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// Copyright 2015 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 cookiejar
import (
"encoding/json"
"io"
"log"
"os"
"path/filepath"
"sort"
"time"
"gopkg.in/retry.v1"
filelock "go4.org/lock"
"gopkg.in/errgo.v1"
)
// Save saves the cookies to the persistent cookie file.
// Before the file is written, it reads any cookies that
// have been stored from it and merges them into j.
func (j *Jar) Save() error {
if j.filename == "" {
return nil
}
return j.save(time.Now())
}
// MarshalJSON implements json.Marshaler by encoding all persistent cookies
// currently in the jar.
func (j *Jar) MarshalJSON() ([]byte, error) {
j.mu.Lock()
defer j.mu.Unlock()
// Marshaling entries can never fail.
data, _ := json.Marshal(j.allPersistentEntries())
return data, nil
}
// save is like Save but takes the current time as a parameter.
func (j *Jar) save(now time.Time) error {
locked, err := lockFile(lockFileName(j.filename))
if err != nil {
return errgo.Mask(err)
}
defer locked.Close()
f, err := os.OpenFile(j.filename, os.O_RDWR|os.O_CREATE, 0600)
if err != nil {
return errgo.Mask(err)
}
defer f.Close()
// TODO optimization: if the file hasn't changed since we
// loaded it, don't bother with the merge step.
j.mu.Lock()
defer j.mu.Unlock()
if err := j.mergeFrom(f); err != nil {
// The cookie file is probably corrupt.
log.Printf("cannot read cookie file to merge it; ignoring it: %v", err)
}
j.deleteExpired(now)
if err := f.Truncate(0); err != nil {
return errgo.Notef(err, "cannot truncate file")
}
if _, err := f.Seek(0, 0); err != nil {
return errgo.Mask(err)
}
return j.writeTo(f)
}
// load loads the cookies from j.filename. If the file does not exist,
// no error will be returned and no cookies will be loaded.
func (j *Jar) load() error {
if _, err := os.Stat(filepath.Dir(j.filename)); os.IsNotExist(err) {
// The directory that we'll store the cookie jar
// in doesn't exist, so don't bother trying
// to acquire the lock.
return nil
}
locked, err := lockFile(lockFileName(j.filename))
if err != nil {
return errgo.Mask(err)
}
defer locked.Close()
f, err := os.Open(j.filename)
if err != nil {
if os.IsNotExist(err) {
return nil
}
return err
}
defer f.Close()
if err := j.mergeFrom(f); err != nil {
return errgo.Mask(err)
}
return nil
}
// mergeFrom reads all the cookies from r and stores them in the Jar.
func (j *Jar) mergeFrom(r io.Reader) error {
decoder := json.NewDecoder(r)
// Cope with old cookiejar format by just discarding
// cookies, but still return an error if it's invalid JSON.
var data json.RawMessage
if err := decoder.Decode(&data); err != nil {
if err == io.EOF {
// Empty file.
return nil
}
return err
}
var entries []entry
if err := json.Unmarshal(data, &entries); err != nil {
log.Printf("warning: discarding cookies in invalid format (error: %v)", err)
return nil
}
j.merge(entries)
return nil
}
// writeTo writes all the cookies in the jar to w
// as a JSON array.
func (j *Jar) writeTo(w io.Writer) error {
encoder := json.NewEncoder(w)
entries := j.allPersistentEntries()
if err := encoder.Encode(entries); err != nil {
return err
}
return nil
}
// allPersistentEntries returns all the entries in the jar, sorted by primarly by canonical host
// name and secondarily by path length.
func (j *Jar) allPersistentEntries() []entry {
var entries []entry
for _, submap := range j.entries {
for _, e := range submap {
if e.Persistent {
entries = append(entries, e)
}
}
}
sort.Sort(byCanonicalHost{entries})
return entries
}
// lockFileName returns the name of the lock file associated with
// the given path.
func lockFileName(path string) string {
return path + ".lock"
}
var attempt = retry.LimitTime(3*time.Second, retry.Exponential{
Initial: 100 * time.Microsecond,
Factor: 1.5,
MaxDelay: 100 * time.Millisecond,
})
func lockFile(path string) (io.Closer, error) {
for a := retry.Start(attempt, nil); a.Next(); {
locker, err := filelock.Lock(path)
if err == nil {
return locker, nil
}
if !a.More() {
return nil, errgo.Notef(err, "file locked for too long; giving up")
}
}
panic("unreachable")
}
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