急救，大老板们指点~
运行的时候直接报错，The view bookstore.views.update_book didn't return an HttpResponse object. It returned None instead.
**尝试按照网上的方案去修改缩进量，但是无效。__**
```python
def update_book(request, book_id):
try:
book = Book.objects.get(id=book_id, is_active=True)
except Exception as e:
print('update book error is %s' % e)
return HttpResponse('book is not existed')
if request == 'GET':
return render(request, 'bookstore/update_book.html', locals())
elif request == 'POST':
market_price = request.POST['market_price']
price = request.POST['price']
book.price = price
book.market_price = market_price
book.save()
return HttpResponseRedirect('/bookstore/all_book')
template 里面的html 如下：
```html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>update book</title>
</head>
<body>
<form action="/bookstore/update_book/{{ book.id }}" method="POST">
<p>
title <input type="text" value="{{ book.title }}" disabled="disabled">
</p>
<P>
pub <input type="text" value="{{ book.pub }}" disabled="disabled" >
</P>
<p>
price <input type="text" name="price" value="{{ book.price }}">
</p>
<p>
market_price <input type="text" name="market_price" value="{{ book.market_price }}" >
</p>
<p>
<input type="submit" value="renew">
</p>
</form>
</body>
</html>
运行结果及详细报错内容
The view bookstore.views.update_book didn't return an HttpResponse object. It returned None instead.
Request Method: GET
Request URL: http://127.0.0.1:8000/bookstore/update_book/1
Django Version: 4.1.7
Exception Type: ValueError
Exception Value:
The view bookstore.views.update_book didn't return an HttpResponse object. It returned None instead.
Exception Location: D:\JNU\mysite\venv\Lib\site-packages\django\core\handlers\base.py, line 332, in check_response
Raised during: bookstore.views.update_book
Python Executable: D:\JNU\mysite\venv\Scripts\python.exe
Python Version: 3.11.2
