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 "io/ioutil" 19 "mime" 20 "mime/multipart" 21 "net" 22 "net/http/httptrace" 23 "net/textproto" 24 "net/url" 25 "strconv" 26 "strings" 27 "sync" 28 29 "golang_org/x/net/idna" 30 ) 31 32 const ( 33 defaultMaxMemory = 32 << 20 // 32 MB 34 ) 35 36 // ErrMissingFile is returned by FormFile when the provided file field name 37 // is either not present in the request or not a file field. 38 var ErrMissingFile = errors.New("http: no such file") 39 40 // ProtocolError represents an HTTP protocol error. 41 // 42 // Deprecated: Not all errors in the http package related to protocol errors 43 // are of type ProtocolError. 44 type ProtocolError struct { 45 ErrorString string 46 } 47 48 func (pe *ProtocolError) Error() string { return pe.ErrorString } 49 50 var ( 51 // ErrNotSupported is returned by the Push method of Pusher 52 // implementations to indicate that HTTP/2 Push support is not 53 // available. 54 ErrNotSupported = &ProtocolError{"feature not supported"} 55 56 // ErrUnexpectedTrailer is returned by the Transport when a server 57 // replies with a Trailer header, but without a chunked reply. 58 ErrUnexpectedTrailer = &ProtocolError{"trailer header without chunked transfer encoding"} 59 60 // ErrMissingBoundary is returned by Request.MultipartReader when the 61 // request's Content-Type does not include a "boundary" parameter. 62 ErrMissingBoundary = &ProtocolError{"no multipart boundary param in Content-Type"} 63 64 // ErrNotMultipart is returned by Request.MultipartReader when the 65 // request's Content-Type is not multipart/form-data. 66 ErrNotMultipart = &ProtocolError{"request Content-Type isn't multipart/form-data"} 67 68 // Deprecated: ErrHeaderTooLong is no longer returned by 69 // anything in the net/http package. Callers should not 70 // compare errors against this variable. 71 ErrHeaderTooLong = &ProtocolError{"header too long"} 72 73 // Deprecated: ErrShortBody is no longer returned by 74 // anything in the net/http package. Callers should not 75 // compare errors against this variable. 76 ErrShortBody = &ProtocolError{"entity body too short"} 77 78 // Deprecated: ErrMissingContentLength is no longer returned by 79 // anything in the net/http package. Callers should not 80 // compare errors against this variable. 81 ErrMissingContentLength = &ProtocolError{"missing ContentLength in HEAD response"} 82 ) 83 84 type badStringError struct { 85 what string 86 str string 87 } 88 89 func (e *badStringError) Error() string { return fmt.Sprintf("%s %q", e.what, e.str) } 90 91 // Headers that Request.Write handles itself and should be skipped. 92 var reqWriteExcludeHeader = map[string]bool{ 93 "Host": true, // not in Header map anyway 94 "User-Agent": true, 95 "Content-Length": true, 96 "Transfer-Encoding": true, 97 "Trailer": true, 98 } 99 100 // A Request represents an HTTP request received by a server 101 // or to be sent by a client. 102 // 103 // The field semantics differ slightly between client and server 104 // usage. In addition to the notes on the fields below, see the 105 // documentation for Request.Write and RoundTripper. 106 type Request struct { 107 // Method specifies the HTTP method (GET, POST, PUT, etc.). 108 // For client requests an empty string means GET. 109 // 110 // Go's HTTP client does not support sending a request with 111 // the CONNECT method. See the documentation on Transport for 112 // details. 113 Method string 114 115 // URL specifies either the URI being requested (for server 116 // requests) or the URL to access (for client requests). 117 // 118 // For server requests the URL is parsed from the URI 119 // supplied on the Request-Line as stored in RequestURI. For 120 // most requests, fields other than Path and RawQuery will be 121 // empty. (See RFC 7230, Section 5.3) 122 // 123 // For client requests, the URL's Host specifies the server to 124 // connect to, while the Request's Host field optionally 125 // specifies the Host header value to send in the HTTP 126 // request. 127 URL *url.URL 128 129 // The protocol version for incoming server requests. 130 // 131 // For client requests these fields are ignored. The HTTP 132 // client code always uses either HTTP/1.1 or HTTP/2. 133 // See the docs on Transport for details. 134 Proto string // "HTTP/1.0" 135 ProtoMajor int // 1 136 ProtoMinor int // 0 137 138 // Header contains the request header fields either received 139 // by the server or to be sent by the client. 140 // 141 // If a server received a request with header lines, 142 // 143 // Host: example.com 144 // accept-encoding: gzip, deflate 145 // Accept-Language: en-us 146 // fOO: Bar 147 // foo: two 148 // 149 // then 150 // 151 // Header = map[string][]string{ 152 // "Accept-Encoding": {"gzip, deflate"}, 153 // "Accept-Language": {"en-us"}, 154 // "Foo": {"Bar", "two"}, 155 // } 156 // 157 // For incoming requests, the Host header is promoted to the 158 // Request.Host field and removed from the Header map. 159 // 160 // HTTP defines that header names are case-insensitive. The 161 // request parser implements this by using CanonicalHeaderKey, 162 // making the first character and any characters following a 163 // hyphen uppercase and the rest lowercase. 164 // 165 // For client requests, certain headers such as Content-Length 166 // and Connection are automatically written when needed and 167 // values in Header may be ignored. See the documentation 168 // for the Request.Write method. 169 Header Header 170 171 // Body is the request's body. 172 // 173 // For client requests a nil body means the request has no 174 // body, such as a GET request. The HTTP Client's Transport 175 // is responsible for calling the Close method. 176 // 177 // For server requests the Request Body is always non-nil 178 // but will return EOF immediately when no body is present. 