pgsql-http (pramsey/pgsql-http) as a separate pgembed extension package.

Install alongside the base package (which stays HTTP-free):

pip install pgembed pgembed-http

import pgembed

assert pgembed.has_extension("pgsql_http")

server = pgembed.get_server("/path/to/data")
server.create_extension("http")   # CREATE EXTENSION http

Available functions depend on the bundled pgsql-http version (SELECT * FROM pg_available_extensions WHERE name = 'http' after install). Typical entry points: http_get, http_post, http_header, http_response, http_response_code.

Requires libcurl dev headers at build time only (libcurl4-openssl-dev on Debian/Ubuntu); the wheel ships a prebuilt http.so, one file per OS/arch.