Allowing web-openccg to be run in a subdirectory.

This is achieved by mounting it at the directory specified using the
environment variable APPLICATION_ROOT.

app/ccgapp.py

 import json
+import os
 import uuid
 
-from flask import Flask, render_template, request
+from flask import Flask, render_template, request, redirect
+from werkzeug.wsgi import DispatcherMiddleware
 
 import wccg
+import graphs
 
-app = Flask(__name__)
+
+def create_redirecting_app(to):
+    """Creates a dummy flask app which redirects to 'to' for the root url."""
+    app = Flask('redirector')
+
+    @app.route('/')
+    def index():
+        return redirect(to, code=301)
+
+    return app
+
+
+def create_app():
+    """Initializes the Flask app.
+
+    Reads the environment variable APPLICATION_ROOT and creates a
+    DispatcherMiddleware if it is set to something different than /.
+    This allows to mount the app in a subdirectory.
+    """
+    app = Flask(__name__)
+    app.config['APPLICATION_ROOT'] = os.environ.get('APPLICATION_ROOT', '/')
+
+    if app.config['APPLICATION_ROOT'] != '/':
+        if app.config['APPLICATION_ROOT'].endswith('/'):
+            app.config['APPLICATION_ROOT'] = app.config['APPLICATION_ROOT'][:-1]
+
+        redirector = create_redirecting_app(app.config['APPLICATION_ROOT'])
+        mounts = {
+            app.config['APPLICATION_ROOT']: app.wsgi_app
+        }
+        app.wsgi_app = DispatcherMiddleware(redirector, mounts)
+
+    app.logger.info('APPLICATION_ROOT=%s', app.config['APPLICATION_ROOT'])
+
+    return app
+
+
+app = create_app()
 
 
 def create_response(sentence):
@@ -22,11 +62,12 @@ def create_response(sentence):
     content = wccg.parse(sentence)
 
     response = {
-        'version': '2.1.0',
+        'version': '2.2.0',
         'application': 'web-openccg',
         'uuid': str(uuid.uuid4())
     }
     response.update(content)
+    response.update(graphs.create_graphs(response['json_parses']))
 
     return response