Node-fetch: HTTP and HTTPS agent

[normanrz]

I am trying to use keep-alive agent with node-fetch as described in #423, but I have a problem with HTTPS redirects. Initially, I call a HTTP resource which returns a redirect to a HTTPS resource. In the default node-fetch this is not a problem, because the agent is set based on the current request. When overriding the agent there is no way of having per-request agents.

I would propose an API that allows a function instead of a fixed agent:

fetch(url, { agent: (protocol) => protocol === 'https' ? httpsAgent : httpAgent })

[bitinn]

Yes this is a known limit, but since agent is non-standard I doubt there will be much change to this.

However, if you are lucky enough to be using nodejs 11.7.0+, globalAgent is now replaceable, meaning you can control this precisely:

• https://github.com/nodejs/node/blob/master/doc/changelogs/CHANGELOG_V11.md#2019-01-17-version-1170-current-bridgear
• https://github.com/nodejs/node/pull/25170

[normanrz]

Thanks for pointing to that change in node 11.

[bitinn]

this issue is addressed in v2.6.0, options.agent now accepts a function, see readme:

https://github.com/bitinn/node-fetch#custom-agent