { 712 return err 713 } 714 715 err = r.Header.writeSubset(w, reqWriteExcludeHeader, trace) 716 if err != nil { 717 return err 718 } 719 720 if extraHeaders != nil { 721 err = extraHeaders.write(w, trace) 722 if err != nil { 723 return err 724 } 725 } 726 727 _, err = io.WriteString(w, "\r\n") 728 if err != nil { 729 return err 730 } 731 732 if trace != nil && trace.WroteHeaders != nil { 733 trace.WroteHeaders() 734 } 735 736 // Flush and wait for 100-continue if expected. 737 if waitForContinue != nil { 738 if bw, ok := w.(*bufio.Writer); ok { 739 err = bw.Flush() 740 if err != nil { 741 return err 742 } 743 } 744 if trace != nil && trace.Wait100Continue != nil { 745 trace.Wait100Continue() 746 } 747 if !waitForContinue() { 748 closed = true 749 r.closeBody() 750 return nil 751 } 752 } 753 754 if bw, ok := w.(*bufio.Writer); ok && tw.FlushHeaders { 755 if err := bw.Flush(); err != nil { 756 return err 757 } 758 } 759 760 // Write body and trailer 761 closed = true 762 err = tw.writeBody(w) 763 if err != nil { 764 if tw.bodyReadError == err { 765 err = requestBodyReadError{err} 766 } 767 return err 768 } 769 770 if bw != nil { 771 return bw.Flush() 772 } 773 return nil 774 } 775 776 // requestBodyReadError wraps an error from (*Request).write to indicate 777 // that the error came from a Read call on the Request.Body. 778 // This error type should not escape the net/http package to users. 779 type requestBodyReadError struct{ error } 780 781 func idnaASCII(v string) (string, error) { 782 // TODO: Consider removing this check after verifying performance is okay. 783 // Right now punycode verification, length checks, context checks, and the 784 // permissible character tests are all omitted. It also prevents the ToASCII 785 // call from salvaging an invalid IDN, when possible. As a result it may be 786 // possible to have two IDNs that appear identical to the user where the 787 // ASCII-only version causes an error downstream whereas the non-ASCII 788 // version does not. 789 // Note that for correct ASCII IDNs ToASCII will only do considerably more 790 // work, but it will not cause an allocation. 791 if ascii.Is(v) { 792 return v, nil 793 } 794 return idna.Lookup.ToASCII(v) 795 } 796 797 // removeZone removes IPv6 zone identifier from host. 798 // E.g., "[fe80::1%en0]:8080" to "[fe80::1]:8080" 799 func removeZone(host string) string { 800 if !strings.HasPrefix(host, "[") { 801 return host 802 } 803 i := strings.LastIndex(host, "]") 804 if i < 0 { 805 return host 806 } 807 j := strings.LastIndex(host[:i], "%") 808 if j < 0 { 809 return host 810 } 811 return host[:j] + host[i:] 812 } 813 814 // ParseHTTPVersion parses an HTTP version string according to RFC 7230, section 2.6. 815 // "HTTP/1.0" returns (1, 0, true). Note that strings without 816 // a minor version, such as "HTTP/2", are not valid. 817 func ParseHTTPVersion(vers string) (major, minor int, ok bool) { 818 switch vers { 819 case "HTTP/1.1": 820 return 1, 1, true 821 case "HTTP/1.0": 822 return 1, 0, true 823 } 824 if !strings.HasPrefix(vers, "HTTP/") { 825 return 0, 0, false 826 } 827 if len(vers) != len("HTTP/X.Y") { 828 return 0, 0, false 829 } 830 if vers[6] != '.' { 831 return 0, 0, false 832 } 833 maj, err := strconv.ParseUint(vers[5:6], 10, 0) 834 if err != nil { 835 return 0, 0, false 836 } 837 min, err := strconv.ParseUint(vers[7:8], 10, 0) 838 if err != nil { 839 return 0, 0, false 840 } 841 return int(maj), int(min), true 842 } 843 844 func validMethod(method string) bool { 845 /* 846 Method = "OPTIONS" ; Section 9.2 847 | "GET" ; Section 9.3 848 | "HEAD" ; Section 9.4 849 | "POST" ; Section 9.5 850 | "PUT" ; Section 9.6 851 | "DELETE" ; Section 9.7 852 | "TRACE" ; Section 9.8 853 | "CONNECT" ; Section 9.9 854 | extension-method 855 extension-method = token 856 token = 1*<any CHAR except CTLs or separators> 857 */ 858 return len(method) > 0 && strings.IndexFunc(method, isNotToken) == -1 859 } 860 861 // NewRequest wraps [NewRequestWithContext] using [context.Background]. 