179 // The Server will close the request body. The ServeHTTP 180 // Handler does not need to. 181 Body io.ReadCloser 182 183 // GetBody defines an optional func to return a new copy of 184 // Body. It is used for client requests when a redirect requires 185 // reading the body more than once. Use of GetBody still 186 // requires setting Body. 187 // 188 // For server requests it is unused. 189 GetBody func() (io.ReadCloser, error) 190 191 // ContentLength records the length of the associated content. 192 // The value -1 indicates that the length is unknown. 193 // Values >= 0 indicate that the given number of bytes may 194 // be read from Body. 195 // For client requests, a value of 0 with a non-nil Body is 196 // also treated as unknown. 197 ContentLength int64 198 199 // TransferEncoding lists the transfer encodings from outermost to 200 // innermost. An empty list denotes the "identity" encoding. 201 // TransferEncoding can usually be ignored; chunked encoding is 202 // automatically added and removed as necessary when sending and 203 // receiving requests. 204 TransferEncoding []string 205 206 // Close indicates whether to close the connection after 207 // replying to this request (for servers) or after sending this 208 // request and reading its response (for clients). 209 // 210 // For server requests, the HTTP server handles this automatically 211 // and this field is not needed by Handlers. 212 // 213 // For client requests, setting this field prevents re-use of 214 // TCP connections between requests to the same hosts, as if 215 // Transport.DisableKeepAlives were set. 216 Close bool 217 218 // For server requests Host specifies the host on which the URL 219 // is sought. Per RFC 7230, section 5.4, this is either the value 220 // of the "Host" header or the host name given in the URL itself. 221 // It may be of the form "host:port". For international domain 222 // names, Host may be in Punycode or Unicode form. Use 223 // golang.org/x/net/idna to convert it to either format if 224 // needed. 225 // To prevent DNS rebinding attacks, server Handlers should 226 // validate that the Host header has a value for which the 227 // Handler considers itself authoritative. The included 228 // ServeMux supports patterns registered to particular host 229 // names and thus protects its registered Handlers. 230 // 231 // For client requests Host optionally overrides the Host 232 // header to send. If empty, the Request.Write method uses 233 // the value of URL.Host. Host may contain an international 234 // domain name. 235 Host string 236 237 // Form contains the parsed form data, including both the URL 238 // field's query parameters and the POST or PUT form data. 239 // This field is only available after ParseForm is called. 240 // The HTTP client ignores Form and uses Body instead. 241 Form url.Values 242 243 // PostForm contains the parsed form data from POST, PATCH, 244 // or PUT body parameters. 245 // 246 // This field is only available after ParseForm is called. 247 // The HTTP client ignores PostForm and uses Body instead. 248 PostForm url.Values 249 250 // MultipartForm is the parsed multipart form, including file uploads. 251 // This field is only available after ParseMultipartForm is called. 252 // The HTTP client ignores MultipartForm and uses Body instead. 253 MultipartForm *multipart.Form 254 255 // Trailer specifies additional headers that are sent after the request 256 // body. 257 // 258 // For server requests the Trailer map initially contains only the 259 // trailer keys, with nil values. (The client declares which trailers it 260 // will later send.) While the handler is reading from Body, it must 261 // not reference Trailer. After reading from Body returns EOF, Trailer 262 // can be read again and will contain non-nil values, if they were sent 263 // by the client. 264 // 265 // For client requests Trailer must be initialized to a map containing 266 // the trailer keys to later send. The values may be nil or their final 267 // values. The ContentLength must be 0 or -1, to send a chunked request. 268 // After the HTTP request is sent the map values can be updated while 269 // the request body is read. Once the body returns EOF, the caller must 270 // not mutate Trailer. 271 // 272 // Few HTTP clients, servers, or proxies support HTTP trailers. 273 Trailer Header 274 275 // RemoteAddr allows HTTP servers and other software to record 276 // the network address that sent the request, usually for 277 // logging. This field is not filled in by ReadRequest and 278 // has no defined format. The HTTP server in this package 279 // sets RemoteAddr to an "IP:port" address before invoking a 280 // handler. 281 // This field is ignored by the HTTP client. 282 RemoteAddr string 283 284 // RequestURI is the unmodified request-target of the 285 // Request-Line (RFC 7230, Section 3.1.1) as sent by the client 286 // to a server. Usually the URL field should be used instead. 287 // It is an error to set this field in an HTTP client request. 288 RequestURI string 289 290 // TLS allows HTTP servers and other software to record 291 // information about the TLS connection on which the request 292 // was received. This field is not filled in by ReadRequest. 293 // The HTTP server in this package sets the field for 294 // TLS-enabled connections before invoking a handler; 295 // otherwise it leaves the field nil. 296 // This field is ignored by the HTTP client. 297 TLS *tls.ConnectionState 298 299 // Cancel is an optional channel whose closure indicates that the client 300 // request should be regarded as canceled. Not all implementations of 301 // RoundTripper may support Cancel. 302 // 303 // For server requests, this field is not applicable. 