src/net/http/header.go - go - Git at Google

 // Copyright 2010 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 (
 	"io"
 	"net/http/httptrace"
 	"net/textproto"
 	"sort"
 	"strings"
 	"sync"
 	"time"
 )

 // A Header represents the key-value pairs in an HTTP header.
 //
 // The keys should be in canonical form, as returned by
 // CanonicalHeaderKey.
 type Header map[string][]string

 // Add adds the key, value pair to the header.
 // It appends to any existing values associated with key.
 // The key is case insensitive; it is canonicalized by
 // CanonicalHeaderKey.
 func (h Header) Add(key, value string) {
 	textproto.MIMEHeader(h).Add(key, value)
 }

 // Set sets the header entries associated with key to the
 // single element value. It replaces any existing values
 // associated with key. The key is case insensitive; it is
 // canonicalized by textproto.CanonicalMIMEHeaderKey.
 // To use non-canonical keys, assign to the map directly.
 func (h Header) Set(key, value string) {
 	textproto.MIMEHeader(h).Set(key, value)
 }

 // Get gets the first value associated with the given key. If
 // there are no values associated with the key, Get returns "".
 // It is case insensitive; textproto.CanonicalMIMEHeaderKey is
 // used to canonicalize the provided key. To access multiple
 // values of a key, or to use non-canonical keys, access the
 // map directly.
 func (h Header) Get(key string) string {
 	return textproto.MIMEHeader(h).Get(key)
 }

 // get is like Get, but key must already be in CanonicalHeaderKey form.
 func (h Header) get(key string) string {
 	if v := h[key]; len(v) > 0 {
 		return v[0]
 	}
 	return ""
 }

 // has reports whether h has the provided key defined, even if it's
 // set to 0-length slice.
 func (h Header) has(key string) bool {
 	_, ok := h[key]
 	return ok
 }

 // Del deletes the values associated with key.
 // The key is case insensitive; it is canonicalized by
 // CanonicalHeaderKey.
 func (h Header) Del(key string) {
 	textproto.MIMEHeader(h).Del(key)
 }

 // Write writes a header in wire format.
 func (h Header) Write(w io.Writer) error {
 	return h.write(w, nil)
 }

 func (h Header) write(w io.Writer, trace *httptrace.ClientTrace) error {
 	return h.writeSubset(w, nil, trace)
 }

 // Clone returns a copy of h.
 func (h Header) Clone() Header {
 	// Find total number of values.
 	nv := 0
 	for _, vv := range h {
 		nv += len(vv)
 	}
 	sv := make([]string, nv) // shared backing array for headers' values
 	h2 := make(Header, len(h))
 	for k, vv := range h {
 		n := copy(sv, vv)
 		h2[k] = sv[:n:n]
 		sv = sv[n:]
 	}
 	return h2
 }

 var timeFormats = []string{
 	TimeFormat,
 	time.RFC850,
 	time.ANSIC,
 }

 // ParseTime parses a time header (such as the Date: header),
 // trying each of the three formats allowed by HTTP/1.1:
 // TimeFormat, time.RFC850, and time.ANSIC.
 func ParseTime(text string) (t time.Time, err error) {
 	for _, layout := range timeFormats {
 		t, err = time.Parse(layout, text)
 		if err == nil {
 			return
 		}
 	}
 	return
 }

 var headerNewlineToSpace = strings.NewReplacer("\n", " ", "\r", " ")

 // stringWriter implements WriteString on a Writer.
 type stringWriter struct {
 	w io.Writer
 }

 func (w stringWriter) WriteString(s string) (n int, err error) {
 	return w.w.Write([]byte(s))
 }

 type keyValues struct {
 	key    string
 	values []string
 }

 // A headerSorter implements sort.Interface by sorting a []keyValues
 // by key. It's used as a pointer, so it can fit in a sort.Interface
 // interface value without allocation.
 type headerSorter struct {
 	kvs []keyValues
 }

 func (s *headerSorter) Len() int           { return len(s.kvs) }
 func (s *headerSorter) Swap(i, j int)      { s.kvs[i], s.kvs[j] = s.kvs[j], s.kvs[i] }
 func (s *headerSorter) Less(i, j int) bool { return s.kvs[i].key < s.kvs[j].key }

 var headerSorterPool = sync.Pool{
 	New: func() interface{} { return new(headerSorter) },
 }

