Allows parse_dotenv(stream=StringIO()) (theskumar#78)

alanjds · theskumar · commit 84d16c4edbf3 · 2018-03-03T12:49:48.000+05:30
* allows `parse_dotenv(stream=StringIO())

* Test: parse_dotenv accepting a filelike stream

* Docs on parse_dotenv(stream=...)

* Oops. Forgot to commit the import

* Py3 / Py2 compatibility

* Docs compat on Py2/Py3
diff --git a/README.rst b/README.rst
@@ -111,6 +111,34 @@ Django
 If you are using django you should add the above loader script at the
 top of ``wsgi.py`` and ``manage.py``.
 
+
+In-memory filelikes
+-------------------
+
+Is possible to not rely on the filesystem to parse filelikes from other sources
+(e.g. from a network storage). ``parse_dotenv`` accepts a filelike `stream`.
+Just be sure to rewind it before passing.
+
+.. code:: python
+
+    from io import StringIO     # Python2: from StringIO import StringIO
+    from dotenv.main import parse_dotenv
+    filelike = StringIO('SPAM=EGSS\n')
+    filelike.seek(0)
+    parsed = parse_dotenv(stream=filelike)
+
+The returned lazy generator yields ``(key,value)`` tuples.
+To ease the consumption, is suggested to unpack it into a dictionary.
+
+.. code:: python
+
+    os_env_like = dict(iter(parsed))
+    assert os_env_like['SPAM'] == 'EGGS'
+
+This could be useful if you need to *consume* the envfile but not *apply*  it
+directly into the system environment.
+
+
 Installation
 ============
 
diff --git a/dotenv/main.py b/dotenv/main.py
@@ -95,24 +95,31 @@ def dotenv_values(dotenv_path):
     return values
 
 
-def parse_dotenv(dotenv_path):
-    with open(dotenv_path) as f:
-        for line in f:
-            line = line.strip()
-            if not line or line.startswith('#') or '=' not in line:
-                continue
-            k, v = line.split('=', 1)
+def parse_dotenv(dotenv_path=None, stream=None):
+    if dotenv_path:
+        f = open(dotenv_path)
+    elif stream:
+        f = stream
 
-            # Remove any leading and trailing spaces in key, value
-            k, v = k.strip(), v.strip().encode('unicode-escape').decode('ascii')
+    for line in f:
+        line = line.strip()
+        if not line or line.startswith('#') or '=' not in line:
+            continue
+        k, v = line.split('=', 1)
 
-            if len(v) > 0:
-                quoted = v[0] == v[-1] in ['"', "'"]
+        # Remove any leading and trailing spaces in key, value
+        k, v = k.strip(), v.strip().encode('unicode-escape').decode('ascii')
 
-                if quoted:
-                    v = decode_escaped(v[1:-1])
+        if len(v) > 0:
+            quoted = v[0] == v[-1] in ['"', "'"]
 
-            yield k, v
+            if quoted:
+                v = decode_escaped(v[1:-1])
+
+        yield k, v
+
+    if dotenv_path:
+        f.close()
 
 
 def resolve_nested_variables(values):
diff --git a/tests/test_core.py b/tests/test_core.py
@@ -4,8 +4,13 @@
 import tempfile
 import warnings
 import sh
+try:
+    from StringIO import StringIO
+except ImportError:
+    from io import StringIO
 
 from dotenv import load_dotenv, find_dotenv, set_key
+from dotenv.main import parse_dotenv
 from IPython.terminal.embed import InteractiveShellEmbed
 
 
@@ -110,3 +115,12 @@ def test_ipython_override():
     ipshell.magic("load_ext dotenv")
     ipshell.magic("dotenv -o")
     assert os.environ["MYNEWVALUE"] == 'q1w2e3'
+
+
+def test_parse_dotenv_stream():
+    stream = StringIO('DOTENV=WORKS\n')
+    stream.seek(0)
+    parsed_generator = parse_dotenv(stream=stream)
+    parsed_dict = dict(iter(parsed_generator))
+    assert 'DOTENV' in parsed_dict
+    assert parsed_dict['DOTENV'] == 'WORKS'
