django1.9+xadmin设置主题功能失败的解决方法

环境:
python 2.7
django 1.9
xadmin采用源代码的方式引入到项目中

在xadmin使用的过程中，设置“use_bootswatch = True”，企图调出主题菜单，显示更多主题。然而设置了后，发现主题还是默认和bootstrap2，深入跟踪源代码，发现/xadmin/plugins/themes.py下的

block_top_navmenu

方法，当use_bootswatch 为True的时候，就会使用httplib2去

http://bootswatch.com/api/3.json

网址获取主题菜单项。但是使用浏览器打开这个网址，http会被替换成https的。httplib2访问这个https的网址，就会报错。报错信息为：

[SSL: SSLV3_ALERT_HANDSHAKE_FAILURE] sslv3 alert handshake failure 

但是这个报错信息，不知道为嘛，没显示在后台...

httplib2访问这个网址，我没试验成功，于是我使用requests库来替代httplib2.
1.安装requests

pip install requests

2./xadmin/plugins/themes.py 引入requests

import requests

3.修改block_top_navmenu方法：
 

    def block_top_navmenu(self, context, nodes):

        themes = [
            {'name': _(u"Default"), 'description': _(u"Default bootstrap theme"), 'css': self.default_theme},
            {'name': _(u"Bootstrap2"), 'description': _(u"Bootstrap 2.x theme"), 'css': self.bootstrap2_theme},
            ]
        select_css = context.get('site_theme', self.default_theme)

        if self.user_themes:
            themes.extend(self.user_themes)

        if self.use_bootswatch:
            ex_themes = cache.get(THEME_CACHE_KEY)
            if ex_themes:
                themes.extend(json.loads(ex_themes))
            else:
                ex_themes = []
                try:
                    flag = False#假如为True使用原来的代码，假如为Flase，使用requests库来访问
                    if flag:
                        h = httplib2.Http()
                        resp, content = h.request("http://bootswatch.com/api/3.json", 'GET', '',
                            headers={"Accept": "application/json", "User-Agent": self.request.META['HTTP_USER_AGENT']})
                        if six.PY3:
                            content = content.decode()
                        watch_themes = json.loads(content)['themes']
                    else:
                        content = requests.get("https://bootswatch.com/api/3.json")
                        if six.PY3:
                            content = content.text.decode()
                        watch_themes = json.loads(content.text)['themes']

                    ex_themes.extend([
                        {'name': t['name'], 'description': t['description'],
                            'css': t['cssMin'], 'thumbnail': t['thumbnail']}
                        for t in watch_themes])
                except Exception as e:
                    print(e)

                cache.set(THEME_CACHE_KEY, json.dumps(ex_themes), 24 * 3600)
                themes.extend(ex_themes)

        nodes.append(loader.render_to_string('xadmin/blocks/comm.top.theme.html', {'themes': themes, 'select_css': select_css}))