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-rw-r--r--src/net/http/transfer.go1124
1 files changed, 1124 insertions, 0 deletions
diff --git a/src/net/http/transfer.go b/src/net/http/transfer.go
new file mode 100644
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--- /dev/null
+++ b/src/net/http/transfer.go
@@ -0,0 +1,1124 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package http
+
+import (
+ "bufio"
+ "bytes"
+ "errors"
+ "fmt"
+ "io"
+ "net/http/httptrace"
+ "net/http/internal"
+ "net/http/internal/ascii"
+ "net/textproto"
+ "reflect"
+ "sort"
+ "strconv"
+ "strings"
+ "sync"
+ "time"
+
+ "golang.org/x/net/http/httpguts"
+)
+
+// ErrLineTooLong is returned when reading request or response bodies
+// with malformed chunked encoding.
+var ErrLineTooLong = internal.ErrLineTooLong
+
+type errorReader struct {
+ err error
+}
+
+func (r errorReader) Read(p []byte) (n int, err error) {
+ return 0, r.err
+}
+
+type byteReader struct {
+ b byte
+ done bool
+}
+
+func (br *byteReader) Read(p []byte) (n int, err error) {
+ if br.done {
+ return 0, io.EOF
+ }
+ if len(p) == 0 {
+ return 0, nil
+ }
+ br.done = true
+ p[0] = br.b
+ return 1, io.EOF
+}
+
+// transferWriter inspects the fields of a user-supplied Request or Response,
+// sanitizes them without changing the user object and provides methods for
+// writing the respective header, body and trailer in wire format.
+type transferWriter struct {
+ Method string
+ Body io.Reader
+ BodyCloser io.Closer
+ ResponseToHEAD bool
+ ContentLength int64 // -1 means unknown, 0 means exactly none
+ Close bool
+ TransferEncoding []string
+ Header Header
+ Trailer Header
+ IsResponse bool
+ bodyReadError error // any non-EOF error from reading Body
+
+ FlushHeaders bool // flush headers to network before body
+ ByteReadCh chan readResult // non-nil if probeRequestBody called
+}
+
+func newTransferWriter(r any) (t *transferWriter, err error) {
+ t = &transferWriter{}
+
+ // Extract relevant fields
+ atLeastHTTP11 := false
+ switch rr := r.(type) {
+ case *Request:
+ if rr.ContentLength != 0 && rr.Body == nil {
+ return nil, fmt.Errorf("http: Request.ContentLength=%d with nil Body", rr.ContentLength)
+ }
+ t.Method = valueOrDefault(rr.Method, "GET")
+ t.Close = rr.Close
+ t.TransferEncoding = rr.TransferEncoding
+ t.Header = rr.Header
+ t.Trailer = rr.Trailer
+ t.Body = rr.Body
+ t.BodyCloser = rr.Body
+ t.ContentLength = rr.outgoingLength()
+ if t.ContentLength < 0 && len(t.TransferEncoding) == 0 && t.shouldSendChunkedRequestBody() {
+ t.TransferEncoding = []string{"chunked"}
+ }
+ // If there's a body, conservatively flush the headers
+ // to any bufio.Writer we're writing to, just in case
+ // the server needs the headers early, before we copy
+ // the body and possibly block. We make an exception
+ // for the common standard library in-memory types,
+ // though, to avoid unnecessary TCP packets on the
+ // wire. (Issue 22088.)
+ if t.ContentLength != 0 && !isKnownInMemoryReader(t.Body) {
+ t.FlushHeaders = true
+ }
+
+ atLeastHTTP11 = true // Transport requests are always 1.1 or 2.0
+ case *Response:
+ t.IsResponse = true
+ if rr.Request != nil {
+ t.Method = rr.Request.Method
+ }
+ t.Body = rr.Body
+ t.BodyCloser = rr.Body
+ t.ContentLength = rr.ContentLength
+ t.Close = rr.Close
+ t.TransferEncoding = rr.TransferEncoding
+ t.Header = rr.Header
+ t.Trailer = rr.Trailer
+ atLeastHTTP11 = rr.ProtoAtLeast(1, 1)
+ t.ResponseToHEAD = noResponseBodyExpected(t.Method)
+ }
+
+ // Sanitize Body,ContentLength,TransferEncoding
+ if t.ResponseToHEAD {
+ t.Body = nil
+ if chunked(t.TransferEncoding) {
+ t.ContentLength = -1
+ }
+ } else {
+ if !atLeastHTTP11 || t.Body == nil {
+ t.TransferEncoding = nil
+ }
+ if chunked(t.TransferEncoding) {
+ t.ContentLength = -1
+ } else if t.Body == nil { // no chunking, no body
+ t.ContentLength = 0
+ }
+ }
+
+ // Sanitize Trailer
+ if !chunked(t.TransferEncoding) {
+ t.Trailer = nil
+ }
+
+ return t, nil
+}
+
+// shouldSendChunkedRequestBody reports whether we should try to send a
+// chunked request body to the server. In particular, the case we really
+// want to prevent is sending a GET or other typically-bodyless request to a
+// server with a chunked body when the body has zero bytes, since GETs with
+// bodies (while acceptable according to specs), even zero-byte chunked
+// bodies, are approximately never seen in the wild and confuse most
+// servers. See Issue 18257, as one example.
