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 "math" 20 "mime" 21 "mime/multipart" 22 "net/http/httptrace" 23 "net/http/internal/ascii" 24 "net/textproto" 25 "net/url" 26 urlpkg "net/url" 27 "strconv" 28 "strings" 29 "sync" 30 _ "unsafe" // for linkname 31 32 "golang.org/x/net/http/httpguts" 33 "golang.org/x/net/idna" 34 ) 35 36 const ( 37 defaultMaxMemory = 32 << 20 // 32 MB 38 ) 39 40 // ErrMissingFile is returned by FormFile when the provided file field name 41 // is either not present in the request or not a file field. 42 var ErrMissingFile = errors.New("http: no such file") 43 44 // ProtocolError represents an HTTP protocol error. 45 // 46 // Deprecated: Not all errors in the http package related to protocol errors 47 // are of type ProtocolError. 48 type ProtocolError struct { 49 ErrorString string 50 } 51 52 func (pe *ProtocolError) Error() string { return pe.ErrorString } 53 54 // Is lets http.ErrNotSupported match errors.ErrUnsupported. 55 func (pe *ProtocolError) Is(err error) bool { 56 return pe == ErrNotSupported && err == errors.ErrUnsupported 57 } 58 59 var ( 60 // ErrNotSupported indicates that a feature is not supported. 61 // 62 // It is returned by ResponseController methods to indicate that 63 // the handler does not support the method, and by the Push method 64 // of Pusher implementations to indicate that HTTP/2 Push support 65 // is not available. 66 ErrNotSupported = &ProtocolError{"feature not supported"} 67 68 // Deprecated: ErrUnexpectedTrailer is no longer returned by 69 // anything in the net/http package. Callers should not 70 // compare errors against this variable. 71 ErrUnexpectedTrailer = &ProtocolError{"trailer header without chunked transfer encoding"} 72 73 // ErrMissingBoundary is returned by Request.MultipartReader when the 74 // request's Content-Type does not include a "boundary" parameter. 75 ErrMissingBoundary = &ProtocolError{"no multipart boundary param in Content-Type"} 76 77 // ErrNotMultipart is returned by Request.MultipartReader when the 78 // request's Content-Type is not multipart/form-data. 79 ErrNotMultipart = &ProtocolError{"request Content-Type isn't multipart/form-data"} 80 81 // Deprecated: ErrHeaderTooLong is no longer returned by 82 // anything in the net/http package. Callers should not 83 // compare errors against this variable. 84 ErrHeaderTooLong = &ProtocolError{"header too long"} 85 86 // Deprecated: ErrShortBody is no longer returned by 87 // anything in the net/http package. Callers should not 88 // compare errors against this variable. 89 ErrShortBody = &ProtocolError{"entity body too short"} 90 91 // Deprecated: ErrMissingContentLength is no longer returned by 92 // anything in the net/http package. Callers should not 93 // compare errors against this variable. 94 ErrMissingContentLength = &ProtocolError{"missing ContentLength in HEAD response"} 95 ) 96 97 func badStringError(what, val string) error { return fmt.Errorf("%s %q", what, val) } 98 99 // Headers that Request.Write handles itself and should be skipped. 100 var reqWriteExcludeHeader = map[string]bool{ 101 "Host": true, // not in Header map anyway 102 "User-Agent": true, 103 "Content-Length": true, 104 "Transfer-Encoding": true, 105 "Trailer": true, 106 } 107 108 // A Request represents an HTTP request received by a server 109 // or to be sent by a client. 110 // 111 // The field semantics differ slightly between client and server 112 // usage. In addition to the notes on the fields below, see the 113 // documentation for [Request.Write] and [RoundTripper]. 114 type Request struct { 115 // Method specifies the HTTP method (GET, POST, PUT, etc.). 116 // For client requests, an empty string means GET. 117 Method string 118 119 // URL specifies either the URI being requested (for server 120 // requests) or the URL to access (for client requests). 121 // 122 // For server requests, the URL is parsed from the URI 123 // supplied on the Request-Line as stored in RequestURI. For 124 // most requests, fields other than Path and RawQuery will be 125 // empty. (See RFC 7230, Section 5.3) 126 // 127 // For client requests, the URL's Host specifies the server to 128 // connect to, while the Request's Host field optionally 129 // specifies the Host header value to send in the HTTP 130 // request. 131 URL *url.URL 132 133 // The protocol version for incoming server requests. 134 // 135 // For client requests, these fields are ignored. The HTTP 136 // client code always uses either HTTP/1.1 or HTTP/2. 137 // See the docs on Transport for details. 138 Proto string // "HTTP/1.0" 139 ProtoMajor int // 1 140 ProtoMinor int // 0 141 142 // Header contains the request header fields either received 143 // by the server or to be sent by the client. 144 // 145 // If a server received a request with header lines, 146 // 147 // Host: example.com 148 // accept-encoding: gzip, deflate 149 // Accept-Language: en-us 150 // fOO: Bar 151 // foo: two 152 // 153 // then 154 // 155 // Header = map[string][]string{ 156 // "Accept-Encoding": {"gzip, deflate"}, 157 // "Accept-Language": {"en-us"}, 158 // "Foo": {"Bar", "two"}, 159 // } 160 // 161 // For incoming requests, the Host header is promoted to the 162 // Request.Host field and removed from the Header map. 163 // 164 // HTTP defines that header names are case-insensitive. The 165 // request parser implements this by using CanonicalHeaderKey, 166 // making the first character and any characters following a 167 // hyphen uppercase and the rest lowercase. 168 // 169 // For client requests, certain headers such as Content-Length 170 // and Connection are automatically written when needed and 171 // values in Header may be ignored. See the documentation 172 // for the Request.Write method. 173 Header Header 174 175 // Body is the request's body. 176 // 177 // For client requests, a nil body means the request has no 178 // body, such as a GET request. The HTTP Client's Transport 179 // is responsible for calling the Close method. 180 // 181 // For server requests, the Request Body is always non-nil 182 // but will return EOF immediately when no body is present. 183 // The Server will close the request body. The ServeHTTP 184 // Handler does not need to. 185 // 186 // Body must allow Read to be called concurrently with Close. 187 // In particular, calling Close should unblock a Read waiting 188 // for input. 189 Body io.ReadCloser 190 191 // GetBody defines an optional func to return a new copy of 192 // Body. It is used for client requests when a redirect requires 193 // reading the body more than once. Use of GetBody still 194 // requires setting Body. 195 // 196 // For server requests, it is unused. 197 GetBody func() (io.ReadCloser, error) 198 199 // ContentLength records the length of the associated content. 200 // The value -1 indicates that the length is unknown. 201 // Values >= 0 indicate that the given number of bytes may 202 // be read from Body. 203 // 204 // For client requests, a value of 0 with a non-nil Body is 205 // also treated as unknown. 