mirror of
https://github.com/janeczku/calibre-web
synced 2024-12-11 02:30:30 +00:00
312 lines
11 KiB
Python
312 lines
11 KiB
Python
# -*- coding: utf-8 -*-
|
|
"""
|
|
jinja2.bccache
|
|
~~~~~~~~~~~~~~
|
|
|
|
This module implements the bytecode cache system Jinja is optionally
|
|
using. This is useful if you have very complex template situations and
|
|
the compiliation of all those templates slow down your application too
|
|
much.
|
|
|
|
Situations where this is useful are often forking web applications that
|
|
are initialized on the first request.
|
|
|
|
:copyright: (c) 2010 by the Jinja Team.
|
|
:license: BSD.
|
|
"""
|
|
from os import path, listdir
|
|
import sys
|
|
import marshal
|
|
import tempfile
|
|
import fnmatch
|
|
from hashlib import sha1
|
|
from jinja2.utils import open_if_exists
|
|
from jinja2._compat import BytesIO, pickle, PY2
|
|
|
|
|
|
# marshal works better on 3.x, one hack less required
|
|
if not PY2:
|
|
marshal_dump = marshal.dump
|
|
marshal_load = marshal.load
|
|
else:
|
|
|
|
def marshal_dump(code, f):
|
|
if isinstance(f, file):
|
|
marshal.dump(code, f)
|
|
else:
|
|
f.write(marshal.dumps(code))
|
|
|
|
def marshal_load(f):
|
|
if isinstance(f, file):
|
|
return marshal.load(f)
|
|
return marshal.loads(f.read())
|
|
|
|
|
|
bc_version = 2
|
|
|
|
# magic version used to only change with new jinja versions. With 2.6
|
|
# we change this to also take Python version changes into account. The
|
|
# reason for this is that Python tends to segfault if fed earlier bytecode
|
|
# versions because someone thought it would be a good idea to reuse opcodes
|
|
# or make Python incompatible with earlier versions.
|
|
bc_magic = 'j2'.encode('ascii') + \
|
|
pickle.dumps(bc_version, 2) + \
|
|
pickle.dumps((sys.version_info[0] << 24) | sys.version_info[1])
|
|
|
|
|
|
class Bucket(object):
|
|
"""Buckets are used to store the bytecode for one template. It's created
|
|
and initialized by the bytecode cache and passed to the loading functions.
|
|
|
|
The buckets get an internal checksum from the cache assigned and use this
|
|
to automatically reject outdated cache material. Individual bytecode
|
|
cache subclasses don't have to care about cache invalidation.
|
|
"""
|
|
|
|
def __init__(self, environment, key, checksum):
|
|
self.environment = environment
|
|
self.key = key
|
|
self.checksum = checksum
|
|
self.reset()
|
|
|
|
def reset(self):
|
|
"""Resets the bucket (unloads the bytecode)."""
|
|
self.code = None
|
|
|
|
def load_bytecode(self, f):
|
|
"""Loads bytecode from a file or file like object."""
|
|
# make sure the magic header is correct
|
|
magic = f.read(len(bc_magic))
|
|
if magic != bc_magic:
|
|
self.reset()
|
|
return
|
|
# the source code of the file changed, we need to reload
|
|
checksum = pickle.load(f)
|
|
if self.checksum != checksum:
|
|
self.reset()
|
|
return
|
|
self.code = marshal_load(f)
|
|
|
|
def write_bytecode(self, f):
|
|
"""Dump the bytecode into the file or file like object passed."""
|
|
if self.code is None:
|
|
raise TypeError('can\'t write empty bucket')
|
|
f.write(bc_magic)
|
|
pickle.dump(self.checksum, f, 2)
|
|
marshal_dump(self.code, f)
|
|
|
|
def bytecode_from_string(self, string):
|
|
"""Load bytecode from a string."""
|
|
self.load_bytecode(BytesIO(string))
|
|
|
|
def bytecode_to_string(self):
|
|
"""Return the bytecode as string."""
