isPlainHostName called with url
medium
isPlainHostName returns true for names without a dot. A URL always contains dots (and slashes), so isPlainHostName(url) is permanently false and the branch never fires.
Why it matters
The intent is almost always “single-label intranet names go direct”. Passing url defeats
it: http://intranet/ contains a dot nowhere in the hostname but the string as a whole is
not a plain hostname by the function’s definition, and real URLs contain dots in the host
part anyway. The DIRECT branch for intranet names never applies and they go to the proxy,
which may not be able to resolve them.
How to fix
Call isPlainHostName(host).
Examples
Bad
function FindProxyForURL(url, host) {
if (isPlainHostName(url)) {
return "DIRECT";
}
return "PROXY proxy.corp.example:8080";
}
Good
function FindProxyForURL(url, host) {
if (isPlainHostName(host)) {
return "DIRECT";
}
return "PROXY proxy.corp.example:8080";
}