doc: Rework the tutorial (#1009)

Rework the tutorial to be more consistent, and to better explain
certain principles that drive Falcon's design.

Along the way, polish a few other areas of the docs where someone
might land during or immediate after walking through the tutorial.

.travis.yml

@@ -16,6 +16,8 @@ matrix:
         #   env: TOXENV=pypy3
         - python: 2.7
           env: TOXENV=pep8
+        - python: 2.7
+          env: TOXENV=pep8-examples
         - python: 2.6
           env: TOXENV=py26
         - python: 2.7

docs/_templates/sidebar-top.html

@@ -11,7 +11,7 @@ $(document).ready(function() {
 
 <div id="logo">
     <div id="logo-text"><a href="{{ pathto(master_doc) }}">Falcon</a></div>
-    <a href="{{ pathto(master_doc) }}"><img src="{{ pathto('_static/img/logo.png', 1) }}" width="163" height="211" alt="Falcon Web Framework Logo"/></a>
+    <a href="{{ pathto(master_doc) }}"><img src="{{ pathto('_static/img/logo.jpg', 1) }}" width="163" height="211" alt="Falcon Web Framework Logo"/></a>
 </div>
 
 <div id="gh-buttons">

docs/api/errors.rst

@@ -23,8 +23,7 @@ overriding the default serializer via
     "+xml" suffix, the default serializer will convert the error to JSON
     or XML, respectively.
 
-Error classes are available directly from the `falcon` package
-namespace::
+All classes are available directly in the ``falcon`` package namespace::
 
     import falcon
 
@@ -58,6 +57,8 @@ Mixins
 .. autoclass:: falcon.http_error.NoRepresentation
     :members:
 
+.. _predefined_errors:
+
 Predefined Errors
 -----------------
 

docs/conf.py

@@ -156,9 +156,9 @@ html_theme_options = {
     'fixed_sidebar': False,
     'show_powered_by': False,
     'extra_nav_links': OrderedDict([
-      ('Falcon Home', 'http://falconframework.org/'),
+      ('Falcon Home', 'https://falconframework.org/'),
       ('Falcon Wiki', 'https://github.com/falconry/falcon/wiki'),
-      ('Get Help', 'community/help.html'),
+      ('Get Help', '/community/help.html'),
     ]),
 }
 

examples/look/look/app.py

@@ -1,17 +1,18 @@
 import os
 
 import falcon
-from .images import ImageSaver, Resource
+
+from .images import ImageStore, Resource
 
 
-def create_app(image_saver):
-    image_resource = Resource(image_saver)
+def create_app(image_store):
+    image_resource = Resource(image_store)
     api = falcon.API()
     api.add_route('/images', image_resource)
     return api
 
 
 def get_app():
-    storage_path = os.environ.get('LOOK_STORAGE', '.')
-    image_saver = ImageSaver(storage_path)
-    return create_app(image_saver)
+    storage_path = os.environ.get('LOOK_STORAGE_PATH', '.')
+    image_store = ImageStore(storage_path)
+    return create_app(image_store)

examples/look/look/images.py

@@ -1,43 +1,58 @@
+import io
 import mimetypes
 import os
 import uuid
 
-import msgpack
-
 import falcon
+import msgpack
 
 
 class Resource(object):
 
-    def __init__(self, image_saver):
-        self.image_saver = image_saver
+    def __init__(self, image_store):
+        self._image_store = image_store
 
     def on_get(self, req, resp):
-        resp.data = msgpack.packb({'message': 'Hello world!'})
+        doc = {
+            'images': [
+                {
+                    'href': '/images/1eaf6ef1-7f2d-4ecc-a8d5-6e8adba7cc0e.png'
+                }
+            ]
+        }
+
+        resp.data = msgpack.packb(doc, use_bin_type=True)
         resp.content_type = 'application/msgpack'
         resp.status = falcon.HTTP_200
 
     def on_post(self, req, resp):
-        filename = self.image_saver.save(req.stream, req.content_type)
+        name = self._image_store.save(req.stream, req.content_type)
         resp.status = falcon.HTTP_201
-        resp.location = '/images/' + filename
+        resp.location = '/images/' + name
 
 
-class ImageSaver:
+class ImageStore(object):
 
