Migration from SQLite to PostgreSQL for compatibility with Heroku

requirements.txt

@@ -1,2 +1,3 @@
 flask
 mock
+psycopg2

smash/__init__.py

@@ -1,6 +1,6 @@
 import os
 from flask import Flask
-from . import config, database, log, models
+from . import config, database_postgresql, log, models
 
 
 log.configure_logging()
@@ -36,7 +36,7 @@ if 'SECRETKEY' in conf.config:
 else:
     exit("Secret key not set.")
 
-db = database.Database(conf.config["DBNAME"])
+db = database_postgresql.PostgreSQL(conf.config["DBNAME"])
 models.init_models(db)
 
 

smash/database_postgresql.py

@@ -0,0 +1,66 @@
+import os
+import psycopg2
+import urlparse
+
+class DatabasePostgreSQL(object):
+    """Interface to the heroku PostgreSQL database plugin.
+    """
+    def __init__(self):
+        urlparse.uses_netloc.append("postgres")
+        self.url = urlparse.urlparse(os.environ["DATABASE_URL"])
+
+
+    @property
+    def conn(self):
+        return psycopg2.connect(
+            database=self.url.path[1:],
+            user=self.url.username,
+            password=self.url.password,
+            host=self.url.hostname,
+            port=self.url.port
+        )
+
+
+    @property
+    def cursor(self):
+        return self.conn.cursor()
+
+
+    def select(self, table, fields, condition=None):
+        cur = self.cursor
+
+        if condition is not None:
+            cur.execute("SELECT {} FROM {} WHERE {}".format(fields, table,
+                                                                    condition))
+        else:
+            cur.execute("SELECT {} FROM {}".format(fields, table))
+
+        return cur.fetchall()
+
+
+    def create_table(self, table, cols):
+        conn = self.conn
+        cur = conn.cursor()
+
+        query = "CREATE TABLE {}({})".format(table, cols)
+        cur.execute(query)
+        conn.commit()
+
+
+    def insert(self, table, columns, values, params):
+        conn = self.conn
+        cur = conn.cursor()
+
+        query = "INSERT INTO {}({}) VALUES ({})".format(table, columns, values)
+        cur.execute(query, params)
+        conn.commit()
+        return cur
+
+
+    def delete(self, table, condition):
+        conn = self.conn
+        cur = conn.cursor()
+
+        query = "DELETE FROM {} WHERE {}".format(table, condition)
+        cur.execute(query)
+        conn.commit()

smash/models.py

@@ -1,5 +1,3 @@
-import sqlite3
-
 class Model(object):
     #Name of the table to be created
     tablename = "abstractmodel"

smash/views.py

@@ -1,6 +1,6 @@
 import datetime
 import logging
-import sqlite3
+import psycopg2
 from flask import render_template, Markup, request, abort, session
 
 from smash import app, conf, db
@@ -155,7 +155,7 @@ def add_new():
                         (tag,)
                     )
                     tid = cur.lastrowid
-                except sqlite3.IntegrityError:
+                except psycopg2.IntegrityError:
                     logger.warning("Tag {} already exists".format(tag))
 
                 if tid != -1:
@@ -166,7 +166,7 @@ def add_new():
                             "?, ?",
                             (tid, qid)
                         )
-                    except sqlite3.Error:
+                    except psycopg2.Error:
                         logger.warning("Database error while inserting into tagsToQuotes")
                         return render_template(
                             "message.html",