__init__.py 文件源码

def generate_and_store_short_code(node):
    nodes_coll = current_app.data.driver.db['nodes']
    node_id = node['_id']

    log.debug('Creating new short link for node %s', node_id)

    max_attempts = 10
    for attempt in range(1, max_attempts):

        # Generate a new short code
        short_code = create_short_code(node)
        log.debug('Created short code for node %s: %s', node_id, short_code)

        node['short_code'] = short_code

        # Store it in MongoDB
        try:
            result = nodes_coll.update_one({'_id': node_id},
                                           {'$set': {'short_code': short_code}})
            break
        except pymongo.errors.DuplicateKeyError:
            log.info('Duplicate key while creating short code, retrying (attempt %i/%i)',
                     attempt, max_attempts)
            pass
    else:
        log.error('Unable to find unique short code for node %s after %i attempts, failing!',
                  node_id, max_attempts)
        raise wz_exceptions.InternalServerError('Unable to create unique short code for node %s' %
                                                node_id)

    # We were able to store a short code, now let's verify the result.
    if result.matched_count != 1:
        log.warning('Unable to update node %s with new short_links=%r', node_id, node['short_code'])
        raise wz_exceptions.InternalServerError('Unable to update node %s with new short links' %
                                                node_id)

    return short_code