Split out from wp-cli/core-command#292

• php-curl happens to honor the http_proxy env var
• Requests defers honoring that env var to the library user (e.g., WordPress core or WP-CLI) (see also Auto use Proxy if HTTP_PROXY & HTTPS_PROXY Environment variable is set WordPress/Requests#218)
• WP-CLI doesn't want to blindly trust that env var
• One should be able to manually configure proxy support via wp-cli.yml and the extra-php config

You might be able to do something like this:

# In wp-cli.yml require: - path-to/proxy.php

// proxy.php $proxy_host = getenv( 'HTTP_PROXY' ); if ( ! $proxy_host ) { return; } $proxy_url = parse_url( $proxy_host ); if ( $proxy_url['host'] ) { define( 'WP_PROXY_HOST', $proxy_url['host'] ); } if ( $proxy_url['port'] ) { define( 'WP_PROXY_PORT', $proxy_url['port'] ); }

This would configure the proxy for HTTP requests in core when using WP-CLI, similar to when you define this in wp-config.php. The setup would be slightly more complex for modifying HTTP requests from WP-CLI itself.