Django视图main.views.home未返回HttpResponse及name未定义报错排查

初始报错 #

The view main.views.home didn't return an HttpResponse object. It returned None instead

排查过程 #

• 查阅Slack平台多则同类ValueError讨论帖，多数同类问题诱因是视图未返回render响应，但自查代码已经编写了render返回逻辑
• 判断问题与代码中if判断语句有关，但无法定位具体错误点，不清楚如何调整代码才能正常校验浏览器发送的表单请求
• 按评论建议临时移除is_valid校验逻辑，尝试触发新报错排查问题，此时出现名称错误：name 'name' is not defined，确认代码无法将用户在表单中输入的内容传递到API请求中

views.py #

from http.client import responses
from django.shortcuts import render
from .forms import SearchUser
from .search import search


def home(request):
    if request.method == "POST":
        form = SearchUser(request.POST)
        form.cleaned_data["name"]
    else:
            return render(request, "main/home.html", {
                'form': SearchUser(),  # Reference to form
                'userid': search(request),
                # 'mmr':NA,
            })

search.py #

import requests


def search(request):
    data = requests.get(
        f"https://americas.api.riotgames.com/riot/account/v1/accounts/by-riot-id/{name}/NA1?api_key=RGAPI-d1224a2c-9130-45ff-8c05-0656d56d105f")
    return data.json()['puuid']

urls.py #

from django.urls import path
from . import views


urlpatterns = [
    path("", views.home, name=""),
    #path("", views.search, name=""),
]

home.html #

{% extends 'main/base.html'%}


{% block content %}
    <h2>Valorant Ranked Checker</h2>
    <form method="post" action="">
        {% csrf_token %}
        {{form}}
        <button type="submit" name="search">
            Get rank
        </button>
    </form>
    <p><strong>{{userid}} - {{mmr}}</strong></p>
{% endblock %}

forms.py #

from django import forms


class SearchUser(forms.Form):
    name = forms.CharField(label="Name", max_length=200)

代码存在3个核心错误：

1. 视图响应缺失：home视图仅对非POST请求分支做了return render处理，用户提交表单走POST分支时，代码没有任何返回值，Django收到None就会抛出未返回HttpResponse的错误
2. 表单取值逻辑错误：访问form.cleaned_data前必须先调用form.is_valid()做合法性校验，否则清洗后的数据不会生成，无法拿到用户输入的值
3. 参数传递逻辑错误：
   • 从表单取到的name值没有传递给search函数，search函数内部直接使用未定义的name变量，触发名称错误
   • GET请求是首次打开页面的场景，此时用户还没有输入查询ID，直接调用search函数请求API必然出错

1. 调整视图逻辑，不管是GET还是POST请求，最终统一返回render响应，避免出现无返回值的分支
2. 表单取值前先做合法性校验，校验通过后再取cleaned_data里的值
3. 修改search函数的参数定义，显式接收要查询的name值，不要在函数内部使用未定义的变量
4. 仅在表单校验通过后再调用API查询，GET请求阶段不触发接口调用

修复后的代码参考：

修复后的views.py #

from django.shortcuts import render
from .forms import SearchUser
from .search import search


def home(request):
    form = SearchUser()
    userid = None
    if request.method == "POST":
        form = SearchUser(request.POST)
        if form.is_valid():
            search_name = form.cleaned_data["name"]
            userid = search(search_name)
    return render(request, "main/home.html", {
        'form': form,
        'userid': userid,
    })

修复后的search.py #

import requests


def search(name):
    resp = requests.get(
        f"https://americas.api.riotgames.com/riot/account/v1/accounts/by-riot-id/{name}/NA1?api_key=RGAPI-d1224a2c-9130-45ff-8c05-0656d56d105f")
    resp.raise_for_status()
    return resp.json()['puuid']

内容的提问来源于stack exchange，提问作者Blue