206 ContentLength int64 207 208 // TransferEncoding lists the transfer encodings from outermost to 209 // innermost. An empty list denotes the "identity" encoding. 210 // TransferEncoding can usually be ignored; chunked encoding is 211 // automatically added and removed as necessary when sending and 212 // receiving requests. 213 TransferEncoding []string 214 215 // Close indicates whether to close the connection after 216 // replying to this request (for servers) or after sending this 217 // request and reading its response (for clients). 218 // 219 // For server requests, the HTTP server handles this automatically 220 // and this field is not needed by Handlers. 221 // 222 // For client requests, setting this field prevents re-use of 223 // TCP connections between requests to the same hosts, as if 224 // Transport.DisableKeepAlives were set. 225 Close bool 226 227 // For server requests, Host specifies the host on which the 228 // URL is sought. For HTTP/1 (per RFC 7230, section 5.4), this 229 // is either the value of the "Host" header or the host name 230 // given in the URL itself. For HTTP/2, it is the value of the 231 // ":authority" pseudo-header field. 232 // It may be of the form "host:port". For international domain 233 // names, Host may be in Punycode or Unicode form. Use 234 // golang.org/x/net/idna to convert it to either format if 235 // needed. 236 // To prevent DNS rebinding attacks, server Handlers should 237 // validate that the Host header has a value for which the 238 // Handler considers itself authoritative. The included 239 // ServeMux supports patterns registered to particular host 240 // names and thus protects its registered Handlers. 241 // 242 // For client requests, Host optionally overrides the Host 243 // header to send. If empty, the Request.Write method uses 244 // the value of URL.Host. Host may contain an international 245 // domain name. 246 Host string 247 248 // Form contains the parsed form data, including both the URL 249 // field's query parameters and the PATCH, POST, or PUT form data. 250 // This field is only available after ParseForm is called. 251 // The HTTP client ignores Form and uses Body instead. 252 Form url.Values 253 254 // PostForm contains the parsed form data from PATCH, POST 255 // or PUT body parameters. 256 // 257 // This field is only available after ParseForm is called. 258 // The HTTP client ignores PostForm and uses Body instead. 259 PostForm url.Values 260 261 // MultipartForm is the parsed multipart form, including file uploads. 262 // This field is only available after ParseMultipartForm is called. 263 // The HTTP client ignores MultipartForm and uses Body instead. 264 MultipartForm *multipart.Form 265 266 // Trailer specifies additional headers that are sent after the request 267 // body. 268 // 269 // For server requests, the Trailer map initially contains only the 270 // trailer keys, with nil values. (The client declares which trailers it 271 // will later send.) While the handler is reading from Body, it must 272 // not reference Trailer. After reading from Body returns EOF, Trailer 273 // can be read again and will contain non-nil values, if they were sent 274 // by the client. 275 // 276 // For client requests, Trailer must be initialized to a map containing 277 // the trailer keys to later send. The values may be nil or their final 278 // values. The ContentLength must be 0 or -1, to send a chunked request. 279 // After the HTTP request is sent the map values can be updated while 280 // the request body is read. Once the body returns EOF, the caller must 281 // not mutate Trailer. 282 // 283 // Writing a request whose Trailer contains a key with invalid bytes 284 // (such as CR or LF), or such a value present when Write begins, 285 // returns an error. 286 // 287 // Few HTTP clients, servers, or proxies support HTTP trailers. 288 Trailer Header 289 290 // RemoteAddr allows HTTP servers and other software to record 291 // the network address that sent the request, usually for 292 // logging. This field is not filled in by ReadRequest and 293 // has no defined format. The HTTP server in this package 294 // sets RemoteAddr to an "IP:port" address before invoking a 295 // handler. 296 // This field is ignored by the HTTP client. 297 RemoteAddr string 298 299 // RequestURI is the unmodified request-target of the 300 // Request-Line (RFC 7230, Section 3.1.1) as sent by the client 301 // to a server. Usually the URL field should be used instead. 302 // It is an error to set this field in an HTTP client request. 303 RequestURI string 304 305 // TLS allows HTTP servers and other software to record 306 // information about the TLS connection on which the request 307 // was received. This field is not filled in by ReadRequest. 308 // The HTTP server in this package sets the field for 309 // TLS-enabled connections before invoking a handler; 310 // otherwise it leaves the field nil. 311 // This field is ignored by the HTTP client. 312 TLS *tls.ConnectionState 313 314 // Cancel is an optional channel whose closure indicates that the client 315 // request should be regarded as canceled. Not all implementations of 316 // RoundTripper may support Cancel. 317 // 318 // For server requests, this field is not applicable. 319 // 320 // Deprecated: Set the Request's context with NewRequestWithContext 321 // instead. If a Request's Cancel field and context are both 322 // set, it is undefined whether Cancel is respected. 323 Cancel <-chan struct{} 324 325 // Response is the redirect response which caused this request 326 // to be created. This field is only populated during client 327 // redirects. 328 Response *Response 329 330 // Pattern is the [ServeMux] pattern that matched the request. 331 // It is empty if the request was not matched against a pattern. 332 Pattern string 333 334 // ctx is either the client or server context. It should only 335 // be modified via copying the whole Request using Clone or WithContext. 336 // It is unexported to prevent people from using Context wrong 337 // and mutating the contexts held by callers of the same request. 338 ctx context.Context 339 340 // The following fields are for requests matched by ServeMux. 341 pat *pattern // the pattern that matched 342 matches []string // values for the matching wildcards in pat 343 otherValues map[string]string // for calls to SetPathValue that don't match a wildcard 344 } 345 346 // Context returns the request's context. To change the context, use 347 // [Request.Clone] or [Request.WithContext]. 348 // 349 // The returned context is always non-nil; it defaults to the 350 // background context. 351 // 352 // For outgoing client requests, the context controls cancellation. 353 // 354 // For incoming server requests, the context is canceled when the 355 // client's connection closes, the request is canceled (with HTTP/2), 356 // or when the ServeHTTP method returns. 