862 func NewRequest(method, url string, body io.Reader) (*Request, error) { 863 return NewRequestWithContext(context.Background(), method, url, body) 864 } 865 866 // NewRequestWithContext returns a new [Request] given a method, URL, and 867 // optional body. 868 // 869 // If the provided body is also an [io.Closer], the returned 870 // [Request.Body] is set to body and will be closed (possibly 871 // asynchronously) by the Client methods Do, Post, and PostForm, 872 // and [Transport.RoundTrip]. 873 // 874 // NewRequestWithContext returns a Request suitable for use with 875 // [Client.Do] or [Transport.RoundTrip]. To create a request for use with 876 // testing a Server Handler, either use the [NewRequest] function in the 877 // net/http/httptest package, use [ReadRequest], or manually update the 878 // Request fields. For an outgoing client request, the context 879 // controls the entire lifetime of a request and its response: 880 // obtaining a connection, sending the request, and reading the 881 // response headers and body. See the Request type's documentation for 882 // the difference between inbound and outbound request fields. 883 // 884 // If body is of type [*bytes.Buffer], [*bytes.Reader], or 885 // [*strings.Reader], the returned request's ContentLength is set to its 886 // exact value (instead of -1), GetBody is populated (so 307 and 308 887 // redirects can replay the body), and Body is set to [NoBody] if the 888 // ContentLength is 0. 889 func NewRequestWithContext(ctx context.Context, method, url string, body io.Reader) (*Request, error) { 890 if method == "" { 891 // We document that "" means "GET" for Request.Method, and people have 892 // relied on that from NewRequest, so keep that working. 893 // We still enforce validMethod for non-empty methods. 894 method = "GET" 895 } 896 if !validMethod(method) { 897 return nil, fmt.Errorf("net/http: invalid method %q", method) 898 } 899 if ctx == nil { 900 return nil, errors.New("net/http: nil Context") 901 } 902 u, err := urlpkg.Parse(url) 903 if err != nil { 904 return nil, err 905 } 906 rc, ok := body.(io.ReadCloser) 907 if !ok && body != nil { 908 rc = io.NopCloser(body) 909 } 910 // The host's colon:port should be normalized. See Issue 14836. 911 u.Host = removeEmptyPort(u.Host) 912 req := &Request{ 913 ctx: ctx, 914 Method: method, 915 URL: u, 916 Proto: "HTTP/1.1", 917 ProtoMajor: 1, 918 ProtoMinor: 1, 919 Header: make(Header), 920 Body: rc, 921 Host: u.Host, 922 } 923 if body != nil { 924 switch v := body.(type) { 925 case *bytes.Buffer: 926 req.ContentLength = int64(v.Len()) 927 buf := v.Bytes() 928 req.GetBody = func() (io.ReadCloser, error) { 929 r := bytes.NewReader(buf) 930 return io.NopCloser(r), nil 931 } 932 case *bytes.Reader: 933 req.ContentLength = int64(v.Len()) 934 snapshot := *v 935 req.GetBody = func() (io.ReadCloser, error) { 936 r := snapshot 937 return io.NopCloser(&r), nil 938 } 939 case *strings.Reader: 940 req.ContentLength = int64(v.Len()) 941 snapshot := *v 942 req.GetBody = func() (io.ReadCloser, error) { 943 r := snapshot 944 return io.NopCloser(&r), nil 945 } 946 default: 947 // This is where we'd set it to -1 (at least 948 // if body != NoBody) to mean unknown, but 949 // that broke people during the Go 1.8 testing 950 // period. People depend on it being 0 I 951 // guess. Maybe retry later. See Issue 18117. 