304 // 305 // Deprecated: Use the Context and WithContext methods 306 // instead. If a Request's Cancel field and context are both 307 // set, it is undefined whether Cancel is respected. 308 Cancel <-chan struct{} 309 310 // Response is the redirect response which caused this request 311 // to be created. This field is only populated during client 312 // redirects. 313 Response *Response 314 315 // ctx is either the client or server context. It should only 316 // be modified via copying the whole Request using WithContext. 317 // It is unexported to prevent people from using Context wrong 318 // and mutating the contexts held by callers of the same request. 319 ctx context.Context 320 } 321 322 // Context returns the request's context. To change the context, use 323 // WithContext. 324 // 325 // The returned context is always non-nil; it defaults to the 326 // background context. 327 // 328 // For outgoing client requests, the context controls cancelation. 329 // 330 // For incoming server requests, the context is canceled when the 331 // client's connection closes, the request is canceled (with HTTP/2), 332 // or when the ServeHTTP method returns. 333 func (r *Request) Context() context.Context { 334 if r.ctx != nil { 335 return r.ctx 336 } 337 return context.Background() 338 } 339 340 // WithContext returns a shallow copy of r with its context changed 341 // to ctx. The provided ctx must be non-nil. 342 // 343 // For outgoing client request, the context controls the entire 344 // lifetime of a request and its response: obtaining a connection, 345 // sending the request, and reading the response headers and body. 346 func (r *Request) WithContext(ctx context.Context) *Request { 347 if ctx == nil { 348 panic("nil context") 349 } 350 r2 := new(Request) 351 *r2 = *r 352 r2.ctx = ctx 353 354 // Deep copy the URL because it isn't 355 // a map and the URL is mutable by users 356 // of WithContext. 357 if r.URL != nil { 358 r2URL := new(url.URL) 359 *r2URL = *r.URL 360 r2.URL = r2URL 361 } 362 363 return r2 364 } 365 366 // ProtoAtLeast reports whether the HTTP protocol used 367 // in the request is at least major.minor. 368 func (r *Request) ProtoAtLeast(major, minor int) bool { 369 return r.ProtoMajor > major || 370 r.ProtoMajor == major && r.ProtoMinor >= minor 371 } 372 373 // UserAgent returns the client's User-Agent, if sent in the request. 374 func (r *Request) UserAgent() string { 375 return r.Header.Get("User-Agent") 376 } 377 378 // Cookies parses and returns the HTTP cookies sent with the request. 379 func (r *Request) Cookies() []*Cookie { 380 return readCookies(r.Header, "") 381 } 382 383 // ErrNoCookie is returned by Request's Cookie method when a cookie is not found. 384 var ErrNoCookie = errors.New("http: named cookie not present") 385 386 // Cookie returns the named cookie provided in the request or 387 // ErrNoCookie if not found. 388 // If multiple cookies match the given name, only one cookie will 389 // be returned. 390 func (r *Request) Cookie(name string) (*Cookie, error) { 391 for _, c := range readCookies(r.Header, name) { 392 return c, nil 393 } 394 return nil, ErrNoCookie 395 } 396 397 // AddCookie adds a cookie to the request. Per RFC 6265 section 5.4, 398 // AddCookie does not attach more than one Cookie header field. That 399 // means all cookies, if any, are written into the same line, 400 // separated by semicolon. 401 func (r *Request) AddCookie(c *Cookie) { 402 s := fmt.Sprintf("%s=%s", sanitizeCookieName(c.Name), sanitizeCookieValue(c.Value)) 403 if c := r.Header.Get("Cookie"); c != "" { 404 r.Header.Set("Cookie", c+"; "+s) 405 } else { 406 r.Header.Set("Cookie", s) 407 } 408 } 409 410 // Referer returns the referring URL, if sent in the request. 411 // 412 // Referer is misspelled as in the request itself, a mistake from the 413 // earliest days of HTTP. This value can also be fetched from the 414 // Header map as Header["Referer"]; the benefit of making it available 415 // as a method is that the compiler can diagnose programs that use the 416 // alternate (correct English) spelling req.Referrer() but cannot 417 // diagnose programs that use Header["Referrer"]. 418 func (r *Request) Referer() string { 419 return r.Header.Get("Referer") 420 } 421 422 // multipartByReader is a sentinel value. 423 // Its presence in Request.MultipartForm indicates that parsing of the request 424 // body has been handed off to a MultipartReader instead of ParseMultipartFrom. 425 var multipartByReader = &multipart.Form{ 426 Value: make(map[string][]string), 427 File: make(map[string][]*multipart.FileHeader), 428 } 429 430 // MultipartReader returns a MIME multipart reader if this is a 431 // multipart/form-data or a multipart/mixed POST request, else returns nil and an error. 432 // Use this function instead of ParseMultipartForm to 433 // process the request body as a stream. 434 func (r *Request) MultipartReader() (*multipart.Reader, error) { 435 if r.MultipartForm == multipartByReader { 436 return nil, errors.New("http: MultipartReader called twice") 437 } 438 if r.MultipartForm != nil { 439 return nil, errors.New("http: multipart handled by ParseMultipartForm") 440 } 441 r.MultipartForm = multipartByReader 442 return r.multipartReader(true) 443 } 444 445 func (r *Request) multipartReader(allowMixed bool) (*multipart.Reader, error) { 446 v := r.Header.Get("Content-Type") 447 if v == "" { 448 return nil, ErrNotMultipart 449 } 450 d, params, err := mime.ParseMediaType(v) 451 if err != nil || !(d == "multipart/form-data" || allowMixed && d == "multipart/mixed") { 452 return nil, ErrNotMultipart 453 } 454 boundary, ok := params["boundary"] 455 if !ok { 456 return nil, ErrMissingBoundary 457 } 458 return multipart.NewReader(r.Body, boundary), nil 459 } 460 461 // isH2Upgrade reports whether r represents the http2 "client preface" 462 // magic string. 