281 Flask学习【第10篇】:自定义Form组件

自定义Form组件

一、wtforms源码流程

1、实例化流程分析

281 Flask学习【第10篇】:自定义Form组件
 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
View Code

2、验证流程分析

281 Flask学习【第10篇】:自定义Form组件
 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】
View Code

二、自定义Form组件

281 Flask学习【第10篇】: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):

    </span><span style="color: rgba(0, 0, 255, 1)">return</span> <span style="color: rgba(128, 0, 0, 1)">"</span><span style="color: rgba(128, 0, 0, 1)">&lt;input type='text' name='name'&gt;</span><span style="color: rgba(128, 0, 0, 1)">"</span>

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}

<span style="color: rgba(0, 0, 255, 1)">def</span><span style="color: rgba(0, 0, 0, 1)"> validate(self,request_data):
    </span><span style="color: rgba(0, 128, 0, 1)">#</span><span style="color: rgba(0, 128, 0, 1)">先找到所有的字段,在执行每一个字段的validate方法</span>
    flag =<span style="color: rgba(0, 0, 0, 1)"> True
    </span><span style="color: rgba(0, 0, 255, 1)">for</span> name, field <span style="color: rgba(0, 0, 255, 1)">in</span><span style="color: rgba(0, 0, 0, 1)"> self._fields.items():
        input_val </span>= request_data.get(name,<span style="color: rgba(128, 0, 0, 1)">""</span>) <span style="color: rgba(0, 128, 0, 1)">#</span><span style="color: rgba(0, 128, 0, 1)">用户输入的值</span>
        result= field.validate(input_val)  <span style="color: rgba(0, 128, 0, 1)">#</span><span style="color: rgba(0, 128, 0, 1)">每一个字段自己校验</span>
        <span style="color: rgba(0, 0, 255, 1)">print</span>(<span style="color: rgba(128, 0, 0, 1)">"</span><span style="color: rgba(128, 0, 0, 1)">???????????</span><span style="color: rgba(128, 0, 0, 1)">"</span><span style="color: rgba(0, 0, 0, 1)">,input_val,result)
        </span><span style="color: rgba(0, 0, 255, 1)">if</span> <span style="color: rgba(0, 0, 255, 1)">not</span><span style="color: rgba(0, 0, 0, 1)"> result:
            flag </span>=<span style="color: rgba(0, 0, 0, 1)"> False
        </span><span style="color: rgba(0, 0, 255, 1)">else</span><span style="color: rgba(0, 0, 0, 1)">:
            self.data[name] </span>=<span style="color: rgba(0, 0, 0, 1)"> input_val
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> 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 = ".@."

<span style="color: rgba(0, 0, 255, 1)">def</span><span style="color: rgba(0, 0, 0, 1)"> validate(self,val):
    </span><span style="color: rgba(0, 0, 255, 1)">import</span><span style="color: rgba(0, 0, 0, 1)"> re
    </span><span style="color: rgba(0, 0, 255, 1)">print</span>(re.match(self.reg,val),<span style="color: rgba(128, 0, 0, 1)">"</span><span style="color: rgba(128, 0, 0, 1)">************</span><span style="color: rgba(128, 0, 0, 1)">"</span><span style="color: rgba(0, 0, 0, 1)">)
    </span><span style="color: rgba(0, 0, 255, 1)">if</span><span style="color: rgba(0, 0, 0, 1)"> re.match(self.reg,val):
        </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> 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()

281 Flask学习【第10篇】:自定义Form组件

 

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