+//
+// The only reason we'd send such a request is if the user set the Body to a
+// non-nil value (say, io.NopCloser(bytes.NewReader(nil))) and didn't
+// set ContentLength, or NewRequest set it to -1 (unknown), so then we assume
+// there's bytes to send.
+//
+// This code tries to read a byte from the Request.Body in such cases to see
+// whether the body actually has content (super rare) or is actually just
+// a non-nil content-less ReadCloser (the more common case). In that more
+// common case, we act as if their Body were nil instead, and don't send
+// a body.
+func (t *transferWriter) shouldSendChunkedRequestBody() bool {
+ // Note that t.ContentLength is the corrected content length
+ // from rr.outgoingLength, so 0 actually means zero, not unknown.
+ if t.ContentLength >= 0 || t.Body == nil { // redundant checks; caller did them
+ return false
+ }
+ if t.Method == "CONNECT" {
+ return false
+ }
+ if requestMethodUsuallyLacksBody(t.Method) {
+ // Only probe the Request.Body for GET/HEAD/DELETE/etc
+ // requests, because it's only those types of requests
+ // that confuse servers.
+ t.probeRequestBody() // adjusts t.Body, t.ContentLength
+ return t.Body != nil
+ }
+ // For all other request types (PUT, POST, PATCH, or anything
+ // made-up we've never heard of), assume it's normal and the server
+ // can deal with a chunked request body. Maybe we'll adjust this
+ // later.
+ return true
+}
+
+// probeRequestBody reads a byte from t.Body to see whether it's empty
+// (returns io.EOF right away).
+//
+// But because we've had problems with this blocking users in the past
+// (issue 17480) when the body is a pipe (perhaps waiting on the response
+// headers before the pipe is fed data), we need to be careful and bound how
+// long we wait for it. This delay will only affect users if all the following
+// are true:
+// - the request body blocks
+// - the content length is not set (or set to -1)
+// - the method doesn't usually have a body (GET, HEAD, DELETE, ...)
+// - there is no transfer-encoding=chunked already set.
+//
+// In other words, this delay will not normally affect anybody, and there
+// are workarounds if it does.
+func (t *transferWriter) probeRequestBody() {
+ t.ByteReadCh = make(chan readResult, 1)
+ go func(body io.Reader) {
+ var buf [1]byte
+ var rres readResult
+ rres.n, rres.err = body.Read(buf[:])
+ if rres.n == 1 {
+ rres.b = buf[0]
+ }
+ t.ByteReadCh <- rres
+ close(t.ByteReadCh)
+ }(t.Body)
+ timer := time.NewTimer(200 * time.Millisecond)
+ select {
+ case rres := <-t.ByteReadCh:
+ timer.Stop()
+ if rres.n == 0 && rres.err == io.EOF {
+ // It was empty.
+ t.Body = nil
+ t.ContentLength = 0
+ } else if rres.n == 1 {
+ if rres.err != nil {
+ t.Body = io.MultiReader(&byteReader{b: rres.b}, errorReader{rres.err})
+ } else {
+ t.Body = io.MultiReader(&byteReader{b: rres.b}, t.Body)
+ }
+ } else if rres.err != nil {
+ t.Body = errorReader{rres.err}
+ }
+ case <-timer.C:
+ // Too slow. Don't wait. Read it later, and keep
+ // assuming that this is ContentLength == -1
+ // (unknown), which means we'll send a
+ // "Transfer-Encoding: chunked" header.
+ t.Body = io.MultiReader(finishAsyncByteRead{t}, t.Body)
+ // Request that Request.Write flush the headers to the
+ // network before writing the body, since our body may not
+ // become readable until it's seen the response headers.
