From c2a0cb62e9f7bdab6b4725e8d23a52266afe02a9 Mon Sep 17 00:00:00 2001
From: Mark Huang <mlhuang@cs.princeton.edu>
Date: Fri, 27 Oct 2006 15:33:05 +0000
Subject: [PATCH] - interface to sessions table

---
 PLC/Sessions.py | 119 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 119 insertions(+)
 create mode 100644 PLC/Sessions.py

diff --git a/PLC/Sessions.py b/PLC/Sessions.py
new file mode 100644
index 0000000..b91ca12
--- /dev/null
+++ b/PLC/Sessions.py
@@ -0,0 +1,119 @@
+import random
+import base64
+import time
+
+from PLC.Faults import *
+from PLC.Parameter import Parameter
+from PLC.Table import Row, Table
+from PLC.Persons import Person, Persons
+from PLC.Nodes import Node, Nodes
+
+class Session(Row):
+    """
+    Representation of a row in the sessions table. To use, instantiate
+    with a dict of values.
+    """
+
+    table_name = 'sessions'
+    primary_key = 'session_id'
+    join_tables = ['person_session', 'node_session']
+    fields = {
+        'session_id': Parameter(str, "Session key"),
+        'person_id': Parameter(int, "Account identifier, if applicable"),
+        'node_id': Parameter(int, "Node identifier, if applicable"),
+        'expires': Parameter(int, "Date and time when session expires, in seconds since UNIX epoch"),
+        }
+
+    def validate_expires(self, expires):
+        if expires < time.time():
+            raise PLCInvalidArgument, "Expiration date must be in the future"
+
+        return time.strftime("%Y-%m-%d %H:%M:%S", time.gmtime(expires))
+
+    def add_person(self, person, commit = True):
+        """
+        Associate person with session.
+        """
+
+        assert 'session_id' in self
+        assert isinstance(person, Person)
+        assert 'person_id' in person
+
+        session_id = self['session_id']
+        person_id = person['person_id']
+
+        self.api.db.do("INSERT INTO person_session (session_id, person_id)" \
+                       " VALUES(%(session_id)s, %(person_id)d)",
+                       locals())
+
+        if commit:
+            self.api.db.commit()
+
+        self['person_id'] = person_id
+
+    def add_node(self, node, commit = True):
+        """
+        Associate node with session.
+        """
+
+        assert 'session_id' in self
+        assert isinstance(node, Node)
+        assert 'node_id' in node
+
+        session_id = self['session_id']
+        node_id = node['node_id']
+
+        # Nodes can have only one session at a time
+        self.api.db.do("DELETE FROM node_session WHERE node_id = %(node_id)d",
+                       locals())
+
+        self.api.db.do("INSERT INTO node_session (session_id, node_id)" \
+                       " VALUES(%(session_id)s, %(node_id)d)",
+                       locals())
+
+        if commit:
+            self.api.db.commit()
+
+        self['node_id'] = node_id
+
+    def sync(self, commit = True, insert = None):
+        if not self.has_key('session_id'):
+            # Before a new session is added, delete expired sessions
+            expired = Sessions(self.api, expires = -int(time.time())).values()
+            for session in expired:
+                session.delete(commit)
+
+            # Generate 32 random bytes
+            bytes = random.sample(xrange(0, 256), 32)
+            # Base64 encode their string representation
+            self['session_id'] = base64.b64encode("".join(map(chr, bytes)))
+            # Force insert
+            insert = True
+
+        Row.sync(self, commit, insert)
+
+class Sessions(Table):
+    """
+    Representation of row(s) from the session table in the database.
+    """
+
+    def __init__(self, api, session_ids = None, expires = int(time.time())):
+	self.api = api
+
+        sql = "SELECT %s FROM view_sessions WHERE True" % \
+              ", ".join(Session.fields)
+
+        if session_ids:
+            sql += " AND session_id IN (%s)" % ", ".join(api.db.quote(session_ids))
+
+        if expires is not None:
+            if expires >= 0:
+                sql += " AND expires > %(expires)d"
+            else:
+                expires = -expires
+                sql += " AND expires < %(expires)d"
+
+        rows = self.api.db.selectall(sql, locals())
+ 
+        for row in rows:
+            self[row['session_id']] = Session(api, row)
-- 
2.43.0