add a class providing access methods to a projectb database

This class provides an alternative to daklib/database.py for accessing a
projectb database.  This benefits to this alternative are that it uses the
psycopg2 module instead of the pg module, and I object oriented.  My
motivation for creating this class is to keep the new code for generating
Contents.gz files free from the pg module, and therefore, the only functions
I've moved into this class so far are those needed for generating the
Contents.gz files.

Signed-off-by: Mike O'Connor <stew@vireo.org>

diff --git a/daklib/projectb.py b/daklib/projectb.py
new file mode 100644 (file)
index 0000000..8222ab1
--- /dev/null
+++ b/daklib/projectb.py
@@ -0,0 +1,129 @@
+#!/usr/bin/python
+
+"""
+Class providing access to a projectb database
+
+This class provides convenience functions for common queries to a
+projectb database using psycopg2.
+
+Copyright (C) 2009  Mike O'Connor <stew@vireo.org>
+"""
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+################################################################################
+
+import psycopg2
+
+################################################################################
+
+class Projectb(object):
+    """
+    Object providing methods for accessing the projectb database
+    """
+    def __init__(self,Cnf):
+        connect_str = "dbname=%s"% (Cnf["DB::Name"])
+        if Cnf["DB::Host"] != '': connect_str += " host=%s" % (Cnf["DB::Host"])
+        if Cnf["DB::Port"] != '-1': connect_str += " port=%d" % (int(Cnf["DB::Port"]))
+
+        self.dbh = psycopg2.connect(connect_str)
+        self.suite_id_cache = {}
+        self.architecture_id_cache = {}
+        self.section_id_cache = {}
+
+    def get_suite_id(self, suite_name):
+        """
+        return the id for the given suite_name
+
+        @param suite_name: name of a suite such as "unsatble" or "testing"
+
+        @rtype: int
+        @return: id of given suite or None if suite_name not matched
+
+        >>> Cnf = {'DB::Name' : "projectb","DB::Host":"","DB::Port":'-1' }
+        >>> pb = Projectb( Cnf )
+        >>> pb.get_suite_id("unstable")
+        5
+        >>> pb.get_suite_id("n'existe pas")
+        """
+        if not self.suite_id_cache.has_key(suite_name):
+            c = self.dbh.cursor()
+            c.execute("SELECT id FROM suite WHERE suite_name=%(suite_name)s",
+                      {'suite_name':suite_name})
+            r = c.fetchone()
+            if r:
+                self.suite_id_cache[suite_name] = r[0]
+            else:
+                self.suite_id_cache[suite_name] = None
+
+        return self.suite_id_cache[suite_name]
+
+    def get_architecture_id(self, architecture_name):
+        """
+        return the id for the given architecture_name
+
+        @param architecture_name: name of a architecture such as "i386" or "source"
+
+        @rtype: int
+        @return: id of given architecture or None if architecture_name not matched
+
+        >>> Cnf = {'DB::Name' : "projectb","DB::Host":"","DB::Port":'-1' }
+        >>> pb = Projectb( Cnf )
+        >>> pb.get_architecture_id("i386")
+        7
+        >>> pb.get_architecture_id("n'existe pas")
+        """
+        if not self.architecture_id_cache.has_key(architecture_name):
+            c = self.dbh.cursor()
+            c.execute("SELECT id FROM architecture WHERE arch_string=%(architecture_name)s",
+                      {'architecture_name':architecture_name})
+            r = c.fetchone()
+            if r:
+                self.architecture_id_cache[architecture_name] = r[0]
+            else:
+                self.architecture_id_cache[architecture_name] = None
+
+        return self.architecture_id_cache[architecture_name]
+
+    def get_section_id(self, section_name):
+        """
+        return the id for the given section_name
+
+        @param section_name: name of a section such as "x11" or "non-free/libs"
+
+        @rtype: int
+        @return: id of given section or None if section_name not matched
+
+        >>> Cnf = {'DB::Name' : "projectb","DB::Host":"","DB::Port":'-1' }
+        >>> pb = Projectb( Cnf )
+        >>> pb.get_section_id("non-free/libs")
+        285
+        >>> pb.get_section_id("n'existe pas")
+        """
+        if not self.section_id_cache.has_key(section_name):
+            c = self.dbh.cursor()
+            c.execute("SELECT id FROM section WHERE section=%(section_name)s",
+                      {'section_name':section_name})
+            r = c.fetchone()
+            if r:
+                self.section_id_cache[section_name] = r[0]
+            else:
+                self.section_id_cache[section_name] = None
+
+        return self.section_id_cache[section_name]
+
+if __name__ == "__main__":
+    import doctest
+    doctest.testmod()