95 lines
3.6 KiB
Python
95 lines
3.6 KiB
Python
import brotli as brotli_
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from flask import request, make_response
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from threading import Thread
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from hashlib import sha256
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import redis as libredis
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import os.path
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import mimetypes
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from redis.exceptions import RedisError
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class BrotliCache(object):
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def __init__(self, redis_uri='redis://', timeout=0.100, expire=60*60*6):
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self._redis = None
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self._redis_uri = redis_uri
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self.timeout = timeout
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self.expire = expire
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@property
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def redis(self):
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if not self._redis:
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self._redis = libredis.StrictRedis.from_url(self._redis_uri)
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self._redis.client_setname('brotlicache')
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return self._redis
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def compress_and_cache(self, cache_key, lock_key, body, mode=brotli_.MODE_GENERIC):
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encbody = brotli_.compress(body, mode=mode)
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self.redis.set(cache_key, encbody, px=int(self.expire*1000))
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self.redis.delete(lock_key)
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def wrap_response(self, response):
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if 'br' not in request.accept_encodings or response.is_streamed:
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return response
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body = response.get_data()
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digest = sha256(body).hexdigest()
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cache_key = 'brotlicache:{}'.format(digest)
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try:
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encbody = self.redis.get(cache_key)
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response.headers.set('brotli-cache', 'HIT')
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if not encbody:
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response.headers.set('brotli-cache', 'MISS')
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lock_key = 'brotlicache:lock:{}'.format(digest)
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if self.redis.set(lock_key, 1, nx=True, ex=10):
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mode = (
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brotli_.MODE_TEXT
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if response.content_type.startswith('text/')
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else brotli_.MODE_GENERIC)
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t = Thread(
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target=self.compress_and_cache,
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args=(cache_key, lock_key, body, mode))
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t.start()
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if self.timeout > 0:
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t.join(self.timeout)
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encbody = self.redis.get(cache_key)
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if not encbody:
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response.headers.set('brotli-cache', 'TIMEOUT')
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else:
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response.headers.set('brotli-cache', 'LOCKED')
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if encbody:
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response.headers.set('content-encoding', 'br')
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response.headers.set('vary', 'accept-encoding')
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response.set_data(encbody)
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return response
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except RedisError:
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response.headers.set('brotli-cache', 'ERROR')
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return response
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def brotli(app, static=True, dynamic=True, **kwargs):
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original_static = app.view_functions['static']
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def static_maybe_gzip_brotli(filename=None):
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path = os.path.join(app.static_folder, filename)
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for encoding, extension in (('br', '.br'), ('gzip', '.gz')):
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if encoding not in request.accept_encodings:
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continue
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encpath = path + extension
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if os.path.isfile(encpath):
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resp = make_response(
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original_static(filename=filename + extension))
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resp.headers.set('content-encoding', encoding)
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resp.headers.set('vary', 'accept-encoding')
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mimetype = (mimetypes.guess_type(filename)[0]
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or 'application/octet-stream')
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resp.headers.set('content-type', mimetype)
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return resp
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return original_static(filename=filename)
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if static:
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app.view_functions['static'] = static_maybe_gzip_brotli
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if dynamic:
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cache = BrotliCache(redis_uri=app.config.get('REDIS_URI'), **kwargs)
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app.after_request(cache.wrap_response)
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