Bake to iTXt, allow double baking.

package.json

@@ -9,7 +9,7 @@
   "bin": "bin/oven",
   "dependencies": {
     "request": "~2.11.4",
-    "streampng": "0.1.6",
+    "streampng": "0.1.7",
     "optimist": "~0.3.5",
     "cheerio": "~0.12.3",
     "concat-stream": "~1.1.0",

png.js

@@ -17,9 +17,8 @@ function bake(options, callback) {
   if (!data)
     return callback(new Error('must pass a `data` or `url` option'));
 
-  if (typeof data === 'object') {
+  if (typeof data === 'object')
     data = JSON.stringify(data);
-  }
 
   const png = streampng(buffer);
   const chunk = createChunk(data);
@@ -40,13 +39,9 @@ function bake(options, callback) {
   png.on('end', function () {
     if (hadError) return;
 
-    if (existingChunk) {
-      const msg = util.format('This image already has a chunk with the `%s` keyword (contains: %j)', KEYWORD, chunk.text);
-      const error = new Error(msg);
-      error.code = 'IMAGE_ALREADY_BAKED';
-      error.contents = existingChunk.text;
-      return callback(error);
-    }
+    if (existingChunk)
+      existingChunk.set('text', chunk.text)
+
     return png.out(callback);
   })
 }
@@ -61,6 +56,7 @@ function extract(img, callback) {
       return;
     found = true;
     png.removeListener('tEXt', textListener);
+    png.removeListener('iTXt', textListener);
     return callback(null, chunk.text);
   }
 
@@ -78,13 +74,14 @@ function extract(img, callback) {
   }
 
   png.on('tEXt', textListener);
+  png.on('iTXt', textListener);
   png.once('end', endListener);
   png.once('error', errorListener);
 }
 
-function createChunk(url) {
-  return streampng.Chunk.tEXt({
+function createChunk(data) {
+  return streampng.Chunk.iTXt({
     keyword: KEYWORD,
-    text: url
-  });
+    text: data
+  })
 }

test/png.test.js

@@ -10,14 +10,6 @@ const IMG_PATH = pathutil.join(__dirname, 'unbaked.png');
 const ASSERTION_URL = "http://example.org";
 const ASSERTION = { verify: {} };
 
-test('png.createChunk', function (t) {
-  var chunk = png.createChunk(ASSERTION_URL);
-  t.same(chunk.keyword, png.keyword, 'uses the right keyword');
-  t.same(chunk.text, ASSERTION_URL, 'assigns the text properly');
-  t.ok(chunk instanceof streampng.Chunk.tEXt, 'makes a tEXt chunk');
-  t.end();
-});
-
 test('png.extract', function (t) {
   var nonImageBuffer = new Buffer('Totally not a png');
   png.extract(nonImageBuffer, function (err, url) {
@@ -80,11 +72,11 @@ test('png.bake: takes a stream', function (t) {
 test('png.bake: do not bake something twice', function (t) {
   preheat(function (_, img) {
     png.bake({image: img, url: 'wut'}, function (err, baked) {
-      t.ok(err, 'should be an error');
-      t.notOk(baked, 'should not get an image back');
-      t.same(err.code, 'IMAGE_ALREADY_BAKED', 'should get correct error code');
-      t.same(err.contents, ASSERTION_URL, 'should get the contents of the chunk');
-      t.end();
+      png.extract(baked, function (err, url) {
+        t.notOk(err, 'there should be a matching iTXt chunk');
+        t.same(url, 'wut', 'should be able to find the right url');
+        t.end();
+      });
     })
   });
 });