openmedialibrary_platform/Shared/lib/python2.7/site-packages/ox/cache.py

330 lines
10 KiB
Python

# -*- coding: utf-8 -*-
# vi:si:et:sw=4:sts=4:ts=4
# GPL 2011
from __future__ import with_statement
import gzip
import zlib
import hashlib
import os
import StringIO
import time
import urlparse
import urllib2
import sqlite3
import chardet
from utils import json
from .file import makedirs
import net
from net import DEFAULT_HEADERS, detect_encoding
cache_timeout = 30*24*60*60 # default is 30 days
COMPRESS_TYPES = (
'text/html',
'text/plain',
'text/xml',
'application/xhtml+xml',
'application/x-javascript',
'application/javascript',
'application/ecmascript',
'application/rss+xml'
)
def status(url, data=None, headers=DEFAULT_HEADERS, timeout=cache_timeout):
'''
>>> status('http://google.com')
200
>>> status('http://google.com/mysearch')
404
'''
headers = get_headers(url, data, headers)
return int(headers['status'])
def exists(url, data=None, headers=DEFAULT_HEADERS, timeout=cache_timeout):
'''
>>> exists('http://google.com')
True
>>> exists('http://google.com/mysearch')
False
'''
s = status(url, data, headers, timeout)
if s >= 200 and s < 400:
return True
return False
def get_headers(url, data=None, headers=DEFAULT_HEADERS, timeout=cache_timeout):
url_headers = store.get(url, data, headers, timeout, "headers")
if not url_headers:
url_headers = net.get_headers(url, data, headers)
store.set(url, data, -1, url_headers)
return url_headers
class InvalidResult(Exception):
"""Base class for exceptions in this module."""
def __init__(self, result, headers):
self.result = result
self.headers = headers
def _fix_unicode_url(url):
if isinstance(url, unicode):
url = url.encode('utf-8')
return url
def read_url(url, data=None, headers=DEFAULT_HEADERS, timeout=cache_timeout, valid=None, unicode=False):
'''
url - url to load
data - possible post data
headers - headers to send with request
timeout - get from cache if cache not older than given seconds, -1 to get from cache
valid - function to check if result is ok, its passed result and headers
if this function fails, InvalidResult will be raised deal with it in your code
'''
if net.DEBUG:
print 'ox.cache.read_url', url
#FIXME: send last-modified / etag from cache and only update if needed
url = _fix_unicode_url(url)
result = store.get(url, data, headers, timeout)
if not result:
try:
url_headers, result = net.read_url(url, data, headers, return_headers=True)
except urllib2.HTTPError, e:
e.headers['Status'] = "%s" % e.code
url_headers = dict(e.headers)
result = e.read()
if url_headers.get('content-encoding', None) == 'gzip':
result = gzip.GzipFile(fileobj=StringIO.StringIO(result)).read()
if not valid or valid(result, url_headers):
store.set(url, post_data=data, data=result, headers=url_headers)
else:
raise InvalidResult(result, url_headers)
if unicode:
encoding = detect_encoding(result)
if not encoding:
encoding = 'latin-1'
result = result.decode(encoding)
return result
def save_url(url, filename, overwrite=False):
if not os.path.exists(filename) or overwrite:
dirname = os.path.dirname(filename)
if not os.path.exists(dirname):
os.makedirs(dirname)
data = read_url(url)
f = open(filename, 'w')
f.write(data)
f.close()
def cache_path():
return os.environ.get('oxCACHE', os.path.expanduser('~/.ox/cache'))
class Cache:
def __init__(self):
pass
def get(self, url, data, headers=DEFAULT_HEADERS, timeout=-1, value="data"):
'''
if value == 'data' return data of url if its in the cache else None
if value == 'headers' return headers for url
'''
pass
def set(self, url, post_data, data, headers):
pass
class SQLiteCache(Cache):
def __init__(self):
path = cache_path()
if not os.path.exists(path):
os.makedirs(path)
self.db = os.path.join(path, "cache.sqlite")
self.create()
def connect(self):
conn = sqlite3.connect(self.db, timeout=10)
conn.text_factory = str
return conn
def create(self):
conn = self.connect()
c = conn.cursor()
# Create table and indexes
c.execute('''CREATE TABLE IF NOT EXISTS cache (url_hash varchar(42) unique, domain text, url text,
post_data text, headers text, created int, data blob, only_headers int)''')
c.execute('''CREATE INDEX IF NOT EXISTS cache_domain ON cache (domain)''')
c.execute('''CREATE INDEX IF NOT EXISTS cache_url ON cache (url)''')
c.execute('''CREATE INDEX IF NOT EXISTS cache_url_hash ON cache (url_hash)''')
c.execute('''CREATE TABLE IF NOT EXISTS setting (key varchar(1024) unique, value text)''')
if int(self.get_setting(c, 'version', 0)) < 1:
self.set_setting(c, 'version', 1)
c.execute('''ALTER TABLE cache ADD compressed INT DEFAULT 0''')
conn.commit()
def get_setting(self, c, key, default=None):
c.execute('SELECT value FROM setting WHERE key = ?', (key, ))
for row in c:
return row[0]
return default
def set_setting(self, c, key, value):
c.execute(u'INSERT OR REPLACE INTO setting values (?, ?)', (key, str(value)))
def get(self, url, data={}, headers=DEFAULT_HEADERS, timeout=-1, value="data"):
r = None
if timeout == 0:
return r
if data:
url_hash = hashlib.sha1(url + '?' + data).hexdigest()
else:
url_hash = hashlib.sha1(url).hexdigest()
conn = self.connect()
c = conn.cursor()
sql = 'SELECT %s, compressed FROM cache WHERE url_hash=?' % value
if timeout > 0:
now = time.mktime(time.localtime())
t = (url_hash, now-timeout)
sql += ' AND created > ?'
