fix($http): fix response headers with an empty value

[jamshid]

Empty response header values are legal (http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html).
Return an empty string instead of null, which is returned when the header does not exist.

Closes #7779

[caitp]

Since this change uses hasOwnProperty, add a test for header values in the object prototype, like ToString or Constructor, too.

[jamshid]

Do you mean adding a test like this?

@@ -818,11 +818,13 @@ describe('$http', function() {

       it('should handle empty response header', function() {
        $httpBackend.expect('GET', '/url', undefined)
-           .respond(200, '', { 'Custom-Empty-Response-Header': '' });
+           .respond(200, '', { 'Custom-Empty-Response-Header': '', 'Constructor': '' });
        $http.get('/url').success(callback);
        $httpBackend.flush();
        expect(callback).toHaveBeenCalledOnce();
        expect(callback.mostRecentCall.args[2]('custom-empty-response-Header')).toBe('');
+       expect(callback.mostRecentCall.args[2]('ToString')).toBe(null);
+       expect(callback.mostRecentCall.args[2]('Constructor')).toBe('');
      });

I see, the Constructor test is failing. How do I make headersObject['Constructor'] return the header value, not the Constructor function itself?

      return Object.prototype.hasOwnProperty.call(headersObj, name) ? headersObj[name] : null;

Chrome 38.0.2125 (Mac OS X 10.10.0) $http the instance short methods should handle empty response header FAILED
    Expected 'function Object() { [native code] }, ' to be ''.
    Error: Expected 'function Object() { [native code] }, ' to be ''.
        at null.<anonymous> (/Users/jamshid/work/angular.js/test/ng/httpSpec.js:827:63)

[jamshid]

I assume @cruz210 or @caitp saw my note about not knowing how to fix the failing "Constructor" test case. If you know how to fix please let me know and I'll make a final fix and squash commits.

[caitp]

I didn't, but I'll take another look at this (you can just ping me with PTAL in the message, it works)

[caitp]

You can use just hasOwnProperty.call(), it's fine

[caitp]

So the test is failing on the Constructor header --- I think the reason is we need to fix the parseHeaders function so that it uses createMap() instead of {} when initializing parsed.

EG:

parsed = createMap(); // rather than `parsed = {}`

[caitp]

Pretty sure that will fix it and help us merge it.

[jamshid]

Thanks, createMap() fixed it. Now I need to squash these 3 commits but don't know how. I did not create a "feature" branch when I first forked and made the changes, is that a necessary step? Not very familiar with git, any tips appreciated.

[caitp]

you should be good with git rebase -i HEAD~3 and setting the first letter on each of the last 2 commits to "f" --- then after that you might want to git pull --rebase origin master

[jamshid]

Did I do this right, it doesn't seem like the single squashed commit is showing up here.

$ git rebase -i HEAD~3
[detached HEAD 0ef0dce] fix($http): fix response headers with an empty value
 2 files changed, 14 insertions(+), 2 deletions(-)
Successfully rebased and updated refs/heads/master.
$ git pull --rebase origin master
From https://github.com/jamshid/angular.js
 * branch            master     -> FETCH_HEAD
First, rewinding head to replay your work on top of it...
Applying: fix($http): fix response headers with an empty value
Using index info to reconstruct a base tree...
M   src/ng/http.js
M   test/ng/httpSpec.js
Falling back to patching base and 3-way merge...
No changes -- Patch already applied.
$ git push origin master
Everything up-to-date

[pkozlowski-opensource]

@jamshid you would have to force-push to see your single commit here: git push origin master --force

But don't worry about this too much, we can always sqash commits when merging.

[caitp]

Anyways, LGTM, will land

[caitp]

@jamshid I made some very minor changes to it because the hasOwnProperty is not necessary given that there is a null prototype (unless someone does something unsupported like Object.setPrototypeOf(headersGetter(), new Object()) or something, but I'm not too worried there)