cymongoose 0.1.12

High-performance Python bindings for the Mongoose embedded networking library

cymongoose

Python bindings for the Mongoose embedded networking library, built with Cython.

Overview

cymongoose provides Pythonic access to Mongoose, a lightweight embedded networking library written in C. It supports HTTP servers, WebSocket, TCP/UDP sockets, and more through a clean, event-driven API.

Features

Core Protocols

• HTTP/HTTPS: Server and client with TLS support, chunked transfer encoding, SSE
• WebSocket/WSS: Full WebSocket support with text/binary frames over TLS
• MQTT/MQTTS: Publish/subscribe messaging with QoS support
• TCP/UDP: Raw socket support with custom protocols
• DNS: Asynchronous hostname resolution
• SNTP: Network time synchronization

Advanced Features

• TLS/SSL: Certificate-based encryption with custom CA support
• Timers: Periodic callbacks with precise timing control
• Flow Control: Backpressure handling and buffer management
• Authentication: HTTP Basic Auth, MQTT credentials
• JSON Parsing: Built-in JSON extraction utilities
• URL Encoding: Safe URL parameter encoding

Technical

• Event-driven: Non-blocking I/O with a simple event loop
• Low overhead: Thin Cython wrapper over native C library
• Python 3.10+: Modern Python with type hints
• Comprehensive: 244 tests, 100% pass rate
• Production Examples: 17 complete examples from Mongoose tutorials
• TLS Support: Built-in TLS/SSL encryption (MG_TLS_BUILTIN)
• GIL Optimization: 21 methods release GIL for true parallel execution
• High Performance: 60k+ req/sec (6-37x faster than pure Python frameworks)

Installation

From pypi

pip install cymongoose

From source

# Clone the repository
git clone https://github.com/shakfu/cymongoose
cd cymongoose
make

Also type make help gives you a list of commands

Requirements

• Python 3.10 or higher
• CMake 3.15+
• Cython 3.0+
• C compiler (gcc, clang, or MSVC)

Quick Start

Note: These examples bind to 127.0.0.1 (localhost only). For production, use 0.0.0.0 to listen on all interfaces.

Simple HTTP Server

from cymongoose import Manager, MG_EV_HTTP_MSG

def handler(conn, event, data):
    if event == MG_EV_HTTP_MSG:
        conn.reply(200, "Hello, World!")

mgr = Manager(handler)
mgr.listen("http://127.0.0.1:8000", http=True)
print("Server running on http://localhost:8000. Press Ctrl+C to stop.")
mgr.run()

Serve Static Files

from cymongoose import Manager, MG_EV_HTTP_MSG

def handler(conn, event, data):
    if event == MG_EV_HTTP_MSG:
        conn.serve_dir(data, root_dir="./public")

mgr = Manager(handler)
mgr.listen("http://127.0.0.1:8000", http=True)
mgr.run()

WebSocket Echo Server

from cymongoose import Manager, MG_EV_HTTP_MSG, MG_EV_WS_MSG

def handler(conn, event, data):
    if event == MG_EV_HTTP_MSG:
        conn.ws_upgrade(data)  # Upgrade HTTP to WebSocket
    elif event == MG_EV_WS_MSG:
        conn.ws_send(data.text)  # Echo back

mgr = Manager(handler)
mgr.listen("http://127.0.0.1:8000", http=True)
mgr.run()

Per-Listener Handlers (new)

Run different handlers on different ports. Accepted connections automatically inherit the handler from their listener:

from cymongoose import Manager, MG_EV_HTTP_MSG

def api_handler(conn, event, data):
    if event == MG_EV_HTTP_MSG:
        conn.reply(200, '{"status":"ok"}', {"Content-Type": "application/json\r\n"})

def web_handler(conn, event, data):
    if event == MG_EV_HTTP_MSG:
        conn.serve_dir(data, root_dir="./public")

mgr = Manager()  # no default handler needed
mgr.listen("http://127.0.0.1:8080", handler=api_handler, http=True)
mgr.listen("http://127.0.0.1:8090", handler=web_handler, http=True)
mgr.run()

