Tornado and WTForms | 易学教程

问题

I am using WTForms for the first time. Using WTForms to validate POST requests in Tornado Below is my forms forms.py

class UserForm(Form):
    user = TextField('user', [validators.Length(min=23, max=23)])

In the tonado handler I have

def post(self):
    form = UserForm(self.request.body)

The error message i get is: formdata should be a multidict-type wrapper that supports the 'getlist' method"

How could I make this work?

回答1:

wtforms-tornado 0.0.1

WTForms extensions for Tornado.

pip install wtforms-tornado

WTForms-Tornado

回答2:

You'll need an object that can translate the Tornado form object into something WTForms expects. I use this:

class TornadoFormMultiDict(object): 
"""Wrapper class to provide form values to wtforms.Form

This class is tightly coupled to a request handler, and more importantly one of our BaseHandlers
which has a 'context'. At least if you want to use the save/load functionality.

Some of this more difficult that it otherwise seems like it should be because of nature
of how tornado handles it's form input.
"""
def __init__(self, handler): 
    # We keep a weakref to prevent circular references
    # This object is tightly coupled to the handler... which certainly isn't nice, but it's the
    # way it's gonna have to be for now.
    self.handler = weakref.ref(handler)

@property
def _arguments(self):        
    return self.handler().request.arguments

def __iter__(self): 
    return iter(self._arguments) 

def __len__(self):
    return len(self._arguments)

def __contains__(self, name): 
    # We use request.arguments because get_arguments always returns a 
    # value regardless of the existence of the key. 
    return (name in self._arguments)

def getlist(self, name): 
    # get_arguments by default strips whitespace from the input data, 
    # so we pass strip=False to stop that in case we need to validate 
    # on whitespace. 
    return self.handler().get_arguments(name, strip=False) 

def __getitem__(self, name):
    return self.handler().get_argument(name)

Then in your base handler, you'd do something like:

self.form = TornadoFormMultiDict(self)

Note: I think this adapted from a mailing list topic on this subject.

回答3:

I didn't find replacing a basic html form contained within a Tornado template with a WTForms form as intuitive as I might have hoped.

Here's an example of a very simple form using wtforms-tornado:

The template:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">

<html lang="en">
<head>
  <meta charset="utf-8">
    <title>A Simple Form</title>
    <meta name="description" content="Submit Track to Infinite Glitch">
</head>
<body>
<p><h1>Submit Info</h1></p>
<form enctype="multipart/form-data" action="/simple" method="post">
{{ form.name }}<br/>
{{ form.email }}<br/>
{{ form.message }}<br/>
<input type="submit"/>
</form>
</body>
</html>

The app code:

import wtforms
from wtforms_tornado import Form

class EasyForm(Form):
          name = wtforms.TextField('name', validators=[wtforms.validators.DataRequired()], default=u'test')
          email = wtforms.TextField('email', validators=[wtforms.validators.Email(), wtforms.validators.DataRequired()])
          message = wtforms.TextAreaField('message', validators=[wtforms.validators.DataRequired()])

class SimpleForm(tornado.web.RequestHandler):
    def get(self):
        form = EasyForm()
        self.write(templates.load("simpleform.html").generate(compiled=compiled, form=form))

    def post(self):
        form = EasyForm(self.request.arguments)
        details = '';
        if form.validate():
            for f in self.request.arguments:
                details += "<hr/>" + self.get_argument(f, default=None, strip=False)
            self.write(details)
        else:
            self.set_status(400)
            self.write(form.errors)

if __name__ == "__main__":

    application = tornado.web.Application(
        tornadio2.TornadioRouter(SocketConnection).apply_routes([
            (r"/simple", SimpleForm),
        ]),
    )

    application.listen(8888)
    tornado.ioloop.IOLoop.instance().start()

来源：https://stackoverflow.com/questions/16448913/tornado-and-wtforms

标签

python

forms

python-2.7

tornado

wtforms