+ t.FlushHeaders = true
+ }
+}
+
+func noResponseBodyExpected(requestMethod string) bool {
+ return requestMethod == "HEAD"
+}
+
+func (t *transferWriter) shouldSendContentLength() bool {
+ if chunked(t.TransferEncoding) {
+ return false
+ }
+ if t.ContentLength > 0 {
+ return true
+ }
+ if t.ContentLength < 0 {
+ return false
+ }
+ // Many servers expect a Content-Length for these methods
+ if t.Method == "POST" || t.Method == "PUT" || t.Method == "PATCH" {
+ return true
+ }
+ if t.ContentLength == 0 && isIdentity(t.TransferEncoding) {
+ if t.Method == "GET" || t.Method == "HEAD" {
+ return false
+ }
+ return true
+ }
+
+ return false
+}
+
+func (t *transferWriter) writeHeader(w io.Writer, trace *httptrace.ClientTrace) error {
+ if t.Close && !hasToken(t.Header.get("Connection"), "close") {
+ if _, err := io.WriteString(w, "Connection: close\r\n"); err != nil {
+ return err
+ }
+ if trace != nil && trace.WroteHeaderField != nil {
+ trace.WroteHeaderField("Connection", []string{"close"})
+ }
+ }
+
+ // Write Content-Length and/or Transfer-Encoding whose values are a
+ // function of the sanitized field triple (Body, ContentLength,
+ // TransferEncoding)
+ if t.shouldSendContentLength() {
+ if _, err := io.WriteString(w, "Content-Length: "); err != nil {
+ return err
+ }
+ if _, err := io.WriteString(w, strconv.FormatInt(t.ContentLength, 10)+"\r\n"); err != nil {
+ return err
+ }
+ if trace != nil && trace.WroteHeaderField != nil {
+ trace.WroteHeaderField("Content-Length", []string{strconv.FormatInt(t.ContentLength, 10)})
+ }
+ } else if chunked(t.TransferEncoding) {
+ if _, err := io.WriteString(w, "Transfer-Encoding: chunked\r\n"); err != nil {
+ return err
+ }
+ if trace != nil && trace.WroteHeaderField != nil {
+ trace.WroteHeaderField("Transfer-Encoding", []string{"chunked"})
+ }
+ }
+
+ // Write Trailer header
+ if t.Trailer != nil {
+ keys := make([]string, 0, len(t.Trailer))
+ for k := range t.Trailer {
+ k = CanonicalHeaderKey(k)
+ switch k {
+ case "Transfer-Encoding", "Trailer", "Content-Length":
+ return badStringError("invalid Trailer key", k)
+ }
+ keys = append(keys, k)
+ }
+ if len(keys) > 0 {
+ sort.Strings(keys)
+ // TODO: could do better allocation-wise here, but trailers are rare,
+ // so being lazy for now.
+ if _, err := io.WriteString(w, "Trailer: "+strings.Join(keys, ",")+"\r\n"); err != nil {
+ return err
+ }
+ if trace != nil && trace.WroteHeaderField != nil {
+ trace.WroteHeaderField("Trailer", keys)
+ }
+ }
+ }
+
+ return nil
+}
+
+// always closes t.BodyCloser
+func (t *transferWriter) writeBody(w io.Writer) (err error) {
+ var ncopy int64
+ closed := false
+ defer func() {
+ if closed || t.BodyCloser == nil {
+ return
+ }
+ if closeErr := t.BodyCloser.Close(); closeErr != nil && err == nil {
+ err = closeErr
+ }
+ }()
+
+ // Write body. We "unwrap" the body first if it was wrapped in a
+ // nopCloser or readTrackingBody. This is to ensure that we can take advantage of
+ // OS-level optimizations in the event that the body is an
+ // *os.File.
+ if t.Body != nil {
+ var body = t.unwrapBody()
+ if chunked(t.TransferEncoding) {
+ if bw, ok := w.(*bufio.Writer); ok && !t.IsResponse {
+ w = &internal.FlushAfterChunkWriter{Writer: bw}
+ }
+ cw := internal.NewChunkedWriter(w)
+ _, err = t.doBodyCopy(cw, body)
+ if err == nil {
+ err = cw.Close()
+ }
+ } else if t.ContentLength == -1 {
+ dst := w
+ if t.Method == "CONNECT" {
+ dst = bufioFlushWriter{dst}
+ }
+ ncopy, err = t.doBodyCopy(dst, body)
+ } else {
+ ncopy, err = t.doBodyCopy(w, io.LimitReader(body, t.ContentLength))
+ if err != nil {
+ return err
+ }
+ var nextra int64
+ nextra, err = t.doBodyCopy(io.Discard, body)
+ ncopy += nextra
+ }
+ if err != nil {
+ return err
+ }
+ }
+ if t.BodyCloser != nil {
+ closed = true
+ if err := t.BodyCloser.Close(); err != nil {
+ return err
+ }
+ }
+
+ if !t.ResponseToHEAD && t.ContentLength != -1 && t.ContentLength != ncopy {
+ return fmt.Errorf("http: ContentLength=%d with Body length %d",
+ t.ContentLength, ncopy)
+ }
+
+ if chunked(t.TransferEncoding) {
+ // Write Trailer header
+ if t.Trailer != nil {
+ if err := t.Trailer.Write(w); err != nil {
+ return err
+ }
+ }
+ // Last chunk, empty trailer
+ _, err = io.WriteString(w, "\r\n")
+ }
+ return err
+}
+
+// doBodyCopy wraps a copy operation, with any resulting error also
+// being saved in bodyReadError.
