Use base64-like (dashes in place of slashes) paste-ids with (configurable) 8-char length limit

zerobin/default_settings.py

@@ -70,3 +70,8 @@ MENU = (
 # limit size of pasted text in bytes. Be careful allowing too much size can
 # slow down user's browser
 MAX_SIZE = 1024 * 500
+
+# length of base64-like paste-id string in the url, int from 4 to 27 (length of sha1 digest)
+# total number of unique pastes can be calculated as 2^(6*PASTE_ID_LENGTH)
+# for PASTE_ID_LENGTH=8, for example, it's 2^(6*8) = 281 474 976 710 656
+PASTE_ID_LENGTH = 8

zerobin/paste.py

@@ -24,8 +24,8 @@ class Paste(object):
     }
 
 
-    def __init__(self, uuid=None, content=None,
-                 expiration=None):
+    def __init__(self, uuid=None, uuid_length=None,
+                 content=None, expiration=None):
 
         self.content = content
         self.expiration = expiration
@@ -35,7 +35,11 @@ class Paste(object):
 
         self.expiration = self.get_expiration(expiration)
 
-        self.uuid = uuid or hashlib.sha1(self.content).hexdigest()
+        if not uuid:
+            uuid = hashlib.sha1(self.content)\
+                .digest().encode('base64').rstrip('=\n').replace('/', '-')
+            if uuid_length: uuid = uuid[:uuid_length]
+        self.uuid = uuid
 
 
     def get_expiration(self, expiration):
@@ -260,4 +264,3 @@ class Paste(object):
             Delete the paste file.
         """
         os.remove(self.path)
-

zerobin/routes.py

@@ -15,7 +15,7 @@ from datetime import datetime, timedelta
 
 # add project dir and libs dir to the PYTHON PATH to ensure they are
 # importable
-from utils import settings
+from utils import settings, SettingsValidationError
 
 import bottle
 from bottle import (Bottle, run, static_file, view, request)
@@ -70,7 +70,8 @@ def create_paste():
         # system.  need to be improved
         if len(content) < settings.MAX_SIZE:
             expiration = body.get('expiration', [u'burn_after_reading'])[0]
-            paste = Paste(expiration=expiration, content=content)
+            paste = Paste(expiration=expiration, content=content,
+                          uuid_length=settings.PASTE_ID_LENGTH)
             paste.save()
 
             # display counter
@@ -141,7 +142,8 @@ def server_static(filename):
     return static_file(filename, root=settings.STATIC_FILES_ROOT)
 
 
-def get_app(debug=None, settings_file='', compressed_static=None):
+def get_app(debug=None, settings_file='',
+            compressed_static=None, settings=settings):
     """
         Return a tuple (settings, app) configured using passed
         parameters and/or a setting file.
@@ -149,6 +151,9 @@ def get_app(debug=None, settings_file='', compressed_static=None):
     if settings_file:
         settings.update_with_file(os.path.abspath(settings_file))
 
+    if settings.PASTE_ID_LENGTH < 4:
+        raise SettingsValidationError('PASTE_ID_LENGTH cannot be lower than 4')
+
     if compressed_static is not None:
         settings.COMPRESSED_STATIC_FILES = compressed_static
 
@@ -167,9 +172,8 @@ def get_app(debug=None, settings_file='', compressed_static=None):
 
 @clize.clize(coerce={'debug': bool, 'compressed_static': bool})
 def runserver(host='', port='', debug=None, user='', group='',
-              settings_file='', compressed_static=None, version=False):
-
-    settings, app = get_app(debug, settings_file, compressed_static)
+              settings_file='', compressed_static=None,
+              version=False, paste_id_length=None):
 
     if version:
         print '0bin V%s' % settings.VERSION
@@ -179,6 +183,13 @@ def runserver(host='', port='', debug=None, user='', group='',
     settings.PORT = port or settings.PORT
     settings.USER = user or settings.USER
     settings.GROUP = group or settings.GROUP
+    settings.PASTE_ID_LENGTH = paste_id_length or settings.PASTE_ID_LENGTH
+
+    try:
+        _, app = get_app(debug, settings_file, compressed_static, settings=settings)
+    except SettingsValidationError as err:
+        print >>sys.stderr, 'Configuration error: %s' % err.message
+        sys.exit(1)
 
     thread.start_new_thread(drop_privileges, (settings.USER, settings.GROUP))
 

zerobin/utils.py

@@ -53,6 +53,9 @@ def dmerge(*args):
     return dictionary
 
 
+class SettingsValidationError(Exception): pass
+
+
 class SettingsContainer(object):
     """
         Singleton containing the settings for the whole app