登录之后更新导航（2017.11.24）

1、用上下文处理器app_context_processor定义函数

获取session中保存的值

返回字典

处理器：

@app.context_processor
def mycontext():
    usern=session.get('user')
    if usern:
        return{'username':usern}
    else:
        return{}

首页：

</nav>
{% block main %}    <p>{{ username }}呆梨</p>
{% endblock %}

<a href="https://baike.so.com/create/edit/?eid=4909310&sid=5127865">
    <img src="https://p1.ssl.qhmsg.com/t01d08b6f07a9225737.png" style=" 200px"></a>
<h4 class="textblue">代表作品：</h4>
<div class="recommend">
    <div class="img">
        <h5><a herf="https://baike.baidu.com/item/%E6%9D%8E%E6%98%93%E5%B3%B0/3908480?fr=aladdin"></a></h5>
        <img src="https://gss1.bdstatic.com/9vo3dSag_xI4khGkpoWK1HF6hhy/baike/c0%3Dbaike80%2C5%2C5%2C80%2C26/sign=ccb6b48247166d222c7a1dc6274a6292/48540923dd54564e0b15d770b7de9c82d1584f02.jpg"></a>
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        </div>
    </div>
    <div class="img">
        <a herf="https://baike.baidu.com/item/%E6%9D%8E%E6%98%93%E5%B3%B0/3908480?fr=aladdin">
            <img src="https://gss1.bdstatic.com/-vo3dSag_xI4khGkpoWK1HF6hhy/baike/c0%3Dbaike272%2C5%2C5%2C272%2C90/sign=1c3a441f8a025aafc73f76999a84c001/b21bb051f8198618fb53ed5b42ed2e738ad4e6dd.jpg"></a>
        <div class="desc"><a href="https://baike.baidu.com/item/%E9%BA%BB%E9%9B%80/17612774">麻雀</a></div>
    </div>
    <div class="img">
        <a herf="https://baike.baidu.com/item/%E6%9D%8E%E6%98%93%E5%B3%B0/3908480?fr=aladdin">
            <img src="https://gss3.bdstatic.com/7Po3dSag_xI4khGkpoWK1HF6hhy/baike/c0%3Dbaike150%2C5%2C5%2C150%2C50/sign=06534c58b0fd5266b3263446ca71fc4e/8326cffc1e178a823e993f13f003738da877e8d8.jpg"></a>
        <div class="desc"><a href="https://baike.baidu.com/item/%E6%A0%80%E5%AD%90%E8%8A%B1%E5%BC%80/15839944">栀子花开</a>
        </div>
    </div>
    <div class="img">
        <a herf="https://baike.baidu.com/item/%E6%9D%8E%E6%98%93%E5%B3%B0/3908480?fr=aladdin">
            <img src="https://gss0.bdstatic.com/94o3dSag_xI4khGkpoWK1HF6hhy/baike/c0%3Dbaike116%2C5%2C5%2C116%2C38/sign=e95988cb652762d09433acedc185639f/bf096b63f6246b604c86859cedf81a4c500fa249.jpg"></a>
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    </div>
    <br>
</div>
<nav class="navbar navbar-default navbar-fixed-bottom" role="navigation">
    <div class="container-fluid">
        <div class="navbar-header">
            <a class="navbar-brand" href="http://music.baidu.com/artist/1370">音乐作品</a>
        </div>
        <div>
            <ul class="nav navbar-nav">
                <li class="active"><a href="http://music.baidu.com/?fr=baikePC">热门歌曲</a></li>
                <li><a href="https://baike.baidu.com/item/%E6%98%93%E5%B3%B0%E6%83%85%E4%B9%A6/15815910">专辑</a></li>
                <li class="active"><a
                        href="http://bd.kuwo.cn/mingxing/%E6%9D%8E%E6%98%93%E5%B3%B0.htm?from=baidu">单曲</a></li>
                </li>
            </ul>
        </div>
    </div>
</nav>
<footer>
    <div class="foot">
        <div><a href="#"> 点我呀</a> · <a href="#"> 加入我们</a> · <a href="#"> 歌曲或歌名 </a> · <a href="#">帮助中心</a> · <a
                href="#">合作伙伴</a></div>
        <div>中国大陆男演员</div>
    </div>
</footer>

结果：

2、在父模板中更新导航，插入登录状态判断代码。、

注意用{% ... %}表示指令。

{{ }}表示变量

3、完成注销功能。

清除session

跳转

父模板：

{% if username %}
                <a href="#">
                <button type="button" class="btn btn-default"><span class="glyphicon glyphicon-log-in"></span>{{ username }}
                </button>
                </a>
                <a href="{{ url_for('logout') }}">
                    <button type="button" class="btn btn-default"><span class="glyphicon glyphicon-user"></span> 注销                   </button>
                </a>
                {% else %}
                <a href="{{ url_for('login') }}">
                    <button type="button" class="btn btn-default"><span class="glyphicon glyphicon-log-in"></span>登录
                    </button>
                </a>
                <a href="{{ url_for('regist') }}">
                    <button type="button" class="btn btn-default"><span class="glyphicon glyphicon-user"></span> 注册
                    </button>
                </a>
                {%  endif %}<a href="#">
                <button type="button" class="btn btn-default"><span class="glyphicon glyphicon-log-in"></span>{{ username }}
                </button>
                </a>
                <a href="{{ url_for('logout') }}">
                    <button type="button" class="btn btn-default"><span class="glyphicon glyphicon-user"></span> 注销                   </button>
                </a>
                {% else %}
                <a href="{{ url_for('login') }}">
                    <button type="button" class="btn btn-default"><span class="glyphicon glyphicon-log-in"></span>登录
                    </button>
                </a>
                <a href="{{ url_for('regist') }}">
                    <button type="button" class="btn btn-default"><span class="glyphicon glyphicon-user"></span> 注册
                    </button>
                </a>
                {%  endif %}

处理器：

@app.route('/logout')
def logout():
    session.clear()
    return redirect(url_for('base'))

结果：