463 func (r *Request) isH2Upgrade() bool { 464 return r.Method == "PRI" && len(r.Header) == 0 && r.URL.Path == "*" && r.Proto == "HTTP/2.0" 465 } 466 467 // Return value if nonempty, def otherwise. 468 func valueOrDefault(value, def string) string { 469 if value != "" { 470 return value 471 } 472 return def 473 } 474 475 // NOTE: This is not intended to reflect the actual Go version being used. 476 // It was changed at the time of Go 1.1 release because the former User-Agent 477 // had ended up on a blacklist for some intrusion detection systems. 478 // See https://codereview.appspot.com/7532043. 479 const defaultUserAgent = "Go-http-client/1.1" 480 481 // Write writes an HTTP/1.1 request, which is the header and body, in wire format. 482 // This method consults the following fields of the request: 483 // Host 484 // URL 485 // Method (defaults to "GET") 486 // Header 487 // ContentLength 488 // TransferEncoding 489 // Body 490 // 491 // If Body is present, Content-Length is <= 0 and TransferEncoding 492 // hasn't been set to "identity", Write adds "Transfer-Encoding: 493 // chunked" to the header. Body is closed after it is sent. 494 func (r *Request) Write(w io.Writer) error { 495 return r.write(w, false, nil, nil) 496 } 497 498 // WriteProxy is like Write but writes the request in the form 499 // expected by an HTTP proxy. In particular, WriteProxy writes the 500 // initial Request-URI line of the request with an absolute URI, per 501 // section 5.3 of RFC 7230, including the scheme and host. 502 // In either case, WriteProxy also writes a Host header, using 503 // either r.Host or r.URL.Host. 504 func (r *Request) WriteProxy(w io.Writer) error { 505 return r.write(w, true, nil, nil) 506 } 507 508 // errMissingHost is returned by Write when there is no Host or URL present in 509 // the Request. 510 var errMissingHost = errors.New("http: Request.Write on Request with no Host or URL set") 511 512 // extraHeaders may be nil 513 // waitForContinue may be nil 514 func (r *Request) write(w io.Writer, usingProxy bool, extraHeaders Header, waitForContinue func() bool) (err error) { 515 trace := httptrace.ContextClientTrace(r.Context()) 516 if trace != nil && trace.WroteRequest != nil { 517 defer func() { 518 trace.WroteRequest(httptrace.WroteRequestInfo{ 519 Err: err, 520 }) 521 }() 522 } 523 524 // Find the target host. Prefer the Host: header, but if that 525 // is not given, use the host from the request URL. 526 // 527 // Clean the host, in case it arrives with unexpected stuff in it. 528 host := cleanHost(r.Host) 529 if host == "" { 530 if r.URL == nil { 531 return errMissingHost 532 } 533 host = cleanHost(r.URL.Host) 534 } 535 536 // According to RFC 6874, an HTTP client, proxy, or other 537 // intermediary must remove any IPv6 zone identifier attached 538 // to an outgoing URI. 539 host = removeZone(host) 540 541 ruri := r.URL.RequestURI() 542 if usingProxy && r.URL.Scheme != "" && r.URL.Opaque == "" { 543 ruri = r.URL.Scheme + "://" + host + ruri 544 } else if r.Method == "CONNECT" && r.URL.Path == "" { 545 // CONNECT requests normally give just the host and port, not a full URL. 546 ruri = host 547 } 548 // TODO(bradfitz): escape at least newlines in ruri? 549 550 // Wrap the writer in a bufio Writer if it's not already buffered. 551 // Don't always call NewWriter, as that forces a bytes.Buffer 552 // and other small bufio Writers to have a minimum 4k buffer 553 // size. 554 var bw *bufio.Writer 555 if _, ok := w.(io.ByteWriter); !ok { 556 bw = bufio.NewWriter(w) 557 w = bw 558 } 559 560 _, err = fmt.Fprintf(w, "%s %s HTTP/1.1\r\n", valueOrDefault(r.Method, "GET"), ruri) 561 if err != nil { 562 return err 563 } 564 565 // Header lines 566 _, err = fmt.Fprintf(w, "Host: %s\r\n", host) 567 if err != nil { 568 return err 569 } 570 if trace != nil && trace.WroteHeaderField != nil { 571 trace.WroteHeaderField("Host", []string{host}) 572 } 573 574 // Use the defaultUserAgent unless the Header contains one, which 575 // may be blank to not send the header. 576 userAgent := defaultUserAgent 577 if _, ok := r.Header["User-Agent"]; ok { 578 userAgent = r.Header.Get("User-Agent") 579 } 580 if userAgent != "" { 581 _, err = fmt.Fprintf(w, "User-Agent: %s\r\n", userAgent) 582 if err != nil { 583 return err 584 } 585 if trace != nil && trace.WroteHeaderField != nil { 586 trace.WroteHeaderField("User-Agent", []string{userAgent}) 587 } 588 } 589 590 // Process Body,ContentLength,Close,Trailer 591 tw, err := newTransferWriter(r) 592 if err != nil { 593 return err 594 } 595 err = tw.writeHeader(w, trace) 596 if err != nil { 597 return err 598 } 599 600 err = r.Header.writeSubset(w, reqWriteExcludeHeader, trace) 601 if err != nil { 602 return err 603 } 604 605 if extraHeaders != nil { 606 err = extraHeaders.write(w, trace) 607 if err != nil { 608 return err 609 } 610 } 611 612 _, err = io.WriteString(w, "\r\n") 613 if err != nil { 614 return err 615 } 616 617 if trace != nil && trace.WroteHeaders != nil { 618 trace.WroteHeaders() 619 } 620 621 // Flush and wait for 100-continue if expected. 622 if waitForContinue != nil { 623 if bw, ok := w.(*bufio.Writer); ok { 624 err = bw.Flush() 625 if err != nil { 626 return err 627 } 628 } 629 if trace != nil && trace.Wait100Continue != nil { 630 trace.Wait100Continue() 631 } 632 if !waitForContinue() { 633 r.closeBody() 634 return nil 635 } 636 } 637 638 if bw, ok := w.(*bufio.Writer); ok && tw.FlushHeaders { 639 if err := bw.Flush(); err != nil { 640 return err 641 } 642 } 643 644 // Write body and trailer 645 err = tw.writeBody(w) 646 if err != nil { 647 if tw.bodyReadError == err { 648 err = requestBodyReadError{err} 649 } 650 return err 651 } 652 653 if bw != nil { 654 return bw.Flush() 655 } 656 return nil 657 } 658 659 // requestBodyReadError wraps an error from (*Request).write to indicate 660 // that the error came from a Read call on the Request.Body. 661 // This error type should not escape the net/http package to users. 