在Django模板中，如何指定一个本身就是属性的字典键？ [英] In a Django template, how to specify a dictionary key which is itself an attribute?
问题描述
我正在使用一个带有 ListView 的Django项目，它有一个搜索窗体，在视图的上下文中已知为 search_form 和一个过滤器表单， filter_form 。界面如下所示：
据我所知， p>
为什么在这种情况下属性查找不起作用？
更新2 p>
回应Lemayzeur的评论，完整的追溯是：
追溯：
内部$ b中的/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/core/handlers/exception.py文件$ b 41. response = get_response（request）
文件/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/core /手lers / base.pyin _get_response
187. response = self.process_exception_by_middleware（e，request）
文件/ Users / kurtpeek / Documents / Dev / lucy / lucy-web / venv /lib/python3.6/site-packages/django/core/handlers/base.pyin _get_response
185. response = wrapped_callback（request，* callback_args，** callback_kwargs）
文件/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/views/generic/base.pyin view
68. return self。 dispatch（request，* args，** kwargs）
文件/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/two_factor/ views / mixins.py在
82. return super（OTPRequiredMixin，self）.dispatch（request，* args，** kwargs）
文件/ Users / kurtpeek / Documents / dev / lucy / lucy-web / venv / lib / python3.6 / site-packages / django / contrib / auth / mixins.py
56. return super（LoginRequiredMixin，self）.dispatch（request，* args，** kwargs）
文件/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/contrib/auth/调用
92. return super（PermissionRequiredMixin，self）.dispatch（request，* args，** kwargs）
文件/ Users / kurtpeek / Documents / Dev / lucy / lucy-web / venv / lib / python3.6 / site-packages / django / views / generic / base.py
88. return handler（request，* args，** kwargs）
文件/Users/kurtpeek/Documents/Dev/lucy/lucy-web/dashboard/views/families.pyin get
74. return super（）。get（request，* args ，** kwargs）
文件/Users/kurtpeek/Documents/Dev/lucy/lucy-web/dashboard/views/base.pyin get
111. return super（） .get（request，* args，** kwargs）
文件/Users/kurtpeek/Documents/Dev/lucy/lucy-web/dashboard/views/base.pyin get
74. return super（）。get（request，* args，** kwargs）
文件/ Users / kurtpeek / Documents / Dev / lucy / lucy-web / venv / lib / python self.object_list = self.get_queryset（）
文件/ Users / kurtpeek / Documents / 3.6 / site-packages / django / views / generic / list.pyin get
160。 dev / lucy / lucy-web / dashboard / views / families.pyin get_queryset
122. queryset = queryset.filter（lucy_guide__in = guide）
文件/ Users / kurtpeek / Documents /Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/db/models/query.pyin filter
784. return self._filter_or_exclude（False，* args，* * kwargs）
文件/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/db/models/query.py in _filter_or_exclude
802. clone.query.add_q（Q（* args，** kwargs））
文件/ Users / kurtpeek / Documents / Dev / lucy / lucy-web / venv /lib/python3.6/site-packages/django/db/models/sql/query.pyin add_q
1250. clause，_ = self._add_q（q_object，self.used_aliases）
文件/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-pac在/add_q
1276. allow_joins = allow_joins，split_subq = split_subq，
文件/ Users / kurtpeek / Documents / Dev / lucy中的kages / django / db / models / sql / query.py /lucy-web/venv/lib/python3.6/site-packages/django/db/models/sql/query.pyin build_filter
1206. condition = lookup_class（lhs，value）
文件/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/db/models/lookups.pyin __init__
24。 self.rhs = self.get_prep_lookup（）
文件/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/db/ self.rhs = [target_field.get_prep_value（v）for v in self.rhs]
文件/ Users / kurtpeek / Documents / models / fields / related_lookups.pyin get_prep_lookup
56. self.rhs = [target_field.get_prep_value /dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/db/models/fields/related_lookups.py中的< listcomp>
56. self.rhs = [target_field.get_prep_value（v）for v in self.rhs]
文件/ Users / kurtpeek / Documents / Dev / lucy / lucy-web / venv /lib/python3.6/site-packages/django/db/models/fields/__init__.pyin get_prep_value
966. return int（value）
异常类型：ValueError at /仪表板/系列
异常值：以10为基数的int（）无效字面值：''
如果我在视图的 get_queryset（）方法中设置一个跟踪，就在堆栈跟踪的122之前，我看到 guide self.request.GET 中：
> /Users/kurtpeek/Documents/Dev/lucy/lucy-web/dashboard/views/families.py（121）get_queryset（）
120
- > 121如果指南：
122 queryset = queryset.filter（lucy_guide__in = guide）
ipdb>指南
['']
ipdb> self.request.GET
< QueryDict：{'q'：['Christine']，'status'：['']，'next_outreach'：['']，'country'：[''] ，'vip'：['']，'app'：['']，'guide'：['']，'package'：['']}>
除了提交空值的困难之外，实际上我预计指导 request.GET 的字段在这里有一个非空值。例如，如果我只返回到隐藏过滤器表单的简化版本，只有指南字段：
< form action ={％url action％}method =getclass =left search col s6 hide-on-small-and-downnovalidate>
< div class =input-field>
< input id =searchplaceholder ={{placeholder}}
autocomplete =offtype =searchname =q
value ={{search_form .q.value.strip | default：''}}
data-query ={{search_form.q.value.strip | default：''}}>
< label for =searchclass =active>< i class =material-icons search-icon>搜索< / i>< / label>
class =material-icons search-icon
{％if search_form.q.value％} style =display： none;{％endif％}>关闭< / i>
< / div>
< input type =hiddenname =guidevalue ={{request.GET.guide}}/>
< / form>
然后我选择一个过滤器，然后在搜索栏中输入一个搜索词：
来执行字典查找 field.name ？
我终于通过编写自定义的 get 过滤器来解决这个问题，如
请注意，这也适用于未应用的过滤器 - 它们的值 None 而不是空字符串 - 不需要在表单中过滤它们。
I'm working on a Django project with a ListView that has both a search form, known in the view's context as search_form, and a filter form, filter_form. The interface looks like this:
Both the search_form and the filter_form ultimately change what is returned by the ListView's get_queryset method. I would like to make it such that when you first apply a filter and then do a search, it will search the filtered results.
