Consolidating on httpx

[jamesbraza]

Before: aiohttp and httpx coexisted in this repo

After: we just have httpx

[Copilot]

Pull Request Overview

This PR consolidates HTTP client libraries by replacing aiohttp with httpx throughout the repository to achieve a single, unified HTTP client approach.

• Replace aiohttp.ClientSession with httpx.AsyncClient across all test files
• Update exception handling from aiohttp.ClientResponseError to httpx.HTTPStatusError
• Refresh test cassettes with new HTTP request headers and formatting changes from the httpx client

Reviewed Changes

Copilot reviewed 41 out of 51 changed files in this pull request and generated no comments.

File	Description
tests/test_clinical_trials.py	Updates test fixtures and mocks to use httpx instead of aiohttp for clinical trials API testing
tests/test_clients.py	Replaces aiohttp.ClientSession with httpx.AsyncClient in metadata client tests and updates citation count test data
tests/cassettes/*.yaml	Updates VCR cassettes with new request headers and response formatting from httpx instead of aiohttp

[whitead]

Why the rename? Won't that break backwards compatibility?

[jamesbraza]

Why the rename? Won't that break backwards compatibility?

You mean rename from session to client? Yeah this PR is breaking in two ways:

1. The actual type is incompatible (aiohttp.ClientSession vs httpx.AsyncClient)
2. The name is incompatible (session vs client)

I thought the name change was good because:

• NameError is safer than silent aiohttp.ClientSession | None mismatches with None fallback
• It resolves the name collision between paperqa.PQASession and atiohttp.ClientSession

[whitead]

Nice