Add support for URL Encoded Remote URLs #250

- URL encoding of remote urls is now supported (but still optional). - Options parameter is no longer optional. - You can pass empty/no-op options (`//http...` or `/x/http...` or `/0x0/http...`), - but not `/http...`. - Added more test cases.
willnorris · Mar 8, 2022 · 1aa29ff · 1aa29ff
1 parent 6022f6a
commit 1aa29ff
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diff --git a/README.md b/README.md
@@ -48,11 +48,10 @@ See the full list of available options at
 ### Remote URL ###
 
 The URL of the original image to load is specified as the remainder of the
-path, without any encoding.  For example,
+path and may be URL encoded.  For example,
 `http://localhost/200/https://willnorris.com/logo.jpg`.
 
-In order to [optimize caching][], it is recommended that URLs not contain query
-strings.
+If remote image URLs contain query strings, it is recommended to URL-encode them when passing to imageproxy in order to [optimize caching][].
 
 [optimize caching]: http://www.stevesouders.com/blog/2008/08/23/revving-filenames-dont-use-querystring/
 
@@ -75,6 +74,7 @@ x0.15   | 15% original height, proportional width  | <a href="https://imageproxy
 200x,q60 | 200px wide, proportional height, 60% quality | <a href="https://imageproxy.willnorris.com/200x,q60/https://willnorris.com/2013/12/small-things.jpg"><img src="https://imageproxy.willnorris.com/200x,q60/https://willnorris.com/2013/12/small-things.jpg" alt="200x,q60"></a>
 200x,png | 200px wide, converted to PNG format | <a href="https://imageproxy.willnorris.com/200x,png/https://willnorris.com/2013/12/small-things.jpg"><img src="https://imageproxy.willnorris.com/200x,png/https://willnorris.com/2013/12/small-things.jpg" alt="200x,png"></a>
 cx175,cw400,ch300,100x | crop to 400x300px starting at (175,0), scale to 100px wide | <a href="https://imageproxy.willnorris.com/cx175,cw400,ch300,100x/https://willnorris.com/2013/12/small-things.jpg"><img src="https://imageproxy.willnorris.com/cx175,cw400,ch300,100x/https://willnorris.com/2013/12/small-things.jpg" alt="cx175,cw400,ch300,100x"></a>
+x | no options, don't transform, just proxy | <a href="https://imageproxy.willnorris.com/x/https://willnorris.com/2013/12/small-things.jpg"><img src="https://imageproxy.willnorris.com/x/https://willnorris.com/2013/12/small-things.jpg" alt="x"></a>
 
 The [smart crop feature](https://godoc.org/willnorris.com/go/imageproxy#hdr-Smart_Crop)
 can best be seen by comparing crops of [this source image][judah-sheets], with

diff --git a/data.go b/data.go
@@ -308,39 +308,36 @@ func (r Request) String() string {
 
 // NewRequest parses an http.Request into an imageproxy Request.  Options and
 // the remote image URL are specified in the request path, formatted as:
-// /{options}/{remote_url}.  Options may be omitted, so a request path may
-// simply contain /{remote_url}.  The remote URL must be an absolute "http" or
-// "https" URL, should not be URL encoded, and may contain a query string.
+// /{options}/{remote_url}.  Options may not be omitted, but `x` or `0x0` can
+// be used as noop option (/x/{remote_url}).
+// The remote URL must be an absolute "http(s)" URL unless BaseURL is set.
+// The remote URL may be URL encoded.
 //
 // Assuming an imageproxy server running on localhost, the following are all
 // valid imageproxy requests:
 //
 // 	http://localhost/100x200/http://example.com/image.jpg
 // 	http://localhost/100x200,r90/http://example.com/image.jpg?foo=bar
-// 	http://localhost//http://example.com/image.jpg
-// 	http://localhost/http://example.com/image.jpg
+// 	http://localhost/x/http://example.com/image.jpg
+// 	http://localhost/x/http%3A%2F%2Fexample.com%2Fimage.jpg
 func NewRequest(r *http.Request, baseURL *url.URL) (*Request, error) {
 	var err error
 	req := &Request{Original: r}
 