At the moment, the 'reverse' functionality has already been implemented: when you first search and then filter, it will filter the search results. This is because of a hidden input element in the filter_form:
<form action={% url 'dashboard:families' %} method="GET" data-behavior="filters">
<input type="hidden" name="q" value="{{ request.GET.q.strip }}"/>
<div class="input-field col s2">
{{ filter_form.guide }}
<label class="active">Guide</label>
{% if filter_form.is_guide_filled %}
<a href="" class="clear"><i class="material-icons tiny">clear</i></a>
{% endif %}
</div>
For comparison, the search bar has the following template, _search.html:
<form action="{% url action %}" method="get" class="left search col s6 hide-on-small-and-down" novalidate>
<div class="input-field">
<input id="search" placeholder="{{ placeholder }}"
autocomplete="off" type="search" name="q"
value="{{ search_form.q.value.strip|default:'' }}"
data-query="{{ search_form.q.value.strip|default:'' }}">
<label for="search" class="active"><i class="material-icons search-icon">search</i></label>
<i data-behavior="search-clear"
class="material-icons search-icon"
{% if not search_form.q.value %}style="display: none;"{% endif %}>close</i>
</div>
</form>
In the main list view, index.html, the search template is included like so:
{% block search_form %}
{% with action='dashboard:families' placeholder='Search Families' %}
{% include '_search.html' %}
{% endwith %}
{% endblock %}
In order to make the search form persist the filters, I've noticed that for the guide field only, the following works:
<input type="hidden" name="guide" value="{{ request.GET.guide }}"/>
I would like to generalize this to include all the filters. I've tried the following:
{% if filter_form %}
{% for field in filter_form %}
{% with field_name=field.name %}
<input type="hidden" name=field_name value="{{ request.GET.field_name}}"/>
{% endwith %}
{% endfor %}
{% endif %}
However, if I try this I literally get "field_name" in the querystring:
As I understand from the DTL docs, the dot-notation implements dictionary lookup, attribute lookup, and list-index lookup. If I were to try something like
request.GET.field.name
it would probably try to look up "field" in the request.GET dictionary-like object and not find anything. In regular Python, what I'd essentially like to do is
request.GET[field.name]
I thought I could make this work with a with block, but apparently this doesn't work. Any advice on how to implement this?
Update
If I specify the name attribute for the input element as "{{field_name}}" instead of just field_name, like so,
<input type="hidden" name="{{field_name}}" value="{{ request.GET.field_name}}"/>
The problem is that the value is being set to an empty string instead of the desired value, which leads to a ValueError for the guide field (which is a ModelChoiceField expecting an integer as input):
Why is the attribute lookup not working in this case?