952 } 953 // For client requests, Request.ContentLength of 0 954 // means either actually 0, or unknown. The only way 955 // to explicitly say that the ContentLength is zero is 956 // to set the Body to nil. But turns out too much code 957 // depends on NewRequest returning a non-nil Body, 958 // so we use a well-known ReadCloser variable instead 959 // and have the http package also treat that sentinel 960 // variable to mean explicitly zero. 961 if req.GetBody != nil && req.ContentLength == 0 { 962 req.Body = NoBody 963 req.GetBody = func() (io.ReadCloser, error) { return NoBody, nil } 964 } 965 } 966 967 return req, nil 968 } 969 970 // BasicAuth returns the username and password provided in the request's 971 // Authorization header, if the request uses HTTP Basic Authentication. 972 // See RFC 2617, Section 2. 973 func (r *Request) BasicAuth() (username, password string, ok bool) { 974 auth := r.Header.Get("Authorization") 975 if auth == "" { 976 return "", "", false 977 } 978 return parseBasicAuth(auth) 979 } 980 981 // parseBasicAuth parses an HTTP Basic Authentication string. 982 // "Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==" returns ("Aladdin", "open sesame", true). 983 // 984 // parseBasicAuth should be an internal detail, 985 // but widely used packages access it using linkname. 986 // Notable members of the hall of shame include: 987 // - github.com/sagernet/sing 988 // 989 // Do not remove or change the type signature. 990 // See go.dev/issue/67401. 991 // 992 //go:linkname parseBasicAuth 993 func parseBasicAuth(auth string) (username, password string, ok bool) { 994 const prefix = "Basic " 995 // Case insensitive prefix match. See Issue 22736. 996 if len(auth) < len(prefix) || !ascii.EqualFold(auth[:len(prefix)], prefix) { 997 return "", "", false 998 } 999 c, err := base64.StdEncoding.DecodeString(auth[len(prefix):]) 1000 if err != nil { 1001 return "", "", false 1002 } 1003 cs := string(c) 1004 username, password, ok = strings.Cut(cs, ":") 1005 if !ok { 1006 return "", "", false 1007 } 1008 return username, password, true 1009 } 1010 1011 // SetBasicAuth sets the request's Authorization header to use HTTP 1012 // Basic Authentication with the provided username and password. 1013 // 1014 // With HTTP Basic Authentication the provided username and password 1015 // are not encrypted. It should generally only be used in an HTTPS 1016 // request. 1017 // 1018 // The username may not contain a colon. Some protocols may impose 1019 // additional requirements on pre-escaping the username and 1020 // password. For instance, when used with OAuth2, both arguments must 1021 // be URL encoded first with [url.QueryEscape]. 1022 func (r *Request) SetBasicAuth(username, password string) { 1023 r.Header.Set("Authorization", "Basic "+basicAuth(username, password)) 1024 } 1025 1026 // parseRequestLine parses "GET /foo HTTP/1.1" into its three parts. 1027 func parseRequestLine(line string) (method, requestURI, proto string, ok bool) { 1028 method, rest, ok1 := strings.Cut(line, " ") 1029 requestURI, proto, ok2 := strings.Cut(rest, " ") 1030 if !ok1 || !ok2 { 1031 return "", "", "", false 1032 } 1033 return method, requestURI, proto, true 1034 } 1035 1036 var textprotoReaderPool sync.Pool 1037 1038 func newTextprotoReader(br *bufio.Reader) *textproto.Reader { 1039 if v := textprotoReaderPool.Get(); v != nil { 1040 tr := v.