357 func (r *Request) Context() context.Context { 358 if r.ctx != nil { 359 return r.ctx 360 } 361 return context.Background() 362 } 363 364 // WithContext returns a shallow copy of r with its context changed 365 // to ctx. The provided ctx must be non-nil. 366 // 367 // For outgoing client request, the context controls the entire 368 // lifetime of a request and its response: obtaining a connection, 369 // sending the request, and reading the response headers and body. 370 // 371 // To create a new request with a context, use [NewRequestWithContext]. 372 // To make a deep copy of a request with a new context, use [Request.Clone]. 373 func (r *Request) WithContext(ctx context.Context) *Request { 374 if ctx == nil { 375 panic("nil context") 376 } 377 r2 := new(Request) 378 *r2 = *r 379 r2.ctx = ctx 380 return r2 381 } 382 383 // Clone returns a deep copy of r with its context changed to ctx. 384 // The provided ctx must be non-nil. 385 // 386 // Clone only makes a shallow copy of the Body field. 387 // 388 // For an outgoing client request, the context controls the entire 389 // lifetime of a request and its response: obtaining a connection, 390 // sending the request, and reading the response headers and body. 391 func (r *Request) Clone(ctx context.Context) *Request { 392 if ctx == nil { 393 panic("nil context") 394 } 395 r2 := new(Request) 396 *r2 = *r 397 r2.ctx = ctx 398 r2.URL = cloneURL(r.URL) 399 r2.Header = r.Header.Clone() 400 r2.Trailer = r.Trailer.Clone() 401 if s := r.TransferEncoding; s != nil { 402 s2 := make([]string, len(s)) 403 copy(s2, s) 404 r2.TransferEncoding = s2 405 } 406 r2.Form = cloneURLValues(r.Form) 407 r2.PostForm = cloneURLValues(r.PostForm) 408 r2.MultipartForm = cloneMultipartForm(r.MultipartForm) 409 410 // Copy matches and otherValues. See issue 61410. 411 if s := r.matches; s != nil { 412 s2 := make([]string, len(s)) 413 copy(s2, s) 414 r2.matches = s2 415 } 416 r2.otherValues = maps.Clone(r.otherValues) 417 return r2 418 } 419 420 // ProtoAtLeast reports whether the HTTP protocol used 421 // in the request is at least major.minor. 422 func (r *Request) ProtoAtLeast(major, minor int) bool { 423 return r.ProtoMajor > major || 424 r.ProtoMajor == major && r.ProtoMinor >= minor 425 } 426 427 // UserAgent returns the client's User-Agent, if sent in the request. 428 func (r *Request) UserAgent() string { 429 return r.Header.Get("User-Agent") 430 } 431 432 // Cookies parses and returns the HTTP cookies sent with the request. 433 func (r *Request) Cookies() []*Cookie { 434 return readCookies(r.Header, "") 435 } 436 437 // CookiesNamed parses and returns the named HTTP cookies sent with the request 438 // or an empty slice if none matched. 439 func (r *Request) CookiesNamed(name string) []*Cookie { 440 if name == "" { 441 return []*Cookie{} 442 } 443 return readCookies(r.Header, name) 444 } 445 446 // ErrNoCookie is returned by Request's Cookie method when a cookie is not found. 447 var ErrNoCookie = errors.New("http: named cookie not present") 448 449 // Cookie returns the named cookie provided in the request or 450 // [ErrNoCookie] if not found. 451 // If multiple cookies match the given name, only one cookie will 452 // be returned. 453 func (r *Request) Cookie(name string) (*Cookie, error) { 454 if name == "" { 455 return nil, ErrNoCookie 456 } 457 for _, c := range readCookies(r.Header, name) { 458 return c, nil 459 } 460 return nil, ErrNoCookie 461 } 462 463 // AddCookie adds a cookie to the request. Per RFC 6265 section 5.4, 464 // AddCookie does not attach more than one [Cookie] header field. That 465 // means all cookies, if any, are written into the same line, 466 // separated by semicolon. 467 // AddCookie only sanitizes c's name and value, and does not sanitize 468 // a Cookie header already present in the request. 469 func (r *Request) AddCookie(c *Cookie) { 470 s := fmt.Sprintf("%s=%s", sanitizeCookieName(c.Name), sanitizeCookieValue(c.Value, c.Quoted)) 471 if c := r.Header.Get("Cookie"); c != "" { 472 r.Header.Set("Cookie", c+"; "+s) 473 } else { 474 r.Header.Set("Cookie", s) 475 } 476 } 477 478 // Referer returns the referring URL, if sent in the request. 479 // 480 // Referer is misspelled as in the request itself, a mistake from the 481 // earliest days of HTTP. This value can also be fetched from the 482 // [Header] map as Header["Referer"]; the benefit of making it available 483 // as a method is that the compiler can diagnose programs that use the 484 // alternate (correct English) spelling req.Referrer() but cannot 485 // diagnose programs that use Header["Referrer"]. 486 func (r *Request) Referer() string { 487 return r.Header.Get("Referer") 488 } 489 490 // multipartByReader is a sentinel value. 491 // Its presence in Request.MultipartForm indicates that parsing of the request 492 // body has been handed off to a MultipartReader instead of ParseMultipartForm. 493 var multipartByReader = &multipart.Form{ 494 Value: make(map[string][]string), 495 File: make(map[string][]*multipart.FileHeader), 496 } 497 498 // MultipartReader returns a MIME multipart reader if this is a 499 // multipart/form-data or a multipart/mixed POST request, else returns nil and an error. 500 // Use this function instead of [Request.ParseMultipartForm] to 501 // process the request body as a stream. 502 func (r *Request) MultipartReader() (*multipart.Reader, error) { 503 if r.MultipartForm == multipartByReader { 504 return nil, errors.New("http: MultipartReader called twice") 505 } 506 if r.MultipartForm != nil { 507 return nil, errors.New("http: multipart handled by ParseMultipartForm") 508 } 509 r.MultipartForm = multipartByReader 510 return r.multipartReader(true) 511 } 512 513 func (r *Request) multipartReader(allowMixed bool) (*multipart.Reader, error) { 514 v := r.Header.Get("Content-Type") 515 if v == "" { 516 return nil, ErrNotMultipart 517 } 518 if r.Body == nil { 519 return nil, errors.New("missing form body") 520 } 521 d, params, err := mime.ParseMediaType(v) 522 if err != nil || !(d == "multipart/form-data" || allowMixed && d == "multipart/mixed") { 523 return nil, ErrNotMultipart 524 } 525 boundary, ok := params["boundary"] 526 if !ok { 527 return nil, ErrMissingBoundary 528 } 529 return multipart.NewReader(r.Body, boundary), nil 530 } 531 532 // isH2Upgrade reports whether r represents the http2 "client preface" 533 // magic string. 534 func (r *Request) isH2Upgrade() bool { 535 return r.Method == "PRI" && len(r.Header) == 0 && r.URL.Path == "*" && r.Proto == "HTTP/2.0" 536 } 537 538 // Return value if nonempty, def otherwise. 539 func valueOrDefault(value, def string) string { 540 if value != "" { 541 return value 542 } 543 return def 544 } 545 546 // NOTE: This is not intended to reflect the actual Go version being used. 547 // It was changed at the time of Go 1.1 release because the former User-Agent 548 // had ended up blocked by some intrusion detection systems. 