Use digest() method in body if available, and only set ETag header if…

… truthy.
hns · May 24, 2011 · 15e645c · 15e645c
1 parent 1144f34
commit 15e645c
Showing 1 changed file with 16 additions and 10 deletions.
diff --git a/lib/stick/middleware/etag.js b/lib/stick/middleware/etag.js
@@ -34,27 +34,33 @@ exports.middleware = function etag(next, app) {
         var {status, headers, body} = res;
 
         if (status === 200) {
-            var etags;
+            var etags, etag;
             var header = request.headers["if-none-match"];
             if (header) {
                 etags = header.split(",").map(function(s) s.trim());
             }
 
-            // we can't rely on body having map(), so we fake it with forEach()
-            var binBody = [];
-            body.forEach(function(part) {
-                binBody.push(part.toByteString());
-            });
-            var etag = '"' + digest(binBody) + '"';
-            headers = Headers(headers);
-            headers.set("ETag", etag);
+            // if body provides a digest() method use that
+            if (typeof body.digest === "function") {
+                etag = body.digest();
+            } else {
+                // we can't rely on body having map(), so we fake it with forEach()
+                var binBody = [];
+                body.forEach(function(part) {
+                    binBody.push(part.toByteString());
+                });
+                etag = digest(binBody);
+            }
+            if (etag) {
+                headers = Headers(headers);
+                headers.set("ETag", '"' + etag + '"');
+            }
 
             if (etags && strings.contains(etags, etag)) {
                 // return not-modified response
                 headers.unset('Content-Length');
                 return {status: 304, headers: headers, body: []};
             }
-
             // body has been converted to ByteStrings as a byproduct of digest()
             res.body = binBody;
         }