+//
+// This function is only intended for use in writeBody.
+func (t *transferWriter) doBodyCopy(dst io.Writer, src io.Reader) (n int64, err error) {
+ n, err = io.Copy(dst, src)
+ if err != nil && err != io.EOF {
+ t.bodyReadError = err
+ }
+ return
+}
+
+// unwrapBodyReader unwraps the body's inner reader if it's a
+// nopCloser. This is to ensure that body writes sourced from local
+// files (*os.File types) are properly optimized.
+//
+// This function is only intended for use in writeBody.
+func (t *transferWriter) unwrapBody() io.Reader {
+ if r, ok := unwrapNopCloser(t.Body); ok {
+ return r
+ }
+ if r, ok := t.Body.(*readTrackingBody); ok {
+ r.didRead = true
+ return r.ReadCloser
+ }
+ return t.Body
+}
+
+type transferReader struct {
+ // Input
+ Header Header
+ StatusCode int
+ RequestMethod string
+ ProtoMajor int
+ ProtoMinor int
+ // Output
+ Body io.ReadCloser
+ ContentLength int64
+ Chunked bool
+ Close bool
+ Trailer Header
+}
+
+func (t *transferReader) protoAtLeast(m, n int) bool {
+ return t.ProtoMajor > m || (t.ProtoMajor == m && t.ProtoMinor >= n)
+}
+
+// bodyAllowedForStatus reports whether a given response status code
+// permits a body. See RFC 7230, section 3.3.
+func bodyAllowedForStatus(status int) bool {
+ switch {
+ case status >= 100 && status <= 199:
+ return false
+ case status == 204:
+ return false
+ case status == 304:
+ return false
+ }
+ return true
+}
+
+var (
+ suppressedHeaders304 = []string{"Content-Type", "Content-Length", "Transfer-Encoding"}
+ suppressedHeadersNoBody = []string{"Content-Length", "Transfer-Encoding"}
+ excludedHeadersNoBody = map[string]bool{"Content-Length": true, "Transfer-Encoding": true}
+)
+
+func suppressedHeaders(status int) []string {
+ switch {
+ case status == 304:
+ // RFC 7232 section 4.1
+ return suppressedHeaders304
+ case !bodyAllowedForStatus(status):
+ return suppressedHeadersNoBody
+ }
+ return nil
+}
+
+// msg is *Request or *Response.
+func readTransfer(msg any, r *bufio.Reader) (err error) {
+ t := &transferReader{RequestMethod: "GET"}
+
+ // Unify input
+ isResponse := false
+ switch rr := msg.(type) {
+ case *Response:
+ t.Header = rr.Header
+ t.StatusCode = rr.StatusCode
+ t.ProtoMajor = rr.ProtoMajor
+ t.ProtoMinor = rr.ProtoMinor
+ t.Close = shouldClose(t.ProtoMajor, t.ProtoMinor, t.Header, true)
+ isResponse = true
+ if rr.Request != nil {
+ t.RequestMethod = rr.Request.Method
+ }
+ case *Request:
+ t.Header = rr.Header
+ t.RequestMethod = rr.Method
+ t.ProtoMajor = rr.ProtoMajor
+ t.ProtoMinor = rr.ProtoMinor
+ // Transfer semantics for Requests are exactly like those for
+ // Responses with status code 200, responding to a GET method
+ t.StatusCode = 200
+ t.Close = rr.Close
+ default:
+ panic("unexpected type")
+ }
+
+ // Default to HTTP/1.1
+ if t.ProtoMajor == 0 && t.ProtoMinor == 0 {
+ t.ProtoMajor, t.ProtoMinor = 1, 1
+ }
+
+ // Transfer-Encoding: chunked, and overriding Content-Length.
+ if err := t.parseTransferEncoding(); err != nil {
+ return err
+ }
+
+ realLength, err := fixLength(isResponse, t.StatusCode, t.RequestMethod, t.Header, t.Chunked)
+ if err != nil {
+ return err
+ }
+ if isResponse && t.RequestMethod == "HEAD" {
+ if n, err := parseContentLength(t.Header.get("Content-Length")); err != nil {
+ return err
+ } else {
+ t.ContentLength = n
+ }
+ } else {
+ t.ContentLength = realLength
+ }
+
+ // Trailer
+ t.Trailer, err = fixTrailer(t.Header, t.Chunked)
+ if err != nil {
+ return err
+ }
+
+ // If there is no Content-Length or chunked Transfer-Encoding on a *Response
+ // and the status is not 1xx, 204 or 304, then the body is unbounded.
+ // See RFC 7230, section 3.3.