549 // See https://codereview.appspot.com/7532043. 550 const defaultUserAgent = "Go-http-client/1.1" 551 552 // Write writes an HTTP/1.1 request, which is the header and body, in wire format. 553 // This method consults the following fields of the request: 554 // 555 // Host 556 // URL 557 // Method (defaults to "GET") 558 // Header 559 // ContentLength 560 // TransferEncoding 561 // Body 562 // 563 // If Body is present, Content-Length is <= 0 and [Request.TransferEncoding] 564 // hasn't been set to "identity", Write adds "Transfer-Encoding: 565 // chunked" to the header. Body is closed after it is sent. 566 // 567 // Header values for Host, Content-Length, Transfer-Encoding, 568 // and Trailer are not used; these are derived from other Request fields. 569 // If the Header does not contain a User-Agent value, Write uses 570 // "Go-http-client/1.1". 571 func (r *Request) Write(w io.Writer) error { 572 return r.write(w, false, nil, nil) 573 } 574 575 // WriteProxy is like [Request.Write] but writes the request in the form 576 // expected by an HTTP proxy. In particular, [Request.WriteProxy] writes the 577 // initial Request-URI line of the request with an absolute URI, per 578 // section 5.3 of RFC 7230, including the scheme and host. 579 // In either case, WriteProxy also writes a Host header, using 580 // either r.Host or r.URL.Host. 581 func (r *Request) WriteProxy(w io.Writer) error { 582 return r.write(w, true, nil, nil) 583 } 584 585 // errMissingHost is returned by Write when there is no Host or URL present in 586 // the Request. 587 var errMissingHost = errors.New("http: Request.Write on Request with no Host or URL set") 588 589 // extraHeaders may be nil 590 // waitForContinue may be nil 591 // always closes body 592 func (r *Request) write(w io.Writer, usingProxy bool, extraHeaders Header, waitForContinue func() bool) (err error) { 593 trace := httptrace.ContextClientTrace(r.Context()) 594 if trace != nil && trace.WroteRequest != nil { 595 defer func() { 596 trace.WroteRequest(httptrace.WroteRequestInfo{ 597 Err: err, 598 }) 599 }() 600 } 601 closed := false 602 defer func() { 603 if closed { 604 return 605 } 606 if closeErr := r.closeBody(); closeErr != nil && err == nil { 607 err = closeErr 608 } 609 }() 610 611 // Find the target host. Prefer the Host: header, but if that 612 // is not given, use the host from the request URL. 613 // 614 // Clean the host, in case it arrives with unexpected stuff in it. 615 host := r.Host 616 if host == "" { 617 if r.URL == nil { 618 return errMissingHost 619 } 620 host = r.URL.Host 621 } 622 host, err = httpguts.PunycodeHostPort(host) 623 if err != nil { 624 return err 625 } 626 // Validate that the Host header is a valid header in general, 627 // but don't validate the host itself. This is sufficient to avoid 628 // header or request smuggling via the Host field. 629 // The server can (and will, if it's a net/http server) reject 630 // the request if it doesn't consider the host valid. 631 if !httpguts.ValidHostHeader(host) { 632 // Historically, we would truncate the Host header after '/' or ' '. 633 // Some users have relied on this truncation to convert a network 634 // address such as Unix domain socket path into a valid, ignored 635 // Host header (see https://go.dev/issue/61431). 636 // 637 // We don't preserve the truncation, because sending an altered 638 // header field opens a smuggling vector. Instead, zero out the 639 // Host header entirely if it isn't valid. (An empty Host is valid; 640 // see RFC 9112 Section 3.2.) 641 // 642 // Return an error if we're sending to a proxy, since the proxy 643 // probably can't do anything useful with an empty Host header. 644 if !usingProxy { 645 host = "" 646 } else { 647 return errors.New("http: invalid Host header") 648 } 649 } 650 651 // According to RFC 6874, an HTTP client, proxy, or other 652 // intermediary must remove any IPv6 zone identifier attached 653 // to an outgoing URI. 654 host = removeZone(host) 655 656 ruri := r.URL.RequestURI() 657 if usingProxy && r.URL.Scheme != "" && r.URL.Opaque == "" { 658 ruri = r.URL.Scheme + "://" + host + ruri 659 } else if r.Method == "CONNECT" && r.URL.Path == "" { 660 // CONNECT requests normally give just the host and port, not a full URL. 661 ruri = host 662 if r.URL.Opaque != "" { 663 ruri = r.URL.Opaque 664 } 665 } 666 if stringContainsCTLByte(ruri) { 667 return errors.New("net/http: can't write control character in Request.URL") 668 } 669 // TODO: validate r.Method too? At least it's less likely to 670 // come from an attacker (more likely to be a constant in 671 // code). 672 673 // Wrap the writer in a bufio Writer if it's not already buffered. 674 // Don't always call NewWriter, as that forces a bytes.Buffer 675 // and other small bufio Writers to have a minimum 4k buffer 676 // size. 677 var bw *bufio.Writer 678 if _, ok := w.(io.ByteWriter); !ok { 679 bw = bufio.NewWriter(w) 680 w = bw 681 } 682 683 _, err = fmt.Fprintf(w, "%s %s HTTP/1.1\r\n", valueOrDefault(r.Method, "GET"), ruri) 684 if err != nil { 685 return err 686 } 687 688 // Header lines 689 _, err = fmt.Fprintf(w, "Host: %s\r\n", host) 690 if err != nil { 691 return err 692 } 693 if trace != nil && trace.WroteHeaderField != nil { 694 trace.WroteHeaderField("Host", []string{host}) 695 } 696 697 // Use the defaultUserAgent unless the Header contains one, which 698 // may be blank to not send the header. 699 userAgent := defaultUserAgent 700 if r.Header.has("User-Agent") { 701 userAgent = r.Header.Get("User-Agent") 702 } 703 if userAgent != "" { 704 userAgent = headerNewlineToSpace.Replace(userAgent) 705 userAgent = textproto.TrimString(userAgent) 706 _, err = fmt.Fprintf(w, "User-Agent: %s\r\n", userAgent) 707 if err != nil { 708 return err 709 } 710 if trace != nil && trace.WroteHeaderField != nil { 711 trace.WroteHeaderField("User-Agent", []string{userAgent}) 712 } 713 } 714 715 // Process Body,ContentLength,Close,Trailer 716 tw, err := newTransferWriter(r) 717 if err != nil { 718 return err 719 } 720 err = tw.writeHeader(w, trace) 721 if err != nil { 722 return err 723 } 724 725 err = r.Header.writeSubset(w, reqWriteExcludeHeader, trace) 726 if err != nil { 727 return err 728 } 729 730 if extraHeaders != nil { 731 err = extraHeaders.write(w, trace) 732 if err != nil { 733 return err 734 } 735 } 736 737 _, err = io.WriteString(w, "\r\n") 738 if err != nil { 739 return err 740 } 741 742 if trace != nil && trace.WroteHeaders != nil { 743 trace.WroteHeaders() 744 } 745 746 // Flush and wait for 100-continue if expected. 747 if waitForContinue != nil { 748 if bw, ok := w.(*bufio.Writer); ok { 749 err = bw.Flush() 750 if err != nil { 751 return err 752 } 753 } 754 if trace != nil && trace.Wait100Continue != nil { 755 trace.Wait100Continue() 756 } 757 if !waitForContinue() { 758 closed = true 759 r.closeBody() 760 return nil 761 } 762 } 763 764 if bw, ok := w.