SSE Client Execution Flow

1

Connect to SSE Endpoint

                        async with aiohttp.ClientSession() as session:
                            async with session.get(sse_url) as sse_response:
                    

DEBUG: Connecting to SSE endpoint: http://sse-server-py:3001/sse

GET http://sse-server-py:3001/sse 200 OK

DEBUG: Connected to SSE endpoint: http://sse-server-py:3001/sse

2

Extract Session ID from SSE Stream

                        async for line in sse_response.content:
                            if line:
                                decoded_line = line.decode().strip()
                                if decoded_line.startswith('event:'):
                                    event_type = decoded_line[6:].strip()
                                elif decoded_line.startswith('data:'):
                                    data = decoded_line[5:].strip()
                                    if event_type == 'endpoint':
                                        session_id = data.split('session_id=')[1]
                    

event: endpoint

data: {"url":"http://sse-server-py:3001/messages/?session_id=abc123"}

DEBUG: Received line: event: endpoint

DEBUG: Event type: endpoint

DEBUG: Received line: data: {"url":"http://sse-server-py:3001/messages/?session_id=abc123"}

DEBUG: Data: {"url":"http://sse-server-py:3001/messages/?session_id=abc123"}

INFO: Obtained session_id: abc123

3

Send Initialize Request

                        initialize_payload = {
                            "jsonrpc": "2.0",
                            "id": 0,
                            "method": "initialize",
                            "params": {
                                "protocolVersion": "2024-11-05",
                                "capabilities": {
                                    "sampling": {},
                                    "roots": {"listChanged": True}
                                },
                                "clientInfo": {
                                    "name": "mcp",
                                    "version": "0.1.0"
                                }
                            }
                        }
                        async with session.post(url, json=initialize_payload)
                    

POST http://sse-server-py:3001/messages/?session_id=abc123 202 Accepted

{ "jsonrpc": "2.0", "id": 0, "method": "initialize", "params": { "protocolVersion": "2024-11-05", "capabilities": { "sampling": {}, "roots": {"listChanged": true} }, "clientInfo": { "name": "mcp", "version": "0.1.0" } } }

DEBUG: Sending initialize request with payload: {...}

INFO: Initialize request accepted.

4

Send Initialized Notification

                        initialized_notification = {
                            "jsonrpc": "2.0",
                            "method": "notifications/initialized"
                        }
                        async with session.post(url, json=initialized_notification)
                    

POST http://sse-server-py:3001/messages/?session_id=abc123 202 Accepted

{ "jsonrpc": "2.0", "method": "notifications/initialized" }

DEBUG: Sending notifications/initialized notification: {...}

INFO: notifications/initialized notification accepted.

5

Send Fetch Tool Call Request

                        fetch_payload = {
                            "method": "tools/call",
                            "params": {
                              "name": "fetch",
                              "arguments": {"url": "https://httpstat.us/200"}
                            },
                            "jsonrpc": "2.0",
                            "id": 1
                        }
                        async with session.post(url, json=fetch_payload)
                    

POST http://sse-server-py:3001/messages/?session_id=abc123 202 Accepted

{ "method": "tools/call", "params": { "name": "fetch", "arguments": {"url": "https://httpstat.us/200"} }, "jsonrpc": "2.0", "id": 1 }

DEBUG: Sending fetch tool call request with payload: {...}

INFO: fetch tool call request accepted.

6

Listen for SSE Responses

                        async for line in sse_response.content:
                            if line:
                                decoded_line = line.decode().strip()
                                if decoded_line.startswith('data:'):
                                    data = decoded_line[5:].strip()
                                    message = json.loads(data)
                                    if message.get('id') == 1:
                                        logger.info(f"Received response: {message}")
                    

event: message

data: { "jsonrpc": "2.0", "id": 1, "result": { "status": 200, "body": "200 OK", "headers": {...} } }

DEBUG: Received line: data: {...}

INFO: Received fetch tool call sse_response: {...}