+ switch msg.(type) {
+ case *Response:
+ if realLength == -1 && !t.Chunked && bodyAllowedForStatus(t.StatusCode) {
+ // Unbounded body.
+ t.Close = true
+ }
+ }
+
+ // Prepare body reader. ContentLength < 0 means chunked encoding
+ // or close connection when finished, since multipart is not supported yet
+ switch {
+ case t.Chunked:
+ if isResponse && (noResponseBodyExpected(t.RequestMethod) || !bodyAllowedForStatus(t.StatusCode)) {
+ t.Body = NoBody
+ } else {
+ t.Body = &body{src: internal.NewChunkedReader(r), hdr: msg, r: r, closing: t.Close}
+ }
+ case realLength == 0:
+ t.Body = NoBody
+ case realLength > 0:
+ t.Body = &body{src: io.LimitReader(r, realLength), closing: t.Close}
+ default:
+ // realLength < 0, i.e. "Content-Length" not mentioned in header
+ if t.Close {
+ // Close semantics (i.e. HTTP/1.0)
+ t.Body = &body{src: r, closing: t.Close}
+ } else {
+ // Persistent connection (i.e. HTTP/1.1)
+ t.Body = NoBody
+ }
+ }
+
+ // Unify output
+ switch rr := msg.(type) {
+ case *Request:
+ rr.Body = t.Body
+ rr.ContentLength = t.ContentLength
+ if t.Chunked {
+ rr.TransferEncoding = []string{"chunked"}
+ }
+ rr.Close = t.Close
+ rr.Trailer = t.Trailer
+ case *Response:
+ rr.Body = t.Body
+ rr.ContentLength = t.ContentLength
+ if t.Chunked {
+ rr.TransferEncoding = []string{"chunked"}
+ }
+ rr.Close = t.Close
+ rr.Trailer = t.Trailer
+ }
+
+ return nil
+}
+
+// Checks whether chunked is part of the encodings stack
+func chunked(te []string) bool { return len(te) > 0 && te[0] == "chunked" }
+
+// Checks whether the encoding is explicitly "identity".
+func isIdentity(te []string) bool { return len(te) == 1 && te[0] == "identity" }
+
+// unsupportedTEError reports unsupported transfer-encodings.
+type unsupportedTEError struct {
+ err string
+}
+
+func (uste *unsupportedTEError) Error() string {
+ return uste.err
+}
+
+// isUnsupportedTEError checks if the error is of type
+// unsupportedTEError. It is usually invoked with a non-nil err.
+func isUnsupportedTEError(err error) bool {
+ _, ok := err.(*unsupportedTEError)
+ return ok
+}
+
+// parseTransferEncoding sets t.Chunked based on the Transfer-Encoding header.
+func (t *transferReader) parseTransferEncoding() error {
+ raw, present := t.Header["Transfer-Encoding"]
+ if !present {
+ return nil
+ }
+ delete(t.Header, "Transfer-Encoding")
+
+ // Issue 12785; ignore Transfer-Encoding on HTTP/1.0 requests.
+ if !t.protoAtLeast(1, 1) {
+ return nil
+ }
+
+ // Like nginx, we only support a single Transfer-Encoding header field, and
+ // only if set to "chunked". This is one of the most security sensitive
+ // surfaces in HTTP/1.1 due to the risk of request smuggling, so we keep it
+ // strict and simple.
+ if len(raw) != 1 {
+ return &unsupportedTEError{fmt.Sprintf("too many transfer encodings: %q", raw)}
+ }
+ if !ascii.EqualFold(raw[0], "chunked") {
+ return &unsupportedTEError{fmt.Sprintf("unsupported transfer encoding: %q", raw[0])}
+ }
+
+ // RFC 7230 3.3.2 says "A sender MUST NOT send a Content-Length header field
+ // in any message that contains a Transfer-Encoding header field."
+ //
+ // but also: "If a message is received with both a Transfer-Encoding and a
+ // Content-Length header field, the Transfer-Encoding overrides the
+ // Content-Length. Such a message might indicate an attempt to perform
+ // request smuggling (Section 9.5) or response splitting (Section 9.4) and
+ // ought to be handled as an error. A sender MUST remove the received
+ // Content-Length field prior to forwarding such a message downstream."
+ //
+ // Reportedly, these appear in the wild.
+ delete(t.Header, "Content-Length")
+
+ t.Chunked = true
+ return nil
+}
+
+// Determine the expected body length, using RFC 7230 Section 3.3. This
+// function is not a method, because ultimately it should be shared by
+// ReadResponse and ReadRequest.
+func fixLength(isResponse bool, status int, requestMethod string, header Header, chunked bool) (int64, error) {
+ isRequest := !isResponse
+ contentLens := header["Content-Length"]
+
+ // Hardening against HTTP request smuggling
+ if len(contentLens) > 1 {
+ // Per RFC 7230 Section 3.3.2, prevent multiple
+ // Content-Length headers if they differ in value.