Examples

The project includes several complete examples translated from Mongoose C tutorials:

Core HTTP/WebSocket

• HTTP Server - Static files, TLS, multipart uploads, REST API
• HTTP Client - GET/POST, TLS, timeouts, custom headers
• WebSocket Server - Echo, mixed HTTP+WS, client tracking
• WebSocket Broadcasting - Timer-based broadcasts to multiple clients

MQTT

• MQTT Client - Pub/sub, QoS, reconnection, keepalive
• MQTT Broker - Message routing, topic matching, subscriptions

Specialized HTTP

• HTTP Streaming - Chunked transfer encoding, large responses
• HTTP File Upload - Disk streaming, multipart forms
• RESTful Server - JSON API, CRUD operations, routing
• Server-Sent Events - Real-time push updates

Network Protocols

• SNTP Client - Network time sync over UDP
• DNS Client - Async hostname resolution
• TCP Echo Server - Raw TCP sockets, custom protocols
• UDP Echo Server - Connectionless datagrams

Advanced Features

• TLS HTTPS Server - Certificate-based encryption, SNI
• HTTP Proxy Client - CONNECT method tunneling
• Multi-threaded Server - Background workers, Manager.wakeup()

All examples include:

• Production-ready patterns (signal handlers, graceful shutdown)
• Command-line arguments for flexibility
• Comprehensive test coverage (42 tests)
• Detailed documentation with C tutorial references

See tests/examples/README.md for usage instructions and tests/examples/ for source code.

API Reference

Manager

The main event loop manager.

mgr = Manager(handler=None, enable_wakeup=False)

Core Methods:

• poll(timeout_ms=0) - Run one iteration of the event loop
• run(poll_ms=100) - Run the event loop until SIGINT/SIGTERM, then close
• listen(url, handler=None) - Create a listening socket (handler is inherited by accepted children)
• connect(url, handler=None) - Create an outbound connection
• close() - Free resources

Protocol-Specific:

• http_listen(url, handler=None) - Create HTTP server
• http_connect(url, handler=None) - Create HTTP client
• ws_connect(url, handler=None) - WebSocket client
• mqtt_connect(url, handler=None, client_id, username, password, ...) - MQTT client
• mqtt_listen(url, handler=None) - MQTT broker
• sntp_connect(url, handler=None) - SNTP time client
• timer_add(milliseconds, callback, repeat=False, run_now=False) - Add timer, returns Timer with .cancel() and .active
• wakeup(connection_id, data) - Wake connection from another thread

Connection

Represents a network connection.

# Send data
conn.send(data)                    # Raw bytes
conn.reply(status, body, headers)  # HTTP response
conn.ws_upgrade(message)           # Upgrade HTTP to WebSocket
conn.ws_send(data, op)             # WebSocket frame

# HTTP
conn.serve_dir(message, root_dir)  # Serve static files
conn.serve_file(message, path)     # Serve single file
conn.http_chunk(data)              # Send chunked data
conn.http_sse(event_type, data)    # Server-Sent Events
conn.http_basic_auth(user, pass_)  # HTTP Basic Auth

# MQTT
conn.mqtt_pub(topic, message, ..)  # Publish an MQTT message
conn.mqtt_sub(topic, qos=0)        # Subscribe to an MQTT topic
conn.mqtt_ping()                   # Send MQTT ping
conn.mqtt_pong()                   # Send MQTT pong
conn.mqtt_disconnect()             # Send MQTT disconnect message

# SNTP
conn.sntp_request()                # Request time

# TLS
conn.tls_init(TlsOpts(...))        # Initialize TLS
conn.tls_free()                    # Free TLS resources

# DNS
conn.resolve(url)                  # Async DNS lookup
conn.resolve_cancel()              # Cancel DNS lookup

# Connection management
conn.drain()                       # Graceful close (flush buffer first)
conn.close()                       # Immediate close
conn.error(message)                # Trigger error event

