1 files changed, 291 insertions, 0 deletions
diff --git a/src/net/http/response.go b/src/net/http/response.go
new file mode 100644
index 000000000..5d2c39080
--- /dev/null
+++ b/src/net/http/response.go
@@ -0,0 +1,291 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// HTTP Response reading and parsing.
+
+package http
+
+import (
+	"bufio"
+	"bytes"
+	"crypto/tls"
+	"errors"
+	"io"
+	"net/textproto"
+	"net/url"
+	"strconv"
+	"strings"
+)
+
+var respExcludeHeader = map[string]bool{
+	"Content-Length":    true,
+	"Transfer-Encoding": true,
+	"Trailer":           true,
+}
+
+// Response represents the response from an HTTP request.
+//
+type Response struct {
+	Status     string // e.g. "200 OK"
+	StatusCode int    // e.g. 200
+	Proto      string // e.g. "HTTP/1.0"
+	ProtoMajor int    // e.g. 1
+	ProtoMinor int    // e.g. 0
+
+	// Header maps header keys to values.  If the response had multiple
+	// headers with the same key, they may be concatenated, with comma
+	// delimiters.  (Section 4.2 of RFC 2616 requires that multiple headers
+	// be semantically equivalent to a comma-delimited sequence.) Values
+	// duplicated by other fields in this struct (e.g., ContentLength) are
+	// omitted from Header.
+	//
+	// Keys in the map are canonicalized (see CanonicalHeaderKey).
+	Header Header
+
+	// Body represents the response body.
+	//
+	// The http Client and Transport guarantee that Body is always
+	// non-nil, even on responses without a body or responses with
+	// a zero-length body. It is the caller's responsibility to
+	// close Body.
+	//
+	// The Body is automatically dechunked if the server replied
+	// with a "chunked" Transfer-Encoding.
+	Body io.ReadCloser
+
+	// ContentLength records the length of the associated content.  The
+	// value -1 indicates that the length is unknown.  Unless Request.Method
+	// is "HEAD", values >= 0 indicate that the given number of bytes may
+	// be read from Body.
+	ContentLength int64
+
+	// Contains transfer encodings from outer-most to inner-most. Value is
+	// nil, means that "identity" encoding is used.
+	TransferEncoding []string
+
+	// Close records whether the header directed that the connection be
+	// closed after reading Body.  The value is advice for clients: neither
+	// ReadResponse nor Response.Write ever closes a connection.
+	Close bool
+
+	// Trailer maps trailer keys to values, in the same
+	// format as the header.
+	Trailer Header
+
+	// The Request that was sent to obtain this Response.
+	// Request's Body is nil (having already been consumed).
+	// This is only populated for Client requests.
+	Request *Request
+
+	// TLS contains information about the TLS connection on which the
+	// response was received. It is nil for unencrypted responses.
+	// The pointer is shared between responses and should not be
+	// modified.
+	TLS *tls.ConnectionState
+}
+
+// Cookies parses and returns the cookies set in the Set-Cookie headers.
+func (r *Response) Cookies() []*Cookie {
+	return readSetCookies(r.Header)
+}
+
+var ErrNoLocation = errors.New("http: no Location header in response")
+
+// Location returns the URL of the response's "Location" header,
+// if present.  Relative redirects are resolved relative to
+// the Response's Request.  ErrNoLocation is returned if no
+// Location header is present.
+func (r *Response) Location() (*url.URL, error) {
+	lv := r.Header.Get("Location")
+	if lv == "" {
+		return nil, ErrNoLocation
+	}
+	if r.Request != nil && r.Request.URL != nil {
+		return r.Request.URL.Parse(lv)
+	}
+	return url.Parse(lv)
+}
+
+// ReadResponse reads and returns an HTTP response from r.
+// The req parameter optionally specifies the Request that corresponds
+// to this Response. If nil, a GET request is assumed.
+// Clients must call resp.Body.Close when finished reading resp.Body.
+// After that call, clients can inspect resp.Trailer to find key/value
+// pairs included in the response trailer.
+func ReadResponse(r *bufio.Reader, req *Request) (*Response, error) {
+	tp := textproto.NewReader(r)
+	resp := &Response{
+		Request: req,
+	}
+
+	// Parse the first line of the response.
+	line, err := tp.ReadLine()
+	if err != nil {
+		if err == io.EOF {
+			err = io.ErrUnexpectedEOF
+		}
+		return nil, err
+	}
+	f := strings.SplitN(line, " ", 3)
+	if len(f) < 2 {
+		return nil, &badStringError{"malformed HTTP response", line}
+	}
+	reasonPhrase := ""
+	if len(f) > 2 {
+		reasonPhrase = f[2]
+	}
+	resp.Status = f[1] + " " + reasonPhrase
+	resp.StatusCode, err = strconv.Atoi(f[1])
+	if err != nil {
+		return nil, &badStringError{"malformed HTTP status code", f[1]}
+	}
+
+	resp.Proto = f[0]
+	var ok bool
+	if resp.ProtoMajor, resp.ProtoMinor, ok = ParseHTTPVersion(resp.Proto); !ok {
+		return nil, &badStringError{"malformed HTTP version", resp.Proto}
+	}
+
+	// Parse the response headers.
