Proxy support for amp-optimizer

[todoa2c]

Proxy support using node-fetch-with-proxy instead of node-fetch.
If you need to use proxy, just set the environment variable https_proxy.

Thanks.

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[todoa2c]

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[sebastianbenz]

Thanks for creating this! One suggestion: as the code for integrating this is trivial, would you mind implementing this directly instead of adding an additional dependency?

[todoa2c]

@sebastianbenz I searched for this fix that doesn't require any additional libraries.
But that seemed difficult.
If I use node-fetch, you need an agent like HttpProxyAgent, which is also an additional library.
Is there any idea to implement node-fetch agent without using it, implementation without node-fetch, or any other method?

[sebastianbenz]

Sorry for not being more clear. Integrating https://www.npmjs.com/package/http-proxy-agent is fine as it seems to be the "standard" node way of integrating of proxy. What I'd like to avoid is integrating node-fetch-with-proxy as it's a super thin wrapper with only a few LOC and super low usage.

[todoa2c]

@sebastianbenz Sorry for late reaction.
This time https-proxy-agent matches so I added and fixed code.

[sebastianbenz]

Thanks a lot! This looks good! One request: can you also add this here https://github.com/ampproject/amp-toolbox/blob/main/packages/optimizer/lib/DomTransformer.js#L156 to enable proxy support at runtime.

[todoa2c]

@sebastianbenz I checked cross-fetch library but it doesn't support agent like node-fetch.

Should I replace cross-fetch to node-fetch? or any ideas?

[sebastianbenz]

Hm - that's annoying. I think it's fine to replace cross-fetch in that case and we don't release a browser bundle yet which would benefit from cross fetch.

[todoa2c]

@sebastianbenz Ok, so let's try replacing "cross-fetch" with "node-fetch" once in a separate branch.
Is it possible to merge this pull request? I'm using next.js now, but I'm having trouble with next.js because it relies on amp-toolbox and I'm having to wait a huge amount of time for postinstall in a proxy environment.