form 表单可以有效的防止无效的用户名登陆或表单提交而对服务器产生的压力

1. 在app路径下新建forms.py

from django import forms
from captcha.fields import CaptchaField


class LoginForm(forms.Form):
    username = forms.CharField(required=True)
    password = forms.CharField(required=True, min_length=5)


# 注册form
class RegisterForm(forms.Form):
    email = forms.EmailField(required=True)
    password = forms.CharField(required=True, min_length=5)
    captcha = CaptchaField(error_messages={"invalid": u"验证码错误"})


# 忘记密码form
class ForgetForm(forms.Form):
    email = forms.EmailField(required=True)
    captcha = CaptchaField(error_messages={"invalid": u"验证码错误"})


# 重置密码form
class ModifyPwdForm(forms.Form):
    password1 = forms.CharField(required=True, min_length=5)
    password2 = forms.CharField(required=True, min_length=5)

1. html的 input中的name的值必须和form表单中的字段定义一致

<form action="/login/" method="post" autocomplete="off">
                    <div class="form-group marb20 {% if login_form.errors.username %}errorput{% endif %}">
                        <label>用 户 名</label>
                        <input name="username" id="account_l" type="text" value="{{ login_form.username.value }}" placeholder="手机号/邮箱" />
                    </div>
                    <div class="form-group marb8 {% if login_form.errors.password %}errorput{% endif %} ">
                        <label>密     码</label>
                        <input name="password" id="password_l" type="password" value="{{ login_form.password.value }}" placeholder="请输入您的密码" />
                    </div>
                    <div class="error btns login-form-tips" id="jsLoginTips">{% for key, error in login_form.errors.items %}{{ error }}{% endfor %}
                    {{ msg }}</div>
                     <div class="auto-box marb38">

                        <a class="fr" href="{% url 'forget_pwd' %}">忘记密码？</a>
                     </div>
                     <input class="btn btn-green" id="jsLoginBtn" type="submit" value="立即登录 > " />
                {% csrf_token %}
                </form>

1. view方法中的判断

from users.forms import LoginForm

# post方法登录
    def post(self, request):
        login_form = LoginForm(request.POST)
        if login_form.is_valid():
            user_name = request.POST.get("username", "")
            pass_word = request.POST.get("password", "")
            user = authenticate(username=user_name, password=pass_word)  # 认证用户信息
            if user is not None:
                if user.is_active:
                    login(request, user)
                    return render(request, "index.html")
                else:
                    # 未激活的方法--未写
                    pass
            else:
                # 在返回的页面写上     <div>{{ msg }}</div> 可以接收msg信息
                return render(request, "login.html", {"msg": "用户名或密码错误"})
        else:
            return render(request, "login.html", {"login_form": login_form})

1. 前端页面显示forms表单中的错误信息

<div class="form-group marb20 {% if login_form.errors.username %}errorput{% endif %}">
                        <label>用 户 名</label>
                        <input name="username" id="account_l" type="text" placeholder="手机号/邮箱" />
                    </div>
                    <div class="form-group marb8 {% if login_form.errors.password %}errorput{% endif %}">
                        <label>密     码</label>
                        <input name="password" id="password_l" type="password" placeholder="请输入您的密码" />
                    </div>
                    <div class="error btns login-form-tips" id="jsLoginTips">{% for key,error in login_form.errors.items %}{{ error }}{% endfor %}{{ msg }}</div>