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rely on httpcache for response caching

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This commit is contained in:
Will Norris 2013-12-25 18:48:10 -08:00
parent b9584c18cb
commit 73f6357cda
5 changed files with 43 additions and 119 deletions
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63
proxy/proxy.go
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@ -26,7 +26,7 @@ import (
"time"
"github.com/golang/glog"
"github.com/willnorris/go-imageproxy/cache"
"github.com/gregjones/httpcache"
"github.com/willnorris/go-imageproxy/data"
"github.com/willnorris/go-imageproxy/transform"
)
@ -79,7 +79,7 @@ func NewRequest(r *http.Request) (*data.Request, error) {
// Proxy serves image requests.
type Proxy struct {
Client *http.Client // client used to fetch remote URLs
Cache cache.Cache
Cache Cache
// Whitelist specifies a list of remote hosts that images can be proxied from. An empty list means all hosts are allowed.
Whitelist []string
@ -90,11 +90,24 @@ type Proxy struct {
// NewProxy constructs a new proxy. The provided http Client will be used to
// fetch remote URLs. If nil is provided, http.DefaultClient will be used.
func NewProxy(client *http.Client) *Proxy {
func NewProxy(client *http.Client, cache Cache) *Proxy {
if client == nil {
client = http.DefaultClient
}
return &Proxy{Client: client, Cache: cache.NopCache}
if cache == nil {
cache = NopCache
}
return &Proxy{
Client: &http.Client{
Transport: &httpcache.Transport{
Transport: client.Transport,
Cache: cache,
MarkCachedResponses: true,
},
},
Cache: cache,
}
}
// ServeHTTP handles image requests.
@ -122,23 +135,11 @@ func (p *Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
return
}
image, ok := p.Cache.Get(u)
if !ok {
glog.Infof("image not cached")
image, err = p.fetchRemoteImage(u, nil)
if err != nil {
glog.Errorf("error fetching remote image: %v", err)
}
p.Cache.Save(image)
} else if time.Now().After(image.Expires) {
glog.Infof("cached image expired")
image, err = p.fetchRemoteImage(u, image)
if err != nil {
glog.Errorf("error fetching remote image: %v", err)
}
p.Cache.Save(image)
} else {
glog.Infof("serving from cache")
image, err := p.fetchRemoteImage(u)
if err != nil {
glog.Errorf("error fetching remote image: %v", err)
http.Error(w, fmt.Sprintf("Error fetching remote image: %v", err), http.StatusInternalServerError)
return
}
image, _ = transform.Transform(*image, req.Options)
@ -148,29 +149,13 @@ func (p *Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
w.Write(image.Bytes)
}
func (p *Proxy) fetchRemoteImage(u string, cached *data.Image) (*data.Image, error) {
func (p *Proxy) fetchRemoteImage(u string) (*data.Image, error) {
glog.Infof("fetching remote image: %s", u)
req, err := http.NewRequest("GET", u, nil)
resp, err := p.Client.Get(u)
if err != nil {
return nil, err
}
if cached != nil && cached.Etag != "" {
req.Header.Add("If-None-Match", cached.Etag)
}
resp, err := p.Client.Do(req)
if err != nil {
return nil, err
}
if resp.StatusCode == http.StatusNotModified {
glog.Infof("remote image not modified (304 response)")
cached.Expires = parseExpires(resp)
return cached, nil
}
if resp.StatusCode != http.StatusOK {
return nil, errors.New(fmt.Sprintf("HTTP status not OK: %v", resp.Status))
}