Added .env support

.gitignore

@@ -1,4 +1,5 @@
 .DS_Store
+.env
 *.pyc
 *.pyo
 env

CHANGES

@@ -11,6 +11,9 @@ Major release, unreleased
 - Make `app.run()` into a noop if a Flask application is run from the
   development server on the command line.  This avoids some behavior that
   was confusing to debug for newcomers.
+- The `flask` command line tool now loads a `.env` file when it discovers
+  one.  When it finds one it will change into that folder before starting
+  and load environment variables from it.
 
 Version 0.12.1
 --------------

docs/cli.rst

@@ -28,7 +28,10 @@ register more commands there if they desire so.
 For the :command:`flask` script to work, an application needs to be
 discovered.  This is achieved by exporting the ``FLASK_APP`` environment
 variable.  It can be either set to an import path or to a filename of a
-Python module that contains a Flask application.
+Python module that contains a Flask application.  Additionally the
+:command:`flask` command as of 0.13 will look for a ``.env`` file in the
+current folder or any higher folder and automatically load all environment
+variables from it.
 
 In that imported file the name of the app needs to be called ``app`` or
 optionally be specified after a colon.  For instance
@@ -48,6 +51,12 @@ Or with a filename::
     export FLASK_APP=/path/to/hello.py
     flask run
 
+If you use Flask 0.13 or later you can also set the environment variables
+in a ``.env`` file.  For instance like this::
+
+    FLASK_APP=/path/to/hello.py
+    FLASK_DEBUG=1
+
 Virtualenv Integration
 ----------------------
 

flask/app.py

@@ -826,7 +826,8 @@ def run(self, host=None, port=None, debug=None, **options):
         """
         # Change this into a no-op if the server is invoked from the
         # command line.  Have a look at cli.py for more information.
-        if os.environ.get('FLASK_RUN_FROM_CLI_SERVER') == '1':
+        # After the first call we unset the variable however.
+        if os.environ.pop('FLASK_RUN_FROM_CLI', None) == '1':
             from .debughelpers import explain_ignored_app_run
             explain_ignored_app_run()
             return

flask/cli.py

@@ -16,7 +16,7 @@
 
 import click
 
-from ._compat import iteritems, reraise
+from ._compat import iteritems, reraise, text_type, PY2
 from .helpers import get_debug_flag
 from . import __version__
 
@@ -120,6 +120,57 @@ def find_default_import_path():
     return app
 
 
+def find_dotenv():
+    here = os.getcwd()
+    while 1:
+        path = os.path.join(here, '.env')
+        if os.path.isfile(path):
+            return path
+        there = os.path.dirname(here)
+        if there == here:
+            break
+        here = there
+
+
+def _set_env(key, value):
+    if PY2:
+        if isinstance(value, text_type):
+            value = value.encode('utf-8')
+    else:
+        key = key.decode('utf-8', 'surrogateescape')
+        if isinstance(value, bytes):
+            value = value.decode('utf-8', 'surrogateescape')
+    os.environ[key] = value
+
+
+def _unquote(s):
+    if len(s) >= 2 and s[0] == s[-1] and s[0] in '"\'':
+        return s[1:-1] \
+            .decode('utf-8', 'replace') \
+            .encode('utf-8', 'unicode-escape') \
+            .decode('unicode-escape')
+    return s
+
+
+def load_dotenv():
+    """Loads a dotenv file for flask."""
+    path = find_dotenv()
+    if path is None:
+        return
+    os.chdir(os.path.dirname(path))
+    with open(path, 'rb') as f:
+        for line in f:
+            line = line.strip()
+            if not line or line[:1] == b'#' or b'=' not in line:
+                continue
+            key, value = line.split(b'=', 1)
+            value = _unquote(value.strip())
+            _set_env(key.strip(), value)
+
+
+_load_dotenv = load_dotenv
+
+
 def get_version(ctx, param, value):
     if not value or ctx.resilient_parsing:
         return
@@ -199,7 +250,17 @@ class ScriptInfo(object):
     onwards as click object.
     """
 
-    def __init__(self, app_import_path=None, create_app=None):
+    def __init__(self, app_import_path=None, create_app=None,
+                 load_dotenv=True):
+        # Set a global flag that indicates that we were invoked from the
+        # command line interface.  This is detected by Flask.run to make
+        # the call into a no-op.  This is necessary to avoid ugly errors
+        # when the script that is loaded here also attempts to start a
+        # server.
+        os.environ['FLASK_RUN_FROM_CLI'] = '1'
+
+        if load_dotenv:
+            _load_dotenv()
         if create_app is None:
             if app_import_path is None:
                 app_import_path = find_default_import_path()
@@ -412,13 +473,6 @@ def run_command(info, host, port, reload, debugger, eager_loading,
     """
     from werkzeug.serving import run_simple
 
-    # Set a global flag that indicates that we were invoked from the
-    # command line interface provided server command.  This is detected
-    # by Flask.run to make the call into a no-op.  This is necessary to
-    # avoid ugly errors when the script that is loaded here also attempts
-    # to start a server.
-    os.environ['FLASK_RUN_FROM_CLI_SERVER'] = '1'
-
     debug = get_debug_flag()
     if reload is None:
         reload = bool(debug)