|
|
out = BytesIO()
|
|
self.write_bytecode(out)
|
|
return out.getvalue()
|
|
|
|
|
|
class BytecodeCache(object):
|
|
"""To implement your own bytecode cache you have to subclass this class
|
|
and override :meth:`load_bytecode` and :meth:`dump_bytecode`. Both of
|
|
these methods are passed a :class:`~jinja2.bccache.Bucket`.
|
|
|
|
A very basic bytecode cache that saves the bytecode on the file system::
|
|
|
|
from os import path
|
|
|
|
class MyCache(BytecodeCache):
|
|
|
|
def __init__(self, directory):
|
|
self.directory = directory
|
|
|
|
def load_bytecode(self, bucket):
|
|
filename = path.join(self.directory, bucket.key)
|
|
if path.exists(filename):
|
|
with open(filename, 'rb') as f:
|
|
bucket.load_bytecode(f)
|
|
|
|
def dump_bytecode(self, bucket):
|
|
filename = path.join(self.directory, bucket.key)
|
|
with open(filename, 'wb') as f:
|
|
bucket.write_bytecode(f)
|
|
|
|
A more advanced version of a filesystem based bytecode cache is part of
|
|
Jinja2.
|
|
"""
|
|
|
|
def load_bytecode(self, bucket):
|
|
"""Subclasses have to override this method to load bytecode into a
|
|
bucket. If they are not able to find code in the cache for the
|
|
bucket, it must not do anything.
|
|
"""
|
|
raise NotImplementedError()
|
|
|
|
def dump_bytecode(self, bucket):
|
|
"""Subclasses have to override this method to write the bytecode
|
|
from a bucket back to the cache. If it unable to do so it must not
|
|
fail silently but raise an exception.
|
|
"""
|
|
raise NotImplementedError()
|
|
|
|
def clear(self):
|
|
"""Clears the cache. This method is not used by Jinja2 but should be
|
|
implemented to allow applications to clear the bytecode cache used
|
|
by a particular environment.
|
|
"""
|
|
|
|
def get_cache_key(self, name, filename=None):
|
|
"""Returns the unique hash key for this template name."""
|
|
hash = sha1(name.encode('utf-8'))
|
|
if filename is not None:
|
|
filename = '|' + filename
|
|
if isinstance(filename, unicode):
|
|
filename = filename.encode('utf-8')
|
|
hash.update(filename)
|
|
return hash.hexdigest()
|
|
|
|
def get_source_checksum(self, source):
|
|
"""Returns a checksum for the source."""
|
|
return sha1(source.encode('utf-8')).hexdigest()
|
|
|
|
def get_bucket(self, environment, name, filename, source):
|
|
"""Return a cache bucket for the given template. All arguments are
|
|
mandatory but filename may be `None`.
|
|
"""
|
|
key = self.get_cache_key(name, filename)
|
|
checksum = self.get_source_checksum(source)
|
|
bucket = Bucket(environment, key, checksum)
|
|
self.load_bytecode(bucket)
|
|
return bucket
|
|
|
|
def set_bucket(self, bucket):
|
|
"""Put the bucket into the cache."""
|
|
self.dump_bytecode(bucket)
|
|
|
|
|
|
class FileSystemBytecodeCache(BytecodeCache):
|
|
"""A bytecode cache that stores bytecode on the filesystem. It accepts
|
|
two arguments: The directory where the cache items are stored and a
|
|
pattern string that is used to build the filename.
|
|
|
|
If no directory is specified the system temporary items folder is used.
|
|
|
|
The pattern can be used to have multiple separate caches operate on the
|
|
same directory. The default pattern is ``'__jinja2_%s.cache'``. ``%s``
|
|
is replaced with the cache key.
|
|
|
|
>>> bcc = FileSystemBytecodeCache('/tmp/jinja_cache', '%s.cache')
|
|
|
|
This bytecode cache supports clearing of the cache using the clear method.