Update 2
Responding to Lemayzeur's comment, the full traceback is:
Traceback:
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/core/handlers/exception.py" in inner
41. response = get_response(request)
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/core/handlers/base.py" in _get_response
187. response = self.process_exception_by_middleware(e, request)
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/core/handlers/base.py" in _get_response
185. response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/views/generic/base.py" in view
68. return self.dispatch(request, *args, **kwargs)
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/two_factor/views/mixins.py" in dispatch
82. return super(OTPRequiredMixin, self).dispatch(request, *args, **kwargs)
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/contrib/auth/mixins.py" in dispatch
56. return super(LoginRequiredMixin, self).dispatch(request, *args, **kwargs)
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/contrib/auth/mixins.py" in dispatch
92. return super(PermissionRequiredMixin, self).dispatch(request, *args, **kwargs)
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/views/generic/base.py" in dispatch
88. return handler(request, *args, **kwargs)
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/dashboard/views/families.py" in get
74. return super().get(request, *args, **kwargs)
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/dashboard/views/base.py" in get
111. return super().get(request, *args, **kwargs)
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/dashboard/views/base.py" in get
74. return super().get(request, *args, **kwargs)
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/views/generic/list.py" in get
160. self.object_list = self.get_queryset()
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/dashboard/views/families.py" in get_queryset
122. queryset = queryset.filter(lucy_guide__in=guide)
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/db/models/query.py" in filter
784. return self._filter_or_exclude(False, *args, **kwargs)
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/db/models/query.py" in _filter_or_exclude
802. clone.query.add_q(Q(*args, **kwargs))
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/db/models/sql/query.py" in add_q
1250. clause, _ = self._add_q(q_object, self.used_aliases)
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/db/models/sql/query.py" in _add_q
1276. allow_joins=allow_joins, split_subq=split_subq,
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/db/models/sql/query.py" in build_filter
1206. condition = lookup_class(lhs, value)
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/db/models/lookups.py" in __init__
24. self.rhs = self.get_prep_lookup()
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/db/models/fields/related_lookups.py" in get_prep_lookup
56. self.rhs = [target_field.get_prep_value(v) for v in self.rhs]
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/db/models/fields/related_lookups.py" in <listcomp>
56. self.rhs = [target_field.get_prep_value(v) for v in self.rhs]
File "/Users/kurtpeek/Documents/Dev/lucy/lucy-web/venv/lib/python3.6/site-packages/django/db/models/fields/__init__.py" in get_prep_value
966. return int(value)
Exception Type: ValueError at /dashboard/families
Exception Value: invalid literal for int() with base 10: ''
If I set a trace in the view's get_queryset() method, just before 122 in the stack trace, I see that guide is indeed an empty list containing an empty string, as it is in self.request.GET:
> /Users/kurtpeek/Documents/Dev/lucy/lucy-web/dashboard/views/families.py(121)get_queryset()
120
--> 121 if guide:
122 queryset = queryset.filter(lucy_guide__in=guide)
ipdb> guide
['']
ipdb> self.request.GET
<QueryDict: {'q': ['Christine'], 'status': [''], 'next_outreach': [''], 'country': [''], 'vip': [''], 'app': [''], 'guide': [''], 'package': ['']}>
Aside from the difficulties in submitting the empty value, I actually would expect the guide field of request.GET to have a non-empty value here. For example, if I return to the 'simplified' version of the hidden filter form, with only the guide field:
<form action="{% url action %}" method="get" class="left search col s6 hide-on-small-and-down" novalidate>
<div class="input-field">
<input id="search" placeholder="{{ placeholder }}"
autocomplete="off" type="search" name="q"
value="{{ search_form.q.value.strip|default:'' }}"
data-query="{{ search_form.q.value.strip|default:'' }}">
<label for="search" class="active"><i class="material-icons search-icon">search</i></label>
<i data-behavior="search-clear"
class="material-icons search-icon"
{% if not search_form.q.value %}style="display: none;"{% endif %}>close</i>
</div>
<input type="hidden" name="guide" value="{{ request.GET.guide }}"/>
</form>
Then I select a filter, and enter a search term in the search bar:
Then when I set a trace just after the view's get method, like so:
def get(self, request, *args, **kwargs):
import ipdb; ipdb.set_trace()
I do see that both q and guide are in request.GET:
ipdb> request.GET
<QueryDict: {'q': ['Christine'], 'guide': ['6']}>
So in the 'general' form with request.GET.field_name, I would also expect the request.GET to look like this, with also empty lists for the other fields. It seems like the Django Template Language's dot notation is trying to literally do a dictionary or attribute lookup for 'field_name' and not finding anything; perhaps I should write a custom filter as described in Django template how to look up a dictionary value with a variable to perform the dictionary lookup of field.name?
I finally solved this by writing a custom get filter as described in Django template how to look up a dictionary value with a variable:
from django import template
register = template.Library()
@register.filter
def get(dictionary, key):
return dictionary.get(key)
I updated _search.html as follows:
{% load get %}
<form action="{% url action %}" method="get" class="left search col s6 hide-on-small-and-down" novalidate>
<div class="input-field">
<input id="search" placeholder="{{ placeholder }}"
autocomplete="off" type="search" name="q"
value="{{ search_form.q.value.strip|default:'' }}"
data-query="{{ search_form.q.value.strip|default:'' }}">
<label for="search" class="active"><i class="material-icons search-icon">search</i></label>
<i data-behavior="search-clear"
class="material-icons search-icon"
{% if not search_form.q.value %}style="display: none;"{% endif %}>close</i>
</div>
{% if filter_form %}
{% for field in filter_form %}
<input type="hidden" name="{{ field.name }}" value="{{ request.GET|get:field.name }}"/>
{% endfor %}
{% endif %}
</form>
Now, if I try to search a filtered result, it works as expected:
Note that this also works fine for the filters that are not applied - these have the value None instead of an empty string - without any need to filter them out in the form.
这篇关于在Django模板中，如何指定一个本身就是属性的字典键？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