+	mimeHeader, err := tp.ReadMIMEHeader()
+	if err != nil {
+		if err == io.EOF {
+			err = io.ErrUnexpectedEOF
+		}
+		return nil, err
+	}
+	resp.Header = Header(mimeHeader)
+
+	fixPragmaCacheControl(resp.Header)
+
+	err = readTransfer(resp, r)
+	if err != nil {
+		return nil, err
+	}
+
+	return resp, nil
+}
+
+// RFC2616: Should treat
+//	Pragma: no-cache
+// like
+//	Cache-Control: no-cache
+func fixPragmaCacheControl(header Header) {
+	if hp, ok := header["Pragma"]; ok && len(hp) > 0 && hp[0] == "no-cache" {
+		if _, presentcc := header["Cache-Control"]; !presentcc {
+			header["Cache-Control"] = []string{"no-cache"}
+		}
+	}
+}
+
+// ProtoAtLeast reports whether the HTTP protocol used
+// in the response is at least major.minor.
+func (r *Response) ProtoAtLeast(major, minor int) bool {
+	return r.ProtoMajor > major ||
+		r.ProtoMajor == major && r.ProtoMinor >= minor
+}
+
+// Writes the response (header, body and trailer) in wire format. This method
+// consults the following fields of the response:
+//
+//  StatusCode
+//  ProtoMajor
+//  ProtoMinor
+//  Request.Method
+//  TransferEncoding
+//  Trailer
+//  Body
+//  ContentLength
+//  Header, values for non-canonical keys will have unpredictable behavior
+//
+// Body is closed after it is sent.
+func (r *Response) Write(w io.Writer) error {
+	// Status line
+	text := r.Status
+	if text == "" {
+		var ok bool
+		text, ok = statusText[r.StatusCode]
+		if !ok {
+			text = "status code " + strconv.Itoa(r.StatusCode)
+		}
+	}
+	protoMajor, protoMinor := strconv.Itoa(r.ProtoMajor), strconv.Itoa(r.ProtoMinor)
+	statusCode := strconv.Itoa(r.StatusCode) + " "
+	text = strings.TrimPrefix(text, statusCode)
+	if _, err := io.WriteString(w, "HTTP/"+protoMajor+"."+protoMinor+" "+statusCode+text+"\r\n"); err != nil {
+		return err
+	}
+
+	// Clone it, so we can modify r1 as needed.
+	r1 := new(Response)
+	*r1 = *r
+	if r1.ContentLength == 0 && r1.Body != nil {
+		// Is it actually 0 length? Or just unknown?
+		var buf [1]byte
+		n, err := r1.Body.Read(buf[:])
+		if err != nil && err != io.EOF {
+			return err
+		}
+		if n == 0 {
+			// Reset it to a known zero reader, in case underlying one
+			// is unhappy being read repeatedly.
+			r1.Body = eofReader
+		} else {
+			r1.ContentLength = -1
+			r1.Body = struct {
+				io.Reader
+				io.Closer
+			}{
+				io.MultiReader(bytes.NewReader(buf[:1]), r.Body),
+				r.Body,
+			}
+		}
+	}
+	// If we're sending a non-chunked HTTP/1.1 response without a
+	// content-length, the only way to do that is the old HTTP/1.0
+	// way, by noting the EOF with a connection close, so we need
+	// to set Close.
+	if r1.ContentLength == -1 && !r1.Close && r1.ProtoAtLeast(1, 1) && !chunked(r1.TransferEncoding) {
+		r1.Close = true
+	}
+
+	// Process Body,ContentLength,Close,Trailer
+	tw, err := newTransferWriter(r1)
+	if err != nil {
+		return err
+	}
+	err = tw.WriteHeader(w)
+	if err != nil {
+		return err
+	}
+
+	// Rest of header
+	err = r.Header.WriteSubset(w, respExcludeHeader)
+	if err != nil {
+		return err
+	}
+
+	// contentLengthAlreadySent may have been already sent for
+	// POST/PUT requests, even if zero length. See Issue 8180.
+	contentLengthAlreadySent := tw.shouldSendContentLength()
+	if r1.ContentLength == 0 && !chunked(r1.TransferEncoding) && !contentLengthAlreadySent {
+		if _, err := io.WriteString(w, "Content-Length: 0\r\n"); err != nil {
+			return err
+		}
+	}
+
+	// End-of-header
+	if _, err := io.WriteString(w, "\r\n"); err != nil {
+		return err
+	}
+
+	// Write body and trailer
+	err = tw.WriteBody(w)
+	if err != nil {
+		return err
+	}
+
+	// Success
+	return nil
+}