Split interface into frontend and rest modules (#34)

* factor helper functions into own class for better modularity

 When refactoring the main app into different flask blueprints I will have to have access to these methods from a central location. This static helper class will enable me to do this. The name is still quite stupid. I will have to think about it in more detail.

* refactor rest api into a flask blueprint

 This allows us to better separate logic from front-end in the future and easier extend the API and web front-end.

picasso/__init__.py

@@ -7,13 +7,15 @@
 from flask import Flask
 import os
 import sys
+from picasso.interfaces.rest import API
 
 if sys.version_info.major < 3 or (sys.version_info.major == 3 and
                                   sys.version_info.minor < 5):
     raise SystemError('Python 3.5+ required, found {}'.format(sys.version))
 
 app = Flask(__name__)
 app.config.from_object('picasso.config.Default')
+app.register_blueprint(API, url_prefix='/api')
 
 if os.getenv('PICASSO_SETTINGS'):
     app.config.from_envvar('PICASSO_SETTINGS')

picasso/interfaces/rest.py

@@ -0,0 +1,110 @@
+# -*- coding: utf-8 -*-
+"""Flask blueprint for accessing and manipulating image ressources
+
+This is used by the main flask application to provide a REST API.
+"""
+
+import os
+import shutil
+from PIL import Image
+from werkzeug.utils import secure_filename
+from flask import (
+    Blueprint,
+    current_app,
+    jsonify,
+    session,
+    request
+    )
+from picasso import __version__
+from picasso.utils import get_visualizations
+
+API = Blueprint('api', __name__)
+
+
+@API.route('/', methods=['GET'])
+def root():
+    """The root of the REST API
+
+    displays a hello world message.
+
+    """
+    return jsonify(message='Picasso {version}. '
+                   'See API documentation at: '
+                   'https://picasso.readthedocs.io/en/latest/api.html'
+                   .format(version=__version__),
+                   version=__version__)
+
+
+@API.route('/images', methods=['POST', 'GET'])
+def images():
+    """Upload images via REST interface
+
+    Check if file upload was successful and sanatize user input.
+
+    TODO: return file URL instead of filename
+
+    """
+    if request.method == 'POST':
+        file_upload = request.files['file']
+        if file_upload:
+            image = {}
+            image['filename'] = secure_filename(file_upload.filename)
+            full_path = os.path.join(session['img_input_dir'],
+                                     image['filename'])
+            file_upload.save(full_path)
+            image['uid'] = session['image_uid_counter']
+            session['image_uid_counter'] += 1
+            current_app.logger.debug('File %d is saved as %s',
+                                     image['uid'],
+                                     image['filename'])
+            session['image_list'].append(image)
+            return jsonify(ok="true", file=image['filename'], uid=image['uid'])
+        return jsonify(ok="false")
+    if request.method == 'GET':
+        return jsonify(images=session['image_list'])
+
+
+@API.route('/visualize', methods=['GET'])
+def visualize():
+    """Trigger a visualization via the REST API
+
+    Takes a single image and generates the visualization data, returning the
+    output exactly as given by the target visualization.
+
+    """
+
+    session['settings'] = {}
+    image_uid = request.args.get('image')
+    vis_name = request.args.get('visualizer')
+    vis = get_visualizations()[vis_name]
+    if hasattr(vis, 'settings'):
+        for key in vis.settings.keys():
+            if request.args.get(key) is not None:
+                session['settings'][key] = request.args.get(key)
+            else:
+                session['settings'][key] = vis.settings[key][0]
+    inputs = []
+    for image in session['image_list']:
+        if image['uid'] == int(image_uid):
+            full_path = os.path.join(session['img_input_dir'],
+                                     image['filename'])
+            entry = {}
+            entry['filename'] = image['filename']
+            entry['data'] = Image.open(full_path)
+            inputs.append(entry)
+    if 'settings' in session:
+        vis.update_settings(session['settings'])
+    output = vis.make_visualization(
+        inputs, output_dir=session['img_output_dir'])
+    return jsonify(output=output)
+
+
+@API.route('/reset', methods=['GET'])
+def reset():
+    """Delete the session and clear temporary directories
+
+    """
+    shutil.rmtree(session['img_input_dir'])
+    shutil.rmtree(session['img_output_dir'])
+    session.clear()
+    return jsonify(ok='true')

picasso/picasso.py

@@ -25,60 +25,28 @@
         Visualization classes available for rendering.
 
