359 lines
10 KiB
Go
359 lines
10 KiB
Go
// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package http
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import (
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"encoding/json"
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"io"
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"net/textproto"
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"sort"
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"strings"
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"sync"
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"time"
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)
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var raceEnabled = false // set by race.go
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var knownHeaders = map[string]bool{
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"accept": true,
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"accept_charset": true,
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"accept_encoding": true,
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"accept_language": true,
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"accept_patch": true,
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"accept_ranges": true,
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"access_control_allow_origin": true,
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"age": true,
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"allow": true,
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"alt_svc": true,
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"alternate_protocol": true,
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"authorization": true,
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"cache_control": true,
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"connection": true,
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"content_disposition": true,
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"content_encoding": true,
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"content_language": true,
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"content_length": true,
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"content_location": true,
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"content_md5": true,
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"content_range": true,
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"content_security_policy": true,
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"content_type": true,
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"cookie": true,
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"date": true,
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"etag": true,
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"expect": true,
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"expires": true,
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"from": true,
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"host": true,
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"if_match": true,
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"if_modified_since": true,
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"if_none_match": true,
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"if_unmodified_since": true,
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"last_modified": true,
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"link": true,
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"location": true,
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"max_forwards": true,
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"p3p": true,
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"pragma": true,
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"proxy_agent": true,
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"proxy_authenticate": true,
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"proxy_authorization": true,
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"public_key_pins": true,
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"range": true,
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"referer": true,
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"refresh": true,
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"retry_after": true,
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"server": true,
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"set_cookie": true,
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"status": true,
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"strict_transport_security": true,
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"trailer": true,
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"transfer_encoding": true,
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"upgrade": true,
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"user_agent": true,
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"vary": true,
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"via": true,
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"warning": true,
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"www_authenticate": true,
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"x_content_duration": true,
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"x_content_security_policy": true,
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"x_content_type_options": true,
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"x_forwarded_for": true,
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"x_frame_options": true,
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"x_powered_by": true,
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"x_real_ip": true,
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"x_ua_compatible": true,
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"x_webkit_csp": true,
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"x_xss_protection": true,
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}
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// A Header represents the key-value pairs in an HTTP header.
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type Header map[string][]string
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// Add adds the key, value pair to the header.
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// It appends to any existing values associated with key.
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func (h Header) Add(key, value string) {
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textproto.MIMEHeader(h).Add(key, value)
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}
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// Set sets the header entries associated with key to
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// the single element value. It replaces any existing
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// values associated with key.
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func (h Header) Set(key, value string) {
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textproto.MIMEHeader(h).Set(key, value)
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}
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// Get gets the first value associated with the given key.
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// It is case insensitive; textproto.CanonicalMIMEHeaderKey is used
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// to canonicalize the provided key.
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// If there are no values associated with the key, Get returns "".
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// To access multiple values of a key, or to use non-canonical keys,
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// access the map directly.
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func (h Header) Get(key string) string {
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return textproto.MIMEHeader(h).Get(key)
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}
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// get is like Get, but key must already be in CanonicalHeaderKey form.
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func (h Header) get(key string) string {
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if v := h[key]; len(v) > 0 {
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return v[0]
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}
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return ""
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}
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// Del deletes the values associated with key.
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func (h Header) Del(key string) {
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textproto.MIMEHeader(h).Del(key)
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}
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// Write writes a header in wire format.
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func (h Header) Write(w io.Writer) error {
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return h.WriteSubset(w, nil)
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}
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func (h Header) clone() Header {
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h2 := make(Header, len(h))
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for k, vv := range h {
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vv2 := make([]string, len(vv))
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copy(vv2, vv)
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h2[k] = vv2
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}
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return h2
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}
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var timeFormats = []string{
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TimeFormat,
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time.RFC850,
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time.ANSIC,
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}
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// ParseTime parses a time header (such as the Date: header),
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// trying each of the three formats allowed by HTTP/1.1:
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// TimeFormat, time.RFC850, and time.ANSIC.
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func ParseTime(text string) (t time.Time, err error) {
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for _, layout := range timeFormats {
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t, err = time.Parse(layout, text)
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if err == nil {
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return
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}
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}
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return
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}
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var headerNewlineToSpace = strings.NewReplacer("\n", " ", "\r", " ")
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type writeStringer interface {
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WriteString(string) (int, error)
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}
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// stringWriter implements WriteString on a Writer.
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type stringWriter struct {
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w io.Writer
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}
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func (w stringWriter) WriteString(s string) (n int, err error) {
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return w.w.Write([]byte(s))
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}
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type keyValues struct {
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key string
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values []string
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}
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// A headerSorter implements sort.Interface by sorting a []keyValues
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// by key. It's used as a pointer, so it can fit in a sort.Interface
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// interface value without allocation.
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type headerSorter struct {
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kvs []keyValues
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}
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func (s *headerSorter) Len() int { return len(s.kvs) }
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func (s *headerSorter) Swap(i, j int) { s.kvs[i], s.kvs[j] = s.kvs[j], s.kvs[i] }
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func (s *headerSorter) Less(i, j int) bool { return s.kvs[i].key < s.kvs[j].key }
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var headerSorterPool = sync.Pool{
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New: func() interface{} { return new(headerSorter) },
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}
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// sortedKeyValues returns h's keys sorted in the returned kvs
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// slice. The headerSorter used to sort is also returned, for possible
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// return to headerSorterCache.