(*bufio.Writer); ok && tw.FlushHeaders { 765 if err := bw.Flush(); err != nil { 766 return err 767 } 768 } 769 770 // Write body and trailer 771 closed = true 772 err = tw.writeBody(w) 773 if err != nil { 774 if tw.bodyReadError == err { 775 err = requestBodyReadError{err} 776 } 777 return err 778 } 779 780 if bw != nil { 781 return bw.Flush() 782 } 783 return nil 784 } 785 786 // requestBodyReadError wraps an error from (*Request).write to indicate 787 // that the error came from a Read call on the Request.Body. 788 // This error type should not escape the net/http package to users. 789 type requestBodyReadError struct{ error } 790 791 func idnaASCII(v string) (string, error) { 792 // TODO: Follow the WHATWG URL Specification. 793 // 794 // WHATWG accepts all ASCII-only names (although sometimes with advisory 795 // validation errors), so skipping the relatively expensive IDNA processing 796 // on them is fine. 797 if ascii.Is(v) { 798 return v, nil 799 } 800 return idna.Lookup.ToASCII(v) 801 } 802 803 // removeZone removes IPv6 zone identifier from host. 804 // E.g., "[fe80::1%en0]:8080" to "[fe80::1]:8080" 805 func removeZone(host string) string { 806 if !strings.HasPrefix(host, "[") { 807 return host 808 } 809 i := strings.LastIndex(host, "]") 810 if i < 0 { 811 return host 812 } 813 j := strings.LastIndex(host[:i], "%") 814 if j < 0 { 815 return host 816 } 817 return host[:j] + host[i:] 818 } 819 820 // ParseHTTPVersion parses an HTTP version string according to RFC 7230, section 2.6. 821 // "HTTP/1.0" returns (1, 0, true). Note that strings without 822 // a minor version, such as "HTTP/2", are not valid. 823 func ParseHTTPVersion(vers string) (major, minor int, ok bool) { 824 switch vers { 825 case "HTTP/1.1": 826 return 1, 1, true 827 case "HTTP/1.0": 828 return 1, 0, true 829 } 830 if !strings.HasPrefix(vers, "HTTP/") { 831 return 0, 0, false 832 } 833 if len(vers) != len("HTTP/X.Y") { 834 return 0, 0, false 835 } 836 if vers[6] != '.' { 837 return 0, 0, false 838 } 839 maj, err := strconv.ParseUint(vers[5:6], 10, 0) 840 if err != nil { 841 return 0, 0, false 842 } 843 min, err := strconv.ParseUint(vers[7:8], 10, 0) 844 if err != nil { 845 return 0, 0, false 846 } 847 return int(maj), int(min), true 848 } 849 850 func validMethod(method string) bool { 851 /* 852 Method = "OPTIONS" ; Section 9.2 853 | "GET" ; Section 9.3 854 | "HEAD" ; Section 9.4 855 | "POST" ; Section 9.5 856 | "PUT" ; Section 9.6 857 | "DELETE" ; Section 9.7 858 | "TRACE" ; Section 9.8 859 | "CONNECT" ; Section 9.9 860 | extension-method 861 extension-method = token 862 token = 1*<any CHAR except CTLs or separators> 863 */ 864 return isToken(method) 865 } 866 867 // NewRequest wraps [NewRequestWithContext] using [context.Background]. 868 func NewRequest(method, url string, body io.Reader) (*Request, error) { 869 return NewRequestWithContext(context.Background(), method, url, body) 870 } 871 872 // NewRequestWithContext returns a new [Request] given a method, URL, and 873 // optional body. 874 // 875 // If the provided body is also an [io.Closer], the returned 876 // [Request.Body] is set to body and will be closed (possibly 877 // asynchronously) by the Client methods Do, Post, and PostForm, 878 // and [Transport.RoundTrip]. 879 // 880 // NewRequestWithContext returns a Request suitable for use with 881 // [Client.Do] or [Transport.RoundTrip]. To create a request for use with 882 // testing a Server Handler, either use the [net/http/httptest.NewRequest] function, 883 // use [ReadRequest], or manually update the Request fields. 884 // For an outgoing client request, the context 885 // controls the entire lifetime of a request and its response: 886 // obtaining a connection, sending the request, and reading the 887 // response headers and body. See the [Request] type's documentation for 888 // the difference between inbound and outbound request fields. 889 // 890 // If body is of type [*bytes.Buffer], [*bytes.Reader], or 891 // [*strings.Reader], the returned request's ContentLength is set to its 892 // exact value (instead of -1), GetBody is populated (so 307 and 308 893 // redirects can replay the body), and Body is set to [NoBody] if the 894 // ContentLength is 0. 895 func NewRequestWithContext(ctx context.Context, method, url string, body io.Reader) (*Request, error) { 896 if method == "" { 897 // We document that "" means "GET" for Request.Method, and people have 898 // relied on that from NewRequest, so keep that working. 899 // We still enforce validMethod for non-empty methods. 900 method = "GET" 901 } 902 if !validMethod(method) { 903 return nil, fmt.Errorf("net/http: invalid method %q", method) 904 } 905 if ctx == nil { 906 return nil, errors.New("net/http: nil Context") 907 } 908 u, err := urlpkg.Parse(url) 909 if err != nil { 910 return nil, err 911 } 912 rc, ok := body.(io.ReadCloser) 913 if !ok && body != nil { 914 rc = io.NopCloser(body) 915 } 916 // The host's colon:port should be normalized. See Issue 14836. 917 u.Host = strings.TrimSuffix(u.Host, ":") 918 req := &Request{ 919 ctx: ctx, 920 Method: method, 921 URL: u, 922 Proto: "HTTP/1.1", 923 ProtoMajor: 1, 924 ProtoMinor: 1, 925 Header: make(Header), 926 Body: rc, 927 Host: u.Host, 928 } 929 if body != nil { 930 switch v := body.(type) { 931 case *bytes.Buffer: 932 req.ContentLength = int64(v.Len()) 933 buf := v.Bytes() 934 req.GetBody = func() (io.ReadCloser, error) { 935 r := bytes.NewReader(buf) 936 return io.NopCloser(r), nil 937 } 938 case *bytes.Reader: 939 req.ContentLength = int64(v.Len()) 940 snapshot := *v 941 req.GetBody = func() (io.ReadCloser, error) { 942 r := snapshot 943 return io.NopCloser(&r), nil 944 } 945 case *strings.Reader: 946 req.ContentLength = int64(v.Len()) 947 snapshot := *v 948 req.GetBody = func() (io.ReadCloser, error) { 949 r := snapshot 950 return io.NopCloser(&r), nil 951 } 952 default: 953 // This is where we'd set it to -1 (at least 954 // if body != NoBody) to mean unknown, but 955 // that broke people during the Go 1.8 testing 956 // period. People depend on it being 0 I 957 // guess. Maybe retry later. See Issue 18117. 958 } 959 // For client requests, Request.ContentLength of 0 960 // means either actually 0, or unknown. The only way 961 // to explicitly say that the ContentLength is zero is 962 // to set the Body to nil. But turns out too much code 963 // depends on NewRequest returning a non-nil Body, 964 // so we use a well-known ReadCloser variable instead 965 // and have the http package also treat that sentinel 966 // variable to mean explicitly zero. 967 if req.GetBody != nil && req.ContentLength == 0 { 968 req.Body = NoBody 969 req.GetBody = func() (io.ReadCloser, error) { return NoBody, nil } 970 } 971 } 972 973 return req, nil 974 } 975 976 // BasicAuth returns the username and password provided in the request's 977 // Authorization header, if the request uses HTTP Basic Authentication. 978 // See RFC 2617, Section 2. 