form

评论作为应作为一个独立的应用。

注意要将评论（Comment）和表单（CommentForm）区分开。

数据库模型

from django.db import models

class Comment(models.Model):
    name = models.CharField(max_length=100)
    email = models.EmailField(max_length=255)
    url = models.URLField(blank=True)
    text = models.TextField()
    created_time = models.DateTimeField(auto_now_add=True)

    post = models.ForeignKey('app.Post')   # 文章 Post 作为外键

    def __str__(self):
        return self.text[:20]

评论表单

其实就是表单的具体化，指定表单采用的模型以及字段。
用户提交数据存放在 request.POST 对象中，以此构造 CommentForm 实例。

# comments/forms.py

from django import forms
from .models import Comment

class CommentForm(forms.ModelForm):
    class meta:
        model = Comment   # 绑定模型和字段
        fields = [name, email, text, url,]   # created_time、post 字段是自动获取的

评论视图

redirect 函数：可用 URL 作为参数；也可用模型实例作为参数 ，前提是该实例有 get_absolute_url 方法。

from django.shortcuts import render, get_object_or_404, redirct
from .models import Comment
from .forms import CommentForm

from app.models import Post

def post_comment(request, post_pk):
    post = get_object_or_404(Post, pk=post_pk)  # 获取当前文章
        if request.method == 'Post':
        form = CommentForm(request.POST)
        if form.is_valid():
            comment = form.save(commit=Flase) 
            comment.post = post 
            comment.save() 
            redirct(post)
        else: 
            comment_list = post.comment_set.all()
            context = {
                'post': post,
                'form': form,
                'comment_list': comment_list,
            }
            render(request, 'app/detail.html', context=context)
        redirct(post)

配置 URL

from django.conf.urls import url  

from . import views 

app_name = 'comments'   

urlpatterns = [
    url(r'^/comment/post/(?P<post_pk>/d+)/$', views.post_comment, name='post_comment')
]    

# blog/urls.py

urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'', include('app.urls')), 
    url(r'', include('comments.urls')),
]

文章详情页视图

form = CommentForm()
comment_list = post.comment_set.all()
context = {
    'post': post,
    'form': form,
    'comment_list': comment_list,
}
return render(requests, 'app/detail.html', context=context)

前端渲染

        <form action="{% url 'comments:post_comment' post.pk %}" method="post" class="comment-form">
            {% csrf_token %}
            <div class="row">
                <div class="col-md-4">
                    <label for="{{ form.name.id_for_label }}">名字：</label>
                    {{ form.name }}
                    {{ form.name.errors }}
                </div>
                <div class="col-md-4">
                    <label for="{{ form.email.id_for_label }}">邮箱：</label>
                    {{ form.email }}
                    {{ form.email.errors }}
                </div>
                <div class="col-md-4">
                    <label for="{{ form.url.id_for_label }}">URL：</label>
                    {{ form.url }}
                    {{ form.url.errors }}
                </div>
                <div class="col-md-12">
                    <label for="{{ form.text.id_for_label }}">评论：</label>
                    {{ form.text }}
                    {{ form.text.errors }}
                    <button type="submit" class="comment-btn">发表</button>
                </div>
            </div>    <!-- row -->
        </form>