1 "File-based cache backend" |
1 "File-based cache backend" |
2 |
2 |
3 import md5 |
3 import os |
4 import os, time |
4 import time |
5 try: |
5 try: |
6 import cPickle as pickle |
6 import cPickle as pickle |
7 except ImportError: |
7 except ImportError: |
8 import pickle |
8 import pickle |
|
9 |
9 from django.core.cache.backends.base import BaseCache |
10 from django.core.cache.backends.base import BaseCache |
|
11 from django.utils.hashcompat import md5_constructor |
10 |
12 |
11 class CacheClass(BaseCache): |
13 class CacheClass(BaseCache): |
12 def __init__(self, dir, params): |
14 def __init__(self, dir, params): |
13 BaseCache.__init__(self, params) |
15 BaseCache.__init__(self, params) |
14 |
16 |
15 max_entries = params.get('max_entries', 300) |
17 max_entries = params.get('max_entries', 300) |
16 try: |
18 try: |
17 self._max_entries = int(max_entries) |
19 self._max_entries = int(max_entries) |
18 except (ValueError, TypeError): |
20 except (ValueError, TypeError): |
19 self._max_entries = 300 |
21 self._max_entries = 300 |
20 |
22 |
21 cull_frequency = params.get('cull_frequency', 3) |
23 cull_frequency = params.get('cull_frequency', 3) |
22 try: |
24 try: |
23 self._cull_frequency = int(cull_frequency) |
25 self._cull_frequency = int(cull_frequency) |
24 except (ValueError, TypeError): |
26 except (ValueError, TypeError): |
25 self._cull_frequency = 3 |
27 self._cull_frequency = 3 |
26 |
28 |
27 self._dir = dir |
29 self._dir = dir |
28 if not os.path.exists(self._dir): |
30 if not os.path.exists(self._dir): |
29 self._createdir() |
31 self._createdir() |
30 |
32 |
31 def add(self, key, value, timeout=None): |
33 def add(self, key, value, timeout=None): |
32 if self.has_key(key): |
34 if self.has_key(key): |
33 return None |
35 return False |
34 |
36 |
35 self.set(key, value, timeout) |
37 self.set(key, value, timeout) |
|
38 return True |
36 |
39 |
37 def get(self, key, default=None): |
40 def get(self, key, default=None): |
38 fname = self._key_to_file(key) |
41 fname = self._key_to_file(key) |
39 try: |
42 try: |
40 f = open(fname, 'rb') |
43 f = open(fname, 'rb') |
50 return default |
53 return default |
51 |
54 |
52 def set(self, key, value, timeout=None): |
55 def set(self, key, value, timeout=None): |
53 fname = self._key_to_file(key) |
56 fname = self._key_to_file(key) |
54 dirname = os.path.dirname(fname) |
57 dirname = os.path.dirname(fname) |
55 |
58 |
56 if timeout is None: |
59 if timeout is None: |
57 timeout = self.default_timeout |
60 timeout = self.default_timeout |
58 |
61 |
59 self._cull() |
62 self._cull() |
60 |
63 |
61 try: |
64 try: |
62 if not os.path.exists(dirname): |
65 if not os.path.exists(dirname): |
63 os.makedirs(dirname) |
66 os.makedirs(dirname) |
64 |
67 |
65 f = open(fname, 'wb') |
68 f = open(fname, 'wb') |
101 return False |
104 return False |
102 |
105 |
103 def _cull(self): |
106 def _cull(self): |
104 if int(self._num_entries) < self._max_entries: |
107 if int(self._num_entries) < self._max_entries: |
105 return |
108 return |
106 |
109 |
107 try: |
110 try: |
108 filelist = os.listdir(self._dir) |
111 filelist = os.listdir(self._dir) |
109 except (IOError, OSError): |
112 except (IOError, OSError): |
110 return |
113 return |
111 |
114 |
112 if self._cull_frequency == 0: |
115 if self._cull_frequency == 0: |
113 doomed = filelist |
116 doomed = filelist |
114 else: |
117 else: |
115 doomed = [os.path.join(self._dir, k) for (i, k) in enumerate(filelist) if i % self._cull_frequency == 0] |
118 doomed = [os.path.join(self._dir, k) for (i, k) in enumerate(filelist) if i % self._cull_frequency == 0] |
116 |
119 |
131 def _key_to_file(self, key): |
134 def _key_to_file(self, key): |
132 """ |
135 """ |
133 Convert the filename into an md5 string. We'll turn the first couple |
136 Convert the filename into an md5 string. We'll turn the first couple |
134 bits of the path into directory prefixes to be nice to filesystems |
137 bits of the path into directory prefixes to be nice to filesystems |
135 that have problems with large numbers of files in a directory. |
138 that have problems with large numbers of files in a directory. |
136 |
139 |
137 Thus, a cache key of "foo" gets turnned into a file named |
140 Thus, a cache key of "foo" gets turnned into a file named |
138 ``{cache-dir}ac/bd/18db4cc2f85cedef654fccc4a4d8``. |
141 ``{cache-dir}ac/bd/18db4cc2f85cedef654fccc4a4d8``. |
139 """ |
142 """ |
140 path = md5.new(key.encode('utf-8')).hexdigest() |
143 path = md5_constructor(key.encode('utf-8')).hexdigest() |
141 path = os.path.join(path[:2], path[2:4], path[4:]) |
144 path = os.path.join(path[:2], path[2:4], path[4:]) |
142 return os.path.join(self._dir, path) |
145 return os.path.join(self._dir, path) |
143 |
146 |
144 def _get_num_entries(self): |
147 def _get_num_entries(self): |
145 count = 0 |
148 count = 0 |
146 for _,_,files in os.walk(self._dir): |
149 for _,_,files in os.walk(self._dir): |
147 count += len(files) |
150 count += len(files) |
148 return count |
151 return count |
149 _num_entries = property(_get_num_entries) |
152 _num_entries = property(_get_num_entries) |
150 |
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