662 type requestBodyReadError struct{ error } 663 664 func idnaASCII(v string) (string, error) { 665 // TODO: Consider removing this check after verifying performance is okay. 666 // Right now punycode verification, length checks, context checks, and the 667 // permissible character tests are all omitted. It also prevents the ToASCII 668 // call from salvaging an invalid IDN, when possible. As a result it may be 669 // possible to have two IDNs that appear identical to the user where the 670 // ASCII-only version causes an error downstream whereas the non-ASCII 671 // version does not. 672 // Note that for correct ASCII IDNs ToASCII will only do considerably more 673 // work, but it will not cause an allocation. 674 if isASCII(v) { 675 return v, nil 676 } 677 return idna.Lookup.ToASCII(v) 678 } 679 680 // cleanHost cleans up the host sent in request's Host header. 681 // 682 // It both strips anything after '/' or ' ', and puts the value 683 // into Punycode form, if necessary. 684 // 685 // Ideally we'd clean the Host header according to the spec: 686 // https://tools.ietf.org/html/rfc7230#section-5.4 (Host = uri-host [ ":" port ]") 687 // https://tools.ietf.org/html/rfc7230#section-2.7 (uri-host -> rfc3986's host) 688 // https://tools.ietf.org/html/rfc3986#section-3.2.2 (definition of host) 689 // But practically, what we are trying to avoid is the situation in 690 // issue 11206, where a malformed Host header used in the proxy context 691 // would create a bad request. So it is enough to just truncate at the 692 // first offending character. 693 func cleanHost(in string) string { 694 if i := strings.IndexAny(in, " /"); i != -1 { 695 in = in[:i] 696 } 697 host, port, err := net.SplitHostPort(in) 698 if err != nil { // input was just a host 699 a, err := idnaASCII(in) 700 if err != nil { 701 return in // garbage in, garbage out 702 } 703 return a 704 } 705 a, err := idnaASCII(host) 706 if err != nil { 707 return in // garbage in, garbage out 708 } 709 return net.JoinHostPort(a, port) 710 } 711 712 // removeZone removes IPv6 zone identifier from host. 713 // E.g., "[fe80::1%en0]:8080" to "[fe80::1]:8080" 714 func removeZone(host string) string { 715 if !strings.HasPrefix(host, "[") { 716 return host 717 } 718 i := strings.LastIndex(host, "]") 719 if i < 0 { 720 return host 721 } 722 j := strings.LastIndex(host[:i], "%") 723 if j < 0 { 724 return host 725 } 726 return host[:j] + host[i:] 727 } 728 729 // ParseHTTPVersion parses a HTTP version string. 730 // "HTTP/1.0" returns (1, 0, true). 731 func ParseHTTPVersion(vers string) (major, minor int, ok bool) { 732 const Big = 1000000 // arbitrary upper bound 733 switch vers { 734 case "HTTP/1.1": 735 return 1, 1, true 736 case "HTTP/1.0": 737 return 1, 0, true 738 } 739 if !strings.HasPrefix(vers, "HTTP/") { 740 return 0, 0, false 741 } 742 dot := strings.Index(vers, ".") 743 if dot < 0 { 744 return 0, 0, false 745 } 746 major, err := strconv.Atoi(vers[5:dot]) 747 if err != nil || major < 0 || major > Big { 748 return 0, 0, false 749 } 750 minor, err = strconv.Atoi(vers[dot+1:]) 751 if err != nil || minor < 0 || minor > Big { 752 return 0, 0, false 753 } 754 return major, minor, true 755 } 756 757 func validMethod(method string) bool { 758 /* 759 Method = "OPTIONS" ; Section 9.2 760 | "GET" ; Section 9.3 761 | "HEAD" ; Section 9.4 762 | "POST" ; Section 9.5 763 | "PUT" ; Section 9.6 764 | "DELETE" ; Section 9.7 765 | "TRACE" ; Section 9.8 766 | "CONNECT" ; Section 9.9 767 | extension-method 768 extension-method = token 769 token = 1*<any CHAR except CTLs or separators> 770 */ 771 return len(method) > 0 && strings.IndexFunc(method, isNotToken) == -1 772 } 773 774 // NewRequest returns a new Request given a method, URL, and optional body. 775 // 776 // If the provided body is also an io.Closer, the returned 777 // Request.Body is set to body and will be closed by the Client 778 // methods Do, Post, and PostForm, and Transport.RoundTrip. 779 // 780 // NewRequest returns a Request suitable for use with Client.Do or 781 // Transport.RoundTrip. To create a request for use with testing a 782 // Server Handler, either use the NewRequest function in the 783 // net/http/httptest package, use ReadRequest, or manually update the 784 // Request fields. See the Request type's documentation for the 785 // difference between inbound and outbound request fields. 786 // 787 // If body is of type *bytes.Buffer, *bytes.Reader, or 788 // *strings.Reader, the returned request's ContentLength is set to its 789 // exact value (instead of -1), GetBody is populated (so 307 and 308 790 // redirects can replay the body), and Body is set to NoBody if the 791 // ContentLength is 0. 792 func NewRequest(method, url string, body io.Reader) (*Request, error) { 793 if method == "" { 794 // We document that "" means "GET" for Request.Method, and people have 795 // relied on that from NewRequest, so keep that working. 796 // We still enforce validMethod for non-empty methods. 797 method = "GET" 798 } 799 if !validMethod(method) { 800 return nil, fmt.Errorf("net/http: invalid method %q", method) 801 } 802 u, err := parseURL(url) // Just url.Parse (url is shadowed for godoc). 803 if err != nil { 804 return nil, err 805 } 806 rc, ok := body.(io.ReadCloser) 807 if !ok && body != nil { 808 rc = ioutil.NopCloser(body) 809 } 810 // The host's colon:port should be normalized. See Issue 14836. 811 u.Host = removeEmptyPort(u.Host) 812 req := &Request{ 813 Method: method, 814 URL: u, 815 Proto: "HTTP/1.1", 816 ProtoMajor: 1, 817 ProtoMinor: 1, 818 Header: make(Header), 819 Body: rc, 820 Host: u.Host, 821 } 822 if body != nil { 823 switch v := body.