979 func (r *Request) BasicAuth() (username, password string, ok bool) { 980 auth := r.Header.Get("Authorization") 981 if auth == "" { 982 return "", "", false 983 } 984 return parseBasicAuth(auth) 985 } 986 987 // parseBasicAuth parses an HTTP Basic Authentication string. 988 // "Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==" returns ("Aladdin", "open sesame", true). 989 // 990 // parseBasicAuth should be an internal detail, 991 // but widely used packages access it using linkname. 992 // Notable members of the hall of shame include: 993 // - github.com/sagernet/sing 994 // 995 // Do not remove or change the type signature. 996 // See go.dev/issue/67401. 997 // 998 //go:linkname parseBasicAuth 999 func parseBasicAuth(auth string) (username, password string, ok bool) { 1000 const prefix = "Basic " 1001 // Case insensitive prefix match. See Issue 22736. 1002 if len(auth) < len(prefix) || !ascii.EqualFold(auth[:len(prefix)], prefix) { 1003 return "", "", false 1004 } 1005 c, err := base64.StdEncoding.DecodeString(auth[len(prefix):]) 1006 if err != nil { 1007 return "", "", false 1008 } 1009 cs := string(c) 1010 username, password, ok = strings.Cut(cs, ":") 1011 if !ok { 1012 return "", "", false 1013 } 1014 return username, password, true 1015 } 1016 1017 // SetBasicAuth sets the request's Authorization header to use HTTP 1018 // Basic Authentication with the provided username and password. 1019 // 1020 // With HTTP Basic Authentication the provided username and password 1021 // are not encrypted. It should generally only be used in an HTTPS 1022 // request. 1023 // 1024 // The username may not contain a colon. Some protocols may impose 1025 // additional requirements on pre-escaping the username and 1026 // password. For instance, when used with OAuth2, both arguments must 1027 // be URL encoded first with [url.QueryEscape]. 1028 func (r *Request) SetBasicAuth(username, password string) { 1029 r.Header.Set("Authorization", "Basic "+basicAuth(username, password)) 1030 } 1031 1032 // parseRequestLine parses "GET /foo HTTP/1.1" into its three parts. 1033 func parseRequestLine(line string) (method, requestURI, proto string, ok bool) { 1034 method, rest, ok1 := strings.Cut(line, " ") 1035 requestURI, proto, ok2 := strings.Cut(rest, " ") 1036 if !ok1 || !ok2 { 1037 return "", "", "", false 1038 } 1039 return method, requestURI, proto, true 1040 } 1041 1042 var textprotoReaderPool sync.Pool 1043 1044 func newTextprotoReader(br *bufio.Reader) *textproto.Reader { 1045 if v := textprotoReaderPool.Get(); v != nil { 1046 tr := v.(*textproto.Reader) 1047 tr.R = br 1048 return tr 1049 } 1050 return textproto.NewReader(br) 1051 } 1052 1053 func putTextprotoReader(r *textproto.Reader) { 1054 r.R = nil 1055 textprotoReaderPool.Put(r) 1056 } 1057 1058 // ReadRequest reads and parses an incoming request from b. 1059 // 1060 // ReadRequest is a low-level function and should only be used for 1061 // specialized applications; most code should use the [Server] to read 1062 // requests and handle them via the [Handler] interface. ReadRequest 1063 // only supports HTTP/1.x requests. For HTTP/2, use golang.org/x/net/http2. 1064 func ReadRequest(b *bufio.Reader) (*Request, error) { 1065 req, err := readRequest(b) 1066 if err != nil { 1067 return nil, err 1068 } 1069 1070 delete(req.Header, "Host") 1071 return req, nil 1072 } 1073 1074 // readMIMEHeader is defined in package [net/textproto]. 1075 // 1076 //go:linkname readMIMEHeader net/textproto.readMIMEHeader 1077 func readMIMEHeader(r *textproto.Reader, maxMemory, maxHeaders int64) (textproto.MIMEHeader, error) 1078 1079 // readRequest should be an internal detail, 1080 // but widely used packages access it using linkname. 1081 // Notable members of the hall of shame include: 1082 // - github.com/sagernet/sing 1083 // - github.com/v2fly/v2ray-core/v4 1084 // - github.com/v2fly/v2ray-core/v5 1085 // 1086 // Do not remove or change the type signature. 1087 // See go.dev/issue/67401. 1088 // 1089 //go:linkname readRequest 1090 func readRequest(b *bufio.Reader) (req *Request, err error) { 1091 return readRequestLimit(b, math.MaxInt64) 1092 } 1093 1094 func readRequestLimit(b *bufio.Reader, maxHeaders int64) (req *Request, err error) { 1095 tp := newTextprotoReader(b) 1096 defer putTextprotoReader(tp) 1097 1098 req = new(Request) 1099 1100 // First line: GET /index.html HTTP/1.0 1101 var s string 1102 if s, err = tp.ReadLine(); err != nil { 1103 return nil, err 1104 } 1105 defer func() { 1106 if err == io.EOF { 1107 err = io.ErrUnexpectedEOF 1108 } 1109 }() 1110 1111 var ok bool 1112 req.Method, req.RequestURI, req.Proto, ok = parseRequestLine(s) 1113 if !ok { 1114 return nil, badStringError("malformed HTTP request", s) 1115 } 1116 if !validMethod(req.Method) { 1117 return nil, badStringError("invalid method", req.Method) 1118 } 1119 rawurl := req.RequestURI 1120 if req.ProtoMajor, req.ProtoMinor, ok = ParseHTTPVersion(req.Proto); !ok { 1121 return nil, badStringError("malformed HTTP version", req.Proto) 1122 } 1123 1124 // CONNECT requests are used two different ways, and neither uses a full URL: 1125 // The standard use is to tunnel HTTPS through an HTTP proxy. 1126 // It looks like "CONNECT www.google.com:443 HTTP/1.1", and the parameter is 1127 // just the authority section of a URL. This information should go in req.URL.Host. 1128 // 1129 // The net/rpc package also uses CONNECT, but there the parameter is a path 1130 // that starts with a slash. It can be parsed with the regular URL parser, 1131 // and the path will end up in req.URL.Path, where it needs to be in order for 1132 // RPC to work. 1133 justAuthority := req.Method == "CONNECT" && !strings.HasPrefix(rawurl, "/") 1134 if justAuthority { 1135 rawurl = "http://" + rawurl 1136 } 1137 1138 if req.URL, err = url.ParseRequestURI(rawurl); err != nil { 1139 return nil, err 1140 } 1141 1142 if justAuthority { 1143 // Strip the bogus "http://" back off. 1144 req.URL.Scheme = "" 1145 } 1146 1147 // Subsequent lines: Key: value. 1148 mimeHeader, err := readMIMEHeader(tp, math.MaxInt64, maxHeaders) 1149 if err != nil { 1150 // TODO: Add a distinguishable error to net/textproto. 1151 if err.Error() == "message too large" { 1152 return nil, errTooLarge 1153 } 1154 return nil, err 1155 } 1156 req.Header = Header(mimeHeader) 1157 if len(req.Header["Host"]) > 1 { 1158 return nil, fmt.Errorf("too many Host headers") 1159 } 1160 1161 // RFC 7230, section 5.3: Must treat 1162 // GET /index.html HTTP/1.1 1163 // Host: www.google.com 1164 // and 1165 // GET http://www.google.com/index.html HTTP/1.1 1166 // Host: doesntmatter 1167 // the same. In the second case, any Host line is ignored. 