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488539f636
Back-ports from Blockly Games: * db is old and busted, ndb is the new hotness (there’s no known difference, just pointless API churn). * Use SHA1 which is consistent, rather than Python’s hash() which has started changing between executions. This stops duplicate programs from being stored. * Restructure so that storage.py can be used as a library, with xmlToKey and keyToXml being callable by external programs. * Use print function compatible with Python 3.
88 lines
2.6 KiB
Python
88 lines
2.6 KiB
Python
"""Blockly Demo: Storage
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Copyright 2012 Google Inc.
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https://developers.google.com/blockly/
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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"""
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"""Store and retrieve XML with App Engine.
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"""
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__author__ = "q.neutron@gmail.com (Quynh Neutron)"
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import cgi
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import hashlib
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from random import randint
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from google.appengine.api import memcache
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from google.appengine.ext import ndb
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def keyGen():
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# Generate a random string of length KEY_LEN.
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KEY_LEN = 6
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CHARS = "abcdefghijkmnopqrstuvwxyz23456789" # Exclude l, 0, 1.
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max_index = len(CHARS) - 1
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return "".join([CHARS[randint(0, max_index)] for x in range(KEY_LEN)])
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class Xml(ndb.Model):
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# A row in the database.
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xml_hash = ndb.IntegerProperty()
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xml_content = ndb.TextProperty()
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def xmlToKey(xml_content):
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# Store XML and return a generated key.
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xml_hash = long(hashlib.sha1(xml_content).hexdigest(), 16)
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xml_hash = int(xml_hash % (2 ** 64) - (2 ** 63))
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lookup_query = Xml.query(Xml.xml_hash == xml_hash)
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lookup_result = lookup_query.get()
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if lookup_result:
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xml_key = lookup_result.key.string_id()
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else:
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trials = 0
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result = True
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while result:
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trials += 1
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if trials == 100:
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raise Exception("Sorry, the generator failed to get a key for you.")
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xml_key = keyGen()
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result = Xml.get_by_id(xml_key)
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row = Xml(id = xml_key, xml_hash = xml_hash, xml_content = xml_content)
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row.put()
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return xml_key
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def keyToXml(key_provided):
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# Retrieve stored XML based on the provided key.
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# Normalize the string.
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key_provided = key_provided.lower().strip()
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# Check memcache for a quick match.
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xml = memcache.get("XML_" + key_provided)
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if xml is None:
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# Check datastore for a definitive match.
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result = Xml.get_by_id(key_provided)
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if not result:
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xml = ""
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else:
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xml = result.xml_content
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# Save to memcache for next hit.
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memcache.add("XML_" + key_provided, xml, 3600)
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return xml.encode("utf-8")
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if __name__ == "__main__":
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print("Content-Type: text/plain\n")
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forms = cgi.FieldStorage()
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if "xml" in forms:
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print(xmlToKey(forms["xml"].value))
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if "key" in forms:
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print(keyToXml(forms["key"].value))
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