def gen_post_map(file_name, ext_url=''):
    '''
    Generate the urls for posts.
    :return: None
    '''
    with open(file_name, 'a') as fout:
        for kind_key in router_post:
            recent_posts = MPost.query_all(kind=kind_key, limit=1000000)
            for recent_post in recent_posts:
                url = os.path.join(SITE_CFG['site_url'],
                                   router_post[recent_post.kind],
                                   ext_url,
                                   recent_post.uid)
                fout.write('{url}\n'.format(url=url))
Generate the urls for posts.
    :return: None