+ // If there are dups of the value, remove the dups.
+ // See Issue 16490.
+ first := textproto.TrimString(contentLens[0])
+ for _, ct := range contentLens[1:] {
+ if first != textproto.TrimString(ct) {
+ return 0, fmt.Errorf("http: message cannot contain multiple Content-Length headers; got %q", contentLens)
+ }
+ }
+
+ // deduplicate Content-Length
+ header.Del("Content-Length")
+ header.Add("Content-Length", first)
+
+ contentLens = header["Content-Length"]
+ }
+
+ // Logic based on response type or status
+ if isResponse && noResponseBodyExpected(requestMethod) {
+ return 0, nil
+ }
+ if status/100 == 1 {
+ return 0, nil
+ }
+ switch status {
+ case 204, 304:
+ return 0, nil
+ }
+
+ // Logic based on Transfer-Encoding
+ if chunked {
+ return -1, nil
+ }
+
+ // Logic based on Content-Length
+ var cl string
+ if len(contentLens) == 1 {
+ cl = textproto.TrimString(contentLens[0])
+ }
+ if cl != "" {
+ n, err := parseContentLength(cl)
+ if err != nil {
+ return -1, err
+ }
+ return n, nil
+ }
+ header.Del("Content-Length")
+
+ if isRequest {
+ // RFC 7230 neither explicitly permits nor forbids an
+ // entity-body on a GET request so we permit one if
+ // declared, but we default to 0 here (not -1 below)
+ // if there's no mention of a body.
+ // Likewise, all other request methods are assumed to have
+ // no body if neither Transfer-Encoding chunked nor a
+ // Content-Length are set.
+ return 0, nil
+ }
+
+ // Body-EOF logic based on other methods (like closing, or chunked coding)
+ return -1, nil
+}
+
+// Determine whether to hang up after sending a request and body, or
+// receiving a response and body
+// 'header' is the request headers
+func shouldClose(major, minor int, header Header, removeCloseHeader bool) bool {
+ if major < 1 {
+ return true
+ }
+
+ conv := header["Connection"]
+ hasClose := httpguts.HeaderValuesContainsToken(conv, "close")
+ if major == 1 && minor == 0 {
+ return hasClose || !httpguts.HeaderValuesContainsToken(conv, "keep-alive")
+ }
+
+ if hasClose && removeCloseHeader {
+ header.Del("Connection")
+ }
+
+ return hasClose
+}
+
+// Parse the trailer header
+func fixTrailer(header Header, chunked bool) (Header, error) {
+ vv, ok := header["Trailer"]
+ if !ok {
+ return nil, nil
+ }
+ if !chunked {
+ // Trailer and no chunking:
+ // this is an invalid use case for trailer header.
+ // Nevertheless, no error will be returned and we
+ // let users decide if this is a valid HTTP message.
+ // The Trailer header will be kept in Response.Header
+ // but not populate Response.Trailer.
+ // See issue #27197.
+ return nil, nil
+ }
+ header.Del("Trailer")
+
+ trailer := make(Header)
+ var err error
+ for _, v := range vv {
+ foreachHeaderElement(v, func(key string) {
+ key = CanonicalHeaderKey(key)
+ switch key {
+ case "Transfer-Encoding", "Trailer", "Content-Length":
+ if err == nil {
+ err = badStringError("bad trailer key", key)
+ return
+ }
+ }
+ trailer[key] = nil
+ })
+ }
+ if err != nil {
+ return nil, err
+ }
+ if len(trailer) == 0 {
+ return nil, nil
+ }
+ return trailer, nil
+}
+
+// body turns a Reader into a ReadCloser.
+// Close ensures that the body has been fully read
+// and then reads the trailer if necessary.
+type body struct {
+ src io.Reader
+ hdr any // non-nil (Response or Request) value means read trailer
+ r *bufio.Reader // underlying wire-format reader for the trailer
+ closing bool // is the connection to be closed after reading body?
+ doEarlyClose bool // whether Close should stop early
+
+ mu sync.Mutex // guards following, and calls to Read and Close
+ sawEOF bool
+ closed bool
+ earlyClose bool // Close called and we didn't read to the end of src
+ onHitEOF func() // if non-nil, func to call when EOF is Read
+}
+
+// ErrBodyReadAfterClose is returned when reading a Request or Response
+// Body after the body has been closed. This typically happens when the body is
+// read after an HTTP Handler calls WriteHeader or Write on its
+// ResponseWriter.
+var ErrBodyReadAfterClose = errors.New("http: invalid Read on closed Body")
+
+func (b *body) Read(p []byte) (n int, err error) {
+ b.mu.Lock()
+ defer b.mu.Unlock()
+ if b.closed {
+ return 0, ErrBodyReadAfterClose
+ }
+ return b.readLocked(p)
+}
+
+// Must hold b.mu.