 	path := r.URL.EscapedPath()[1:] // strip leading slash
-	req.URL, err = parseURL(path)
-	if err != nil || !req.URL.IsAbs() {
-		// first segment should be options
-		parts := strings.SplitN(path, "/", 2)
-		if len(parts) != 2 {
-			return nil, URLError{"too few path segments", r.URL}
-		}
-
-		var err error
-		req.URL, err = parseURL(parts[1])
-		if err != nil {
-			return nil, URLError{fmt.Sprintf("unable to parse remote URL: %v", err), r.URL}
-		}
+	// first segment should be options
+	parts := strings.SplitN(path, "/", 2)
+	if len(parts) != 2 {
+		return nil, URLError{"too few path segments", r.URL}
+	}
 
-		req.Options = ParseOptions(parts[0])
+	req.URL, err = parseURL(parts[1])
+	if err != nil {
+		return nil, URLError{fmt.Sprintf("unable to parse remote URL: %v", err), r.URL}
 	}
 
+	req.Options = ParseOptions(parts[0])
+
 	if baseURL != nil {
 		req.URL = baseURL.ResolveReference(req.URL)
 	}
@@ -353,8 +350,16 @@ func NewRequest(r *http.Request, baseURL *url.URL) (*Request, error) {
 		return nil, URLError{"remote URL must have http or https scheme", r.URL}
 	}
 
-	// query string is always part of the remote URL
-	req.URL.RawQuery = r.URL.RawQuery
+	// only append original (unencoded) query string
+	// if we don't have one already. Example:
+	// http://localhost/x/https%3A%2F%2Fexample.com%2Ffoo%2Fbar%3Fhello%3Dworld?more=query
+	// should be https://example.com/foo/bar?hello=world
+	// not https://example.com/foo/bar?more=query
+	if len(r.URL.RawQuery) > 0 && len(req.URL.RawQuery) == 0 {
+		// query string is always part of the remote URL
+		req.URL.RawQuery = r.URL.RawQuery
+	}
+
 	return req, nil
 }
 
@@ -363,6 +368,42 @@ var reCleanedURL = regexp.MustCompile(`^(https?):/+([^/])`)
 // parseURL parses s as a URL, handling URLs that have been munged by
 // path.Clean or a webserver that collapses multiple slashes.
 func parseURL(s string) (*url.URL, error) {
+	var err error
+
+	// convert http:/example.com to http://example.com
 	s = reCleanedURL.ReplaceAllString(s, "$1://$2")
+
+	s, err = decodeURL(s)
+	if err != nil {
+		return nil, err
+	}
+
 	return url.Parse(s)
 }
+
+var reAbsURL = regexp.MustCompile(`^https?`)
+var reDecodedURL = regexp.MustCompile(`^https?://`)
+
+func decodeURL(s string) (string, error) {
+	var err error
+	// don't try to decode unless looks like abs url
+	if !reAbsURL.MatchString(s) {
+		return s, nil
+	}
+
+	// preserve original value in case we are not able to decode
+	decodedURL := s
+	maxDecodeAttempts := 3
+	for i := 0; !reDecodedURL.MatchString(decodedURL) && i < maxDecodeAttempts; i++ {
+		decodedURL, err = url.QueryUnescape(decodedURL)
+		if err != nil {
+			return "", URLError{"remote URL could not be decoded", nil}
+		}
+	}
+	if reDecodedURL.MatchString(decodedURL) {
+		return decodedURL, nil
+	} else {
+		// return original value. might be relative url (e.g. https/foo.jpg)
+		return s, nil
+	}
+}
diff --git a/data_test.go b/data_test.go
@@ -113,6 +113,9 @@ func TestNewRequest(t *testing.T) {
 		{"http://localhost//example.com/foo", "", emptyOptions, true},
 		{"http://localhost//ftp://example.com/foo", "", emptyOptions, true},
 
