fix(http): use proxy agent setup that supports proxy env variables with no_proxy

[jontze]

Fixes a bug introduced in #762, where the "no-proxy" environment configuration was ignored.

With this PR I moved from the usage of https-proxy-agent to proxy-agent. This was done as https-proxy-agent was configured to take the proxy url from the environment but the library itself doesn't handle NO_PROXY / no_proxy configuration.

proxy-agent on the other side, is sitting on top of the https-proxy-agent and http-proxy-agent library and decides if the proxy is used based on the request URL and the domains specified in the "no proxy" environment variables.

---

To test this

1. Set the configuration for your proxy in the usual environment variables HTTP_PROXY , HTTPS_PROXY, http_proxy, https_proxy, NO_PROXY, no_proxy.
2. You can set your custom repository download url in the generator-cli.repository.downloadUrl config
3. Append your domain to the no_proxy and NO_PROXY environment variables OR if you don't have a mirror at hand, just add the default domain specified in config.schema.json and ensure that you have a way to verify that the traffic went not through the proxy.
4. Execute the generator

⚠️ Define both variables! If you only set the upper case NO_PROXY variable, the lower case one will have presence!

ℹ️ The downloaded jar will be cached near the dist files of the generator cli (so usually in you node_modules), beside you patched the version like this in your package.json of your project, then it's not in your node_modules:

  "@openapitools/openapi-generator-cli": "file:../openapi-generator-cli/dist/apps/generator-cli"

[gonzalad]

I am not sure all the explicit http_proxy and https_proxy handling is necessary in the current codebase.

Axios already handles those environment variables automatically.

From https://github.com/axios/axios#request-config:

{quote}
proxy defines the hostname, port, and protocol of the proxy server.
You can also define your proxy using the conventional http_proxy and
https_proxy environment variables. If you are using environment
variables for your proxy configuration, you can also define a no_proxy environment
variable as a comma-separated list of domains that should not be proxied.
{quote}

[gonzalad]

I am not sure all the explicit http_proxy and https_proxy handling is necessary in the current codebase.

Axios already handles those environment variables automatically.

I just read issue axios/axios#5256 (400 Bad Request using axios proxy default handling) and now I understand that you handle the proxy explicitly to avoid this issue.

Sorry for the noise !

[gonzalad]

@jontze : I just tested your PR in my corporate environment, it works great thanks !

@wing328 : could this PR be reviewed and merged to provide support for NO_PROXY environment variable ?

Thanks very much to both of you :)

[wing328]

@jontze can you please resolve the merge conflicts when you've time?

[jontze]

Thanks for testing and validating the fix in your corp environment! @gonzalad

@wing328 I rebased to the latest master branch and resolved the conflicts in the package.json and lock file.

[wing328]

@jontze thank you

I'll merge it next monday as we try to avoid changes on Friday :)

When you've time, can you please also PM me via Slack?

https://join.slack.com/t/openapi-generator/shared_invite/zt-12jxxd7p2-XUeQM~4pzsU9x~eGLQqX2g

[github-actions]

🎉 This PR is included in version 2.14.1 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀

[wing328]

PR merged.

Please give it a try with the latest release.

[gonzalad]

@wing328 : I've just tested the version 2.14.1 in my corporate environment and it works fine.

Thanks to both of you !