python - Django HTML POST 参数导致NoReverseMatch

Question

我有一个包含两个下拉列表的 HTML 帖子，我想将这些列表中选定的 Country 发送到 views 中的 search() 方法。 py ，然后将我发送到 结果 View 。每当我添加 government 和 location 作为 html POST 操作的参数或在搜索正则表达式中添加它们的值时，我尝试这样做，我得到一个 NoReverseMatch从我的 index 页面:

Reverse for 'search' with arguments '('', '')' and keyword arguments '{}' not found. 1 pattern(s) tried: ['search/(?P[A-Z]{3})/(?P[A-Z]{3})/']

我不知道我做错了什么导致了这个错误。 (见代码中的注释)

应用程序名称/views.py:

from django.shortcuts import get_object_or_404, render
from django.http import HttpResponseRedirect, HttpResponse
from .models import Country, Embassy
from django.template import loader
from django.urls import reverse


def index(request):
    country = Country.objects.filter()
    template = loader.get_template('appname/index.html')
    context = {'countries': country}
    return render(request, 'appname/index.html', context)

def results(request, government, location):
    return HttpResponse("Here are the Embassies sent by %s, located in %s." % (government, location))

def search(request):
    countries  = Country.objects.all()
    form = request.POST
    if request.method == 'POST':
        try:
            selected_government = get_object_or_404(pk=request.POST['government'])
        except (KeyError, Country.DoesNotExist):
            return render(request, 'appname/index.html', {
                'error_message': "You didn't select a government.",
            })
        try:
            selected_location = get_object_or_404(pk=request.POST['location'])
        except (KeyError, Country.DoesNotExist):
            return render(request, 'appname/index.html', {
                'error_message': "You didn't select a location.",
            })
        else:
            return HttpResponseRedirect(reverse('appname:results', args=(selected_government.code,selected_location.code,)))

应用程序名称/模板/应用程序名称/index.html:

{% if error_message %}<p><strong>{{ error_message }}</strong></p>{% endif %}

# government and location in the form action causes a NoReverse Match
<form action="{% url 'appname:search' government location %}" method="POST"> 
    {% csrf_token %}
    <label>Find Embassies sent by</label>
    <select name="government">
        {% for entry in countries %}
            <option value="{{ entry.code }}">{{ entry.name }}</option>
        {% endfor %}
    </select>
    <label>that are located in</label>
    <select name="location">
        {% for entry in countries %}
            <option value="{{ entry.code }}">{{ entry.name }}</option>
        {% endfor %}
    </select>
    <input type="submit" value="Search" />
</form>

url.py:

from django.conf.urls import include, url
from django.contrib import admin

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

应用程序名称/urls.py:

from django.conf.urls import url

from . import views

app_name = 'appname'
urlpatterns = [
    url(r'^$', views.index, name='index'),
    url(r'^(?P<embassy_id>[0-9]+)/$', views.embassy_info, name='embassy_info'),
    url(r'^(?P<code>[A-Z]{3})/$', views.country_info, name='country_info'),
    url(r'^find/(?P<government>[A-Z]{3})/(?P<location>[A-Z]{3})/$', views.results, name='results'),
    # the government and location values in search regex also cause a NoReverse Match   
    url(r'^search/(?P<government>[A-Z]{3})/(?P<location>[A-Z]{3})/', views.search, name='search'),
]

应用程序名称/models.py:

from django.db import models

class Country(models.Model):
    code = models.CharField(primary_key=True, max_length=3)
    name = models.CharField(max_length=50, db_column="Name")

    def __str__(self):
        return self.name

    class Meta:
        verbose_name = 'Country'
        verbose_name_plural = 'Countries'


class Embassy(models.Model):
    government = models.ForeignKey(Country, on_delete=models.CASCADE, related_name="government")
    location = models.ForeignKey(Country, on_delete=models.CASCADE, related_name="location")
    name = models.CharField(max_length=200, db_column="Name")
    street_address = models.CharField(max_length=200, db_column="Address")
    city = models.CharField(max_length=50, db_column="City")
    phone_number = models.IntegerField(default=-1, db_column="Phone Number")
    fax_number = models.IntegerField(null=True, blank=True, db_column="Fax Number")
    email_address = models.CharField(max_length=200, db_column="Email")
    website = models.CharField(max_length=200, db_column="Link")

    def __str__(self):
        return self.name

    class Meta:
        verbose_name = 'Embassy'
        verbose_name_plural = 'Embassies'

Answer 1

事情不是这样的。 url 标记的参数(实际上与任何模板标记一样)必须来自渲染时传递给模板的上下文。但是您正在尝试动态使用表单本身的值。

您应该从 URL 模式中完全删除参数。无论如何，您都没有在 View 中使用它们，因为您从 request.POST 正确获取了值。

url(r'^search/$', views.search, name='search'),

...

<form action="{% url 'search' %}" ...