How to Build a Batch Operations Multi-Status 207 Mock Server in Python

Build a mock HTTP server that accepts a batch of operations and returns HTTP 207 Multi-Status with per-operation status codes in JSON.

Medium Python 3.9+ Aug 9, 2026 API design & gRPC 13 views 0 copies

http-server batch multi-status mock json

Python code

41 lines
Python 3.9+
Run it 
from http.server import BaseHTTPRequestHandler, HTTPServer
import json

class BatchHandler(BaseHTTPRequestHandler):
    def do_POST(self):
        if self.path != "/batch":
            self.send_response(404)
            self.end_headers()
            return

        content_length = int(self.headers.get("Content-Length", 0))
        body = json.loads(self.rfile.read(content_length) or b"{}")
        operations = body.get("operations", [])

        results = []
        for op in operations:
            op_id = op.get("id")
            action = op.get("action")
            if action == "create":
                results.append({"id": op_id, "status": 201, "message": "Created"})
            elif action == "update":
                results.append({"id": op_id, "status": 200, "message": "Updated"})
            elif action == "delete":
                results.append({"id": op_id, "status": 200, "message": "Deleted"})
            else:
                results.append({"id": op_id, "status": 422, "message": "Invalid action"})

        response_body = json.dumps({"results": results}).encode()
        self.send_response(207)
        self.send_header("Content-Type", "application/json")
        self.send_header("Content-Length", str(len(response_body)))
        self.end_headers()
        self.wfile.write(response_body)

    def log_message(self, format, *args):
        pass

if __name__ == "__main__":
    server = HTTPServer(("localhost", 8080))
    print("Batch server running on http://localhost:8080")
    server.serve_forever()

Output

stdout 
Batch server running on http://localhost:8080

# When POSTing to /batch with operations, the response will be 207 with:
{
  "results": [
    {"id": "1", "status": 201, "message": "Created"},
    {"id": "2", "status": 200, "message": "Updated"},
    {"id": "3", "status": 422, "message": "Invalid action"}
  ]
}

How it works

The handler uses BaseHTTPRequestHandler to create a simple HTTP server without third-party dependencies. The do_POST method reads the request body, parses JSON, and iterates over operations, building a list of per-operation statuses. It always responds with HTTP 207 Multi-Status as defined by WebDAV, even if individual operations fail. This pattern is common in APIs that need to report partial success or failure for batch requests.

Common mistakes

  • Not checking Content-Length and reading too little or too much data
  • Returning 404 for unknown paths but still sending a JSON body
  • Forgetting to set Content-Type header to application/json
  • Not handling malformed JSON input gracefully

Variations

  1. Use Flask or FastAPI with a JSON request validation library instead of raw BaseHTTPRequestHandler
  2. Add async support with aiohttp or Tornado for higher concurrency

Real-world use cases

  • Mocking an external API's batch endpoints during integration testing to simulate mixed success/failure responses.
  • Building a lightweight internal tool that accepts bulk data operations and reports per-item errors for data cleanup.
  • Implementing a rate-limiting or throttling proxy that forwards batch requests and aggregates statuses for clients.

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