Implemented methods to fetch a list of available problems and the problem description.

JavaScript no longer parses pythonic problem descriptions, instead they are loaded by server and JSONized.

1 files changed, 86 insertions, 42 deletions

diff --git a/wsgi_server.py b/wsgi_server.py
index 0f70b40..9b3a51e 100644
--- a/wsgi_server.py
+++ b/wsgi_server.py
@@ -12,7 +12,15 @@ 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')):
+    content_type_parts = req.content_type.split(';')
+    content_type = content_type_parts[0].strip()
+    encoding = 'utf-8'
+    if len(content_type_parts) > 1:
+        for part in content_type_parts[1:]:
+            subparts = part.strip().split('=')
+            if (len(subparts) == 2) and subparts[0] == 'charset':
+                encoding = subparts[1]
+    if not ((content_type == 'application/json') or (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:
@@ -28,95 +36,121 @@ def get_json_payload(req, session_is_optional=False):
     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")
+        js = json.loads(txt.decode(encoding=encoding, errors='replace'))
     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
+            return js, None
         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
+            return js, None
         raise falcon.HTTPBadRequest('Session Expired', 'This user session has expired. Please log-in again.')
-    req.context['session'] = session
-    return js
+    return js, session
 
 
-class Login(object):
+class CodeqService(object):
+    """Base class for all CodeQ services.
+     It only support the POST method and JSON data.
+     Handles JSON decoding and encoding, and session retrieval which can be optional.
+    """
+    session_is_optional = False
+
     def on_post(self, req, resp):
+        js, session = get_json_payload(req, self.session_is_optional)
+        resp.body = json.dumps(self.process(js, session))
         resp.cache_control = 'private, no-cache, no-store'
-        js = get_json_payload(req, True)
+        resp.content_type = 'application/json'
+        resp.status = falcon.HTTP_200
+
+    def process(self, js, session):
+        raise falcon.HTTPNotFound()
+
+class ProblemList(CodeqService):
+    session_is_optional = True
+
+    def process(self, js, session):
+        language = js.get('language')
+        if language is None:
+            return {'code': 1, 'message': 'Language was not provided'}
+        else:
+            return {'code': 0, 'message': 'ok', 'problems': client.list_problems_in_groups(language)}
+
+class Login(CodeqService):
+    session_is_optional = True
+
+    def process(self, js, old_session):
         username = js.get('username')
         password = js.get('password')
         if username is None:
-            response = {'code': 1, 'message': 'Username was not provided'}
+            return {'code': 1, 'message': 'Username was not provided'}
         elif password is None:
-            response = {'code': 2, 'message': 'Password was not provided'}
+            return {'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'}
+                return {'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
+                return {'code': 0, 'message': 'OK', 'sid':session.get_sid()}
 
-class Activity(object):
+class Activity(CodeqService):
     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']
+class Query(CodeqService):
+    def process(self, js, session):
         step = js.get('step')
         if step is None:
-            response = {'code': 1, 'message': '"step" is not set'}
+            return {'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')
+                problem_id = js.get('problem_id')
                 if program is None:
-                    response = {'code': 2, 'message': 'No program specified'}
+                    return {'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'}
+                    return {'code': 3, 'message': 'No query specified'}
+                elif problem_id is None:
+                    return {'code': 4, 'message': 'Problem ID 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}}
+                    messages, status, have_more = prolog.run_for_user(session.get_uid(), problem_id, program, query)
+                    return {'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}}
+                return {'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}}
+                return {'code': 0, 'message': 'ok', 'terminal': {'messages': messages, 'status': status, 'have_more': have_more}}
             else:
-                response = {'code': 7, 'message': 'Unknown prolog step: {0}'.format(step)}
+                return {'code': 5, 'message': 'Unknown prolog step: {0}'.format(step)}
 
-        resp.body = json.dumps(response)
-        resp.content_type = 'application/json'
-        resp.status = falcon.HTTP_200
+class GetProblem(CodeqService):
+    def process(self, js, session):
+        language = js.get('language')
+        problem_group = js.get('problem_group')
+        problem = js.get('problem')
+        if language is None:
+            return {'code': 1, 'message': 'Language identifier not given'}
+        elif problem_group is None:
+            return {'code': 2, 'message': 'Problem group identifier not given'}
+        elif problem is None:
+            return {'code': 3, 'message': 'Problem identifier not given'}
+        else:
+            return {'code': 0, 'message': 'ok', 'data': session.get_problem_data(language, problem_group, problem)}
+
+problem_list = ProblemList()
+api.add_route('/list_problems', problem_list)
 
 login = Login()
 api.add_route('/login', login)
@@ -126,3 +160,13 @@ api.add_route('/activity', activity)
 
 query = Query()
 api.add_route('/query', query)
+
+get_problem = GetProblem()
+api.add_route('/get_problem', get_problem)
+
+if __name__ == '__main__':
+    import logging
+    from waitress import serve
+    logger = logging.getLogger('waitress')
+    logger.setLevel(logging.DEBUG)
+    serve(application, host='0.0.0.0', port=8082)