 // sortedKeyValues returns h's keys sorted in the returned kvs
 // slice. The headerSorter used to sort is also returned, for possible
 // return to headerSorterCache.
 func (h Header) sortedKeyValues(exclude map[string]bool) (kvs []keyValues, hs *headerSorter) {
 	hs = headerSorterPool.Get().(*headerSorter)
 	if cap(hs.kvs) < len(h) {
 		hs.kvs = make([]keyValues, 0, len(h))
 	}
 	kvs = hs.kvs[:0]
 	for k, vv := range h {
 		if !exclude[k] {
 			kvs = append(kvs, keyValues{k, vv})
 		}
 	}
 	hs.kvs = kvs
 	sort.Sort(hs)
 	return kvs, hs
 }

 // WriteSubset writes a header in wire format.
 // If exclude is not nil, keys where exclude[key] == true are not written.
 func (h Header) WriteSubset(w io.Writer, exclude map[string]bool) error {
 	return h.writeSubset(w, exclude, nil)
 }

 func (h Header) writeSubset(w io.Writer, exclude map[string]bool, trace *httptrace.ClientTrace) error {
 	ws, ok := w.(io.StringWriter)
 	if !ok {
 		ws = stringWriter{w}
 	}
 	kvs, sorter := h.sortedKeyValues(exclude)
 	var formattedVals []string
 	for _, kv := range kvs {
 		for _, v := range kv.values {
 			v = headerNewlineToSpace.Replace(v)
 			v = textproto.TrimString(v)
 			for _, s := range []string{kv.key, ": ", v, "\r\n"} {
 				if _, err := ws.WriteString(s); err != nil {
 					headerSorterPool.Put(sorter)
 					return err
 				}
 			}
 			if trace != nil && trace.WroteHeaderField != nil {
 				formattedVals = append(formattedVals, v)
 			}
 		}
 		if trace != nil && trace.WroteHeaderField != nil {
 			trace.WroteHeaderField(kv.key, formattedVals)
 			formattedVals = nil
 		}
 	}
 	headerSorterPool.Put(sorter)
 	return nil
 }

 // CanonicalHeaderKey returns the canonical format of the
 // header key s. The canonicalization converts the first
 // letter and any letter following a hyphen to upper case;
 // the rest are converted to lowercase. For example, the
 // canonical key for "accept-encoding" is "Accept-Encoding".
 // If s contains a space or invalid header field bytes, it is
 // returned without modifications.
 func CanonicalHeaderKey(s string) string { return textproto.CanonicalMIMEHeaderKey(s) }

 // hasToken reports whether token appears with v, ASCII
 // case-insensitive, with space or comma boundaries.
 // token must be all lowercase.
 // v may contain mixed cased.
 func hasToken(v, token string) bool {
 	if len(token) > len(v) || token == "" {
 		return false
 	}
 	if v == token {
 		return true
 	}
 	for sp := 0; sp <= len(v)-len(token); sp++ {
 		// Check that first character is good.
 		// The token is ASCII, so checking only a single byte
 		// is sufficient. We skip this potential starting
 		// position if both the first byte and its potential
 		// ASCII uppercase equivalent (b|0x20) don't match.
 		// False positives ('^' => '~') are caught by EqualFold.
 		if b := v[sp]; b != token[0] && b|0x20 != token[0] {
 			continue
 		}
 		// Check that start pos is on a valid token boundary.
 		if sp > 0 && !isTokenBoundary(v[sp-1]) {
 			continue
 		}
 		// Check that end pos is on a valid token boundary.
 		if endPos := sp + len(token); endPos != len(v) && !isTokenBoundary(v[endPos]) {
 			continue
 		}
 		if strings.EqualFold(v[sp:sp+len(token)], token) {
 			return true
 		}
 	}
 	return false
 }

 func isTokenBoundary(b byte) bool {
 	return b == ' ' || b == ',' || b == '\t'
 }
	// Copyright 2010 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 (
	"io"
	"net/http/httptrace"
	"net/textproto"
	"sort"
	"strings"
	"sync"
	"time"
	)