1168 req.Host = req.URL.Host 1169 if req.Host == "" { 1170 req.Host = req.Header.get("Host") 1171 } 1172 1173 fixPragmaCacheControl(req.Header) 1174 1175 req.Close = shouldClose(req.ProtoMajor, req.ProtoMinor, req.Header, false) 1176 1177 err = readTransfer(req, b, maxHeaders) 1178 if err != nil { 1179 return nil, err 1180 } 1181 1182 if req.isH2Upgrade() { 1183 // Because it's neither chunked, nor declared: 1184 req.ContentLength = -1 1185 1186 // We want to give handlers a chance to hijack the 1187 // connection, but we need to prevent the Server from 1188 // dealing with the connection further if it's not 1189 // hijacked. Set Close to ensure that: 1190 req.Close = true 1191 } 1192 return req, nil 1193 } 1194 1195 // MaxBytesReader is similar to [io.LimitReader] but is intended for 1196 // limiting the size of incoming request bodies. In contrast to 1197 // io.LimitReader, MaxBytesReader's result is a ReadCloser, returns a 1198 // non-nil error of type [*MaxBytesError] for a Read beyond the limit, 1199 // and closes the underlying reader when its Close method is called. 1200 // 1201 // MaxBytesReader prevents clients from accidentally or maliciously 1202 // sending a large request and wasting server resources. If possible, 1203 // it tells the [ResponseWriter] to close the connection after the limit 1204 // has been reached. 1205 func MaxBytesReader(w ResponseWriter, r io.ReadCloser, n int64) io.ReadCloser { 1206 if n < 0 { // Treat negative limits as equivalent to 0. 1207 n = 0 1208 } 1209 return &maxBytesReader{w: w, r: r, i: n, n: n} 1210 } 1211 1212 // MaxBytesError is returned by [MaxBytesReader] when its read limit is exceeded. 1213 type MaxBytesError struct { 1214 Limit int64 1215 } 1216 1217 func (e *MaxBytesError) Error() string { 1218 // Due to Hyrum's law, this text cannot be changed. 1219 return "http: request body too large" 1220 } 1221 1222 type maxBytesReader struct { 1223 w ResponseWriter 1224 r io.ReadCloser // underlying reader 1225 i int64 // max bytes initially, for MaxBytesError 1226 n int64 // max bytes remaining 1227 err error // sticky error 1228 } 1229 1230 func (l *maxBytesReader) Read(p []byte) (n int, err error) { 1231 if l.err != nil { 1232 return 0, l.err 1233 } 1234 if len(p) == 0 { 1235 return 0, nil 1236 } 1237 // If they asked for a 32KB byte read but only 5 bytes are 1238 // remaining, no need to read 32KB. 6 bytes will answer the 1239 // question of the whether we hit the limit or go past it. 1240 // 0 < len(p) < 2^63 1241 if int64(len(p))-1 > l.n { 1242 p = p[:l.n+1] 1243 } 1244 n, err = l.r.Read(p) 1245 1246 if int64(n) <= l.n { 1247 l.n -= int64(n) 1248 l.err = err 1249 return n, err 1250 } 1251 1252 n = int(l.n) 1253 l.n = 0 1254 1255 // The server code and client code both use 1256 // maxBytesReader. This "requestTooLarge" check is 1257 // only used by the server code. To prevent binaries 1258 // which only using the HTTP Client code (such as 1259 // cmd/go) from also linking in the HTTP server, don't 1260 // use a static type assertion to the server 1261 // "*response" type. Check this interface instead: 1262 type requestTooLarger interface { 1263 requestTooLarge() 1264 } 1265 if res, ok := l.w.(requestTooLarger); ok { 1266 res.requestTooLarge() 1267 } 1268 l.err = &MaxBytesError{l.i} 1269 return n, l.err 1270 } 1271 1272 func (l *maxBytesReader) Close() error { 1273 return l.r.Close() 1274 } 1275 1276 func copyValues(dst, src url.Values) { 1277 for k, vs := range src { 1278 dst[k] = append(dst[k], vs...) 1279 } 1280 } 1281 1282 func parsePostForm(r *Request) (vs url.Values, err error) { 1283 if r.Body == nil { 1284 err = errors.New("missing form body") 1285 return 1286 } 1287 ct := r.Header.Get("Content-Type") 1288 // RFC 7231, section 3.1.1.5 - empty type 1289 // MAY be treated as application/octet-stream 1290 if ct == "" { 1291 ct = "application/octet-stream" 1292 } 1293 ct, _, err = mime.ParseMediaType(ct) 1294 switch { 1295 case ct == "application/x-www-form-urlencoded": 1296 var reader io.Reader = r.Body 1297 maxFormSize := int64(1<<63 - 1) 1298 if _, ok := r.Body.(*maxBytesReader); !ok { 1299 maxFormSize = int64(10 << 20) // 10 MB is a lot of text. 1300 reader = io.LimitReader(r.Body, maxFormSize+1) 1301 } 1302 b, e := io.ReadAll(reader) 1303 if e != nil { 1304 if err == nil { 1305 err = e 1306 } 1307 break 1308 } 1309 if int64(len(b)) > maxFormSize { 1310 err = errors.New("http: POST too large") 1311 return 1312 } 1313 vs, e = url.ParseQuery(string(b)) 1314 if err == nil { 1315 err = e 1316 } 1317 case ct == "multipart/form-data": 1318 // handled by ParseMultipartForm (which is calling us, or should be) 1319 // TODO(bradfitz): there are too many possible 1320 // orders to call too many functions here. 1321 // Clean this up and write more tests. 1322 // request_test.go contains the start of this, 1323 // in TestParseMultipartFormOrder and others. 1324 } 1325 return 1326 } 1327 1328 // ParseForm populates r.Form and r.PostForm. 1329 // 1330 // For all requests, ParseForm parses the raw query from the URL and updates 1331 // r.Form. 1332 // 1333 // For POST, PUT, and PATCH requests, it also reads the request body, parses it 1334 // as a form and puts the results into both r.PostForm and r.Form. Request body 1335 // parameters take precedence over URL query string values in r.Form. 1336 // 1337 // If the request Body's size has not already been limited by [MaxBytesReader], 1338 // the size is capped at 10MB. 1339 // 1340 // For other HTTP methods, or when the Content-Type is not 1341 // application/x-www-form-urlencoded, the request Body is not read, and 1342 // r.PostForm is initialized to a non-nil, empty value. 1343 // 1344 // [Request.ParseMultipartForm] calls ParseForm automatically. 1345 // ParseForm is idempotent. 1346 func (r *Request) ParseForm() error { 1347 var err error 1348 if r.PostForm == nil { 1349 if r.Method == "POST" || r.Method == "PUT" || r.Method == "PATCH" { 1350 r.PostForm, err = parsePostForm(r) 1351 } 1352 if r.PostForm == nil { 1353 r.PostForm = make(url.Values) 1354 } 1355 } 1356 if r.Form == nil { 1357 if len(r.PostForm) > 0 { 1358 r.Form = make(url.Values) 1359 copyValues(r.Form, r.PostForm) 1360 } 1361 var newValues url.Values 1362 if r.URL != nil { 1363 var e error 1364 newValues, e = url.ParseQuery(r.URL.RawQuery) 1365 if err == nil { 1366 err = e 1367 } 1368 } 1369 if newValues == nil { 1370 newValues = make(url.Values) 1371 } 1372 if r.Form == nil { 1373 r.Form = newValues 1374 } else { 1375 copyValues(r.Form, newValues) 1376 } 1377 } 1378 return err 1379 } 1380 1381 // ParseMultipartForm parses a request body as multipart/form-data. 1382 // The whole request body is parsed and up to a total of maxMemory bytes of 1383 // its file parts are stored in memory, with the remainder stored on 1384 // disk in temporary files. 1385 // ParseMultipartForm calls [Request.ParseForm] if necessary. 1386 // If ParseForm returns an error, ParseMultipartForm returns it but also 1387 // continues parsing the request body. 1388 // After one call to ParseMultipartForm, subsequent calls have no effect. 