Wasat: Async Gemini Protocol Client Library

Wasat is a fully type-hinted asynchronous client library for the Gemini Protocol, relying only on cryptography for certificate management.

Features

• Async All the Way: Built on top of Python's standard asyncio loop with streaming/chunking support.
• Type Safe: Fully typed API.
• TOFU & Hybrid Verification: Supports CA, TOFU, and Hybrid (CA validation with TOFU fallback) verification modes with built-in file-based trust stores and interactive hooks.
• Auto Redirect Handling: Automatically handles temporary and permanent redirects (with protection against loops and infinite redirect limits), caching permanent redirects locally.
• Client Authentication: Native support for client TLS certificates.
• Minimal Dependencies: Relies only on cryptography for certificate management, otherwise using Python's standard library.
• CLI Utility: Includes a wasat command-line interface out of the box.

Installation

wasat is available from pypi and can be installed with your package installer of choice.

With pip:

pip install wasat

With uv:

uv add wasat

Quick Start

1. Make a Simple Request

Use Client with standard async context managers to query a Gemini capsule and decode the response:

import asyncio
from wasat import Client, WasatError

async def main():
    # 'tofu' mode is ideal for standard Gemini capsules (self-signed certs)
    client = Client(verify_mode="tofu")

    try:
        # Perform the request (automatically resolves host, port, TLS, and redirects)
        async with await client.request("gemini://geminiprotocol.net/") as response:
            print(f"Status: {response.status.value} ({response.status.name})")
            print(f"MIME type: {response.mime_type}")

            # Fetch the decoded body text
            body = await response.text()
            print(body)

    except WasatError as e:
        print(f"Request failed: {e}")

if __name__ == "__main__":
    asyncio.run(main())

2. Streaming Chunk Responses

For large files or media streams, read the response body in chunks to prevent exhausting memory:

async with await client.request("gemini://example.com/large-file.txt") as response:
    if response.status.is_success:
        async for chunk in response.iter_chunks(chunk_size=1024):
            # Process each chunk as it arrives
            sys.stdout.buffer.write(chunk)

3. Client Certificate Authentication

If a server requires client auth (status code 60), supply your certificate files to the client configuration:

client = Client(
    verify_mode="tofu",
    client_cert="/path/to/client.crt",
    client_key="/path/to/client.key"  # Optional if key is embedded in cert
)

4. Interactive TOFU Confirmation

Implement a custom asynchronous callback to prompt the user before trusting new self-signed certificates:

import sys

async def confirm_cert(host: str, port: int, fingerprint: str) -> bool:
    print(f"New certificate encountered for {host}:{port}")
    print(f"Fingerprint: sha256:{fingerprint}")
    response = input("Do you trust this certificate? [y/N]: ").strip().lower()
    return response == "y"

client = Client(
    verify_mode="tofu",
    on_new_certificate=confirm_cert
)

Command Line Interface (CLI)

Wasat comes with a command-line interface to fetch Gemini capsules from your shell:

# Basic fetch using the entrypoint script (uses TOFU)
uv run wasat gemini://geminiprotocol.net/

# Alternatively, execute the package directly using python -m
uv run python -m wasat gemini://geminiprotocol.net/

# Fetch a local or custom port capsule
uv run wasat gemini://localhost:1965/index.gmi

License

MIT