 """
-from importlib import import_module
-import inspect
 import io
 import os
 from operator import itemgetter
-import shutil
 from tempfile import mkdtemp
 import time
-from types import ModuleType
 
 from PIL import Image
 from flask import (
-    g,
     render_template,
     request,
     session,
-    send_from_directory,
-    jsonify
+    send_from_directory
 )
-from werkzeug.utils import secure_filename
 
-from picasso import __version__
 from picasso import app
 from picasso.models.base import load_model
 from picasso.visualizations import *
-from picasso.visualizations.base import BaseVisualization
-
-APP_TITLE = 'Picasso Visualizer'
-
-
-def _get_visualization_classes():
-    """Import visualizations classes dynamically
+from picasso.utils import (
+    get_app_state,
+    get_visualizations
+)
 
-    """
-    visualization_attr = vars(
-        import_module('picasso.visualizations'))
-    visualization_submodules = [
-        visualization_attr[x]
-        for x in visualization_attr
-        if isinstance(visualization_attr[x], ModuleType)]
-
-    visualization_classes = []
-    for submodule in visualization_submodules:
-        attrs = vars(submodule)
-        for attr_name in attrs:
-            attr = attrs[attr_name]
-            if (inspect.isclass(attr)
-                and issubclass(attr, BaseVisualization)
-                and attr is not BaseVisualization):
-                visualization_classes.append(attr)
-    return visualization_classes
-
-
-VISUALIZATION_CLASSES = _get_visualization_classes()
 
 # Use a bogus secret key for debugging ease. No client information is stored;
 # the secret key is only necessary for generating the session cookie.
@@ -117,144 +85,6 @@ def initialize_new_session():
         session['img_output_dir'] = mkdtemp()
 
 
-def get_model():
-    """Get the NN model that's being analyzed from the request context.  Put
-    the model in the request context if it is not yet there.
-
-    Returns:
-        instance of :class:`.models.model.Model` or derived
-        class
-    """
-    if not hasattr(g, 'model'):
-        g.model = model
-    return g.model
-
-
-def get_visualizations():
-    """Get the available visualizations from the request context.  Put the
-    visualizations in the request context if they are not yet there.
-
-    Returns:
-        :obj:`list` of instances of :class:`.BaseVisualization` or
-        derived class
-
-    """
-    if not hasattr(g, 'visualizations'):
-        g.visualizations = {}
-        for VisClass in VISUALIZATION_CLASSES:
-            vis = VisClass(get_model())
-            g.visualizations[vis.__class__.__name__] = vis
-
-    return g.visualizations
-
-
-def get_app_state():
-    """Get current status of application in context
-
-    Returns:
-        :obj:`dict` of application status
-
-    """
-    if not hasattr(g, 'app_state'):
-        model = get_model()
-        g.app_state = {
-            'app_title': APP_TITLE,
-            'model_name': type(model).__name__,
-            'latest_ckpt_name': model.latest_ckpt_name,
-            'latest_ckpt_time': model.latest_ckpt_time
-        }
-    return g.app_state
-
-
-@app.route('/api/', methods=['GET'])
-def api_root():
-    """The root of the REST API
-
-    displays a hello world message.
-
-    """
-    return jsonify(message='Picasso {version}. '
-                   'See API documentation at: '
-                   'https://picasso.readthedocs.io/en/latest/api.html'
-                   .format(version=__version__),
-                  version=__version__)
-
-
-@app.route('/api/images', methods=['POST', 'GET'])
-def api_images():
-    """Upload images via REST interface
-
-    Check if file upload was successful and sanatize user input.
-
-    TODO: return file URL instead of filename
-
-    """
-    if request.method == 'POST':
-        file_upload = request.files['file']
-        if file_upload:
-            image = {}
-            image['filename'] = secure_filename(file_upload.filename)
-            full_path = os.path.join(session['img_input_dir'],
-                                     image['filename'])
-            file_upload.save(full_path)
-            image['uid'] = session['image_uid_counter']
-            session['image_uid_counter'] += 1
-            app.logger.debug('File %d is saved as %s',
-                             image['uid'],
-                             image['filename'])
-            session['image_list'].append(image)
-            return jsonify(ok="true", file=image['filename'], uid=image['uid'])
-        return jsonify(ok="false")
-    if request.method == 'GET':
-        return jsonify(images=session['image_list'])
-
-
-@app.route('/api/visualize', methods=['GET'])
-def api_visualize():
-    """Trigger a visualization via the REST API
-
-    Takes a single image and generates the visualization data, returning the
-    output exactly as given by the target visualization.
-
-    """
-
-    session['settings'] = {}
-    image_uid = request.args.get('image')
-    vis_name = request.args.get('visualizer')
-    vis = get_visualizations()[vis_name]
-    if hasattr(vis, 'settings'):
-        for key in vis.settings.keys():
-            if request.args.get(key) is not None:
-                session['settings'][key] = request.args.get(key)
-            else:
-                session['settings'][key] = vis.settings[key][0]
-    inputs = []
-    for image in session['image_list']:
-        if image['uid'] == int(image_uid):
-            full_path = os.path.join(session['img_input_dir'],
-                                     image['filename'])
-            entry = {}
-            entry['filename'] = image['filename']
-            entry['data'] = Image.open(full_path)
-            inputs.append(entry)
-    if 'settings' in session:
-        vis.update_settings(session['settings'])
-    output = vis.make_visualization(inputs,
-                                    output_dir=session['img_output_dir'])
-    return jsonify(output=output)
-
-
-@app.route('/api/reset', methods=['GET'])
-def end_session():
-    """Delete the session and clear temporary directories
-
-    """
-    shutil.rmtree(session['img_input_dir'])
-    shutil.rmtree(session['img_output_dir'])
-    session.clear()
-    return jsonify(ok='true')
-
-
 @app.route('/', methods=['GET', 'POST'])
 def landing():
     """Landing page for the application