Question

在Django中，我们ManifestStaticFilesStorage用于缓存静态文件，但它可以在Django和浏览器之间工作，但我想在用户和浏览器之间进行正确的缓存。

我想要：每次更改静态文件时，都会重新计算文件的哈希值并使浏览器缓存失效，并且用户在没有运行--collectstatic --no-input的情况下看到没有F5 adn的新静态文件。

我的代码现在不起作用： settings.py

STATICFILES_STORAGE = 'auth.utils.HashPathStaticFilesStorage'

CACHES = {
    'staticfiles': {
        'BACKEND': 'django.core.cache.backends.locmem.LocMemCache',
        'LOCATION': 'staticfiles',
        'TIMEOUT': 3600 * 24 * 7,
        'MAX_ENTRIES': 100,
    }
}

和auth.utils.py：

# -*- coding: utf-8 -*-

import time

from hashlib import sha384

from django.conf import settings
from django.core.cache import cache
from django.contrib.staticfiles.storage import ManifestStaticFilesStorage


try:
    ACCURACY = settings.STATICFILES_HASH_ACCURACY
except AttributeError:
    ACCURACY = 12

try:
    KEY_PREFIX = settings.STATICFILES_HASH_KEY_PREFIX
except AttributeError:
    KEY_PREFIX = 'staticfiles_hash'

class HashPathStaticFilesStorage(ManifestStaticFilesStorage):
    """A static file storage that returns a unique url based on the contents
    of the file. When a static file is changed the url will also change,
    forcing all browsers to download the new version of the file.

    The uniqueness of the url is a GET parameter added to the end of it. It
    contains the first 12 characters of the SHA3 sum of the contents of the
    file.

    Example: {% static "image.jpg" %} -> /static/image.jpg?4e1243

    The accuracy of the hash (number of characters used) can be set in
    settings.py with STATICFILES_HASH_ACCURACY. Setting this value too low
    (1 or 2) can cause different files to get the same hash and is not
    recommended. SHA3 hashes are 40 characters long so all accuracy values
    above 40 have the same effect as 40.

    The values can be cached for faster performance. All keys in the cache have
    the prefix specified in STATICFILES_HASH_KEY_PREFIX in setings.py. This
    value defaults to 'staticfiles_hash'
    """

    @property
    def prefix_key(self):
        return "%s:%s" % (KEY_PREFIX, 'prefix')

    def invalidate_cache(self, nocache=False):
        """Invalidates the cache. Run this when one or more static files change.
        If called with nocache=True the cache will not be used.
        """
        value = int(time.time())
        if nocache:
            value = None
        cache.set(self.prefix_key, value)

    def get_cache_key(self, name):
        hash_prefix = cache.get(self.prefix_key)
        if not hash_prefix:
            return None
        key = "%s:%s:%s" % (KEY_PREFIX, hash_prefix, name)
        return key

    def set_cached_hash(self, name, the_hash):
        key = self.get_cache_key(name)
        if key:
            cache.set(key, the_hash)

    def get_cached_hash(self, name):
        key = self.get_cache_key(name)
        if not key:
            return None
        the_hash = cache.get(key)
        return the_hash

    def calculate_hash(self, name):
        path = self.path(name)
        try:
            the_file = open(path, 'rb')
            the_hash = sha384(the_file.read()).hexdigest()[:ACCURACY]
            the_file.close()
        except IOError:
            return ""
        return the_hash

    def get_hash(self, name):
        the_hash = self.get_cached_hash(name)
        if the_hash:
            return the_hash
        the_hash = self.calculate_hash(name)
        self.set_cached_hash(name, the_hash)
        return the_hash

    def url(self, name):
        base_url = super(HashPathStaticFilesStorage, self).url(name)
        the_hash = self.get_hash(name)
        if "?" in base_url:
            return "%s&%s" % (base_url, the_hash)
        return "%s?%s" % (base_url, the_hash)

Answer 1

避免用户重新加载页面以获取新鲜静态内容的一种常见而简单的方法是在HTML标记中包含静态文件时附加一些可变值，如下所示：

<script src="{% static 'js/library.js' %}?{{ version }}"></script>

通过这种方式，当变量 version 采用不同的值时，浏览器将被迫从服务器下载新版本的静态文件。

您可以使用custom context processor设置版本，例如从设置中读取项目版本。像这样：

from django.conf import settings

def version(request):
    return {
        'version': settings.VERSION
    }

如果您使用git作为VCS，那么当您将修改推送到服务器时，另一种方法是将项目的最后一次提交哈希写入文件中。该文件应采用Python可读的格式。通过这种方式，您可以使用git commit hash作为之前提到的 version 变量。您可以使用GIT post-receive hook：

执行此操作

#!/bin/bash

WORKDIR=/path/to/project/
VERSION_MODULE=${WORKDIR}django_project/project/version.py

# for every branch which has been pushed
while read oldrev newrev ref
do
    # if branch pushed is master, update version.py file in the django project
    if [[ $ref =~ .*/master$ ]]; then
        GIT_WORK_TREE=$WORKDIR git checkout -f master
        echo "GIT_REF = 'master'" > $VERSION_MODULE
        echo "GIT_REV = '$newrev'" >> $VERSION_MODULE
    fi
done

然后你的上下文处理器可能是：

from project.version import GIT_REV

def version(request):
    return {
        'version': GIT_REV[:7]
    }

Answer 2

我只是使用这个非常简单的想法

<img src="{{ company.logo.url }}?v={% now 'U' %}" />

使用 ?v= 强制版本并将版本设置为当前时间戳 {% now 'U' %}，这样它就会随着每个请求而改变

在Django

2 个答案: