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use sqlite for cache

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j 2009-08-20 19:27:11 +02:00
parent f8f7e5f523
commit bfd5d3b8bf
1 changed files with 108 additions and 36 deletions
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144
oxlib/cache.py
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@ -8,6 +8,7 @@ import StringIO
import time
import urlparse
import urllib2
import sqlite3
import chardet
import simplejson
@ -18,6 +19,7 @@ from net import DEFAULT_HEADERS, getEncoding
cache_timeout = 30*24*60*60 # default is 30 days
def status(url, data=None, headers=DEFAULT_HEADERS, timeout=cache_timeout):
'''
>>> status('http://google.com')
@ -41,13 +43,12 @@ def exists(url, data=None, headers=DEFAULT_HEADERS, timeout=cache_timeout):
return False
def getHeaders(url, data=None, headers=DEFAULT_HEADERS, timeout=cache_timeout):
url_cache_file = "%s.headers" % _getUrlCacheFile(url, data, headers)
url_headers = _loadUrlCache(url_cache_file, timeout)
url_headers = _getUrlCache(url, data, headers, timeout, "headers")
if url_headers:
url_headers = simplejson.loads(url_headers)
else:
url_headers = net.getHeaders(url, data, headers)
_saveUrlHeaders(url_cache_file, url_headers)
_saveUrlCache(url, data, -1, url_headers)
return url_headers
class InvalidResult(Exception):
@ -68,9 +69,9 @@ def getUrl(url, data=None, headers=DEFAULT_HEADERS, timeout=cache_timeout, valid
#FIXME: send last-modified / etag from cache and only update if needed
if isinstance(url, unicode):
url = url.encode('utf-8')
url_cache_file = _getUrlCacheFile(url, data, headers)
result = _loadUrlCache(url_cache_file, timeout)
result = _getUrlCache(url, data, headers, timeout)
if not result:
print "get data", url
try:
url_headers, result = net.getUrl(url, data, headers, returnHeaders=True)
except urllib2.HTTPError, e:
@ -80,7 +81,7 @@ def getUrl(url, data=None, headers=DEFAULT_HEADERS, timeout=cache_timeout, valid
if url_headers.get('content-encoding', None) == 'gzip':
result = gzip.GzipFile(fileobj=StringIO.StringIO(result)).read()
if not valid or valid(result, url_headers):
_saveUrlCache(url_cache_file, result, url_headers)
_saveUrlCache(url, data, result, url_headers)
else:
raise InvalidResult(result, url_headers)
return result
@ -96,42 +97,113 @@ def _getCacheBase():
'cache base is eather ~/.ox/cache or can set via env variable oxCACHE'
return os.environ.get('oxCACHE', os.path.expanduser('~/.ox/cache'))
def _getUrlCacheFile(url, data=None, headers=DEFAULT_HEADERS):
def _getCacheDB():
return os.path.join(_getCacheBase(), "cache.sqlite")
def _connectDb():
conn = sqlite3.connect(_getCacheDB(), timeout=10)
conn.text_factory = str
return conn
def _createDb(c):
# Create table and indexes
c.execute('''CREATE TABLE IF NOT EXISTS cache (url_hash varchar(42) unique, 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)''')
def _getUrlCache(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:])
return os.path.join(_getCacheBase(), domain, url_hash[:2], url_hash[2:4], url_hash[4:6], url_hash)
def _loadUrlCache(url_cache_file, timeout=cache_timeout):
if timeout == 0:
return None
if os.path.exists(url_cache_file):
ctime = os.stat(url_cache_file).st_ctime
conn = _connectDb()
c = conn.cursor()
_createDb(c)
sql = 'SELECT %s FROM cache WHERE url_hash=?' % value
if timeout > 0:
now = time.mktime(time.localtime())
file_age = now-ctime
if timeout < 0 or file_age < timeout:
f = open(url_cache_file)
data = f.read()
f.close()
return data
return None
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]
break
def _saveUrlCache(url_cache_file, data, headers):
folder = os.path.dirname(url_cache_file)
if not os.path.exists(folder):
os.makedirs(folder)
f = open(url_cache_file, 'w')
f.write(data)
f.close()
_saveUrlHeaders("%s.headers" % url_cache_file, headers)
c.close()
conn.close()
return r
def _saveUrlHeaders(url_cache_file, headers):
folder = os.path.dirname(url_cache_file)
if not os.path.exists(folder):
os.makedirs(folder)
f = open(url_cache_file, 'w')
f.write(simplejson.dumps(headers))
f.close()
def _saveUrlCache(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 = _connectDb()
c = conn.cursor()
# Create table if not exists
_createDb(c)
# 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())
t = (url_hash, domain, url, post_data, simplejson.dumps(headers), created, data, only_headers)
c.execute(u"""INSERT OR REPLACE INTO cache values (?, ?, ?, ?, ?, ?, ?, ?)""", t)
# Save (commit) the changes and clean up
conn.commit()
c.close()
conn.close()
def migrate_to_db():
import re
import os
import sqlite3
import glob
conn = _connectDb()
c = conn.cursor()
_createDb(c)
files = glob.glob(_getCacheBase() + "/*/*/*/*/*")
_files = filter(lambda x: not x.endswith(".headers"), files)
for f in _files:
info = re.compile("%s/(.*?)/../../../(.*)" % _getCacheBase()).findall(f)
domain = url = info[0][0]
url_hash = info[0][1]
post_data = ""
created = os.stat(f).st_ctime
fd = open(f, "r")
data = fd.read()
fd.close()
fd = open(f + ".headers", "r")
headers = fd.read()
fd.close()
t = (url_hash, domain, url, post_data, headers, created, data, 0)
c.execute(u"""INSERT OR REPLACE INTO cache values (?, ?, ?, ?, ?, ?, ?, ?)""", t)
conn.commit()
c.close()
conn.close()