Fixes #880. Allow visiting /activity/username route directly.

[miketaylr]

r? @karlcow

(sorry for taking so long here @magsout)

[miketaylr]

Let's not merge yet, I should write a test or two for this.

[karlcow]

r+ @miketaylr

not to self. Need to refactor this errorhandler think. We are reusing the same code over and over again.
Probably an opportunity for a function around this code:

    if (request.path.startswith('/api/') and
       request.accept_mimetypes.accept_json and
       not request.accept_mimetypes.accept_html):
        message = {
            'status': 400,
            'message': 'API call. ' + message,
        }
        resp = jsonify(message)
        resp.status_code = 400

More something like (but to think not completely satisfied with the code below)

ERROR_DICT = {
    400: 'Bad Request.',
    401: 'Unauthorized. Please log in.',
    403: 'Forbidden. Maybe that looking at private stuff?',
    404: 'Not Found. Lost in Punk Cat Space',
    }


@app.errorhandler(400)
@app.errorhandler(401)
@app.errorhandler(403)
@app.errorhandler(404)
def custom_error_handler(err):
    if api_call(request):
        return api_message(err.code)
    return render_template(
        'error.html',
        error_code=err.code,
        error_message=ERROR_DICT[err.code])


def api_call(request):
    '''Checks if it's an API call'''
    if (request.path.startswith('/api/') and
       request.accept_mimetypes.accept_json and
       not request.accept_mimetypes.accept_html):
        return True
    else:
        return False


def api_message(code):
    '''Prepares HTTP response for API calls.'''
    message = {
        'status': code,
        'message': ERROR_DICT[code],
    }
    resp = jsonify(message)
    resp.status_code = 404
    return resp

[miketaylr]

thanks @karlcow -- I agree, we could abstract the error handling into a nice little method. Will fix the failing nose test and write some new ones before merging.

[miketaylr]

OK, tests are passing -- let's merge. Thanks for review @karlcow.