Update the proxyPolicy and constants

[zzhxiaofeng]

Add the NO_PROXY and ALL_PROXY to constants, and update the proxyPolicy to support env vars for NO_PROXY and ALL_PROXY Azure/azure-sdk-for-java#5967

[xirzec]

Mostly JS style nits, but some functional questions in here too.

[ramya-rao-a]

@xirzec, @jeremymeng, Can we take another look at this PR?

[jeremymeng]

I would expect isBypassed() used in the proxy policy so that if it returns true for some url, we then don't set proxy settings for the request.

[jeremymeng]

Some question and suggestions

[tzhanl]

@jongio do you want to evaluate this PR? NO_PROXY and ALL_PROXY Env vars.

[jongio]

@zzhxiaofeng - This PR needs to be re-evaluated. It looks like HTTP_PROXY has moved to here: https://github.com/Azure/azure-sdk-for-js/blob/master/sdk/core/core-http/src/policies/proxyPolicy.ts

[zzhxiaofeng]

@jeremymeng I have used function isBypassed in function getDefaultProxySettings to achieve the feature.

[jeremymeng]

@jeremymeng I have used function isBypassed in function getDefaultProxySettings to achieve the feature.

The NO_PROXY environment variable lists urls that should be excluded from proxying. Requests to those urls should be sent to servers directly.

I think isBypassed() should be call on a request url to see whether
the request should be sent through a proxy, instead of calling it on the proxy url. The right place is probably here something like

azure-sdk-for-js/sdk/core/core-http/src/policies/proxyPolicy.ts

Line 100 in dfcc1cd

if (!request.proxySettings) {

  public sendRequest(request: WebResourceLike): Promise<HttpOperationResponse> {
    if (!isBypassed(request.url) && !request.proxySettings) {
      request.proxySettings = this.proxySettings;
    }
    return this._nextPolicy.sendRequest(request);
  }

[zzhxiaofeng]

@jeremymeng Thank you. I have updated the code here.

[xirzec]

This change looks good, there are just a few little style things I'd like to clean up before merging.

Good job on this! 👍

[sadasant]

Looks good!

[jeremymeng]

Merging. Thanks @zzhxiaofeng!