lowhaio 0.0.18

Lightweight Python asyncio HTTP/1.1 client.

lowhaio

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Work in progress. These docs serve as a rough design spec.

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A lightweight Python asyncio HTTP/1.1 client. No additional tasks are created; all code is in a single module; and other than the standard library only a single dependency is required, aiodnsresolver.

Usage

The API is streaming-first: for both request and response bodies, asynchronous generators are used.

import os
from lowhaio import Pool

request, _ = Pool()

path = 'my.file'
content_length = str(os.stat(path).st_size).encode()
async def file_data():
    with open(path, 'rb') as file:
        for chunk in iter(lambda: file.read(65536), b''):
            yield chunk

code, headers, body = await request(
    b'POST', 'https://example.com/path',
    params=(), headers=((b'content-length': content_length),), body=file_data(),
)
async for chunk in body:
    print(chunk)

However, there are helper functions streamed and buffered when this isn't required or possible.

from lowhaio import Pool, streamed, buffered

request, _ = Pool()

content = b'some-data'
content_length = b'9'
code, headers, body = await request(
    b'POST', 'https://example.com/path',
    params=(), headers=((b'content-length': content_length),), body=streamed(content),
)

response = await buffered(body)

Scope

The scope of the core functions is restricted to:

• (TLS) connection opening, closing and pooling;
• passing and receiving HTTP headers and streaming bodies;
• decoding chunked responses.

This is to make the core behaviour useful to a reasonable range of uses, but to not include what can be added by layer(s) on top. Specifically not included:

• following redirects (although this is planned for a helper function);
• cookies;
• compressing/decompressing requests/responses;
• authentication.