U
    R+|j  ã                   @   s~   d Z ddlmZ ddlmZmZ ddlmZmZm	Z	m
Z
mZ ddlmZ G dd„ deƒZG dd	„ d	eƒZG d
d„ deeƒZdS )aÙ  
Cache middleware. If enabled, each Django-powered page will be cached based on
URL. The canonical way to enable cache middleware is to set
``UpdateCacheMiddleware`` as your first piece of middleware, and
``FetchFromCacheMiddleware`` as the last::

    MIDDLEWARE = [
        'django.middleware.cache.UpdateCacheMiddleware',
        ...
        'django.middleware.cache.FetchFromCacheMiddleware'
    ]

This is counter-intuitive, but correct: ``UpdateCacheMiddleware`` needs to run
last during the response phase, which processes middleware bottom-up;
``FetchFromCacheMiddleware`` needs to run last during the request phase, which
processes middleware top-down.

The single-class ``CacheMiddleware`` can be used for some simple sites.
However, if any other piece of middleware needs to affect the cache key, you'll
need to use the two-part ``UpdateCacheMiddleware`` and
``FetchFromCacheMiddleware``. This'll most often happen when you're using
Django's ``LocaleMiddleware``.

More details about how the caching works:

* Only GET or HEAD-requests with status code 200 are cached.

* The number of seconds each page is stored for is set by the "max-age" section
  of the response's "Cache-Control" header, falling back to the
  CACHE_MIDDLEWARE_SECONDS setting if the section was not found.

* This middleware expects that a HEAD request is answered with the same response
  headers exactly like the corresponding GET request.

* When a hit occurs, a shallow copy of the original response object is returned
  from process_request.

* Pages will be cached based on the contents of the request headers listed in
  the response's "Vary" header.

* This middleware also sets ETag, Last-Modified, Expires and Cache-Control
  headers on the response object.

é    )Úsettings)ÚDEFAULT_CACHE_ALIASÚcaches)Úget_cache_keyÚget_max_ageÚhas_vary_headerÚlearn_cache_keyÚpatch_response_headers)ÚMiddlewareMixinc                       s<   e Zd ZdZ‡ fdd„Zedd„ ƒZdd„ Zdd	„ Z‡  Z	S )
ÚUpdateCacheMiddlewarea6  
    Response-phase cache middleware that updates the cache if the response is
    cacheable.

    Must be used as part of the two-part update/fetch cache middleware.
    UpdateCacheMiddleware must be the first piece of middleware in MIDDLEWARE
    so that it'll get called last during the response phase.
    c                    s.   t ƒ  |¡ tj| _d | _tj| _tj| _	d S ©N)
ÚsuperÚ__init__r   ZCACHE_MIDDLEWARE_SECONDSÚcache_timeoutÚpage_timeoutÚCACHE_MIDDLEWARE_KEY_PREFIXÚ
key_prefixÚCACHE_MIDDLEWARE_ALIASÚcache_alias©ÚselfÚget_response©Ú	__class__© ú_c:\users\snmko\desktop\web_content\django_cbt\venv\Lib\site-packages\django/middleware/cache.pyr   D   s
    zUpdateCacheMiddleware.__init__c                 C   s
   t | j S r   ©r   r   ©r   r   r   r   ÚcacheK   s    zUpdateCacheMiddleware.cachec                 C   s   t |dƒo|jS )NÚ_cache_update_cache)Úhasattrr   ©r   ÚrequestÚresponser   r   r   Ú_should_update_cacheO   s    z*UpdateCacheMiddleware._should_update_cachec                    sò   ˆ  ||¡s|S |js |jdkr$|S |js>|jr>t|dƒr>|S d| dd¡krR|S ˆj‰ˆdkr„t|ƒ‰ˆdkrxˆj	‰nˆdkr„|S t
|ˆƒ ˆrî|jdkrît||ˆˆjˆjd	�‰ t|d
ƒrÞt|jƒrÞ| ‡ ‡‡fdd„¡ nˆj ˆ |ˆ¡ |S )zSet the cache, if needed.)éÈ   i0  ÚCookieÚprivatezCache-Controlr   Nr   r%   ©r   Úrenderc                    s   ˆj  ˆ | ˆ¡S r   )r   Úset)Úr©Ú	cache_keyr   Útimeoutr   r   Ú<lambda>{   ó    z8UpdateCacheMiddleware.process_response.<locals>.<lambda>)r$   Z	streamingÚstatus_codeZCOOKIESÚcookiesr   Úgetr   r   r   r	   r   r   r   r    Úcallabler)   Zadd_post_render_callbackr*   r!   r   r,   r   Úprocess_responseR   sF    ÿþý
    ÿÿz&UpdateCacheMiddleware.process_response)
Ú__name__Ú
__module__Ú__qualname__Ú__doc__r   Úpropertyr   r$   r5   Ú__classcell__r   r   r   r   r   :   s   	
r   c                       s4   e Zd ZdZ‡ fdd„Zedd„ ƒZdd„ Z‡  ZS )ÚFetchFromCacheMiddlewarea!  
    Request-phase cache middleware that fetches a page from the cache.

    Must be used as part of the two-part update/fetch cache middleware.
    FetchFromCacheMiddleware must be the last piece of middleware in MIDDLEWARE
    so that it'll get called last during the request phase.
    c                    s    t ƒ  |¡ tj| _tj| _d S r   )r   r   r   r   r   r   r   r   r   r   r   r   ‹   s    z!FetchFromCacheMiddleware.__init__c                 C   s
   t | j S r   r   r   r   r   r   r   �   s    zFetchFromCacheMiddleware.cachec                 C   s”   |j dkrd|_dS t|| jd| jd�}|dkr:d|_dS | j |¡}|dkrx|j dkrxt|| jd| jd�}| j |¡}|dkrŠd|_dS d|_|S )zn
        Check whether the page is already cached and return the cached
        version if available.
        )ÚGETÚHEADFNr=   r(   Tr>   )Úmethodr   r   r   r   r3   )r   r"   r-   r#   r   r   r   Úprocess_request”   s*    
   ÿz(FetchFromCacheMiddleware.process_request)	r6   r7   r8   r9   r   r:   r   r@   r;   r   r   r   r   r<   ‚   s
   
r<   c                       s"   e Zd ZdZd‡ fdd„	Z‡  ZS )ÚCacheMiddlewarezÌ
    Cache middleware that provides basic behavior for many simple sites.

    Also used as the hook point for the cache decorator, which is generated
    using the decorator-from-middleware utility.
    Nc                    sŒ   t ƒ  |¡ z|d }|d kr"d}|| _W n tk
r>   Y nX z|d }|d krVt}|| _W n tk
rr   Y nX |d k	r‚|| _|| _d S )Nr   Ú r   )r   r   r   ÚKeyErrorr   r   r   r   )r   r   r   r   Úkwargsr   r   r   r   r   r   »   s$    

zCacheMiddleware.__init__)NN)r6   r7   r8   r9   r   r;   r   r   r   r   rA   ³   s   rA   N)r9   Zdjango.confr   Zdjango.core.cacher   r   Zdjango.utils.cacher   r   r   r   r	   Zdjango.utils.deprecationr
   r   r<   rA   r   r   r   r   Ú<module>   s   -H1