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proxy_agent: Improve documentation

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Anmol Sethi 2020-12-18 05:30:40 -05:00
parent 3efd515cdf
commit ecb4d07364
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@ -15,18 +15,25 @@ import * as proxyagent from "proxy-agent"
*/
/**
* monkeyPatch patches the node HTTP/HTTPS library to route all requests through our
* custom agent from the proxyAgent package.
* monkeyPatch patches the node http and https modules to route all requests through the
* agent we get from the proxy-agent package.
*
* We do not support $HTTPS_PROXY here as it's equivalent in proxy-agent.
* See the mapping at https://www.npmjs.com/package/proxy-agent
*
* I guess with most proxies support both HTTP and HTTPS proxying on the same port and
* so two variables aren't required anymore. And there's plenty of SOCKS proxies too where
* it wouldn't make sense to have two variables.
*
* It's the most performant/secure setup as using a HTTP proxy for HTTP requests allows
* for caching but then using a HTTPS proxy for HTTPS requests gives full end to end
* security.
*
* See https://stackoverflow.com/a/10442767/4283659 for HTTP vs HTTPS proxy.
* To be clear, both support HTTP/HTTPS resources, the difference is in how they fetch
* them.
*/
export function monkeyPatch(vscode: boolean): void {
// We do not support HTTPS_PROXY here to avoid confusion. proxy-agent will automatically
// use the correct protocol to connect to the proxy depending on the requested URL.
//
// We could implement support ourselves to allow people to configure the proxy used for
// HTTPS vs HTTP but there doesn't seem to be much value in that.
//
// At least of right now, it'd just be plain confusing to support HTTPS_PROXY when proxy-agent
// will still use HTTP to hit it for HTTP requests.
const proxyURL = process.env.HTTP_PROXY || process.env.http_proxy
if (!proxyURL) {
return
@ -47,14 +54,16 @@ export function monkeyPatch(vscode: boolean): void {
pa = new (proxyagent as any).default(proxyURL)
}
/**
* None of our code ever passes in a explicit agent to the http modules but VS Code's
* does sometimes but only when a user sets the http.proxy configuration.
* See https://code.visualstudio.com/docs/setup/network#_legacy-proxy-server-support
*
* Even if they do, it's probably the same proxy so we should be fine! And those are
* deprecated anyway.
*/
// None of our code ever passes in a explicit agent to the http modules but VS Code's
// does sometimes but only when a user sets the http.proxy configuration.
// See https://code.visualstudio.com/docs/setup/network#_legacy-proxy-server-support
//
// Even if they do, it's probably the same proxy so we should be fine! And those are
// deprecated anyway. In fact, they implemented it incorrectly as they won't retrieve
// HTTPS resources over a HTTP proxy which is perfectly valid! Both HTTP and HTTPS proxies
// support HTTP/HTTPS resources.
//
// See https://stackoverflow.com/a/10442767/4283659
const http = require("http")
const https = require("https")
http.globalAgent = pa