restructure imageproxy package

- move binary from imageproxy.go to cmd/imageproxy/main.go
- move proxy package up to top level

proxy/proxy.go

@@ -1,203 +0,0 @@
-// Copyright 2013 Google Inc. 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 proxy provides the image proxy.
-package proxy
-
-import (
-	"bufio"
-	"bytes"
-	"fmt"
-	"io"
-	"io/ioutil"
-	"net/http"
-	"net/url"
-	"reflect"
-	"strings"
-	"time"
-
-	"github.com/golang/glog"
-	"github.com/gregjones/httpcache"
-)
-
-// Proxy serves image requests.
-type Proxy struct {
-	Client *http.Client // client used to fetch remote URLs
-	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
-
-	MaxWidth  int
-	MaxHeight int
-}
-
-// 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(transport http.RoundTripper, cache Cache) *Proxy {
-	if transport == nil {
-		transport = http.DefaultTransport
-	}
-	if cache == nil {
-		cache = NopCache
-	}
-
-	client := new(http.Client)
-	client.Transport = &httpcache.Transport{
-		Transport:           &TransformingTransport{transport, client},
-		Cache:               cache,
-		MarkCachedResponses: true,
-	}
-
-	return &Proxy{
-		Client: client,
-		Cache:  cache,
-	}
-}
-
-// ServeHTTP handles image requests.
-func (p *Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	req, err := NewRequest(r)
-	if err != nil {
-		glog.Errorf("invalid request URL: %v", err)
-		http.Error(w, fmt.Sprintf("invalid request URL: %v", err), http.StatusBadRequest)
-		return
-	}
-
-	if p.MaxWidth > 0 && int(req.Options.Width) > p.MaxWidth {
-		req.Options.Width = float64(p.MaxWidth)
-	}
-	if p.MaxHeight > 0 && int(req.Options.Height) > p.MaxHeight {
-		req.Options.Height = float64(p.MaxHeight)
-	}
-
-	if !p.allowed(req.URL) {
-		glog.Errorf("remote URL is not for an allowed host: %v", req.URL)
-		http.Error(w, fmt.Sprintf("remote URL is not for an allowed host: %v", req.URL), http.StatusBadRequest)
-		return
-	}
-
-	u := req.URL.String()
-	if req.Options != nil && !reflect.DeepEqual(req.Options, emptyOptions) {
-		u += "#" + req.Options.String()
-	}
-	resp, err := p.Client.Get(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
-	}
-
-	if resp.StatusCode != http.StatusOK {
-		http.Error(w, fmt.Sprintf("Remote URL %q returned status: %v", req.URL, resp.Status), http.StatusInternalServerError)
-		return
-	}
-
-	w.Header().Add("Last-Modified", resp.Header.Get("Last-Modified"))
-	w.Header().Add("Expires", resp.Header.Get("Expires"))
-	w.Header().Add("Etag", resp.Header.Get("Etag"))
-
-	if is304 := check304(w, r, resp); is304 {
-		w.WriteHeader(http.StatusNotModified)
-		return
-	}
-
-	w.Header().Add("Content-Length", resp.Header.Get("Content-Length"))
-	defer resp.Body.Close()
-	io.Copy(w, resp.Body)
-}
-
-// allowed returns whether the specified URL is on the whitelist of remote hosts.
-func (p *Proxy) allowed(u *url.URL) bool {
-	if len(p.Whitelist) == 0 {
-		return true
-	}
-
-	for _, host := range p.Whitelist {
-		if u.Host == host {
-			return true
-		}
-		if strings.HasPrefix(host, "*.") && strings.HasSuffix(u.Host, host[2:]) {
-			return true
-		}
-	}
-
-	return false
-}
-
-func check304(w http.ResponseWriter, req *http.Request, resp *http.Response) bool {
-	etag := resp.Header.Get("Etag")
-	if etag != "" && etag == req.Header.Get("If-None-Match") {
-		return true
-	}
-
-	lastModified, err := time.Parse(time.RFC1123, resp.Header.Get("Last-Modified"))
-	if err != nil {
-		return false
-	}
-	ifModSince, err := time.Parse(time.RFC1123, req.Header.Get("If-Modified-Since"))
-	if err != nil {
-		return false
-	}
-	if lastModified.Before(ifModSince) {
-		return true
-	}
-
-	return false
-}
-
-// TransformingTransport is an implementation of http.RoundTripper that
-// optionally transforms images using the options specified in the request URL
-// fragment.
-type TransformingTransport struct {
-	// Transport is used to satisfy non-transform requests (those that do not include a URL fragment)
-	Transport http.RoundTripper
-
-	// Client is used to fetch images to be resized.
-	Client *http.Client
-}
-
-// RoundTrip implements http.RoundTripper.
-func (t *TransformingTransport) RoundTrip(req *http.Request) (*http.Response, error) {
-	if req.URL.Fragment == "" {
-		// normal requests pass through
-		glog.Infof("fetching remote URL: %v", req.URL)
-		return t.Transport.RoundTrip(req)
-	}
-
-	u := *req.URL
-	u.Fragment = ""
-	resp, err := t.Client.Get(u.String())
-
-	defer resp.Body.Close()
-	b, err := ioutil.ReadAll(resp.Body)
-	if err != nil {
-		return nil, err
-	}
-
-	opt := ParseOptions(req.URL.Fragment)
-	img, err := Transform(b, opt)
-	if err != nil {
-		img = b
-	}
-
-	// replay response with transformed image and updated content length
-	buf := new(bytes.Buffer)
-	fmt.Fprintf(buf, "%s %s\n", resp.Proto, resp.Status)
-	resp.Header.WriteSubset(buf, map[string]bool{"Content-Length": true})
-	fmt.Fprintf(buf, "Content-Length: %d\n\n", len(img))
-	buf.Write(img)
-
-	return http.ReadResponse(bufio.NewReader(buf), req)
-}