Re: [Plone-developers] CacheFu overhaul

from OFS.DTMLMethod import DTMLMethod
from OFS.Image import Image, File
from Acquisition import aq_base
from DateTime import DateTime
from Products.CMFCore.FSImage import FSImage
from Products.CMFCore.FSFile import FSFile
from Products.CMFCore.FSDTMLMethod import FSDTMLMethod
from Products.CMFCore.utils import _ViewEmulator, _setCacheHeaders
from Products.StandardCacheManagers.AcceleratedHTTPCacheManager import AcceleratedHTTPCache
from zLOG import LOG, INFO

def log(msg):
    LOG('CacheFu', INFO, msg)

log('Applying high performance cache patch...')

PATTERN = '__CacheFu_%s__'
def call(self, __name__, *args, **kw):
    return getattr(self, PATTERN % __name__)(*args, **kw)

WRAPPER = '__CacheFu_is_wrapper_method__'
ORIG_NAME = '__CacheFu_original_method_name__'
def isWrapperMethod(meth):
    return getattr(meth, WRAPPER, False)

def wrap_method(klass, name, method, pattern=PATTERN):
    old_method = getattr(klass, name)
    if isWrapperMethod(old_method):
        log('Re-wrapping %s.%s.' %
            (klass.__name__, name))
    else:
        log('Wrapping %s.%s.' %
            (klass.__name__, name))
    new_name = pattern % name
    setattr(klass, new_name, old_method)
    setattr(method, ORIG_NAME, new_name)
    setattr(method, WRAPPER, True)
    setattr(klass, name, method)

def unwrap_method(klass, name):
    old_method = getattr(klass, name)
    if not isWrapperMethod(old_method):
        raise ValueError, ('Trying to unwrap non-wrapped '
                           'method %s.%s.' % (klass.__name__, name))
    orig_name = getattr(old_method, ORIG_NAME)
    new_method = getattr(klass, orig_name)
    delattr(klass, orig_name)
    setattr(klass, name, new_method)

def patch_ofs():
    # Set default cache manager to 'CacheSquid' for most objects.
    log('Associating object with HTTP Cache Manager...')
    for klass in (Image, File, FSImage, FSFile):
        log('Associating %s.' % klass.__name__)
        setattr(klass, '_Cacheable__manager_id', 'HTTPCache')

def ZCache_set(self, ob, data, view_name, keywords, mtime_func):
    # Hook AcceleratedHTTPCache to use CMF's caching policy manager.
    res = call(self, 'ZCache_set', ob, data,
               view_name, keywords, mtime_func)
    _setCacheHeaders(_ViewEmulator().__of__(ob), extra_context=keywords)
    return res

def patch_http_cache():
    wrap_method(AcceleratedHTTPCache, 'ZCache_set', ZCache_set)

def fs_modified(self):
    """What's the last modification time for this file?
    """
    self._updateFromFS()
    return DateTime(self._file_mod_time)

def ofs_modified(self):
    """What's the last modification time for this object?
    """
    if hasattr(aq_base(self), 'bobobase_modification_time'):
        return self.bobobase_modification_time()
    if hasattr(aq_base(self), '_p_mtime'):
        return DateTime(self._p_mtime)
    return DateTime()

def patch_ofs_modified():
    # Add 'modified' method to File/Image/DTMLMethod.
    for klass in (Image, File, DTMLMethod):
        if hasattr(klass, 'modified'):
            continue
        log('Adding "modified" method to %s.' % klass.__name__)
        setattr(klass, 'modified', ofs_modified)

def patch_fs_modified():
    # Add 'modified' method to File/Image/DTMLMethod.
    for klass in (FSImage, FSFile, FSDTMLMethod):
        if hasattr(klass, 'modified'):
            continue
        log('Adding "modified" method to %s.' % klass.__name__)
        setattr(klass, 'modified', fs_modified)

patch_ofs_modified()
patch_fs_modified()
patch_ofs()
patch_http_cache()