-    def __init__(self, storage_path):
-        self.storage_path = storage_path
+    _CHUNK_SIZE_BYTES = 4096
+
+    # Note the use of dependency injection for standard library
+    # methods. We'll use these later to avoid monkey-patching.
+    def __init__(self, storage_path, uuidgen=uuid.uuid4, fopen=io.open):
+        self._storage_path = storage_path
+        self._uuidgen = uuidgen
+        self._fopen = fopen
 
     def save(self, image_stream, image_content_type):
         ext = mimetypes.guess_extension(image_content_type)
-        filename = '{uuid}{ext}'.format(uuid=uuid.uuid4(), ext=ext)
-        image_path = os.path.join(self.storage_path, filename)
+        name = '{uuid}{ext}'.format(uuid=self._uuidgen(), ext=ext)
+        image_path = os.path.join(self._storage_path, name)
 
-        with open(image_path, 'wb') as image_file:
+        with self._fopen(image_path, 'wb') as image_file:
             while True:
-                chunk = image_stream.read(4096)
+                chunk = image_stream.read(self._CHUNK_SIZE_BYTES)
                 if not chunk:
                     break
 
                 image_file.write(chunk)
-        return filename
+
+        return name

examples/look/requirements.txt

@@ -1,6 +0,0 @@
-falcon==1.1.0rc1
-gunicorn==19.6.0
-msgpack-python==0.4.8
-python-mimeparse==1.6.0
-requests==2.11.1
-six==1.10.0

examples/look/requirements/look

@@ -0,0 +1,2 @@
+falcon>=1.1.0
+msgpack-python>=0.4.8

examples/look/requirements/test

@@ -0,0 +1,3 @@
+mock>=2.0.0
+pytest>=3.0.6
+requests>=2.13.0

examples/look/tests/requirements.txt

@@ -1,2 +0,0 @@
-py==1.4.31
-pytest==3.0.3

examples/look/tests/test_app.py

@@ -1,30 +1,35 @@
 import io
-from unittest.mock import call, MagicMock, mock_open
+
+import falcon
+from falcon import testing
+from mock import call, MagicMock, mock_open
+import msgpack
+
+import pytest
 
 import look.app
 import look.images
 
-import msgpack
-import pytest
-
-import falcon
-from falcon import testing
-import falcon.request_helpers
-
 
 @pytest.fixture
-def mock_saver():
+def mock_store():
     return MagicMock()
 
 
 @pytest.fixture
-def client(mock_saver):
-    api = look.app.create_app(mock_saver)
+def client(mock_store):
+    api = look.app.create_app(mock_store)
     return testing.TestClient(api)
 
 
-def test_get_message(client):
-    doc = {u'message': u'Hello world!'}
+def test_list_images(client):
+    doc = {
+        'images': [
+            {
+                'href': '/images/1eaf6ef1-7f2d-4ecc-a8d5-6e8adba7cc0e.png'
+            }
+        ]
+    }
 
     response = client.simulate_get('/images')
     result_doc = msgpack.unpackb(response.content, encoding='utf-8')
@@ -35,36 +40,48 @@ def test_get_message(client):
 
 # With clever composition of fixtures, we can observe what happens with
 # the mock injected into the image resource.
-def test_post_image(client, mock_saver):
+def test_post_image(client, mock_store):
     file_name = 'fake-image-name.xyz'
-    # we need to know what ImageSaver method will be used
-    mock_saver.save.return_value = file_name
+
+    # We need to know what ImageStore method will be used
+    mock_store.save.return_value = file_name
     image_content_type = 'image/xyz'
 
-    response = client.simulate_post('/images',
-                                    body=b'some-fake-bytes',
-                                    headers={'content-type': image_content_type})
+    response = client.simulate_post(
+        '/images',
+        body=b'some-fake-bytes',
+        headers={'content-type': image_content_type}
+    )
 
     assert response.status == falcon.HTTP_CREATED
     assert response.headers['location'] == '/images/{}'.format(file_name)
-    saver_call = mock_saver.save.call_args
-    # saver_call is a unittest.mock.call tuple.
-    # It's first element is a tuple of positional arguments supplied when calling the mock.
+    saver_call = mock_store.save.call_args
+
+    # saver_call is a unittest.mock.call tuple. It's first element is a
+    # tuple of positional arguments supplied when calling the mock.
     assert isinstance(saver_call[0][0], falcon.request_helpers.BoundedStream)
     assert saver_call[0][1] == image_content_type
 
