我有一个Flask应用程序,它使用WTForms进行用户输入.它在表单中使用SelectMultipleField.我似乎无法让应用程序在选中时在字段中发布所有项目;它只发送选择的第一个项目,无论用户选择了多少.
Flask documentation说明了这个字段类型发送的数据,但我没有看到这种行为：
The data on the SelectMultipleField is stored as a list of objects,
each of which is checked and coerced from the form input.
这是一个完整的,最小的Flask应用程序,说明了这一点：
#!/usr/bin/env python
from flask import Flask,render_template_string,request
from wtforms import Form,SelectMultipleField
application = app = Flask('wsgi')
class LanguageForm(Form):
language = SelectMultipleField(u'Programming Language',choices=[('cpp','C++'),('py','Python'),('text','Plain Text')])
template_form = """
{% block content %}
<h1>Set Language</h1>
<form method="POST" action="/">
<div>{{ form.language.label }} {{ form.language(rows=3,multiple=True) }}</div>
<button type="submit" class="btn">Submit</button>
</form>
{% endblock %}
"""
completed_template = """
{% block content %}
<h1>Language Selected</h1>
<div>{{ language }}</div>
{% endblock %}
"""
@app.route('/',methods=['GET','POST'])
def index():
form = LanguageForm(request.form)
if request.method == 'POST' and form.validate():
print "POST request and form is valid"
language = request.form['language']
print "languages in wsgi.py: %s" % request.form['language']
return render_template_string(completed_template,language=language)
else:
return render_template_string(template_form,form=form)
if __name__ == '__main__':
app.run(debug=True)
解决方法
Flask将request.form作为werkzeug MultiDict对象返回.这有点像字典,只是为了不警觉的陷阱.
http://flask.pocoo.org/docs/api/#flask.request
http://werkzeug.pocoo.org/docs/datastructures/#werkzeug.datastructures.MultiDict
MultiDict implements all standard dictionary methods. Internally,it saves all values for a key as a list,but the standard dict access methods will only return the first value for a key. If you want to gain access to the other values,too,you have to use the list methods.
但是,我认为有一种更简单的方法.
你可以帮我一个忙吗？
language = request.form['language']
同
language = form.language.data
并看看是否有任何不同？ WTForms应该处理MultiDict对象,并且只是为您自己返回一个列表,因为您已经将表单数据绑定到它.