(type) { 824 case *bytes.Buffer: 825 req.ContentLength = int64(v.Len()) 826 buf := v.Bytes() 827 req.GetBody = func() (io.ReadCloser, error) { 828 r := bytes.NewReader(buf) 829 return ioutil.NopCloser(r), nil 830 } 831 case *bytes.Reader: 832 req.ContentLength = int64(v.Len()) 833 snapshot := *v 834 req.GetBody = func() (io.ReadCloser, error) { 835 r := snapshot 836 return ioutil.NopCloser(&r), nil 837 } 838 case *strings.Reader: 839 req.ContentLength = int64(v.Len()) 840 snapshot := *v 841 req.GetBody = func() (io.ReadCloser, error) { 842 r := snapshot 843 return ioutil.NopCloser(&r), nil 844 } 845 default: 846 // This is where we'd set it to -1 (at least 847 // if body != NoBody) to mean unknown, but 848 // that broke people during the Go 1.8 testing 849 // period. People depend on it being 0 I 850 // guess. Maybe retry later. See Issue 18117. 851 } 852 // For client requests, Request.ContentLength of 0 853 // means either actually 0, or unknown. The only way 854 // to explicitly say that the ContentLength is zero is 855 // to set the Body to nil. But turns out too much code 856 // depends on NewRequest returning a non-nil Body, 857 // so we use a well-known ReadCloser variable instead 858 // and have the http package also treat that sentinel 859 // variable to mean explicitly zero. 860 if req.GetBody != nil && req.ContentLength == 0 { 861 req.Body = NoBody 862 req.GetBody = func() (io.ReadCloser, error) { return NoBody, nil } 863 } 864 } 865 866 return req, nil 867 } 868 869 // BasicAuth returns the username and password provided in the request's 870 // Authorization header, if the request uses HTTP Basic Authentication. 871 // See RFC 2617, Section 2. 872 func (r *Request) BasicAuth() (username, password string, ok bool) { 873 auth := r.Header.Get("Authorization") 874 if auth == "" { 875 return 876 } 877 return parseBasicAuth(auth) 878 } 879 880 // parseBasicAuth parses an HTTP Basic Authentication string. 881 // "Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==" returns ("Aladdin", "open sesame", true). 882 func parseBasicAuth(auth string) (username, password string, ok bool) { 883 const prefix = "Basic " 884 // Case insensitive prefix match. See Issue 22736. 885 if len(auth) < len(prefix) || !strings.EqualFold(auth[:len(prefix)], prefix) { 886 return 887 } 888 c, err := base64.StdEncoding.DecodeString(auth[len(prefix):]) 889 if err != nil { 890 return 891 } 892 cs := string(c) 893 s := strings.IndexByte(cs, ':') 894 if s < 0 { 895 return 896 } 897 return cs[:s], cs[s+1:], true 898 } 899 900 // SetBasicAuth sets the request's Authorization header to use HTTP 901 // Basic Authentication with the provided username and password. 902 // 903 // With HTTP Basic Authentication the provided username and password 904 // are not encrypted. 905 func (r *Request) SetBasicAuth(username, password string) { 906 r.Header.Set("Authorization", "Basic "+basicAuth(username, password)) 907 } 908 909 // parseRequestLine parses "GET /foo HTTP/1.1" into its three parts. 910 func parseRequestLine(line string) (method, requestURI, proto string, ok bool) { 911 s1 := strings.Index(line, " ") 912 s2 := strings.Index(line[s1+1:], " ") 913 if s1 < 0 || s2 < 0 { 914 return 915 } 916 s2 += s1 + 1 917 return line[:s1], line[s1+1 : s2], line[s2+1:], true 918 } 919 920 var textprotoReaderPool sync.Pool 921 922 func newTextprotoReader(br *bufio.Reader) *textproto.Reader { 923 if v := textprotoReaderPool.Get(); v != nil { 924 tr := v.(*textproto.Reader) 925 tr.R = br 926 return tr 927 } 928 return textproto.NewReader(br) 929 } 930 931 func putTextprotoReader(r *textproto.Reader) { 932 r.R = nil 933 textprotoReaderPool.Put(r) 934 } 935 936 // ReadRequest reads and parses an incoming request from b. 937 // 938 // ReadRequest is a low-level function and should only be used for 939 // specialized applications; most code should use the Server to read 940 // requests and handle them via the Handler interface. ReadRequest 941 // only supports HTTP/1.x requests. For HTTP/2, use golang.org/x/net/http2. 942 func ReadRequest(b *bufio.Reader) (*Request, error) { 943 return readRequest(b, deleteHostHeader) 944 } 945 946 // Constants for readRequest's deleteHostHeader parameter. 947 const ( 948 deleteHostHeader = true 949 keepHostHeader = false 950 ) 951 952 func readRequest(b *bufio.Reader, deleteHostHeader bool) (req *Request, err error) { 953 tp := newTextprotoReader(b) 954 req = new(Request) 955 956 // First line: GET /index.html HTTP/1.0 957 var s string 958 if s, err = tp.ReadLine(); err != nil { 959 return nil, err 960 } 961 defer func() { 962 putTextprotoReader(tp) 963 if err == io.EOF { 964 err = io.ErrUnexpectedEOF 965 } 966 }() 967 968 var ok bool 969 req.Method, req.RequestURI, req.Proto, ok = parseRequestLine(s) 970 if !ok { 971 return nil, &badStringError{"malformed HTTP request", s} 972 } 973 if !validMethod(req.Method) { 974 return nil, &badStringError{"invalid method", req.Method} 975 } 976 rawurl := req.RequestURI 977 if req.ProtoMajor, req.ProtoMinor, ok = ParseHTTPVersion(req.Proto); !ok { 978 return nil, &badStringError{"malformed HTTP version", req.Proto} 979 } 980 981 // CONNECT requests are used two different ways, and neither uses a full URL: 982 // The standard use is to tunnel HTTPS through an HTTP proxy. 983 // It looks like "CONNECT www.google.com:443 HTTP/1.1", and the parameter is 984 // just the authority section of a URL. This information should go in req.URL.Host. 985 // 986 // The net/rpc package also uses CONNECT, but there the parameter is a path 987 // that starts with a slash. It can be parsed with the regular URL parser, 988 // and the path will end up in req.URL.Path, where it needs to be in order for 989 // RPC to work. 990 justAuthority := req.Method == "CONNECT" && !strings.HasPrefix(rawurl, "/") 991 if justAuthority { 992 rawurl = "http://" + rawurl 993 } 994 995 if req.URL, err = url.ParseRequestURI(rawurl); err != nil { 996 return nil, err 997 } 998 999 if justAuthority { 1000 // Strip the bogus "http://" back off. 1001 req.URL.Scheme = "" 1002 } 1003 1004 // Subsequent lines: Key: value. 