+func (b *body) readLocked(p []byte) (n int, err error) {
+ if b.sawEOF {
+ return 0, io.EOF
+ }
+ n, err = b.src.Read(p)
+
+ if err == io.EOF {
+ b.sawEOF = true
+ // Chunked case. Read the trailer.
+ if b.hdr != nil {
+ if e := b.readTrailer(); e != nil {
+ err = e
+ // Something went wrong in the trailer, we must not allow any
+ // further reads of any kind to succeed from body, nor any
+ // subsequent requests on the server connection. See
+ // golang.org/issue/12027
+ b.sawEOF = false
+ b.closed = true
+ }
+ b.hdr = nil
+ } else {
+ // If the server declared the Content-Length, our body is a LimitedReader
+ // and we need to check whether this EOF arrived early.
+ if lr, ok := b.src.(*io.LimitedReader); ok && lr.N > 0 {
+ err = io.ErrUnexpectedEOF
+ }
+ }
+ }
+
+ // If we can return an EOF here along with the read data, do
+ // so. This is optional per the io.Reader contract, but doing
+ // so helps the HTTP transport code recycle its connection
+ // earlier (since it will see this EOF itself), even if the
+ // client doesn't do future reads or Close.
+ if err == nil && n > 0 {
+ if lr, ok := b.src.(*io.LimitedReader); ok && lr.N == 0 {
+ err = io.EOF
+ b.sawEOF = true
+ }
+ }
+
+ if b.sawEOF && b.onHitEOF != nil {
+ b.onHitEOF()
+ }
+
+ return n, err
+}
+
+var (
+ singleCRLF = []byte("\r\n")
+ doubleCRLF = []byte("\r\n\r\n")
+)
+
+func seeUpcomingDoubleCRLF(r *bufio.Reader) bool {
+ for peekSize := 4; ; peekSize++ {
+ // This loop stops when Peek returns an error,
+ // which it does when r's buffer has been filled.
+ buf, err := r.Peek(peekSize)
+ if bytes.HasSuffix(buf, doubleCRLF) {
+ return true
+ }
+ if err != nil {
+ break
+ }
+ }
+ return false
+}
+
+var errTrailerEOF = errors.New("http: unexpected EOF reading trailer")
+
+func (b *body) readTrailer() error {
+ // The common case, since nobody uses trailers.
+ buf, err := b.r.Peek(2)
+ if bytes.Equal(buf, singleCRLF) {
+ b.r.Discard(2)
+ return nil
+ }
+ if len(buf) < 2 {
+ return errTrailerEOF
+ }
+ if err != nil {
+ return err
+ }
+
+ // Make sure there's a header terminator coming up, to prevent
+ // a DoS with an unbounded size Trailer. It's not easy to
+ // slip in a LimitReader here, as textproto.NewReader requires
+ // a concrete *bufio.Reader. Also, we can't get all the way
+ // back up to our conn's LimitedReader that *might* be backing
+ // this bufio.Reader. Instead, a hack: we iteratively Peek up
+ // to the bufio.Reader's max size, looking for a double CRLF.
+ // This limits the trailer to the underlying buffer size, typically 4kB.
+ if !seeUpcomingDoubleCRLF(b.r) {
+ return errors.New("http: suspiciously long trailer after chunked body")
+ }
+
+ hdr, err := textproto.NewReader(b.r).ReadMIMEHeader()
+ if err != nil {
+ if err == io.EOF {
+ return errTrailerEOF
+ }
+ return err
+ }
+ switch rr := b.hdr.(type) {
+ case *Request:
+ mergeSetHeader(&rr.Trailer, Header(hdr))
+ case *Response:
+ mergeSetHeader(&rr.Trailer, Header(hdr))
+ }
+ return nil
+}
+
+func mergeSetHeader(dst *Header, src Header) {
+ if *dst == nil {
+ *dst = src
+ return
+ }
+ for k, vv := range src {
+ (*dst)[k] = vv
+ }
+}
+
+// unreadDataSizeLocked returns the number of bytes of unread input.
+// It returns -1 if unknown.
+// b.mu must be held.
+func (b *body) unreadDataSizeLocked() int64 {
+ if lr, ok := b.src.(*io.LimitedReader); ok {
+ return lr.N
+ }
+ return -1
+}
+
+func (b *body) Close() error {
+ b.mu.Lock()
+ defer b.mu.Unlock()
+ if b.closed {
+ return nil
+ }
+ var err error
+ switch {
+ case b.sawEOF:
+ // Already saw EOF, so no need going to look for it.
+ case b.hdr == nil && b.closing:
+ // no trailer and closing the connection next.
+ // no point in reading to EOF.