(*textproto.Reader) 1041 tr.R = br 1042 return tr 1043 } 1044 return textproto.NewReader(br) 1045 } 1046 1047 func putTextprotoReader(r *textproto.Reader) { 1048 r.R = nil 1049 textprotoReaderPool.Put(r) 1050 } 1051 1052 // ReadRequest reads and parses an incoming request from b. 1053 // 1054 // ReadRequest is a low-level function and should only be used for 1055 // specialized applications; most code should use the [Server] to read 1056 // requests and handle them via the [Handler] interface. ReadRequest 1057 // only supports HTTP/1.x requests. For HTTP/2, use golang.org/x/net/http2. 1058 func ReadRequest(b *bufio.Reader) (*Request, error) { 1059 req, err := readRequest(b) 1060 if err != nil { 1061 return nil, err 1062 } 1063 1064 delete(req.Header, "Host") 1065 return req, err 1066 } 1067 1068 // readRequest should be an internal detail, 1069 // but widely used packages access it using linkname. 1070 // Notable members of the hall of shame include: 1071 // - github.com/sagernet/sing 1072 // - github.com/v2fly/v2ray-core/v4 1073 // - github.com/v2fly/v2ray-core/v5 1074 // 1075 // Do not remove or change the type signature. 1076 // See go.dev/issue/67401. 1077 // 1078 //go:linkname readRequest 1079 func readRequest(b *bufio.Reader) (req *Request, err error) { 1080 tp := newTextprotoReader(b) 1081 defer putTextprotoReader(tp) 1082 1083 req = new(Request) 1084 1085 // First line: GET /index.html HTTP/1.0 1086 var s string 1087 if s, err = tp.ReadLine(); err != nil { 1088 return nil, err 1089 } 1090 defer func() { 1091 if err == io.EOF { 1092 err = io.ErrUnexpectedEOF 1093 } 1094 }() 1095 1096 var ok bool 1097 req.Method, req.RequestURI, req.Proto, ok = parseRequestLine(s) 1098 if !ok { 1099 return nil, badStringError("malformed HTTP request", s) 1100 } 1101 if !validMethod(req.Method) { 1102 return nil, badStringError("invalid method", req.Method) 1103 } 1104 rawurl := req.RequestURI 1105 if req.ProtoMajor, req.ProtoMinor, ok = ParseHTTPVersion(req.Proto); !ok { 1106 return nil, badStringError("malformed HTTP version", req.Proto) 1107 } 1108 1109 // CONNECT requests are used two different ways, and neither uses a full URL: 1110 // The standard use is to tunnel HTTPS through an HTTP proxy. 1111 // It looks like "CONNECT www.google.com:443 HTTP/1.1", and the parameter is 1112 // just the authority section of a URL. This information should go in req.URL.Host. 1113 // 1114 // The net/rpc package also uses CONNECT, but there the parameter is a path 1115 // that starts with a slash. It can be parsed with the regular URL parser, 1116 // and the path will end up in req.URL.Path, where it needs to be in order for 1117 // RPC to work. 1118 justAuthority := req.Method == "CONNECT" && !strings.HasPrefix(rawurl, "/") 1119 if justAuthority { 1120 rawurl = "http://" + rawurl 1121 } 1122 1123 if req.URL, err = url.ParseRequestURI(rawurl); err != nil { 1124 return nil, err 1125 } 1126 1127 if justAuthority { 1128 // Strip the bogus "http://" back off. 1129 req.URL.Scheme = "" 1130 } 1131 1132 // Subsequent lines: Key: value. 1133 mimeHeader, err := tp.ReadMIMEHeader() 1134 if err != nil { 1135 return nil, err 1136 } 1137 req.Header = Header(mimeHeader) 1138 if len(req.Header["Host"]) > 1 { 1139 return nil, fmt.Errorf("too many Host headers") 1140 } 1141 1142 // RFC 7230, section 5.3: Must treat 1143 // GET /index.html HTTP/1.1 1144 // Host: www.google.com 1145 // and 1146 // GET http://www.google.com/index.html HTTP/1.1 1147 // Host: doesntmatter 1148 // the same. In the second case, any Host line is ignored. 