python - 如何检查 Python 类中的请求方法？

Question

我有一个 Flask 类:

class Likes(object):
    def __init__(self, model, table_id):
        self.model = model
        self.table_id = table_id

        if request.form["likes"] == 'like':
            query = self.model.query.filter_by(id=table_id).first()
            query.likes += 1
            db.session.commit()
            flash(u'Like =)) ' + query.title, 'info')
        elif request.form["likes"] == 'dislike':
            query = self.model.query.filter_by(id=table_id).first()
            query.likes -= 1
            db.session.commit()
            flash(u"Don't like =(" + query.title, 'info')

每次用户发送 POST 请求时我都想调用这个类，但是每次我创建我的类的实例时我都需要添加检查请求类型:

# ...
if request.method == 'POST':
    Likes(Post, request.form["post_id"])
# ...

我怎样才能改进我的类(class)并在其中添加这个检查:

if request.method == 'POST':
    # ...

解决方案:使用装饰器@app.before_request

@app.before_request
def before_req():
    if request.method == 'POST':
        flash(u'Before request', 'success')

Answer 1

您可以使用 Flask.request_started 信号在每次请求到达时运行一些东西，然后执行您需要的代码。

flask.request_started

This signal is sent before any request processing started but when the request context was set up. Because the request context is already bound, the subscriber can access the request with the standard global proxies such as request.

看看 Flask's Signals chapter了解更多。

在你的代码中使用类似的东西:

def create_like(sender, **extra):
    if request.method == 'POST':
        Likes(Post, request.form["post_id"])


from flask import request_started
request_started.connect(create_like, app)

这改编自 documentation of Core Signals 的示例.