restructure as domain-driven design architecture

src/text_generation/entrypoints/http_api_controller.py

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+import json
+import traceback
+
+from src.text_generation.adapters.llm.llm import Phi3LanguageModel
+from src.text_generation.adapters.llm.llm_rag import Phi3LanguageModelWithRag
+
+class HttpApiController:
+    def __init__(self):
+        self.routes = {}
+        # Register routes
+        self.register_routes()
+        self.llm_svc = Phi3LanguageModel() # TODO: rename this as a service
+        self.llm_rag_svc = Phi3LanguageModelWithRag()
+
+    def register_routes(self):
+        """Register all API routes"""
+        self.routes[('POST', '/api/conversations')] = self.handle_conversations
+        self.routes[('POST', '/api/rag_conversations')] = self.handle_conversations_with_rag
+
+    def __http_415_notsupported(self, env, start_response):
+        response_headers = [('Content-Type', 'application/json')]
+        start_response('415 Unsupported Media Type', response_headers)
+        return [json.dumps({'error': 'Unsupported Content-Type'}).encode('utf-8')]
+
+    def get_service_response(self, prompt):
+        response = self.llm_svc.invoke(user_input=prompt)
+        return response
+    
+    def get_service_response_with_rag(self, prompt):
+        response = self.llm_rag_svc.invoke(user_input=prompt)
+        return response
+
+    def format_response(self, data):
+        """Format response data as JSON with 'response' key"""
+        response_data = {'response': data}
+        try:
+            response_body = json.dumps(response_data).encode('utf-8')
+        except:
+            # If serialization fails, convert data to string first
+            response_body = json.dumps({'response': str(data)}).encode('utf-8')
+        return response_body
+
+    def handle_conversations(self, env, start_response):
+        """Handle POST requests to /api/conversations"""
+        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')
+
+        if not prompt:
+            response_body = json.dumps({'error': 'Missing prompt in request body'}).encode('utf-8')
+            response_headers = [('Content-Type', 'application/json'), ('Content-Length', str(len(response_body)))]
+            start_response('400 Bad Request', response_headers)
+            return [response_body]
+
+        data = self.get_service_response(prompt)
+        response_body = self.format_response(data)
+        
+        response_headers = [('Content-Type', 'application/json'), ('Content-Length', str(len(response_body)))]
+        start_response('200 OK', response_headers)    
+        return [response_body]
+
+    def handle_conversations_with_rag(self, env, start_response):
+        """Handle POST requests to /api/rag_conversations with RAG functionality"""
+        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')
+
+        if not prompt:
+            response_body = json.dumps({'error': 'Missing prompt in request body'}).encode('utf-8')
+            response_headers = [('Content-Type', 'application/json'), ('Content-Length', str(len(response_body)))]
+            start_response('400 Bad Request', response_headers)
+            return [response_body]
+
+        data = self.get_service_response_with_rag(prompt)
+        response_body = self.format_response(data)
+        
+        response_headers = [('Content-Type', 'application/json'), ('Content-Length', str(len(response_body)))]
+        start_response('200 OK', response_headers)    
+        return [response_body]
+
+    def __http_200_ok(self, env, start_response):
+        """Default handler for other routes"""
+        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')
+
+        data = self.get_service_response(prompt)
+        response_body = self.format_response(data)
+        
+        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')
+
+        if method != 'POST':
+            return 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 as e:
+            response_body = json.dumps({'error': f"Invalid JSON: {e.msg}"}).encode('utf-8')
+            response_headers = [('Content-Type', 'application/json'), ('Content-Length', str(len(response_body)))]
+            start_response('400 Bad Request', response_headers)
+            return [response_body]
+        except Exception as e:
+            # Log to stdout so it shows in GitHub Actions
+            print("Exception occurred:")
+            traceback.print_exc()
+
+            # Return more detailed error response (would not do this in Production)
+            error_response = json.dumps({'error': f"Internal Server Error: {str(e)}"}).encode('utf-8')
+            response_headers = [('Content-Type', 'application/json'), ('Content-Length', str(len(error_response)))]
+            start_response('500 Internal Server Error', response_headers)
+            return [error_response]