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// Copyright 2016 The Hugo Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package data
import (
"fmt"
"io/ioutil"
"net/http"
"path/filepath"
"sync"
"time"
"github.com/gohugoio/hugo/config"
"github.com/gohugoio/hugo/helpers"
"github.com/spf13/afero"
jww "github.com/spf13/jwalterweatherman"
)
var (
remoteURLLock = &remoteLock{m: make(map[string]*sync.Mutex)}
resSleep = time.Second * 2 // if JSON decoding failed sleep for n seconds before retrying
resRetries = 1 // number of retries to load the JSON from URL or local file system
)
type remoteLock struct {
sync.RWMutex
m map[string]*sync.Mutex
}
// URLLock locks an URL during download
func (l *remoteLock) URLLock(url string) {
var (
lock *sync.Mutex
ok bool
)
l.Lock()
if lock, ok = l.m[url]; !ok {
lock = &sync.Mutex{}
l.m[url] = lock
}
l.Unlock()
lock.Lock()
}
// URLUnlock unlocks an URL when the download has been finished. Use only in defer calls.
func (l *remoteLock) URLUnlock(url string) {
l.RLock()
defer l.RUnlock()
if um, ok := l.m[url]; ok {
um.Unlock()
}
}
// getRemote loads the content of a remote file. This method is thread safe.
func getRemote(req *http.Request, fs afero.Fs, cfg config.Provider, hc *http.Client) ([]byte, error) {
url := req.URL.String()
c, err := getCache(url, fs, cfg, cfg.GetBool("ignoreCache"))
if err != nil {
return nil, err
}
if c != nil {
return c, nil
}
// avoid race condition with locks, block other goroutines if the current url is processing
remoteURLLock.URLLock(url)
defer func() { remoteURLLock.URLUnlock(url) }()
// avoid multiple locks due to calling getCache twice
c, err = getCache(url, fs, cfg, cfg.GetBool("ignoreCache"))
if err != nil {
return nil, err
}
if c != nil {
return c, nil
}
jww.INFO.Printf("Downloading: %s ...", url)
res, err := hc.Do(req)
if err != nil {
return nil, err
}
if res.StatusCode < 200 || res.StatusCode > 299 {
return nil, fmt.Errorf("Failed to retrieve remote file: %s", http.StatusText(res.StatusCode))
}
c, err = ioutil.ReadAll(res.Body)
res.Body.Close()
if err != nil {
return nil, err
}
err = writeCache(url, c, fs, cfg, cfg.GetBool("ignoreCache"))
if err != nil {
return nil, err
}
jww.INFO.Printf("... and cached to: %s", getCacheFileID(cfg, url))
return c, nil
}
// getLocal loads the content of a local file
func getLocal(url string, fs afero.Fs, cfg config.Provider) ([]byte, error) {
filename := filepath.Join(cfg.GetString("workingDir"), url)
if e, err := helpers.Exists(filename, fs); !e {
return nil, err
}
return afero.ReadFile(fs, filename)
}
// getResource loads the content of a local or remote file
func (ns *Namespace) getResource(req *http.Request) ([]byte, error) {
switch req.URL.Scheme {
case "":
return getLocal(req.URL.String(), ns.deps.Fs.Source, ns.deps.Cfg)
default:
return getRemote(req, ns.deps.Fs.Source, ns.deps.Cfg, ns.client)
}
}
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