else:
t = (url_hash, )
if value != "headers":
sql += ' AND only_headers != 1 '
c.execute(sql, t)
for row in c:
r = row[0]
if value == 'headers':
r = json.loads(r)
elif value == 'data':
if row[1] == 1:
r = zlib.decompress(r)
else:
r = str(r)
break
c.close()
conn.close()
return r
def set(self, url, post_data, data, headers):
if post_data:
url_hash = hashlib.sha1(url + '?' + post_data).hexdigest()
else:
url_hash = hashlib.sha1(url).hexdigest()
domain = ".".join(urlparse.urlparse(url)[1].split('.')[-2:])
conn = self.connect()
c = conn.cursor()
# Insert a row of data
if not post_data: post_data=""
only_headers = 0
if data == -1:
only_headers = 1
data = ""
created = time.mktime(time.localtime())
content_type = headers.get('content-type', '').split(';')[0].strip()
if content_type in COMPRESS_TYPES:
compressed = 1
data = zlib.compress(data)
else:
compressed = 0
data = sqlite3.Binary(data)
#fixme: this looks wrong
try:
_headers = json.dumps(headers)
except:
for h in headers:
headers[h] = headers[h].decode(detect_encoding(headers[h]))
_headers = json.dumps(headers)
t = (url_hash, domain, url, post_data, _headers, created,
data, only_headers, compressed)
c.execute(u"""INSERT OR REPLACE INTO cache values (?, ?, ?, ?, ?, ?, ?, ?, ?)""", t)
# Save (commit) the changes and clean up
conn.commit()
c.close()
conn.close()
class FileCache(Cache):
def __init__(self):
f, self.root = cache_path().split(':')
def files(self, domain, h):
prefix = os.path.join(self.root, domain, h[:2], h[2:4], h[4:6], h[6:8])
i = os.path.join(prefix, '%s.json'%h)
f = os.path.join(prefix, '%s.dat'%h)
return prefix, i, f
def get(self, url, data={}, headers=DEFAULT_HEADERS, timeout=-1, value="data"):
r = None
if timeout == 0:
return r
if data:
url_hash = hashlib.sha1(url + '?' + data).hexdigest()
else:
url_hash = hashlib.sha1(url).hexdigest()
domain = ".".join(urlparse.urlparse(url)[1].split('.')[-2:])
prefix, i, f = self.files(domain, url_hash)
if os.path.exists(i):
with open(i) as _i:
try:
info = json.load(_i)
except:
return r
now = time.mktime(time.localtime())
expired = now-timeout
if value != 'headers' and info['only_headers']:
return None
if timeout < 0 or info['created'] > expired:
if value == 'headers':
r = info['headers']
else:
with open(f) as data:
r = data.read()
if info['compressed']:
r = zlib.decompress(r)
return r
def set(self, url, post_data, data, headers):
if post_data:
url_hash = hashlib.sha1(url + '?' + post_data).hexdigest()
else:
url_hash = hashlib.sha1(url).hexdigest()
domain = ".".join(urlparse.urlparse(url)[1].split('.')[-2:])
prefix, i, f = self.files(domain, url_hash)
makedirs(prefix)
created = time.mktime(time.localtime())
content_type = headers.get('content-type', '').split(';')[0].strip()
info = {
'compressed': content_type in COMPRESS_TYPES,
'only_headers': data == -1,
'created': created,
'headers': headers,
'url': url,
}
if post_data:
info['post_data'] = post_data
if not info['only_headers']:
if info['compressed']:
data = zlib.compress(data)
with open(f, 'w') as _f:
_f.write(data)
with open(i, 'w') as _i:
json.dump(info, _i)
if cache_path().startswith('fs:'):
store = FileCache()
else:
store = SQLiteCache()