|
|
"""
|
|
|
|
def __init__(self, directory=None, pattern='__jinja2_%s.cache'):
|
|
if directory is None:
|
|
directory = tempfile.gettempdir()
|
|
self.directory = directory
|
|
self.pattern = pattern
|
|
|
|
def _get_cache_filename(self, bucket):
|
|
return path.join(self.directory, self.pattern % bucket.key)
|
|
|
|
def load_bytecode(self, bucket):
|
|
f = open_if_exists(self._get_cache_filename(bucket), 'rb')
|
|
if f is not None:
|
|
try:
|
|
bucket.load_bytecode(f)
|
|
finally:
|
|
f.close()
|
|
|
|
def dump_bytecode(self, bucket):
|
|
f = open(self._get_cache_filename(bucket), 'wb')
|
|
try:
|
|
bucket.write_bytecode(f)
|
|
finally:
|
|
f.close()
|
|
|
|
def clear(self):
|
|
# imported lazily here because google app-engine doesn't support
|
|
# write access on the file system and the function does not exist
|
|
# normally.
|
|
from os import remove
|
|
files = fnmatch.filter(listdir(self.directory), self.pattern % '*')
|
|
for filename in files:
|
|
try:
|
|
remove(path.join(self.directory, filename))
|
|
except OSError:
|
|
pass
|
|
|
|
|
|
class MemcachedBytecodeCache(BytecodeCache):
|
|
"""This class implements a bytecode cache that uses a memcache cache for
|
|
storing the information. It does not enforce a specific memcache library
|
|
(tummy's memcache or cmemcache) but will accept any class that provides
|
|
the minimal interface required.
|
|
|
|
Libraries compatible with this class:
|
|
|
|
- `werkzeug <http://werkzeug.pocoo.org/>`_.contrib.cache
|
|
- `python-memcached <http://www.tummy.com/Community/software/python-memcached/>`_
|
|
- `cmemcache <http://gijsbert.org/cmemcache/>`_
|
|
|
|
(Unfortunately the django cache interface is not compatible because it
|
|
does not support storing binary data, only unicode. You can however pass
|
|
the underlying cache client to the bytecode cache which is available
|
|
as `django.core.cache.cache._client`.)
|
|
|
|
The minimal interface for the client passed to the constructor is this:
|
|
|
|
.. class:: MinimalClientInterface
|
|
|
|
.. method:: set(key, value[, timeout])
|
|
|
|
Stores the bytecode in the cache. `value` is a string and
|
|
`timeout` the timeout of the key. If timeout is not provided
|
|
a default timeout or no timeout should be assumed, if it's
|
|
provided it's an integer with the number of seconds the cache
|
|
item should exist.
|
|
|
|
.. method:: get(key)
|
|
|
|
Returns the value for the cache key. If the item does not
|
|
exist in the cache the return value must be `None`.
|
|
|
|
The other arguments to the constructor are the prefix for all keys that
|
|
is added before the actual cache key and the timeout for the bytecode in
|
|
the cache system. We recommend a high (or no) timeout.
|
|
|
|
This bytecode cache does not support clearing of used items in the cache.
|
|
The clear method is a no-operation function.
|
|
|
|
.. versionadded:: 2.7
|
|
Added support for ignoring memcache errors through the
|
|
`ignore_memcache_errors` parameter.
|
|
"""
|
|
|
|
def __init__(self, client, prefix='jinja2/bytecode/', timeout=None,
|
|
ignore_memcache_errors=True):
|
|
self.client = client
|
|
self.prefix = prefix
|
|
self.timeout = timeout
|
|
self.ignore_memcache_errors = ignore_memcache_errors
|
|
|
|
def load_bytecode(self, bucket):
|
|
try:
|
|
code = self.client.get(self.prefix + bucket.key)
|
|
except Exception:
|
|
if not self.ignore_memcache_errors:
|
|
raise
|
|
code = None
|
|
if code is not None:
|
|
bucket.bytecode_from_string(code)
|
|
|
|
def dump_bytecode(self, bucket):
|
|
args = (self.prefix + bucket.key, bucket.bytecode_to_string())
|
|
if self.timeout is not None:
|
|
args += (self.timeout,)
|
|
try:
|
|
self.client.set(*args)
|
|
except Exception:
|
|
if not self.ignore_memcache_errors:
|
|
raise
|