+		// invalid URL because options now required
+		{"http://localhost/http://example.com/foo", "", emptyOptions, true},
+
 		// invalid options.  These won't return errors, but will not fully parse the options
 		{
 			"http://localhost/s/http://example.com/",
@@ -125,37 +128,66 @@ func TestNewRequest(t *testing.T) {
 
 		// valid URLs
 		{
-			"http://localhost/http://example.com/foo",
+			"http://localhost//http://example.com/foo",
 			"http://example.com/foo", emptyOptions, false,
 		},
 		{
-			"http://localhost//http://example.com/foo",
+			"http://localhost/x/http://example.com/foo",
 			"http://example.com/foo", emptyOptions, false,
 		},
 		{
-			"http://localhost//https://example.com/foo",
+			"http://localhost/x/http://example.com/foo",
+			"http://example.com/foo", emptyOptions, false,
+		},
+		{
+			"http://localhost/0x0/https://example.com/foo",
 			"https://example.com/foo", emptyOptions, false,
 		},
 		{
 			"http://localhost/1x2/http://example.com/foo",
 			"http://example.com/foo", Options{Width: 1, Height: 2}, false,
 		},
 		{
-			"http://localhost//http://example.com/foo?bar",
+			"http://localhost/0x0/http://example.com/foo?bar",
 			"http://example.com/foo?bar", emptyOptions, false,
 		},
 		{
-			"http://localhost/http:/example.com/foo",
+			"http://localhost/x/http:/example.com/foo",
 			"http://example.com/foo", emptyOptions, false,
 		},
 		{
-			"http://localhost/http:///example.com/foo",
+			"http://localhost/x/http:///example.com/foo",
 			"http://example.com/foo", emptyOptions, false,
 		},
 		{ // escaped path
-			"http://localhost/http://example.com/%2C",
+			"http://localhost/x/http://example.com/%2C",
 			"http://example.com/%2C", emptyOptions, false,
 		},
+		// unescaped querystring
+		{
+			"http://localhost/x/http://example.com/foo/bar?hello=world",
+			"http://example.com/foo/bar?hello=world", emptyOptions, false,
+		},
+		// escaped remote including querystring
+		{
+			"http://localhost/x/http%3A%2F%2Fexample.com%2Ffoo%2Fbar%3Fhello%3Dworld",
+			"http://example.com/foo/bar?hello=world", emptyOptions, false,
+		},
+		{
+			"http://localhost/x/https%3A%2F%2Fexample.com%2Ffoo%2Fbar%3Fhello%3Dworld",
+			"https://example.com/foo/bar?hello=world", emptyOptions, false,
+		},
+		// multi-escaped remote
+		{
+			"http://localhost/x/https%25253A%25252F%25252Fexample.com%25252Ffoo%25252Fbar%25253Fhello%25253Dworld",
+			"https://example.com/foo/bar?hello=world", emptyOptions, false,
+		},
+		// escaped remote containing double escaped url as param
+		// test that we don't over-decode remote url breaking parameters
+		{
+			"http://localhost/x/http%3A%2F%2Fexample.com%2Ffoo%2Fbar%3Fhello%3Dworld%26url%3Dhttps%253A%252F%252Fwww.example.com%252F%253Ffoo%253Dbar%2526hello%253Dworld",
+			"http://example.com/foo/bar?hello=world&url=https%3A%2F%2Fwww.example.com%2F%3Ffoo%3Dbar%26hello%3Dworld", emptyOptions, false,
+		},
 	}
 
 	for _, tt := range tests {
@@ -186,16 +218,72 @@ func TestNewRequest(t *testing.T) {
 }
 