1149 req.Host = req.URL.Host 1150 if req.Host == "" { 1151 req.Host = req.Header.get("Host") 1152 } 1153 1154 fixPragmaCacheControl(req.Header) 1155 1156 req.Close = shouldClose(req.ProtoMajor, req.ProtoMinor, req.Header, false) 1157 1158 err = readTransfer(req, b) 1159 if err != nil { 1160 return nil, err 1161 } 1162 1163 if req.isH2Upgrade() { 1164 // Because it's neither chunked, nor declared: 1165 req.ContentLength = -1 1166 1167 // We want to give handlers a chance to hijack the 1168 // connection, but we need to prevent the Server from 1169 // dealing with the connection further if it's not 1170 // hijacked. Set Close to ensure that: 1171 req.Close = true 1172 } 1173 return req, nil 1174 } 1175 1176 // MaxBytesReader is similar to [io.LimitReader] but is intended for 1177 // limiting the size of incoming request bodies. In contrast to 1178 // io.LimitReader, MaxBytesReader's result is a ReadCloser, returns a 1179 // non-nil error of type [*MaxBytesError] for a Read beyond the limit, 1180 // and closes the underlying reader when its Close method is called. 1181 // 1182 // MaxBytesReader prevents clients from accidentally or maliciously 1183 // sending a large request and wasting server resources. If possible, 1184 // it tells the [ResponseWriter] to close the connection after the limit 1185 // has been reached. 1186 func MaxBytesReader(w ResponseWriter, r io.ReadCloser, n int64) io.ReadCloser { 1187 if n < 0 { // Treat negative limits as equivalent to 0. 1188 n = 0 1189 } 1190 return &maxBytesReader{w: w, r: r, i: n, n: n} 1191 } 1192 1193 // MaxBytesError is returned by [MaxBytesReader] when its read limit is exceeded. 1194 type MaxBytesError struct { 1195 Limit int64 1196 } 1197 1198 func (e *MaxBytesError) Error() string { 1199 // Due to Hyrum's law, this text cannot be changed. 1200 return "http: request body too large" 1201 } 1202 1203 type maxBytesReader struct { 1204 w ResponseWriter 1205 r io.ReadCloser // underlying reader 1206 i int64 // max bytes initially, for MaxBytesError 1207 n int64 // max bytes remaining 1208 err error // sticky error 1209 } 1210 1211 func (l *maxBytesReader) Read(p []byte) (n int, err error) { 1212 if l.err != nil { 1213 return 0, l.err 1214 } 1215 if len(p) == 0 { 1216 return 0, nil 1217 } 1218 // If they asked for a 32KB byte read but only 5 bytes are 1219 // remaining, no need to read 32KB. 6 bytes will answer the 1220 // question of the whether we hit the limit or go past it. 1221 // 0 < len(p) < 2^63 1222 if int64(len(p))-1 > l.n { 1223 p = p[:l.n+1] 1224 } 1225 n, err = l.r.Read(p) 1226 1227 if int64(n) <= l.n { 1228 l.n -= int64(n) 1229 l.err = err 1230 return n, err 1231 } 1232 1233 n = int(l.n) 1234 l.n = 0 1235 1236 // The server code and client code both use 1237 // maxBytesReader. This "requestTooLarge" check is 1238 // only used by the server code. To prevent binaries 1239 // which only using the HTTP Client code (such as 1240 // cmd/go) from also linking in the HTTP server, don't 1241 // use a static type assertion to the server 1242 // "*response" type. Check this interface instead: 1243 type requestTooLarger interface { 1244 requestTooLarge() 1245 } 1246 if res, ok := l.w.