1005 mimeHeader, err := tp.ReadMIMEHeader() 1006 if err != nil { 1007 return nil, err 1008 } 1009 req.Header = Header(mimeHeader) 1010 1011 // RFC 7230, section 5.3: Must treat 1012 // GET /index.html HTTP/1.1 1013 // Host: www.google.com 1014 // and 1015 // GET http://www.google.com/index.html HTTP/1.1 1016 // Host: doesntmatter 1017 // the same. In the second case, any Host line is ignored. 1018 req.Host = req.URL.Host 1019 if req.Host == "" { 1020 req.Host = req.Header.get("Host") 1021 } 1022 if deleteHostHeader { 1023 delete(req.Header, "Host") 1024 } 1025 1026 fixPragmaCacheControl(req.Header) 1027 1028 req.Close = shouldClose(req.ProtoMajor, req.ProtoMinor, req.Header, false) 1029 1030 err = readTransfer(req, b) 1031 if err != nil { 1032 return nil, err 1033 } 1034 1035 if req.isH2Upgrade() { 1036 // Because it's neither chunked, nor declared: 1037 req.ContentLength = -1 1038 1039 // We want to give handlers a chance to hijack the 1040 // connection, but we need to prevent the Server from 1041 // dealing with the connection further if it's not 1042 // hijacked. Set Close to ensure that: 1043 req.Close = true 1044 } 1045 return req, nil 1046 } 1047 1048 // MaxBytesReader is similar to io.LimitReader but is intended for 1049 // limiting the size of incoming request bodies. In contrast to 1050 // io.LimitReader, MaxBytesReader's result is a ReadCloser, returns a 1051 // non-EOF error for a Read beyond the limit, and closes the 1052 // underlying reader when its Close method is called. 1053 // 1054 // MaxBytesReader prevents clients from accidentally or maliciously 1055 // sending a large request and wasting server resources. 1056 func MaxBytesReader(w ResponseWriter, r io.ReadCloser, n int64) io.ReadCloser { 1057 return &maxBytesReader{w: w, r: r, n: n} 1058 } 1059 1060 type maxBytesReader struct { 1061 w ResponseWriter 1062 r io.ReadCloser // underlying reader 1063 n int64 // max bytes remaining 1064 err error // sticky error 1065 } 1066 1067 func (l *maxBytesReader) Read(p []byte) (n int, err error) { 1068 if l.err != nil { 1069 return 0, l.err 1070 } 1071 if len(p) == 0 { 1072 return 0, nil 1073 } 1074 // If they asked for a 32KB byte read but only 5 bytes are 1075 // remaining, no need to read 32KB. 6 bytes will answer the 1076 // question of the whether we hit the limit or go past it. 1077 if int64(len(p)) > l.n+1 { 1078 p = p[:l.n+1] 1079 } 1080 n, err = l.r.Read(p) 1081 1082 if int64(n) <= l.n { 1083 l.n -= int64(n) 1084 l.err = err 1085 return n, err 1086 } 1087 1088 n = int(l.n) 1089 l.n = 0 1090 1091 // The server code and client code both use 1092 // maxBytesReader. This "requestTooLarge" check is 1093 // only used by the server code. To prevent binaries 1094 // which only using the HTTP Client code (such as 1095 // cmd/go) from also linking in the HTTP server, don't 1096 // use a static type assertion to the server 1097 // "*response" type. Check this interface instead: 1098 type requestTooLarger interface { 1099 requestTooLarge() 1100 } 1101 if res, ok := l.w.(requestTooLarger); ok { 1102 res.requestTooLarge() 1103 } 1104 l.err = errors.New("http: request body too large") 1105 return n, l.err 1106 } 1107 1108 func (l *maxBytesReader) Close() error { 1109 return l.r.Close() 1110 } 1111 1112 func copyValues(dst, src url.Values) { 1113 for k, vs := range src { 1114 for _, value := range vs { 1115 dst.Add(k, value) 1116 } 1117 } 1118 } 1119 1120 func parsePostForm(r *Request) (vs url.Values, err error) { 1121 if r.Body == nil { 1122 err = errors.New("missing form body") 1123 return 1124 } 1125 ct := r.Header.Get("Content-Type") 1126 // RFC 7231, section 3.1.1.5 - empty type 1127 // MAY be treated as application/octet-stream 1128 if ct == "" { 1129 ct = "application/octet-stream" 1130 } 1131 ct, _, err = mime.ParseMediaType(ct) 1132 switch { 1133 case ct == "application/x-www-form-urlencoded": 1134 var reader io.Reader = r.Body 1135 maxFormSize := int64(1<<63 - 1) 1136 if _, ok := r.Body.(*maxBytesReader); !ok { 1137 maxFormSize = int64(10 << 20) // 10 MB is a lot of text. 1138 reader = io.LimitReader(r.Body, maxFormSize+1) 1139 } 1140 b, e := ioutil.ReadAll(reader) 1141 if e != nil { 1142 if err == nil { 1143 err = e 1144 } 1145 break 1146 } 1147 if int64(len(b)) > maxFormSize { 1148 err = errors.New("http: POST too large") 1149 return 1150 } 1151 vs, e = url.ParseQuery(string(b)) 1152 if err == nil { 1153 err = e 1154 } 1155 case ct == "multipart/form-data": 1156 // handled by ParseMultipartForm (which is calling us, or should be) 1157 // TODO(bradfitz): there are too many possible 1158 // orders to call too many functions here. 1159 // Clean this up and write more tests. 1160 // request_test.go contains the start of this, 1161 // in TestParseMultipartFormOrder and others. 1162 } 1163 return 1164 } 1165 1166 // ParseForm populates r.Form and r.PostForm. 1167 // 1168 // For all requests, ParseForm parses the raw query from the URL and updates 1169 // r.Form. 1170 // 1171 // For POST, PUT, and PATCH requests, it also parses the request body as a form 1172 // and puts the results into both r.PostForm and r.Form. Request body parameters 1173 // take precedence over URL query string values in r.Form. 1174 // 1175 // For other HTTP methods, or when the Content-Type is not 1176 // application/x-www-form-urlencoded, the request Body is not read, and 1177 // r.PostForm is initialized to a non-nil, empty value. 1178 // 1179 // If the request Body's size has not already been limited by MaxBytesReader, 1180 // the size is capped at 10MB. 1181 // 1182 // ParseMultipartForm calls ParseForm automatically. 1183 // ParseForm is idempotent. 