1389 func (r *Request) ParseMultipartForm(maxMemory int64) error { 1390 if r.MultipartForm == multipartByReader { 1391 return errors.New("http: multipart handled by MultipartReader") 1392 } 1393 var parseFormErr error 1394 if r.Form == nil { 1395 // Let errors in ParseForm fall through, and just 1396 // return it at the end. 1397 parseFormErr = r.ParseForm() 1398 } 1399 if r.MultipartForm != nil { 1400 return nil 1401 } 1402 1403 mr, err := r.multipartReader(false) 1404 if err != nil { 1405 return err 1406 } 1407 1408 f, err := mr.ReadForm(maxMemory) 1409 if err != nil { 1410 return err 1411 } 1412 1413 if r.PostForm == nil { 1414 r.PostForm = make(url.Values) 1415 } 1416 for k, v := range f.Value { 1417 r.Form[k] = append(r.Form[k], v...) 1418 // r.PostForm should also be populated. See Issue 9305. 1419 r.PostForm[k] = append(r.PostForm[k], v...) 1420 } 1421 1422 r.MultipartForm = f 1423 1424 return parseFormErr 1425 } 1426 1427 // FormValue returns the first value for the named component of the query. 1428 // The precedence order: 1429 // 1. application/x-www-form-urlencoded form body (POST, PUT, PATCH only) 1430 // 2. query parameters (always) 1431 // 3. multipart/form-data form body (always) 1432 // 1433 // FormValue calls [Request.ParseMultipartForm] and [Request.ParseForm] 1434 // if necessary and ignores any errors returned by these functions. 1435 // If key is not present, FormValue returns the empty string. 1436 // To access multiple values of the same key, call ParseForm and 1437 // then inspect [Request.Form] directly. 1438 func (r *Request) FormValue(key string) string { 1439 if r.Form == nil { 1440 r.ParseMultipartForm(defaultMaxMemory) 1441 } 1442 if vs := r.Form[key]; len(vs) > 0 { 1443 return vs[0] 1444 } 1445 return "" 1446 } 1447 1448 // PostFormValue returns the first value for the named component of the POST, 1449 // PUT, or PATCH request body. URL query parameters are ignored. 1450 // PostFormValue calls [Request.ParseMultipartForm] and [Request.ParseForm] if necessary and ignores 1451 // any errors returned by these functions. 1452 // If key is not present, PostFormValue returns the empty string. 1453 func (r *Request) PostFormValue(key string) string { 1454 if r.PostForm == nil { 1455 r.ParseMultipartForm(defaultMaxMemory) 1456 } 1457 if vs := r.PostForm[key]; len(vs) > 0 { 1458 return vs[0] 1459 } 1460 return "" 1461 } 1462 1463 // FormFile returns the first file for the provided form key. 1464 // FormFile calls [Request.ParseMultipartForm] and [Request.ParseForm] if necessary. 1465 func (r *Request) FormFile(key string) (multipart.File, *multipart.FileHeader, error) { 1466 if r.MultipartForm == multipartByReader { 1467 return nil, nil, errors.New("http: multipart handled by MultipartReader") 1468 } 1469 if r.MultipartForm == nil { 1470 err := r.ParseMultipartForm(defaultMaxMemory) 1471 if err != nil { 1472 return nil, nil, err 1473 } 1474 } 1475 if r.MultipartForm != nil && r.MultipartForm.File != nil { 1476 if fhs := r.MultipartForm.File[key]; len(fhs) > 0 { 1477 f, err := fhs[0].Open() 1478 return f, fhs[0], err 1479 } 1480 } 1481 return nil, nil, ErrMissingFile 1482 } 1483 1484 // PathValue returns the value for the named path wildcard in the [ServeMux] pattern 1485 // that matched the request. 1486 // It returns the empty string if the request was not matched against a pattern 1487 // or there is no such wildcard in the pattern. 1488 // 1489 // The value is unescaped. For example, if the pattern "/b/{bucket}" matches 1490 // the path "/b/a%2fb", PathValue("bucket") returns "a/b". 1491 func (r *Request) PathValue(name string) string { 1492 if i := r.patIndex(name); i >= 0 { 1493 return r.matches[i] 1494 } 1495 return r.otherValues[name] 1496 } 1497 1498 // SetPathValue sets name to value, so that subsequent calls to r.PathValue(name) 1499 // return value. 1500 // It does not unescape value. 1501 func (r *Request) SetPathValue(name, value string) { 1502 if i := r.patIndex(name); i >= 0 { 1503 r.matches[i] = value 1504 } else { 1505 if r.otherValues == nil { 1506 r.otherValues = map[string]string{} 1507 } 1508 r.otherValues[name] = value 1509 } 1510 } 1511 1512 // patIndex returns the index of name in the list of named wildcards of the 1513 // request's pattern, or -1 if there is no such name. 1514 func (r *Request) patIndex(name string) int { 1515 // The linear search seems expensive compared to a map, but just creating the map 1516 // takes a lot of time, and most patterns will just have a couple of wildcards. 1517 if r.pat == nil { 1518 return -1 1519 } 1520 i := 0 1521 for _, seg := range r.pat.segments { 1522 if seg.wild && seg.s != "" { 1523 if name == seg.s { 1524 return i 1525 } 1526 i++ 1527 } 1528 } 1529 return -1 1530 } 1531 1532 func (r *Request) expectsContinue() bool { 1533 return hasToken(r.Header.get("Expect"), "100-continue") 1534 } 1535 1536 func (r *Request) wantsHttp10KeepAlive() bool { 1537 if r.ProtoMajor != 1 || r.ProtoMinor != 0 { 1538 return false 1539 } 1540 return hasToken(r.Header.get("Connection"), "keep-alive") 1541 } 1542 1543 func (r *Request) wantsClose() bool { 1544 if r.Close { 1545 return true 1546 } 1547 return hasToken(r.Header.get("Connection"), "close") 1548 } 1549 1550 func (r *Request) closeBody() error { 1551 if r.Body == nil { 1552 return nil 1553 } 1554 return r.Body.Close() 1555 } 1556 1557 func (r *Request) isReplayable() bool { 1558 if r.Body == nil || r.Body == NoBody || r.GetBody != nil { 1559 switch valueOrDefault(r.Method, "GET") { 1560 case "GET", "HEAD", "OPTIONS", "TRACE": 1561 return true 1562 } 1563 // The Idempotency-Key, while non-standard, is widely used to 1564 // mean a POST or other request is idempotent. See 1565 // https://golang.org/issue/19943#issuecomment-421092421 1566 if r.Header.has("Idempotency-Key") || r.Header.has("X-Idempotency-Key") { 1567 return true 1568 } 1569 } 1570 return false 1571 } 1572 1573 // outgoingLength reports the Content-Length of this outgoing (Client) request. 1574 // It maps 0 into -1 (unknown) when the Body is non-nil. 1575 func (r *Request) outgoingLength() int64 { 1576 if r.Body == nil || r.Body == NoBody { 1577 return 0 1578 } 1579 if r.ContentLength != 0 { 1580 return r.ContentLength 1581 } 1582 return -1 1583 } 1584 1585 // requestMethodUsuallyLacksBody reports whether the given request 1586 // method is one that typically does not involve a request body. 1587 // This is used by the Transport (via 1588 // transferWriter.shouldSendChunkedRequestBody) to determine whether 1589 // we try to test-read a byte from a non-nil Request.Body when 1590 // Request.outgoingLength() returns -1. See the comments in 1591 // shouldSendChunkedRequestBody. 1592 func requestMethodUsuallyLacksBody(method string) bool { 1593 switch method { 1594 case "GET", "HEAD", "DELETE", "OPTIONS", "PROPFIND", "SEARCH": 1595 return true 1596 } 1597 return false 1598 } 1599 1600 // requiresHTTP1 reports whether this request requires being sent on 1601 // an HTTP/1 connection. 1602 func (r *Request) requiresHTTP1() bool { 1603 return hasToken(r.Header.Get("Connection"), "upgrade") && 1604 ascii.EqualFold(r.Header.Get("Upgrade"), "websocket") 1605 } 1606