Blog 项目源码：

目录

前文列表

实现 post() 视图函数

• views.py
  在原有的基础上对视图函数 post() 进行修改.

from uuid import uuid4import datetimefrom forms import CommentForm@app.route('/post/
    
     ', methods=('GET', 'POST'))def post(post_id):    """View function for post page"""    # Form object: `Comment`    form = CommentForm()    # form.validate_on_submit() will be true and return the    # data object to form instance from user enter,    # when the HTTP request is POST    if form.validate_on_submit():        new_comment = Comment(id=str(uuid4()),                              name=form.name.data)        new_comment.text = form.text.data        new_comment.date = datetime.datetime.now()        new_comment.post_id = post_id        db.session.add(new_comment)        db.session.commit()    post = Post.query.get_or_404(post_id)    tags = post.tags    comments = post.comments.order_by(Comment.date.desc()).all()    recent, top_tags = sidebar_data()    return render_template('post.html',                           post=post,                           tags=tags,                           comments=comments,                           form=form,                           recent=recent,                           top_tags=top_tags)
    

NOTE: CommentForm 类是在 中定义的, 需要将其导入到该模块中.

• 需要在视图函数 post() 中添加接收 HTTP POST 请求, 路由方法 route() 默认只接收 HTTP GET 请求.

• 在视图函数中创建一个 form 对象, 并以此来获取用户在输入框中输入的数据对象.

• form.validata_on_submit() 方法会隐式的判断该 HTTP 请求是不是 POST, 若是, 则将请求中提交的表单数据对象传入上述的 form 对象并进行数据检验.

• 若提交的表单数据对象通过了 form 对象的检验, 则 form.validata_on_submit() 返回为 True 并且将这些数据传给 form 对象, 成为其实例属性.

• 之后我们就能够通过表单对象 form 来调用其实例属性, 并且赋值给 models 对象, 最后存入到数据库中.

• 最后, 因为在 post.html 页面需要显示这些评论, 所以该模板文件也需要传入 form 对象含有的实例属性值, 那么我们直接在视图函数 post() 中 直接将 form 对象传入到 render_template() 就好了.

在 post.html 中添加表单

{% extends "base.html"%}{% block title %}{
    { post.name }}{% endblock %}
    {% block body %}
{
    { post.title }}
{
    { post.publish_date }}:{
    { post.text }}
    
  
     
New Comment:
  
       
     
          {
    { form.hidden_tag() }}    
      
      
             {
    { form.name.label }}      {% if form.name.errors %}        {% for e in form.name.errors %}          
       
{
    { e }}
        {% endfor %}      {% endif %}      {
    { form.name(class_="form-control") }}    
      
    
      
             {
    { form.text.label }}      {% if form.text.errors %}        {% for e in form.text.errors %}          
       
{
    { e }}
        {% endfor %}      {% endif %}      {
    { form.text(class_='form-control') }}    
      
    
        
     
    
{% endblock %}

• form.hidden_tag(): 提供了预防跨站请求伪造的机制, 常用于表单页面
• field.errors: 列表类型, 用于显示验证失败后的提示信息
• {
  { form.name(class_="form-control") }}: 把字段本身作为方法调用, 会渲染作用于该字段的的 HTML 代码.
• field.label: 为输入框生成对应的 label 标签的 HTML 代码.

效果

查看是否写入到了数据库:

mysql> select * from comments where name='jmilkfan';+--------------------------------------+----------+------+---------------------+--------------------------------------+| id                                   | name     | text | date                | post_id                              |+--------------------------------------+----------+------+---------------------+--------------------------------------+| 0cea03ec-76b4-4ba4-b781-6a0bf056078b | jmilkfan | HI   | 2016-11-25 17:21:05 | 35c8b4f3-c231-4b32-b139-f7647714b87e |+--------------------------------------+----------+------+---------------------+--------------------------------------+1 row in set (0.00 sec)

ERROR LOG:

(env)fanguiju@fanguiju:/opt/JmilkFan-s-Blog$ python manage.py server/opt/JmilkFan-s-Blog/env/local/lib/python2.7/site-packages/flask/exthook.py:71: ExtDeprecationWarning: Importing flask.ext.script is deprecated, use flask_script instead.  .format(x=modname), ExtDeprecationWarning/opt/JmilkFan-s-Blog/env/local/lib/python2.7/site-packages/flask/exthook.py:71: ExtDeprecationWarning: Importing flask.ext.migrate is deprecated, use flask_migrate instead.  .format(x=modname), ExtDeprecationWarning/opt/JmilkFan-s-Blog/env/local/lib/python2.7/site-packages/flask/exthook.py:71: ExtDeprecationWarning: Importing flask.ext.sqlalchemy is deprecated, use flask_sqlalchemy instead.  .format(x=modname), ExtDeprecationWarning/opt/JmilkFan-s-Blog/env/local/lib/python2.7/site-packages/flask_sqlalchemy/__init__.py:800: UserWarning: SQLALCHEMY_TRACK_MODIFICATIONS adds significant overhead and will be disabled by default in the future.  Set it to True to suppress this warning.  warnings.warn('SQLALCHEMY_TRACK_MODIFICATIONS adds significant overhead and will be disabled by default in the future.  Set it to True to suppress this warning.')Traceback (most recent call last):  File "manage.py", line 35, in 
    
         manager.run()  File "/opt/JmilkFan-s-Blog/env/local/lib/python2.7/site-packages/flask_script/__init__.py", line 412, in run    result = self.handle(sys.argv[0], sys.argv[1:])  File "/opt/JmilkFan-s-Blog/env/local/lib/python2.7/site-packages/flask_script/__init__.py", line 383, in handle    res = handle(*args, **config)  File "/opt/JmilkFan-s-Blog/env/local/lib/python2.7/site-packages/flask_script/commands.py", line 425, in __call__    **self.server_options)  File "/opt/JmilkFan-s-Blog/env/local/lib/python2.7/site-packages/flask/app.py", line 843, in run    run_simple(host, port, self, **options)  File "/opt/JmilkFan-s-Blog/env/local/lib/python2.7/site-packages/werkzeug/serving.py", line 677, in run_simple    s.bind((hostname, port))  File "/usr/lib/python2.7/socket.py", line 224, in meth    return getattr(self._sock,name)(*args)socket.error: [Errno 98] Address already in use
    

TSG: 在该运行的环境中, Server() 默认的 IP 或 PORT 被占用了. 所以在 manage.py 中手动的设定其 IP 或 PORT.

manager.add_command("server", Server(host='127.0.0.1', port=8089))