 func TestNewRequest_BaseURL(t *testing.T) {
-	req, _ := http.NewRequest("GET", "/x/path", nil)
-	base, _ := url.Parse("https://example.com/")
-
-	r, err := NewRequest(req, base)
-	if err != nil {
-		t.Errorf("NewRequest(%v, %v) returned unexpected error: %v", req, base, err)
+	tests := []struct {
+		BaseURL     string  // base url to use
+		URL         string  // input URL to parse as an imageproxy request
+		RemoteURL   string  // expected URL of remote image parsed from input
+		Options     Options // expected options parsed from input
+		ExpectError bool    // whether an error is expected from NewRequest
+	}{
+		{
+			"http://example.com/",
+			"http://localhost/x/foo",
+			"http://example.com/foo", emptyOptions, false,
+		},
+		{
+			"http://example.com/hello",
+			"http://localhost/x//foo/bar",
+			"http://example.com/foo/bar", emptyOptions, false,
+		},
+		// if BaseURL doesn't have trailing slash
+		// URL.ResolveReference will strip last directory
+		{
+			"http://example.com/hello/",
+			"http://localhost/x/foo/bar",
+			"http://example.com/hello/foo/bar", emptyOptions, false,
+		},
+		{
+			"http://example.com/hello/",
+			"http://localhost/x/../foo/bar",
+			"http://example.com/foo/bar", emptyOptions, false,
+		},
+		// relative remote urls should not have URL Decoding even if
+		// they start with http... (dirname)
+		{
+			"http://example.com/hello/",
+			"http://localhost/x/httpdir/rela%20tive",
+			"http://example.com/hello/httpdir/rela%20tive", emptyOptions, false,
+		},
 	}
 
-	want := "https://example.com/path#0x0"
-	if got := r.String(); got != want {
-		t.Errorf("NewRequest(%v, %v) returned %q, want %q", req, base, got, want)
+	for _, tt := range tests {
+		req, err := http.NewRequest("GET", tt.URL, nil)
+		if err != nil {
+			t.Errorf("http.NewRequest(%q) returned error: %v", tt.URL, err)
+			continue
+		}
+		base, err := url.Parse(tt.BaseURL)
+		if err != nil {
+			t.Errorf("url.Parse(%q) returned error: %v", tt.BaseURL, err)
+			continue
+		}
+
+		r, err := NewRequest(req, base)
+		if tt.ExpectError {
+			if err == nil {
+				t.Errorf("NewRequest(%v, %v) did not return expected error", req, base)
+			}
+			continue
+		} else if err != nil {
+			t.Errorf("NewRequest(%v, %v) returned unexpected error: %v", req, base, err)
+			continue
+		}
+
+		if got, want := r.URL.String(), tt.RemoteURL; got != want {
+			t.Errorf("NewRequest(%q, %q) request URL = %v, want %v", tt.URL, tt.BaseURL, got, want)
+		}
+		if got, want := r.Options, tt.Options; got != want {
+			t.Errorf("NewRequest(%q, %q) request options = %v, want %v", tt.URL, tt.BaseURL, got, want)
+		}
 	}
 }
diff --git a/imageproxy_test.go b/imageproxy_test.go
@@ -382,10 +382,10 @@ func TestProxy_ServeHTTP(t *testing.T) {
 		code int    // expected response status code
 	}{
 		{"/favicon.ico", http.StatusOK},
-		{"//foo", http.StatusBadRequest},                            // invalid request URL
-		{"/http://bad.test/", http.StatusForbidden},                 // Disallowed host
-		{"/http://good.test/error", http.StatusInternalServerError}, // HTTP protocol error
-		{"/http://good.test/nocontent", http.StatusNoContent},       // non-OK response
+		{"/x/foo", http.StatusBadRequest},                             // invalid request URL
+		{"/x/http://bad.test/", http.StatusForbidden},                 // Disallowed host
+		{"/x/http://good.test/error", http.StatusInternalServerError}, // HTTP protocol error
+		{"/x/http://good.test/nocontent", http.StatusNoContent},       // non-OK response
 		{"/100/http://good.test/png", http.StatusOK},
 		{"/100/http://good.test/plain", http.StatusForbidden}, // non-image response
 
@@ -413,7 +413,7 @@ func TestProxy_ServeHTTP_is304(t *testing.T) {
 		},
 	}
 
-	req, _ := http.NewRequest("GET", "http://localhost/http://good.test/etag", nil)
+	req, _ := http.NewRequest("GET", "http://localhost/x/http://good.test/etag", nil)
 	req.Header.Add("If-None-Match", `"tag"`)
 	resp := httptest.NewRecorder()
 	p.ServeHTTP(resp, req)