# Properties
conn.is_listening                  # Listener socket?
conn.is_websocket                  # WebSocket connection?
conn.is_tls                        # TLS/SSL enabled?
conn.is_udp                        # UDP socket?
conn.is_readable                   # Data available?
conn.is_writable                   # Can write?
conn.is_full                       # Buffer full? (backpressure)
conn.is_draining                   # Draining before close?
conn.id                            # Connection ID
conn.handler                       # Current handler
conn.set_handler(fn)               # Set handler (propagates to children if listener)
conn.userdata                      # Custom Python object
conn.local_addr                    # (ip, port) tuple
conn.remote_addr                   # (ip, port) tuple

# Buffer access
conn.recv_len                      # Bytes in receive buffer
conn.send_len                      # Bytes in send buffer
conn.recv_size                     # Receive buffer capacity
conn.send_size                     # Send buffer capacity
conn.recv_data(n)                  # Read from receive buffer
conn.send_data(n)                  # Read from send buffer

TlsOpts

TLS/SSL configuration.

opts = TlsOpts(
    ca=None,                       # CA certificate (PEM)
    cert=None,                     # Server/client certificate (PEM)
    key=None,                      # Private key (PEM)
    name=None,                     # Server name (SNI)
    skip_verification=False        # Skip cert validation (dev only!)
)

HttpMessage

HTTP request/response view.

msg.method                         # "GET", "POST", etc.
msg.uri                            # "/path"
msg.query                          # "?key=value"
msg.proto                          # "HTTP/1.1"
msg.body_text                      # Body as string
msg.body_bytes                     # Body as bytes
msg.header("Name")                 # Get header value
msg.headers()                      # All headers as list of tuples
msg.query_var("key")               # Extract query parameter
msg.status()                       # HTTP status code
msg.header_var(header, var)        # Extract variable from header

WsMessage

WebSocket frame data.

ws.text                            # Frame data as string
ws.data                            # Frame data as bytes
ws.flags                           # WebSocket flags

MqttMessage

MQTT message data.

mqtt.topic                         # Topic as string
mqtt.data                          # Payload as bytes
mqtt.id                            # Message ID
mqtt.cmd                           # MQTT command
mqtt.qos                           # Quality of Service (0-2)
mqtt.ack                           # Acknowledgment flag

Event Constants

# Core events
MG_EV_ERROR                        # Error occurred
MG_EV_OPEN                         # Connection created
MG_EV_POLL                         # Poll iteration
MG_EV_RESOLVE                      # DNS resolution complete
MG_EV_CONNECT                      # Outbound connection established
MG_EV_ACCEPT                       # Inbound connection accepted
MG_EV_TLS_HS                       # TLS handshake complete
MG_EV_READ                         # Data available to read
MG_EV_WRITE                        # Data written
MG_EV_CLOSE                        # Connection closed

# Protocol events
MG_EV_HTTP_MSG                     # HTTP message received
MG_EV_WS_OPEN                      # WebSocket handshake complete
MG_EV_WS_MSG                       # WebSocket message received
MG_EV_MQTT_CMD                     # MQTT command received
MG_EV_MQTT_MSG                     # MQTT message received
MG_EV_MQTT_OPEN                    # MQTT connection established
MG_EV_SNTP_TIME                    # SNTP time received
MG_EV_WAKEUP                       # Wakeup notification

Utility Functions

# JSON parsing
json_get(json_str, "$.path")           # Get JSON value
json_get_num(json_str, "$.number")     # Get as number
json_get_bool(json_str, "$.bool")      # Get as boolean
json_get_long(json_str, "$.int", default=0)  # Get as long
json_get_str(json_str, "$.string")     # Get as string

# URL encoding
url_encode(data)                       # Encode for URL

# Multipart forms
http_parse_multipart(body, offset=0)   # Parse multipart data

Testing

The project includes a comprehensive test suite with 244 tests (100% passing):

Test Coverage by Feature

Core Functionality (168 tests):