(requestTooLarger); ok { 1247 res.requestTooLarge() 1248 } 1249 l.err = &MaxBytesError{l.i} 1250 return n, l.err 1251 } 1252 1253 func (l *maxBytesReader) Close() error { 1254 return l.r.Close() 1255 } 1256 1257 func copyValues(dst, src url.Values) { 1258 for k, vs := range src { 1259 dst[k] = append(dst[k], vs...) 1260 } 1261 } 1262 1263 func parsePostForm(r *Request) (vs url.Values, err error) { 1264 if r.Body == nil { 1265 err = errors.New("missing form body") 1266 return 1267 } 1268 ct := r.Header.Get("Content-Type") 1269 // RFC 7231, section 3.1.1.5 - empty type 1270 // MAY be treated as application/octet-stream 1271 if ct == "" { 1272 ct = "application/octet-stream" 1273 } 1274 ct, _, err = mime.ParseMediaType(ct) 1275 switch { 1276 case ct == "application/x-www-form-urlencoded": 1277 var reader io.Reader = r.Body 1278 maxFormSize := int64(1<<63 - 1) 1279 if _, ok := r.Body.(*maxBytesReader); !ok { 1280 maxFormSize = int64(10 << 20) // 10 MB is a lot of text. 1281 reader = io.LimitReader(r.Body, maxFormSize+1) 1282 } 1283 b, e := io.ReadAll(reader) 1284 if e != nil { 1285 if err == nil { 1286 err = e 1287 } 1288 break 1289 } 1290 if int64(len(b)) > maxFormSize { 1291 err = errors.New("http: POST too large") 1292 return 1293 } 1294 vs, e = url.ParseQuery(string(b)) 1295 if err == nil { 1296 err = e 1297 } 1298 case ct == "multipart/form-data": 1299 // handled by ParseMultipartForm (which is calling us, or should be) 1300 // TODO(bradfitz): there are too many possible 1301 // orders to call too many functions here. 1302 // Clean this up and write more tests. 1303 // request_test.go contains the start of this, 1304 // in TestParseMultipartFormOrder and others. 1305 } 1306 return 1307 } 1308 1309 // ParseForm populates r.Form and r.PostForm. 1310 // 1311 // For all requests, ParseForm parses the raw query from the URL and updates 1312 // r.Form. 1313 // 1314 // For POST, PUT, and PATCH requests, it also reads the request body, parses it 1315 // as a form and puts the results into both r.PostForm and r.Form. Request body 1316 // parameters take precedence over URL query string values in r.Form. 1317 // 1318 // If the request Body's size has not already been limited by [MaxBytesReader], 1319 // the size is capped at 10MB. 1320 // 1321 // For other HTTP methods, or when the Content-Type is not 1322 // application/x-www-form-urlencoded, the request Body is not read, and 1323 // r.PostForm is initialized to a non-nil, empty value. 1324 // 1325 // [Request.ParseMultipartForm] calls ParseForm automatically. 1326 // ParseForm is idempotent. 1327 func (r *Request) ParseForm() error { 1328 var err error 1329 if r.PostForm == nil { 1330 if r.Method == "POST" || r.Method == "PUT" || r.Method == "PATCH" { 1331 r.PostForm, err = parsePostForm(r) 1332 } 1333 if r.PostForm == nil { 1334 r.PostForm = make(url.Values) 1335 } 1336 } 1337 if r.Form == nil { 1338 if len(r.PostForm) > 0 { 1339 r.Form = make(url.Values) 1340 copyValues(r.Form, r.PostForm) 1341 } 1342 var newValues url.Values 1343 if r.URL != nil { 1344 var e error 1345 newValues, e = url.ParseQuery(r.URL.RawQuery) 1346 if err == nil { 1347 err = e 1348 } 1349 } 1350 if newValues == nil { 1351 newValues = make(url.Values) 1352 } 1353 if r.Form == nil { 1354 r.Form = newValues 1355 } else { 1356 copyValues(r.Form, newValues) 1357 } 1358 } 1359 return err 1360 } 1361 1362 // ParseMultipartForm parses a request body as multipart/form-data. 1363 // The whole request body is parsed and up to a total of maxMemory bytes of 1364 // its file parts are stored in memory, with the remainder stored on 1365 // disk in temporary files. 1366 // ParseMultipartForm calls [Request.ParseForm] if necessary. 