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func (h Header) sortedKeyValues(exclude map[string]bool) (kvs []keyValues, hs *headerSorter) {
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hs = headerSorterPool.Get().(*headerSorter)
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if cap(hs.kvs) < len(h) {
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hs.kvs = make([]keyValues, 0, len(h))
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}
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kvs = hs.kvs[:0]
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for k, vv := range h {
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if !exclude[k] {
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kvs = append(kvs, keyValues{k, vv})
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}
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}
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hs.kvs = kvs
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sort.Sort(hs)
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return kvs, hs
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}
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// WriteSubset writes a header in wire format.
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// If exclude is not nil, keys where exclude[key] == true are not written.
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func (h Header) WriteSubset(w io.Writer, exclude map[string]bool) error {
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ws, ok := w.(writeStringer)
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if !ok {
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ws = stringWriter{w}
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}
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kvs, sorter := h.sortedKeyValues(exclude)
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for _, kv := range kvs {
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for _, v := range kv.values {
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v = headerNewlineToSpace.Replace(v)
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v = textproto.TrimString(v)
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for _, s := range []string{kv.key, ": ", v, "\r\n"} {
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if _, err := ws.WriteString(s); err != nil {
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return err
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}
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}
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}
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}
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headerSorterPool.Put(sorter)
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return nil
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}
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// CanonicalHeaderKey returns the canonical format of the
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// header key s. The canonicalization converts the first
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// letter and any letter following a hyphen to upper case;
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// the rest are converted to lowercase. For example, the
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// canonical key for "accept-encoding" is "Accept-Encoding".
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// If s contains a space or invalid header field bytes, it is
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// returned without modifications.
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func CanonicalHeaderKey(s string) string { return textproto.CanonicalMIMEHeaderKey(s) }
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// hasToken reports whether token appears with v, ASCII
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// case-insensitive, with space or comma boundaries.
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// token must be all lowercase.
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// v may contain mixed cased.
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func hasToken(v, token string) bool {
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if len(token) > len(v) || token == "" {
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return false
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}
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if v == token {
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return true
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}
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for sp := 0; sp <= len(v)-len(token); sp++ {
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// Check that first character is good.
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// The token is ASCII, so checking only a single byte
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// is sufficient. We skip this potential starting
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// position if both the first byte and its potential
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// ASCII uppercase equivalent (b|0x20) don't match.
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// False positives ('^' => '~') are caught by EqualFold.
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if b := v[sp]; b != token[0] && b|0x20 != token[0] {
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continue
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}
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// Check that start pos is on a valid token boundary.
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if sp > 0 && !isTokenBoundary(v[sp-1]) {
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continue
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}
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// Check that end pos is on a valid token boundary.
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if endPos := sp + len(token); endPos != len(v) && !isTokenBoundary(v[endPos]) {
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continue
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}
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if strings.EqualFold(v[sp:sp+len(token)], token) {
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return true
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}
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}
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return false
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}
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func isTokenBoundary(b byte) bool {
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return b == ' ' || b == ',' || b == '\t'
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}
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func cloneHeader(h Header) Header {
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h2 := make(Header, len(h))
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for k, vv := range h {
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vv2 := make([]string, len(vv))
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copy(vv2, vv)
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h2[k] = vv2
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}
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return h2
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}
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func FormatHeaderName(s string) string {
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return strings.Replace(strings.ToLower(s), "-", "_", 30)
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}
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type UnknownHeader struct {
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Key string `json:"key,omitempty"`
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Values []string `json:"value,omitempty"`
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}
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func formatHeaderValues(v []string) {
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for idx := range v {
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if len(v[idx]) >= 8192 {
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v[idx] = v[idx][0:8191]
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}
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}
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}
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func filterHeaders(h Header) {
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var unknownHeaders []UnknownHeader
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for header, values := range h {
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if _, ok := knownHeaders[FormatHeaderName(header)]; !ok {
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unk := UnknownHeader{
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Key: FormatHeaderName(header),
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Values: values,
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}
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unknownHeaders = append(unknownHeaders, unk)
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h.Del(header)
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}
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}
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if len(unknownHeaders) > 0 {
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if unknownHeaderStr, err := json.Marshal(unknownHeaders); err == nil {
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h["Unknown"] = []string{string(unknownHeaderStr)}
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}
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}
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}
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// Custom JSON Marshaller to comply with snake_case header names
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func (h Header) MarshalJSON() ([]byte, error) {
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filterHeaders(h)
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headerMap := make(map[string]interface{})
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for k, v := range h {
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// Need to special-case unknown header object, since it's not a true header (aka map[string][]string)
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if k == "Unknown" && len(v) > 0 {
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var unknownHeader []UnknownHeader
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json.Unmarshal([]byte(v[0]), &unknownHeader)
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for idx := range unknownHeader {
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formatHeaderValues(unknownHeader[idx].Values)
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}
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headerMap[FormatHeaderName(k)] = unknownHeader
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} else {
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formatHeaderValues(v)
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headerMap[FormatHeaderName(k)] = v
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}
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}
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return json.Marshal(headerMap)
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}
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