	// A Header represents the key-value pairs in an HTTP header.
	//
	// The keys should be in canonical form, as returned by
	// CanonicalHeaderKey.
	type Header map[string][]string

	// Add adds the key, value pair to the header.
	// It appends to any existing values associated with key.
	// The key is case insensitive; it is canonicalized by
	// CanonicalHeaderKey.
	func (h Header) Add(key, value string) {
	textproto.MIMEHeader(h).Add(key, value)
	}

	// Set sets the header entries associated with key to the
	// single element value. It replaces any existing values
	// associated with key. The key is case insensitive; it is
	// canonicalized by textproto.CanonicalMIMEHeaderKey.
	// To use non-canonical keys, assign to the map directly.
	func (h Header) Set(key, value string) {
	textproto.MIMEHeader(h).Set(key, value)
	}

	// Get gets the first value associated with the given key. If
	// there are no values associated with the key, Get returns "".
	// It is case insensitive; textproto.CanonicalMIMEHeaderKey is
	// used to canonicalize the provided key. To access multiple
	// values of a key, or to use non-canonical keys, access the
	// map directly.
	func (h Header) Get(key string) string {
	return textproto.MIMEHeader(h).Get(key)
	}

	// get is like Get, but key must already be in CanonicalHeaderKey form.
	func (h Header) get(key string) string {
	if v := h[key]; len(v) > 0 {
	return v[0]
	}
	return ""
	}

	// has reports whether h has the provided key defined, even if it's
	// set to 0-length slice.
	func (h Header) has(key string) bool {
	_, ok := h[key]
	return ok
	}

	// Del deletes the values associated with key.
	// The key is case insensitive; it is canonicalized by
	// CanonicalHeaderKey.
	func (h Header) Del(key string) {
	textproto.MIMEHeader(h).Del(key)
	}

	// Write writes a header in wire format.
	func (h Header) Write(w io.Writer) error {
	return h.write(w, nil)
	}

	func (h Header) write(w io.Writer, trace *httptrace.ClientTrace) error {
	return h.writeSubset(w, nil, trace)
	}

	// Clone returns a copy of h.
	func (h Header) Clone() Header {
	// Find total number of values.
	nv := 0
	for _, vv := range h {
	nv += len(vv)
	}
	sv := make([]string, nv) // shared backing array for headers' values
	h2 := make(Header, len(h))
	for k, vv := range h {
	n := copy(sv, vv)
	h2[k] = sv[:n:n]
	sv = sv[n:]
	}
	return h2
	}

	var timeFormats = []string{
	TimeFormat,
	time.RFC850,
	time.ANSIC,
	}

	// ParseTime parses a time header (such as the Date: header),
	// trying each of the three formats allowed by HTTP/1.1:
	// TimeFormat, time.RFC850, and time.ANSIC.
	func ParseTime(text string) (t time.Time, err error) {
	for _, layout := range timeFormats {
	t, err = time.Parse(layout, text)
	if err == nil {
	return
	}
	}
	return
	}

	var headerNewlineToSpace = strings.NewReplacer("\n", " ", "\r", " ")

	// stringWriter implements WriteString on a Writer.
	type stringWriter struct {
	w io.Writer
	}

	func (w stringWriter) WriteString(s string) (n int, err error) {
	return w.w.Write([]byte(s))
	}

	type keyValues struct {
	key string
	values []string
	}

	// A headerSorter implements sort.Interface by sorting a []keyValues
	// by key. It's used as a pointer, so it can fit in a sort.Interface
	// interface value without allocation.
	type headerSorter struct {
	kvs []keyValues
	}

	func (s *headerSorter) Len() int { return len(s.kvs) }
	func (s *headerSorter) Swap(i, j int) { s.kvs[i], s.kvs[j] = s.kvs[j], s.kvs[i] }
	func (s *headerSorter) Less(i, j int) bool { return s.kvs[i].key < s.kvs[j].key }

	var headerSorterPool = sync.Pool{
	New: func() interface{} { return new(headerSorter) },
	}