+ case b.doEarlyClose:
+ // Read up to maxPostHandlerReadBytes bytes of the body, looking
+ // for EOF (and trailers), so we can re-use this connection.
+ if lr, ok := b.src.(*io.LimitedReader); ok && lr.N > maxPostHandlerReadBytes {
+ // There was a declared Content-Length, and we have more bytes remaining
+ // than our maxPostHandlerReadBytes tolerance. So, give up.
+ b.earlyClose = true
+ } else {
+ var n int64
+ // Consume the body, or, which will also lead to us reading
+ // the trailer headers after the body, if present.
+ n, err = io.CopyN(io.Discard, bodyLocked{b}, maxPostHandlerReadBytes)
+ if err == io.EOF {
+ err = nil
+ }
+ if n == maxPostHandlerReadBytes {
+ b.earlyClose = true
+ }
+ }
+ default:
+ // Fully consume the body, which will also lead to us reading
+ // the trailer headers after the body, if present.
+ _, err = io.Copy(io.Discard, bodyLocked{b})
+ }
+ b.closed = true
+ return err
+}
+
+func (b *body) didEarlyClose() bool {
+ b.mu.Lock()
+ defer b.mu.Unlock()
+ return b.earlyClose
+}
+
+// bodyRemains reports whether future Read calls might
+// yield data.
+func (b *body) bodyRemains() bool {
+ b.mu.Lock()
+ defer b.mu.Unlock()
+ return !b.sawEOF
+}
+
+func (b *body) registerOnHitEOF(fn func()) {
+ b.mu.Lock()
+ defer b.mu.Unlock()
+ b.onHitEOF = fn
+}
+
+// bodyLocked is an io.Reader reading from a *body when its mutex is
+// already held.
+type bodyLocked struct {
+ b *body
+}
+
+func (bl bodyLocked) Read(p []byte) (n int, err error) {
+ if bl.b.closed {
+ return 0, ErrBodyReadAfterClose
+ }
+ return bl.b.readLocked(p)
+}
+
+// parseContentLength trims whitespace from s and returns -1 if no value
+// is set, or the value if it's >= 0.
+func parseContentLength(cl string) (int64, error) {
+ cl = textproto.TrimString(cl)
+ if cl == "" {
+ return -1, nil
+ }
+ n, err := strconv.ParseUint(cl, 10, 63)
+ if err != nil {
+ return 0, badStringError("bad Content-Length", cl)
+ }
+ return int64(n), nil
+
+}
+
+// finishAsyncByteRead finishes reading the 1-byte sniff
+// from the ContentLength==0, Body!=nil case.
+type finishAsyncByteRead struct {
+ tw *transferWriter
+}
+
+func (fr finishAsyncByteRead) Read(p []byte) (n int, err error) {
+ if len(p) == 0 {
+ return
+ }
+ rres := <-fr.tw.ByteReadCh
+ n, err = rres.n, rres.err
+ if n == 1 {
+ p[0] = rres.b
+ }
+ if err == nil {
+ err = io.EOF
+ }
+ return
+}
+
+var nopCloserType = reflect.TypeOf(io.NopCloser(nil))
+var nopCloserWriterToType = reflect.TypeOf(io.NopCloser(struct {
+ io.Reader
+ io.WriterTo
+}{}))
+
+// unwrapNopCloser return the underlying reader and true if r is a NopCloser
+// else it return false
+func unwrapNopCloser(r io.Reader) (underlyingReader io.Reader, isNopCloser bool) {
+ switch reflect.TypeOf(r) {
+ case nopCloserType, nopCloserWriterToType:
+ return reflect.ValueOf(r).Field(0).Interface().(io.Reader), true
+ default:
+ return nil, false
+ }
+}
+
+// isKnownInMemoryReader reports whether r is a type known to not
+// block on Read. Its caller uses this as an optional optimization to
+// send fewer TCP packets.
+func isKnownInMemoryReader(r io.Reader) bool {
+ switch r.(type) {
+ case *bytes.Reader, *bytes.Buffer, *strings.Reader:
+ return true
+ }
+ if r, ok := unwrapNopCloser(r); ok {
+ return isKnownInMemoryReader(r)
+ }
+ if r, ok := r.(*readTrackingBody); ok {
+ return isKnownInMemoryReader(r.ReadCloser)
+ }
+ return false
+}
+
+// bufioFlushWriter is an io.Writer wrapper that flushes all writes
+// on its wrapped writer if it's a *bufio.Writer.
+type bufioFlushWriter struct{ w io.Writer }
+
+func (fw bufioFlushWriter) Write(p []byte) (n int, err error) {
+ n, err = fw.w.Write(p)
+ if bw, ok := fw.w.(*bufio.Writer); n > 0 && ok {
+ ferr := bw.Flush()
+ if ferr != nil && err == nil {
+ err = ferr
+ }
+ }
+ return
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-19 13:29:07 +0000