1184 func (r *Request) ParseForm() error { 1185 var err error 1186 if r.PostForm == nil { 1187 if r.Method == "POST" || r.Method == "PUT" || r.Method == "PATCH" { 1188 r.PostForm, err = parsePostForm(r) 1189 } 1190 if r.PostForm == nil { 1191 r.PostForm = make(url.Values) 1192 } 1193 } 1194 if r.Form == nil { 1195 if len(r.PostForm) > 0 { 1196 r.Form = make(url.Values) 1197 copyValues(r.Form, r.PostForm) 1198 } 1199 var newValues url.Values 1200 if r.URL != nil { 1201 var e error 1202 newValues, e = url.ParseQuery(r.URL.RawQuery) 1203 if err == nil { 1204 err = e 1205 } 1206 } 1207 if newValues == nil { 1208 newValues = make(url.Values) 1209 } 1210 if r.Form == nil { 1211 r.Form = newValues 1212 } else { 1213 copyValues(r.Form, newValues) 1214 } 1215 } 1216 return err 1217 } 1218 1219 // ParseMultipartForm parses a request body as multipart/form-data. 1220 // The whole request body is parsed and up to a total of maxMemory bytes of 1221 // its file parts are stored in memory, with the remainder stored on 1222 // disk in temporary files. 1223 // ParseMultipartForm calls ParseForm if necessary. 1224 // After one call to ParseMultipartForm, subsequent calls have no effect. 1225 func (r *Request) ParseMultipartForm(maxMemory int64) error { 1226 if r.MultipartForm == multipartByReader { 1227 return errors.New("http: multipart handled by MultipartReader") 1228 } 1229 if r.Form == nil { 1230 err := r.ParseForm() 1231 if err != nil { 1232 return err 1233 } 1234 } 1235 if r.MultipartForm != nil { 1236 return nil 1237 } 1238 1239 mr, err := r.multipartReader(false) 1240 if err != nil { 1241 return err 1242 } 1243 1244 f, err := mr.ReadForm(maxMemory) 1245 if err != nil { 1246 return err 1247 } 1248 1249 if r.PostForm == nil { 1250 r.PostForm = make(url.Values) 1251 } 1252 for k, v := range f.Value { 1253 r.Form[k] = append(r.Form[k], v...) 1254 // r.PostForm should also be populated. See Issue 9305. 1255 r.PostForm[k] = append(r.PostForm[k], v...) 1256 } 1257 1258 r.MultipartForm = f 1259 1260 return nil 1261 } 1262 1263 // FormValue returns the first value for the named component of the query. 1264 // POST and PUT body parameters take precedence over URL query string values. 1265 // FormValue calls ParseMultipartForm and ParseForm if necessary and ignores 1266 // any errors returned by these functions. 1267 // If key is not present, FormValue returns the empty string. 1268 // To access multiple values of the same key, call ParseForm and 1269 // then inspect Request.Form directly. 1270 func (r *Request) FormValue(key string) string { 1271 if r.Form == nil { 1272 r.ParseMultipartForm(defaultMaxMemory) 1273 } 1274 if vs := r.Form[key]; len(vs) > 0 { 1275 return vs[0] 1276 } 1277 return "" 1278 } 1279 1280 // PostFormValue returns the first value for the named component of the POST, 1281 // PATCH, or PUT request body. URL query parameters are ignored. 1282 // PostFormValue calls ParseMultipartForm and ParseForm if necessary and ignores 1283 // any errors returned by these functions. 1284 // If key is not present, PostFormValue returns the empty string. 1285 func (r *Request) PostFormValue(key string) string { 1286 if r.PostForm == nil { 1287 r.ParseMultipartForm(defaultMaxMemory) 1288 } 1289 if vs := r.PostForm[key]; len(vs) > 0 { 1290 return vs[0] 1291 } 1292 return "" 1293 } 1294 1295 // FormFile returns the first file for the provided form key. 1296 // FormFile calls ParseMultipartForm and ParseForm if necessary. 1297 func (r *Request) FormFile(key string) (multipart.File, *multipart.FileHeader, error) { 1298 if r.MultipartForm == multipartByReader { 1299 return nil, nil, errors.New("http: multipart handled by MultipartReader") 1300 } 1301 if r.MultipartForm == nil { 1302 err := r.ParseMultipartForm(defaultMaxMemory) 1303 if err != nil { 1304 return nil, nil, err 1305 } 1306 } 1307 if r.MultipartForm != nil && r.MultipartForm.File != nil { 1308 if fhs := r.MultipartForm.File[key]; len(fhs) > 0 { 1309 f, err := fhs[0].Open() 1310 return f, fhs[0], err 1311 } 1312 } 1313 return nil, nil, ErrMissingFile 1314 } 1315 1316 func (r *Request) expectsContinue() bool { 1317 return hasToken(r.Header.get("Expect"), "100-continue") 1318 } 1319 1320 func (r *Request) wantsHttp10KeepAlive() bool { 1321 if r.ProtoMajor != 1 || r.ProtoMinor != 0 { 1322 return false 1323 } 1324 return hasToken(r.Header.get("Connection"), "keep-alive") 1325 } 1326 1327 func (r *Request) wantsClose() bool { 1328 return hasToken(r.Header.get("Connection"), "close") 1329 } 1330 1331 func (r *Request) closeBody() { 1332 if r.Body != nil { 1333 r.Body.Close() 1334 } 1335 } 1336 1337 func (r *Request) isReplayable() bool { 1338 if r.Body == nil || r.Body == NoBody || r.GetBody != nil { 1339 switch valueOrDefault(r.Method, "GET") { 1340 case "GET", "HEAD", "OPTIONS", "TRACE": 1341 return true 1342 } 1343 } 1344 return false 1345 } 1346 1347 // outgoingLength reports the Content-Length of this outgoing (Client) request. 1348 // It maps 0 into -1 (unknown) when the Body is non-nil. 1349 func (r *Request) outgoingLength() int64 { 1350 if r.Body == nil || r.Body == NoBody { 1351 return 0 1352 } 1353 if r.ContentLength != 0 { 1354 return r.ContentLength 1355 } 1356 return -1 1357 } 1358 1359 // requestMethodUsuallyLacksBody reports whether the given request 1360 // method is one that typically does not involve a request body. 1361 // This is used by the Transport (via 1362 // transferWriter.shouldSendChunkedRequestBody) to determine whether 1363 // we try to test-read a byte from a non-nil Request.Body when 1364 // Request.outgoingLength() returns -1. See the comments in 1365 // shouldSendChunkedRequestBody. 1366 func requestMethodUsuallyLacksBody(method string) bool { 1367 switch method { 1368 case "GET", "HEAD", "DELETE", "OPTIONS", "PROPFIND", "SEARCH": 1369 return true 1370 } 1371 return false 1372 } 1373