support JSON request payload passed to LLM service layer

tests/api/controller.py

@@ -0,0 +1,62 @@
+import json
+import os
+import sys
+
+# Add the parent folder (or any relative path)
+sys.path.append(os.path.abspath('./../llm'))
+
+from phi3_language_model import Phi3LanguageModel
+
+
+class ApiController:
+    def __init__(self):
+        self.routes = {}
+
+
+    def __http_415_notsupported(self, env, start_response):
+        start_response('415 Unsupported Media Type', self.response_headers)
+        return [json.dumps({'error': 'Unsupported Content-Type'}).encode('utf-8')]
+
+    def get_service_response(self, prompt):
+        service = Phi3LanguageModel()
+        response = service.get_response(prompt_input=prompt)
+        return response
+
+    def __http_200_ok(self, env, start_response):
+        try:
+            request_body_size = int(env.get('CONTENT_LENGTH', 0))
+        except (ValueError):
+            request_body_size = 0
+
+        request_body = env['wsgi.input'].read(request_body_size)
+        request_json = json.loads(request_body.decode('utf-8'))
+        prompt = request_json.get('prompt')
+        
+        # for now, just reading request and echoing back in response
+        # data = json.loads(prompt)
+        # response_body = json.dumps(data).encode('utf-8')
+
+        data = self.get_service_response(prompt)
+        response_body = json.dumps(data).encode('utf-8')
+        
+        response_headers = [('Content-Type', 'application/json'), ('Content-Length', str(len(response_body)))]
+        start_response('200 OK', response_headers)    
+        return [response_body]
+
+
+    def __call__(self, env, start_response):
+        method = env.get('REQUEST_METHOD').upper()
+        path = env.get('PATH_INFO')
+
+        # TODO: register route for POST /api/conversations
+
+        if not method == 'POST':
+            self.__http_415_notsupported(env, start_response)
+
+        try:                
+            handler = self.routes.get((method,path), self.__http_200_ok)
+            return handler(env, start_response)
+        except json.JSONDecodeError:
+            start_response('400 Bad Request', self.response_headers)
+            return [json.dumps({'error': 'Invalid JSON'}).encode('utf-8')]
+