wtforms源码流程
实例化流程分析
1 # 源码流程
2 1. 执行type的 __call__ 方法，读取字段到静态字段 cls._unbound_fields 中； meta类读取到cls._wtforms_meta中
3 2. 执行构造方法
4
5 a. 循环cls._unbound_fields中的字段，并执行字段的bind方法，然后将返回值添加到 self._fields[name] 中。
6 即：
7 _fields = {
8 name: wtforms.fields.core.StringField(),
9 }
10
11 PS：由于字段中的__new__方法，实例化时：name = simple.StringField(label=‘用户名‘)，创建的是UnboundField(cls, *args, **kwargs)，当执行完bind之后，才变成执行 wtforms.fields.core.StringField()
12
13 b. 循环_fields，为对象设置属性
14 for name, field in iteritems(self._fields):
15 # Set all the fields to attributes so that they obscure the class
16 # attributes with the same names.
17 setattr(self, name, field)
18 c. 执行process，为字段设置默认值：self.process(formdata, obj, data=data, **kwargs)
19 优先级：obj,data,formdata;
20
21 再循环执行每个字段的process方法，为每个字段设置值：
22 for name, field, in iteritems(self._fields):
23 if obj is not None and hasattr(obj, name):
24 field.process(formdata, getattr(obj, name))
25 elif name in kwargs:
26 field.process(formdata, kwargs[name])
27 else:
28 field.process(formdata)
29
30 执行每个字段的process方法，为字段的data和字段的raw_data赋值
31 def process(self, formdata, data=unset_value):
32 self.process_errors = []
33 if data is unset_value:
34 try:
35 data = self.default()
36 except TypeError:
37 data = self.default
38
39 self.object_data = data
40
41 try:
42 self.process_data(data)
43 except ValueError as e:
44 self.process_errors.append(e.args[0])
45
46 if formdata:
47 try:
48 if self.name in formdata:
49 self.raw_data = formdata.getlist(self.name)
50 else:
51 self.raw_data = []
52 self.process_formdata(self.raw_data)
53 except ValueError as e:
54 self.process_errors.append(e.args[0])
55
56 try:
57 for filter in self.filters:
58 self.data = filter(self.data)
59 except ValueError as e:
60 self.process_errors.append(e.args[0])
61
62 d. 页面上执行print(form.name) 时，打印标签
63
64 因为执行了：
65 字段的 __str__ 方法
66 字符的 __call__ 方法
67 self.meta.render_field(self, kwargs)
68 def render_field(self, field, render_kw):
69 other_kw = getattr(field, ‘render_kw‘, None)
70 if other_kw is not None:
71 render_kw = dict(other_kw, **render_kw)
72 return field.widget(field, **render_kw)
73 执行字段的插件对象的 __call__ 方法，返回标签字符串
验证流程分析
1 a. 执行form的validate方法，获取钩子方法
2 def validate(self):
3 extra = {}
4 for name in self._fields:
5 inline = getattr(self.__class__, ‘validate_%s‘ % name, None)
6 if inline is not None:
7 extra[name] = [inline]
8
9 return super(Form, self).validate(extra)
10 b. 循环每一个字段，执行字段的 validate 方法进行校验(参数传递了钩子函数)
11 def validate(self, extra_validators=None):
12 self._errors = None
13 success = True
14 for name, field in iteritems(self._fields):
15 if extra_validators is not None and name in extra_validators:
16 extra = extra_validators[name]
17 else:
18 extra = tuple()
19 if not field.validate(self, extra):
20 success = False
21 return success
22 c. 每个字段进行验证时候
23 字段的pre_validate 【预留的扩展】
24 字段的_run_validation_chain，对正则和字段的钩子函数进行校验
25 字段的post_validate【预留的扩展】
自定义Form组件
#!usr/bin/env python
# -*- coding:utf-8 -*-
from flask import Flask,render_template,request,Markup
app = Flask(__name__,template_folder="templates")
app.debug = True
# ==============通过这几个类就可以显示了-==============
#插件
class Widget(object):
pass
class InputText(Widget):
def __call__(self, *args, **kwargs):
return "<input type=‘text‘ name=‘name‘>"
class TextArea(Widget):
def __call__(self, *args, **kwargs):
return Markup("<textarea name=‘email‘></textarea>")
#Form
class BaseForm(object):
def __init__(self):
#获取当前所有的字段
_fields = {}
for name, field in self.__class__.__dict__.items():
if isinstance(field, Field): # 筛选出字段是name和emailDe
_fields[name] = field
self._fields = _fields
self.data = {}
# print(_fields) # {‘name‘: 111, ‘email‘: 222}
def validate(self,request_data):
#先找到所有的字段，在执行每一个字段的validate方法
flag = True
for name, field in self._fields.items():
input_val = request_data.get(name,"") #用户输入的值
result= field.validate(input_val) #每一个字段自己校验
print("???????????",input_val,result)
if not result:
flag = False
else:
self.data[name] = input_val
return flag
#字段
class Field(object):
‘‘‘所有类的基类‘‘‘
def __str__(self): #python中的静态字段通过类能找到，通过对象也能找到
return Markup(self.widget()) #self就是StringField，self
class StringField(Field): #每个字段打印的时候都要去执行__str__，所以选择放在基类里面，自己没有就调用父类的
widget = InputText()
def validate(self,val):
if val:
return True
class EmaliField(Field):
widget = TextArea()
reg = ".*@.*"
def validate(self,val):
import re
print(re.match(self.reg,val),"************")
if re.match(self.reg,val):
return True
# ===============使用===============
class LoginForm(BaseForm):
name = StringField()
email = EmaliField()
@app.route(‘/index‘, methods=["GET","POST"])
def index():
form = LoginForm()
ret = form.validate(request.form)
print("验证成功",ret)
print("验证成功的值",form.data)
# print(form.name)
# print(form.email)
return render_template("index.html",form=form)
if __name__ == ‘__main__‘:
app.run()
原文地址：https://www.cnblogs.com/596014054-yangdongsheng/p/10228955.html
时间： 2024-08-27 17:11:31