• HTTP/HTTPS: Server, client, headers, query params, chunked encoding, SSE (40 tests)
• WebSocket: Handshake, text/binary frames, opcodes (10 tests)
• MQTT: Connect, publish, subscribe, ping/pong, disconnect (11 tests)
• TLS/SSL: Configuration, initialization, handshake integration (15 tests)
• Timers: Single-shot, repeating, cancellation, thread-safe cancel, GC safety (16 tests)
• DNS: Resolution, cancellation (4 tests)
• SNTP: Time requests, format validation (5 tests)
• JSON: Parsing, type conversion, nested access (9 tests)
• Buffer Access: Direct buffer inspection, flow control (10 tests)
• Connection State: Lifecycle, properties, events (15+ tests)
• Security: HTTP Basic Auth, TLS properties (6 tests)
• Utilities: URL encoding, multipart forms, wakeup (10 tests)
• Flow Control: Drain, backpressure (4 tests)

Example Tests:

• HTTP/WebSocket examples
• MQTT examples
• Specialized HTTP examples
• Network protocols
• Advanced features
• README example validation
• WebSocket broadcast examples

Running Tests

make test                                          # Run all tests (244 tests)
uv run python -m pytest tests/ -v                  # Verbose output
uv run python -m pytest tests/test_http_server.py  # Run specific file
uv run python -m pytest tests/ -k "test_timer"     # Run matching tests
uv run python -m pytest tests/examples/            # Run example tests only

Test Infrastructure

• Dynamic port allocation prevents conflicts
• Background polling threads for async operations
• Proper cleanup in finally blocks
• 100% pass rate (244/244 tests passing)
• WebSocket tests require websocket-client (uv add --dev websocket-client)

Memory Safety Testing

AddressSanitizer (ASAN) support is available for detecting memory errors:

make build-asan                        # Build with ASAN enabled
make test-asan                         # Run tests with memory error detection

This detects use-after-free, buffer overflows, and other memory bugs at runtime.

macOS note: build-asan compiles a small helper (build/run_asan) that injects the ASAN runtime via DYLD_INSERT_LIBRARIES before exec'ing Python. This is necessary because macOS SIP strips DYLD_INSERT_LIBRARIES from processes spawned by system binaries (/usr/bin/make, /bin/sh).

Development

The project uses scikit-build-core with CMake to build the Cython extension, and uv for environment and dependency management.

make build          # Rebuild the Cython extension
make test           # Run all tests
make clean          # Remove build artifacts
make help           # Show all available targets

Architecture

• CMake build (CMakeLists.txt): Cythonizes .pyx and compiles the extension via scikit-build-core
• Cython bindings (src/cymongoose/_mongoose.pyx): Python wrapper classes
• C declarations (src/cymongoose/mongoose.pxd): Cython interface to Mongoose C API
• Vendored Mongoose (thirdparty/mongoose/): Embedded C library

Performance Optimization

The wrapper achieves C-level performance through aggressive optimization:

GIL Release (nogil):

• 21 critical methods release GIL for true parallel execution
• Network: send(), close(), resolve(), resolve_cancel()
• WebSocket: ws_send(), ws_upgrade()
• MQTT: mqtt_pub(), mqtt_sub(), mqtt_ping(), mqtt_pong(), mqtt_disconnect()
• HTTP: reply(), serve_dir(), serve_file(), http_chunk(), http_sse()
• TLS: tls_init(), tls_free()
• Utilities: sntp_request(), http_basic_auth(), error()
• Properties: local_addr, remote_addr
• Thread-safe: Manager.wakeup()

TLS Compatibility:

• TLS and nogil work together safely
• Mongoose's built-in TLS is event-loop based (no internal locks)
• Both optimizations enabled by default

Benchmark Results (Apple Silicon, wrk -t4 -c100 -d10s):

• cymongoose: 60,973 req/sec (1.67ms latency)
• aiohttp: 42,452 req/sec (1.44x slower)
• FastAPI/uvicorn: 9,989 req/sec (6.1x slower)
• Flask: 1,627 req/sec (37.5x slower)

See docs/nogil_optimization_summary.md and benchmarks/RESULTS.md for details.

License

This project is licensed under the GNU General Public License v2.0 or later (GPL-2.0-or-later), matching the Mongoose C library license. See LICENSE for details.

For use in proprietary/closed-source projects, a commercial Mongoose license from Cesanta is required.

Links

• Mongoose Documentation
• GitHub Repository