From 3444fd9cb479db44758600de90f0f60dd1e6970e Mon Sep 17 00:00:00 2001
From: Hugues Alary <hugues@betabrand.com>
Date: Mon, 31 Jul 2017 18:28:48 -0700
Subject: [PATCH] allow custom User-Agent when fetching remote image

Closes #83
---
 cmd/imageproxy/main.go |  2 ++
 imageproxy.go          | 16 +++++++++++-----
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/cmd/imageproxy/main.go b/cmd/imageproxy/main.go
index e9149f8..9c6d04c 100644
--- a/cmd/imageproxy/main.go
+++ b/cmd/imageproxy/main.go
@@ -53,6 +53,7 @@ var timeout = flag.Duration("timeout", 0, "time limit for requests served by thi
 var verbose = flag.Bool("verbose", false, "print verbose logging messages")
 var version = flag.Bool("version", false, "Deprecated: this flag does nothing")
 var contentTypes = flag.String("contentTypes", "image/*", "comma separated list of allowed content types")
+var userAgent = flag.String("userAgent", "willnorris/imageproxy", "specify the user-agent used by imageproxy when fetching images from origin website")
 
 func init() {
 	flag.Var(&cache, "cache", "location to cache images (see https://github.com/willnorris/imageproxy#cache)")
@@ -98,6 +99,7 @@ func main() {
 	p.Timeout = *timeout
 	p.ScaleUp = *scaleUp
 	p.Verbose = *verbose
+	p.UserAgent = *userAgent
 
 	server := &http.Server{
 		Addr:    *addr,
diff --git a/imageproxy.go b/imageproxy.go
index 4152a86..c6c7b15 100644
--- a/imageproxy.go
+++ b/imageproxy.go
@@ -76,6 +76,9 @@ type Proxy struct {
 	// ContentTypes specifies a list of content types to allow. An empty
 	// list means all content types are allowed.
 	ContentTypes []string
+
+	// The User-Agent used by imageproxy when requesting origin image
+	UserAgent string
 }
 
 // NewProxy constructs a new proxy.  The provided http RoundTripper will be
@@ -150,7 +153,11 @@ func (p *Proxy) serveImage(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	resp, err := p.Client.Get(req.String())
+	actualReq, _ := http.NewRequest("GET", req.String(), nil)
+	if p.UserAgent != "" {
+		actualReq.Header.Set("User-Agent", p.UserAgent)
+	}
+	resp, err := p.Client.Do(actualReq)
 	if err != nil {
 		msg := fmt.Sprintf("error fetching remote image: %v", err)
 		log.Print(msg)
@@ -345,9 +352,8 @@ func (t *TransformingTransport) RoundTrip(req *http.Request) (*http.Response, er
 		return t.Transport.RoundTrip(req)
 	}
 
-	u := *req.URL
-	u.Fragment = ""
-	resp, err := t.CachingClient.Get(u.String())
+	req.URL.Fragment = ""
+	resp, err := t.CachingClient.Do(req)
 	if err != nil {
 		return nil, err
 	}
@@ -368,7 +374,7 @@ func (t *TransformingTransport) RoundTrip(req *http.Request) (*http.Response, er
 
 	img, err := Transform(b, opt)
 	if err != nil {
-		log.Printf("error transforming image %s: %v", u.String(), err)
+		log.Printf("error transforming image %s: %v", req.URL.String(), err)
 		img = b
 	}