1367 // If ParseForm returns an error, ParseMultipartForm returns it but also 1368 // continues parsing the request body. 1369 // After one call to ParseMultipartForm, subsequent calls have no effect. 1370 func (r *Request) ParseMultipartForm(maxMemory int64) error { 1371 if r.MultipartForm == multipartByReader { 1372 return errors.New("http: multipart handled by MultipartReader") 1373 } 1374 var parseFormErr error 1375 if r.Form == nil { 1376 // Let errors in ParseForm fall through, and just 1377 // return it at the end. 1378 parseFormErr = r.ParseForm() 1379 } 1380 if r.MultipartForm != nil { 1381 return nil 1382 } 1383 1384 mr, err := r.multipartReader(false) 1385 if err != nil { 1386 return err 1387 } 1388 1389 f, err := mr.ReadForm(maxMemory) 1390 if err != nil { 1391 return err 1392 } 1393 1394 if r.PostForm == nil { 1395 r.PostForm = make(url.Values) 1396 } 1397 for k, v := range f.Value { 1398 r.Form[k] = append(r.Form[k], v...) 1399 // r.PostForm should also be populated. See Issue 9305. 1400 r.PostForm[k] = append(r.PostForm[k], v...) 1401 } 1402 1403 r.MultipartForm = f 1404 1405 return parseFormErr 1406 } 1407 1408 // FormValue returns the first value for the named component of the query. 1409 // The precedence order: 1410 // 1. application/x-www-form-urlencoded form body (POST, PUT, PATCH only) 1411 // 2. query parameters (always) 1412 // 3. multipart/form-data form body (always) 1413 // 1414 // FormValue calls [Request.ParseMultipartForm] and [Request.ParseForm] 1415 // if necessary and ignores any errors returned by these functions. 1416 // If key is not present, FormValue returns the empty string. 1417 // To access multiple values of the same key, call ParseForm and 1418 // then inspect [Request.Form] directly. 1419 func (r *Request) FormValue(key string) string { 1420 if r.Form == nil { 1421 r.ParseMultipartForm(defaultMaxMemory) 1422 } 1423 if vs := r.Form[key]; len(vs) > 0 { 1424 return vs[0] 1425 } 1426 return "" 1427 } 1428 1429 // PostFormValue returns the first value for the named component of the POST, 1430 // PUT, or PATCH request body. URL query parameters are ignored. 1431 // PostFormValue calls [Request.ParseMultipartForm] and [Request.ParseForm] if necessary and ignores 1432 // any errors returned by these functions. 1433 // If key is not present, PostFormValue returns the empty string. 1434 func (r *Request) PostFormValue(key string) string { 1435 if r.PostForm == nil { 1436 r.ParseMultipartForm(defaultMaxMemory) 1437 } 1438 if vs := r.PostForm[key]; len(vs) > 0 { 1439 return vs[0] 1440 } 1441 return "" 1442 } 1443 1444 // FormFile returns the first file for the provided form key. 1445 // FormFile calls [Request.ParseMultipartForm] and [Request.ParseForm] if necessary. 1446 func (r *Request) FormFile(key string) (multipart.File, *multipart.FileHeader, error) { 1447 if r.MultipartForm == multipartByReader { 1448 return nil, nil, errors.New("http: multipart handled by MultipartReader") 1449 } 1450 if r.MultipartForm == nil { 1451 err := r.ParseMultipartForm(defaultMaxMemory) 1452 if err != nil { 1453 return nil, nil, err 1454 } 1455 } 1456 if r.MultipartForm != nil && r.MultipartForm.File != nil { 1457 if fhs := r.MultipartForm.File[key]; len(fhs) > 0 { 1458 f, err := fhs[0].Open() 1459 return f, fhs[0], err 1460 } 1461 } 1462 return nil, nil, ErrMissingFile 1463 } 1464 1465 // PathValue returns the value for the named path wildcard in the [ServeMux] pattern 1466 // that matched the request. 1467 // It returns the empty string if the request was not matched against a pattern 1468 // or there is no such wildcard in the pattern. 