 
 def test_saving_image(monkeypatch):
-    # this still has some mocks, but they are more localized
+    # This still has some mocks, but they are more localized and do not
+    # have to be monkey-patched into standard library modules (always a
+    # risky business).
     mock_file_open = mock_open()
-    monkeypatch.setattr('builtins.open', mock_file_open)
-    fake_uuid = 'blablabla'
-    monkeypatch.setattr('look.images.uuid.uuid4', lambda: fake_uuid)
+
+    fake_uuid = '123e4567-e89b-12d3-a456-426655440000'
+
+    def mock_uuidgen():
+        return fake_uuid
 
     fake_image_bytes = b'fake-image-bytes'
     fake_request_stream = io.BytesIO(fake_image_bytes)
     storage_path = 'fake-storage-path'
-    saver = look.images.ImageSaver(storage_path)
+    store = look.images.ImageStore(
+        storage_path,
+        uuidgen=mock_uuidgen,
+        fopen=mock_file_open
+    )
 
-    assert saver.save(fake_request_stream, 'image/png') == fake_uuid + '.png'
+    assert store.save(fake_request_stream, 'image/png') == fake_uuid + '.png'
     assert call().write(fake_image_bytes) in mock_file_open.mock_calls

examples/look/tests/test_integration.py

@@ -1,18 +1,26 @@
+import os
+
 import requests
 
 
 def test_posted_image_gets_saved():
+    file_save_prefix = '/tmp/'
     location_prefix = '/images/'
     fake_image_bytes = b'fake-image-bytes'
 
-    response = requests.post('http://localhost:8000/images',
-                             data=fake_image_bytes,
-                             headers={'content-type': 'image/png'})
+    response = requests.post(
+        'http://localhost:8000/images',
+        data=fake_image_bytes,
+        headers={'content-type': 'image/png'}
+    )
 
     assert response.status_code == 201
     location = response.headers['location']
     assert location.startswith(location_prefix)
-    filename = location.replace(location_prefix, '')
-    # assuming that the storage path is "/tmp"
-    with open('/tmp/' + filename, 'rb') as image_file:
+    image_name = location.replace(location_prefix, '')
+
+    file_path = file_save_prefix + image_name
+    with open(file_path, 'rb') as image_file:
         assert image_file.read() == fake_image_bytes
+
+    os.remove(file_path)

falcon/testing/__init__.py

@@ -12,15 +12,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-"""Testing utilities.
+"""Functional testing framework for Falcon apps and Falcon itself.
 
-This package contains various test classes and utility functions to
-support functional testing for both Falcon-based apps and the Falcon
-framework itself. Both unittest-style and pytest-style tests are
-supported::
+Falcon's testing module contains various test classes and utility
+functions to support functional testing for both Falcon-based apps and
+the Falcon framework itself.
+
+The testing framework supports both unittest and pytest::
 
     # -----------------------------------------------------------------
-    # unittest-style
+    # unittest
     # -----------------------------------------------------------------
 
     from falcon import testing
@@ -46,7 +47,7 @@ supported::
 
 
     # -----------------------------------------------------------------
-    # pytest-style
+    # pytest
     # -----------------------------------------------------------------
 
     from falcon import testing

tox.ini

@@ -66,7 +66,7 @@ basepython = python3.5
 deps = {[with-debug-tools]deps}
 
 # --------------------------------------------------------------------
-# Cython
+# ujson
 # --------------------------------------------------------------------
 
 [with-ujson]
@@ -146,13 +146,31 @@ basepython = python2.7
 
 commands = flake8 \
              --max-complexity=15 \
-             --exclude=./build,.venv,.tox,dist,docs,.eggs,./falcon/bench/nuts \
+             --exclude=./build,.venv,.tox,dist,docs,.eggs,examples,./falcon/bench/nuts \
              --ignore=F403 \
              --max-line-length=99 \
              --import-order-style=google \
              --application-import-names=falcon \
              []
 
+[testenv:pep8-examples]
+deps = flake8
+       flake8-quotes
+       flake8-import-order
+
+# NOTE(kgriffs): Run with py27 since some code branches assume the
+#   unicode type is defined, and pep8 complains in those cases when
+#   running under py3.
+basepython = python2.7
+
+commands = flake8 examples \
+             --max-complexity=12 \
+             --ignore=F403 \
+             --max-line-length=99 \
+             --import-order-style=google \
+             --application-import-names=look \
+             []
+
 # --------------------------------------------------------------------
 # For viewing environ dicts generated by various WSGI servers
 # --------------------------------------------------------------------