python - 通过创建可重用模板来最大限度地减少代码重复

Question

我有一个模板，其中包含 4 个不同的分页器，它们仅在上下文变量上有所不同(tasks_today、tasks_tomorrow 等)，并且我希望最大限度地减少代码重复，因此我没有 4 个不同的分页器模板。

模板:

<div class="wrapper">
    <h3>Today</h3>
    <table>
    {% if tasks_today %}
        {% for task in tasks_today %}
            {% include 'todo/task_table_row.html' %}
        {% endfor %}
        {% include 'todo/paginator_today.html' %}
    {% else %}
        <p>No tasks for today.</p>
    {% endif %}
    </table>
    <h3>Tomorrow</h3>
    <table>
    {% if tasks_tomorrow %}
        {% for task in tasks_tomorrow %}
            {% include 'todo/task_table_row.html' %}
        {% endfor %}
        {% include 'todo/paginator_tomorrow.html' %}
    {% else %}
        <p>No tasks for tomorrow.</p>
    {% endif %}
    </table>
    <h3>Upcoming</h3>
    <table>
    {% if tasks_upcoming %}
        {% for task in tasks_upcoming %}
            {% include 'todo/task_table_row.html' %}
        {% endfor %}
        {% include 'todo/paginator_upcoming.html' %}
    {% else %}
        <p>No upcoming tasks.</p>
    {% endif %}
    </table>
    <h3>Past</h3>
    <table>
    {% if tasks_past %}
        {% for task in tasks_past %}
            {% include 'todo/task_table_row.html' %}
        {% endfor %}
        {% include 'todo/paginator_past.html' %}
    {% else %}
        <p>No tasks in the past.</p>
    {% endif %}
    </table>
</div>

paginator_today:

{% load url_replace %}

{% if tasks_today %}
<div class='paginator'>
    <nav aria-label="Page navigation">
        <ul class="pagination">
            {% if tasks_today.has_previous %}
                <li class="page-item">
                    <a class="page-link" href="?{% url_replace page_today=1 %}" aria-label="Previous">
                <span aria-hidden="true">&laquo;</span>
                <span class="sr-only">begin</span>
            </a>
                </li>
            {% endif %}

    {% for n in tasks_today.paginator.page_range %}
        {% if tasks_today.number == n %}
        <li class="page-item active">
            <span class="page-link">{{ n }}
                <span class="sr-only">(current)</span>
            </span>
        </li>
        {% elif n > tasks_today.number|add:'-3' and n < tasks_today.number|add:'3' %}
            <li class="page-item">
                <a class="page-link" href="?{% url_replace page_today=n %}">{{ n }}</a>
            </li>
        {% endif %}
    {% endfor %}

    {% if tasks_today.has_next %}
        <li class="page-item">
            <a class="page-link" href="?{% url_replace page_today=tasks_today.paginator.num_pages %}" aria-label="Next">
                <span aria-hidden="true">&raquo;</span>
                <span class="sr-only">end</span>
            </a>
        </li>
    {% endif %}
        </ul>
    </nav>
</div>
{% endif %}

paginator_tomorrow:

{% load url_replace %}

{% if tasks_tomorrow %}
<div class='paginator'>
    <nav aria-label="Page navigation">
        <ul class="pagination">
            {% if tasks_tomorrow.has_previous %}
                <li class="page-item">
                    <a class="page-link" href="?{% url_replace page_tomorrow=1 %}" aria-label="Previous">
                <span aria-hidden="true">&laquo;</span>
                <span class="sr-only">begin</span>
            </a>
                </li>
            {% endif %}

    {% for n in tasks_tomorrow.paginator.page_range %}
        {% if tasks_tomorrow.number == n %}
        <li class="page-item active">
            <span class="page-link">{{ n }}
                <span class="sr-only">(current)</span>
            </span>
        </li>
        {% elif n > tasks_tomorrow.number|add:'-3' and n < tasks_tomorrow.number|add:'3' %}
            <li class="page-item">
                <a class="page-link" href="?{% url_replace page_tomorrow=n %}">{{ n }}</a>
            </li>
        {% endif %}
    {% endfor %}

    {% if tasks_tomorrow.has_next %}
        <li class="page-item">
            <a class="page-link" href="?{% url_replace page_tomorrow=tasks_tomorrow.paginator.num_pages %}" aria-label="Next">
                <span aria-hidden="true">&raquo;</span>
                <span class="sr-only">end</span>
            </a>
        </li>
    {% endif %}
        </ul>
    </nav>
</div>
{% endif %}

我能做什么？

url_replace.py:

from django.utils.http import urlencode
from django import template
​
register = template.Library()
​
@register.simple_tag(takes_context=True)
def url_replace(context, **kwargs):
    query = context['request'].GET.dict()
    query.update(kwargs)
    return urlencode(query)

Answer 1

您可以使用 with 关键字在包含模板中设置某些变量:

{% include 'todo/paginator.html' with tasks=tasks_today page='page_today' %}

然后，您可以将分页器模板中对 tasks_today 的引用替换为 tasks，并将对 page_today 的引用替换为 page

<小时/>

编辑:对 url_replace 的调用是有问题的，因为它使用 kwargs，并且像 {% url_replace page_today = x %} 这样的调用将相当于一个调用到 urlreplace(context, **{'page_today' : x})。

仅使用 page = x 调用 url_replace 将无法正常工作，因为它将传递名称为 page 的关键字参数，而不是 page 的值

最简单的解决方案是将 page 变量传递给 paginator.html 并调用 {% urlreplace **{page : 20} %}，但 Django 模板引擎不允许打包 kwargs。

我认为最好的方法是创建一个 url_replace_single 函数，因为在此用例中您仅替换一个值。为此，您需要在 url_replace 函数上定义一个字段和值参数:

@register.simple_tag(takes_context=True)
def url_replace(context, field, value, **kwargs):
    query = context['request'].GET.dict()
    query_dict = { field : value}
    query.update(query_dict)
    return urlencode(query)

然后从模板中调用该函数，如下所示:

{% url_replace field=page value=x %}

唯一的缺点是，这只能让您替换网址中的一个查询参数。