1469 func (r *Request) PathValue(name string) string { 1470 if i := r.patIndex(name); i >= 0 { 1471 return r.matches[i] 1472 } 1473 return r.otherValues[name] 1474 } 1475 1476 // SetPathValue sets name to value, so that subsequent calls to r.PathValue(name) 1477 // return value. 1478 func (r *Request) SetPathValue(name, value string) { 1479 if i := r.patIndex(name); i >= 0 { 1480 r.matches[i] = value 1481 } else { 1482 if r.otherValues == nil { 1483 r.otherValues = map[string]string{} 1484 } 1485 r.otherValues[name] = value 1486 } 1487 } 1488 1489 // patIndex returns the index of name in the list of named wildcards of the 1490 // request's pattern, or -1 if there is no such name. 1491 func (r *Request) patIndex(name string) int { 1492 // The linear search seems expensive compared to a map, but just creating the map 1493 // takes a lot of time, and most patterns will just have a couple of wildcards. 1494 if r.pat == nil { 1495 return -1 1496 } 1497 i := 0 1498 for _, seg := range r.pat.segments { 1499 if seg.wild && seg.s != "" { 1500 if name == seg.s { 1501 return i 1502 } 1503 i++ 1504 } 1505 } 1506 return -1 1507 } 1508 1509 func (r *Request) expectsContinue() bool { 1510 return hasToken(r.Header.get("Expect"), "100-continue") 1511 } 1512 1513 func (r *Request) wantsHttp10KeepAlive() bool { 1514 if r.ProtoMajor != 1 || r.ProtoMinor != 0 { 1515 return false 1516 } 1517 return hasToken(r.Header.get("Connection"), "keep-alive") 1518 } 1519 1520 func (r *Request) wantsClose() bool { 1521 if r.Close { 1522 return true 1523 } 1524 return hasToken(r.Header.get("Connection"), "close") 1525 } 1526 1527 func (r *Request) closeBody() error { 1528 if r.Body == nil { 1529 return nil 1530 } 1531 return r.Body.Close() 1532 } 1533 1534 func (r *Request) isReplayable() bool { 1535 if r.Body == nil || r.Body == NoBody || r.GetBody != nil { 1536 switch valueOrDefault(r.Method, "GET") { 1537 case "GET", "HEAD", "OPTIONS", "TRACE": 1538 return true 1539 } 1540 // The Idempotency-Key, while non-standard, is widely used to 1541 // mean a POST or other request is idempotent. See 1542 // https://golang.org/issue/19943#issuecomment-421092421 1543 if r.Header.has("Idempotency-Key") || r.Header.has("X-Idempotency-Key") { 1544 return true 1545 } 1546 } 1547 return false 1548 } 1549 1550 // outgoingLength reports the Content-Length of this outgoing (Client) request. 1551 // It maps 0 into -1 (unknown) when the Body is non-nil. 1552 func (r *Request) outgoingLength() int64 { 1553 if r.Body == nil || r.Body == NoBody { 1554 return 0 1555 } 1556 if r.ContentLength != 0 { 1557 return r.ContentLength 1558 } 1559 return -1 1560 } 1561 1562 // requestMethodUsuallyLacksBody reports whether the given request 1563 // method is one that typically does not involve a request body. 1564 // This is used by the Transport (via 1565 // transferWriter.shouldSendChunkedRequestBody) to determine whether 1566 // we try to test-read a byte from a non-nil Request.Body when 1567 // Request.outgoingLength() returns -1. See the comments in 1568 // shouldSendChunkedRequestBody. 1569 func requestMethodUsuallyLacksBody(method string) bool { 1570 switch method { 1571 case "GET", "HEAD", "DELETE", "OPTIONS", "PROPFIND", "SEARCH": 1572 return true 1573 } 1574 return false 1575 } 1576 1577 // requiresHTTP1 reports whether this request requires being sent on 1578 // an HTTP/1 connection. 1579 func (r *Request) requiresHTTP1() bool { 1580 return hasToken(r.Header.Get("Connection"), "upgrade") && 1581 ascii.EqualFold(r.Header.Get("Upgrade"), "websocket") 1582 } 1583