	// sortedKeyValues returns h's keys sorted in the returned kvs
	// slice. The headerSorter used to sort is also returned, for possible
	// return to headerSorterCache.
	func (h Header) sortedKeyValues(exclude map[string]bool) (kvs []keyValues, hs *headerSorter) {
	hs = headerSorterPool.Get().(*headerSorter)
	if cap(hs.kvs) < len(h) {
	hs.kvs = make([]keyValues, 0, len(h))
	}
	kvs = hs.kvs[:0]
	for k, vv := range h {
	if !exclude[k] {
	kvs = append(kvs, keyValues{k, vv})
	}
	}
	hs.kvs = kvs
	sort.Sort(hs)
	return kvs, hs
	}

	// WriteSubset writes a header in wire format.
	// If exclude is not nil, keys where exclude[key] == true are not written.
	func (h Header) WriteSubset(w io.Writer, exclude map[string]bool) error {
	return h.writeSubset(w, exclude, nil)
	}

	func (h Header) writeSubset(w io.Writer, exclude map[string]bool, trace *httptrace.ClientTrace) error {
	ws, ok := w.(io.StringWriter)
	if !ok {
	ws = stringWriter{w}
	}
	kvs, sorter := h.sortedKeyValues(exclude)
	var formattedVals []string
	for _, kv := range kvs {
	for _, v := range kv.values {
	v = headerNewlineToSpace.Replace(v)
	v = textproto.TrimString(v)
	for _, s := range []string{kv.key, ": ", v, "\r\n"} {
	if _, err := ws.WriteString(s); err != nil {
	headerSorterPool.Put(sorter)
	return err
	}
	}
	if trace != nil && trace.WroteHeaderField != nil {
	formattedVals = append(formattedVals, v)
	}
	}
	if trace != nil && trace.WroteHeaderField != nil {
	trace.WroteHeaderField(kv.key, formattedVals)
	formattedVals = nil
	}
	}
	headerSorterPool.Put(sorter)
	return nil
	}

	// CanonicalHeaderKey returns the canonical format of the
	// header key s. The canonicalization converts the first
	// letter and any letter following a hyphen to upper case;
	// the rest are converted to lowercase. For example, the
	// canonical key for "accept-encoding" is "Accept-Encoding".
	// If s contains a space or invalid header field bytes, it is
	// returned without modifications.
	func CanonicalHeaderKey(s string) string { return textproto.CanonicalMIMEHeaderKey(s) }

	// hasToken reports whether token appears with v, ASCII
	// case-insensitive, with space or comma boundaries.
	// token must be all lowercase.
	// v may contain mixed cased.
	func hasToken(v, token string) bool {
	if len(token) > len(v) \|\| token == "" {
	return false
	}
	if v == token {
	return true
	}
	for sp := 0; sp <= len(v)-len(token); sp++ {
	// Check that first character is good.
	// The token is ASCII, so checking only a single byte
	// is sufficient. We skip this potential starting
	// position if both the first byte and its potential
	// ASCII uppercase equivalent (b\|0x20) don't match.
	// False positives ('^' => '~') are caught by EqualFold.
	if b := v[sp]; b != token[0] && b\|0x20 != token[0] {
	continue
	}
	// Check that start pos is on a valid token boundary.
	if sp > 0 && !isTokenBoundary(v[sp-1]) {
	continue
	}
	// Check that end pos is on a valid token boundary.
	if endPos := sp + len(token); endPos != len(v) && !isTokenBoundary(v[endPos]) {
	continue
	}
	if strings.EqualFold(v[sp:sp+len(token)], token) {
	return true
	}
	}
	return false
	}

	func isTokenBoundary(b byte) bool {
	return b == ' ' \|\| b == ',' \|\| b == '\t'
	}