asked on

Can you help me understand this script?

Hi guys,

This is a great code that I found on the internet. I'm having difficulty undrestanding what happens from where it says //Actions? I know there are some comments, but I'd like to really understand it by line?

Any help would be awesome.

function FindProxyForURL(url, host) {
	// SETTINGS
	// your proxy hostname (myproxy.mynetwork.local)
	var proxyHostname = "${asg_hostname}";
	var proxyPort = 8080;

	// regex patterns to exclude from proxy (put your internal networks here)
	var directRegexPatterns = [
	".local/",
	".lan/",
	"192.168.0.",
	"172.16.",
	"172.30.0."
	];

	// networks that should use proxies with optional proxy to use override (put your internal networks that should be proxied here)
	var nets = [
	{ addr: "172.16.0.0", subnet: "255.255.0.0" },
	{ addr: "172.30.0.0", subnet: "255.255.255.0", proxy: "172.30.0.1:" + proxyPort },
	{ addr: "192.168.0.0", subnet: "255.255.255.0" }
	];

	var p = "DIRECT";
	var defaultproxyurl = "PROXY " + proxyHostname + ":" + proxyPort;


	// ACTIONS

	//Don't proxy connections to the proxy web interface
	if (shExpMatch(url, "https://${asg_hostname}*")) { p = "DIRECT"; }
	else if (shExpMatch(url, "https://" + dnsResolve(host) + "*")) { p = "DIRECT"; }
	//Exclude non-fqdn hosts from being proxied
	else if (isPlainHostName(host)) { p = "DIRECT"; }
	else {
	var hasRegexMatch = false;

	// check proxy exclusion regex patterns
	for (var i = 0; i < directRegexPatterns.length; i++) {
	var pattern = directRegexPatterns[i];
	if (shExpMatch(url, pattern)) {
	p = "DIRECT";
	hasRegexMatch = true;
	break;
	}
	}

	if (!hasRegexMatch) {
	// check if client is in proxy network
	var ipstr = "";
	if (typeof myIpAddressEx === "undefined") {
	alert("myIpAddressEx is undefined!"); // this will print to a specific log in the browser
	ipstr = myIpAddress(); // only one ip, not all, but FF does not support the "Ex" version...
	} else {
	ipstr = myIpAddressEx(); // IP1;IP2;IP3
	}

	var ips = ipstr.split(";");
	for (var j = 0; j < nets.length; j++) {
	var net = nets[j];
	for (var i = 0; i < ips.length; i++) {
	var ip = ips[i];
	if (isInNet(ip, net.addr, net.subnet)) {
	var proxyToUse = defaultproxyurl;
	if(net.proxy){
	proxyToUse = "PROXY " + net.proxy;
	}
	p = proxyToUse;
	// alert("found " + proxyToUse + " because: " + ip + " is in net " + net.addr + " / " + net.subnet);
	break;
	}
	}
	}
	}
	}

	return p;
	}

ASKER CERTIFIED SOLUTION

Michel Plungjan

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Yashy

ASKER

As always Michel - thank you. Really helpful.

Yashy

ASKER

Michel - if I wanted to have two proxies rather than one, are you able to help me add that? For example, imagine if I wanted to add the below (this is just a small snippet but a lot of my code uses either one proxy or the other) to the code above (one has a port 8080, another with port 3128, with different networks. I know that I would have to define a variable for that, like proxyPort2 = 3128. I just don't know how to make it part of the code?). I'm happy to create a new question.

if (isInNet(myIpAddress(), "10.200.40.128","255.255.255.128"))
return "PROXY proxy-gs2:8080";

if (isInNet(myIpAddress(), "10.19.0.0","255.255.0.0"))
return "PROXY 10.19.0.250:3128;

SOLUTION

noci

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Michel Plungjan

Yes, your are correct

Yashy

ASKER

Michel - thanks again for the above. If I had a load of other network ranges, instead of entering them manually, can the IP ranges be defined first, such as in the 'var nets' section?

SOLUTION

Michel Plungjan

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Yashy

ASKER

Legend, thank you again.

Michel Plungjan

Sorry, missed a comma between the } {