Split the development into daemon and wsgi_server.

Implemented basic infrastructure for daemon (Prolog), and partial support for services in wsgi_server.

1 files changed, 128 insertions, 0 deletions

diff --git a/wsgi_server.py b/wsgi_server.py
new file mode 100644
index 0000000..0f70b40
--- /dev/null
+++ b/wsgi_server.py
@@ -0,0 +1,128 @@
+#!/usr/bin/python3
+# coding=utf-8
+
+import falcon
+import json
+import client
+from errors.session import NoSuchSession, AuthenticationFailed
+
+MAX_REQUEST_LENGTH = 1024 * 1024  # 1 MB
+
+api = application = falcon.API()
+
+
+def get_json_payload(req, session_is_optional=False):
+    if not ((req.content_type == 'application/json') or (req.content_type == 'text/json')):
+        raise falcon.HTTPUnsupportedMediaType('Unsupported content-type: {0}'.format(req.content_type))
+    length = req.get_header('Content-Length')
+    if length is None:
+        raise falcon.HTTPLengthRequired('Requests without content-length are not accepted')
+    try:
+        l = int(length)
+    except:
+        raise falcon.HTTPBadRequest('Invalid Content-Length', 'The given Content-Length is not a number: {0}'.format(length))
+    if l > MAX_REQUEST_LENGTH:
+        raise falcon.HTTPError(falcon.HTTP_413, 'Request Entity Too Large', 'Cannot accept the request of length {0}: maximum allowed content-length is {1}'.format(length, MAX_REQUEST_LENGTH))
+    try:
+        txt = req.stream.read()
+    except Exception as e:
+        raise falcon.HTTPBadRequest('Error reading request', 'Error while reading the request body: {0}'.format(e.message))
+    try:
+        js = json.loads(txt, encoding="utf-8")
+    except ValueError as e:
+        raise falcon.HTTPBadRequest('Error parsing JSON payload', 'Error while parsing the request as JSON: {0}'.format(e.message))
+    sid = js.get('sid')
+    if sid is None:
+        if session_is_optional:
+            return js
+        raise falcon.HTTPBadRequest('No Session', 'Request is missing a session-ID')
+    del js['sid']
+    try:
+        session = client.get_session_by_id(sid)
+    except NoSuchSession:
+        if session_is_optional:
+            return js
+        raise falcon.HTTPBadRequest('Session Expired', 'This user session has expired. Please log-in again.')
+    req.context['session'] = session
+    return js
+
+
+class Login(object):
+    def on_post(self, req, resp):
+        resp.cache_control = 'private, no-cache, no-store'
+        js = get_json_payload(req, True)
+        username = js.get('username')
+        password = js.get('password')
+        if username is None:
+            response = {'code': 1, 'message': 'Username was not provided'}
+        elif password is None:
+            response = {'code': 2, 'message': 'Password was not provided'}
+        else:
+            try:
+                session = client.authenticate_and_create_session(username, password)
+            except AuthenticationFailed:
+                response = {'code': 3, 'message': 'Username or password do not match'}
+            else:
+                response = {'code': 0, 'message': 'OK', 'sid':session.get_sid()}
+                old_session = req.context.get('session')
+                if old_session:
+                    old_session.destroy()
+        resp.body = json.dumps(response)
+        resp.content_type = 'application/json'
+        resp.status = falcon.HTTP_200
+
+class Activity(object):
+    def on_get(self, req, resp):
+        resp.body = '{}'
+        resp.status = falcon.HTTP_200
+
+class Query(object):
+    def on_post(self, req, resp):
+        resp.cache_control = 'private, no-cache, no-store'
+        js = get_json_payload(req)
+        session = req.context['session']
+        step = js.get('step')
+        if step is None:
+            response = {'code': 1, 'message': '"step" is not set'}
+        else:
+            prolog = session.get_prolog()
+            if step == 'run':
+                program = js.get('program')
+                query = js.get('query')
+                language = js.get('language')
+                problem_group = js.get('problem_group')
+                problem = js.get('problem')
+                if program is None:
+                    response = {'code': 2, 'message': 'No program specified'}
+                elif query is None:
+                    response = {'code': 3, 'message': 'No query specified'}
+                elif language is None:
+                    response = {'code': 4, 'message': 'Language identifier not given'}
+                elif problem_group is None:
+                    response = {'code': 5, 'message': 'Problem group identifier not given'}
+                elif problem is None:
+                    response = {'code': 6, 'message': 'Problem identifier not given'}
+                else:
+                    messages, status, have_more = prolog.run_for_user(session.get_uid(), language, problem_group, problem, program, query)
+                    response = {'code': 0, 'message': 'ok', 'terminal': {'messages': messages, 'status': status, 'have_more': have_more}}
+            elif step == 'next':
+                messages, status, have_more = prolog.step()
+                response = {'code': 0, 'message': 'ok', 'terminal': {'messages': messages, 'status': status, 'have_more': have_more}}
+            elif step == 'end':
+                messages, status, have_more = prolog.end()
+                response = {'code': 0, 'message': 'ok', 'terminal': {'messages': messages, 'status': status, 'have_more': have_more}}
+            else:
+                response = {'code': 7, 'message': 'Unknown prolog step: {0}'.format(step)}
+
+        resp.body = json.dumps(response)
+        resp.content_type = 'application/json'
+        resp.status = falcon.HTTP_200
+
+login = Login()
+api.add_route('/login', login)
+
+activity = Activity()
+api.add_route('/activity', activity)
+
+query = Query()
+api.add_route('/query', query)