From cf8f3dc4d2cde04a1f822627db522c1b021c3359 Mon Sep 17 00:00:00 2001
From: mattack108 <matt.lenc@gmail.com>
Date: Sun, 14 Jul 2013 21:50:52 +0100
Subject: [PATCH 1/4] Allow to use `url` defined as env variable.

---
 dataset/__init__.py | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/dataset/__init__.py b/dataset/__init__.py
index b28eb49..0585378 100644
--- a/dataset/__init__.py
+++ b/dataset/__init__.py
@@ -1,3 +1,4 @@
+import os
 # shut up useless SA warning:
 import warnings
 warnings.filterwarnings(
@@ -10,10 +11,11 @@ from dataset.freeze.app import freeze
 __all__ = ['Database', 'Table', 'freeze', 'connect']
 
 
-def connect(url, reflectMetadata=True):
+def connect(url=None, reflectMetadata=True):
     """
-    Opens a new connection to a database. *url* can be any valid `SQLAlchemy engine URL`_. Returns
-    an instance of :py:class:`Database <dataset.Database>`. Set *reflectMetadata* to False if you
+    Opens a new connection to a database. *url* can be any valid `SQLAlchemy engine URL`_.
+    If *url* is not defined it will try to use *DATABASE_URL* from environment variable.
+    Returns an instance of :py:class:`Database <dataset.Database>`. Set *reflectMetadata* to False if you
     don't want the entire database schema to be pre-loaded. This significantly speeds up
     connecting to large databases with lots of tables.
     ::
@@ -22,4 +24,5 @@ def connect(url, reflectMetadata=True):
 
     .. _SQLAlchemy Engine URL: http://docs.sqlalchemy.org/en/latest/core/engines.html#sqlalchemy.create_engine
     """
+    url = os.environ.get('DATABASE_URL', url)
     return Database(url, reflectMetadata)

From 57a7c58f63b44dca298ae8399a6ff7191eae131d Mon Sep 17 00:00:00 2001
From: mattack108 <matt.lenc@gmail.com>
Date: Sun, 14 Jul 2013 21:51:35 +0100
Subject: [PATCH 2/4] Test case when `url` comes as env variable.

---
 test/test_persistence.py | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/test/test_persistence.py b/test/test_persistence.py
index a29056c..4afa10c 100644
--- a/test/test_persistence.py
+++ b/test/test_persistence.py
@@ -1,3 +1,4 @@
+import os
 import unittest
 from datetime import datetime
 
@@ -9,11 +10,19 @@ from sample_data import TEST_DATA
 class DatabaseTestCase(unittest.TestCase):
 
     def setUp(self):
-        self.db = connect('sqlite:///:memory:')
+        os.environ['DATABASE_URL'] = 'sqlite:///:memory:'
+        self.db = connect()
         self.tbl = self.db['weather']
         for row in TEST_DATA:
             self.tbl.insert(row)
 
+    def tearDown(self):
+        # ensure env variable was unset
+        del os.environ['DATABASE_URL']
+
+    def test_valid_database_url(self):
+        assert self.db.url, os.environ['DATABASE_URL']
+
     def test_tables(self):
         assert self.db.tables == ['weather'], self.db.tables
 
@@ -35,7 +44,7 @@ class DatabaseTestCase(unittest.TestCase):
 class TableTestCase(unittest.TestCase):
 
     def setUp(self):
-        self.db = connect('sqlite:///:memory:')
+        self.db = connect(url='sqlite:///:memory:')
         self.tbl = self.db['weather']
         for row in TEST_DATA:
             self.tbl.insert(row)

From a9be8300aa2c311407c366a6ec261b84a828f28d Mon Sep 17 00:00:00 2001
From: mattack108 <matt.lenc@gmail.com>
Date: Sun, 14 Jul 2013 22:05:52 +0100
Subject: [PATCH 3/4] Update docs.

---
 docs/quickstart.rst | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/docs/quickstart.rst b/docs/quickstart.rst
index a2e65e1..715b626 100644
--- a/docs/quickstart.rst
+++ b/docs/quickstart.rst
@@ -23,6 +23,11 @@ To connect to a database you need to identify it by its `URL <http://docs.sqlalc
    # connecting to a PostgreSQL database
    db = dataset.connect('postgresql://scott:tiger@localhost:5432/mydatabase')
 
+It is also possible to define the `URL` as an environment variable called `DATABASE_URL`
+so you can initialize database connection without explicitly passing an `URL`::
+
+   db = dataset.connect()
+
 Depending on which database you're using, you may also have to install
 the database bindings to support that database. SQLite is included in
 the Python core, but PostgreSQL requires ``psycopg2`` to be installed. 

From 9c7cdf6723ea11d056465550b9cf0af3757c3ece Mon Sep 17 00:00:00 2001
From: mattack108 <matt.lenc@gmail.com>
Date: Sun, 14 Jul 2013 22:07:42 +0100
Subject: [PATCH 4/4] No needs for positional args.

---
 test/test_persistence.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/test_persistence.py b/test/test_persistence.py
index 4afa10c..893ceb3 100644
--- a/test/test_persistence.py
+++ b/test/test_persistence.py
@@ -44,7 +44,7 @@ class DatabaseTestCase(unittest.TestCase):
 class TableTestCase(unittest.TestCase):
 
     def setUp(self):
-        self.db = connect(url='sqlite:///:memory:')
+        self.db = connect('sqlite:///:memory:')
         self.tbl = self.db['weather']
         for row in TEST_DATA:
             self.tbl.insert(row)