In java, I'd like to replace the Host part of an url with a new Host, where both the host and url are supplied as a string.
This should take into account the fact that the host could have a port in it, as defined in the RFC
So for example, given the following inputs
- url: http://localhost/me/out?it=5
- host: myserver:20000
I should get the following output from a function that did this correctly
Does anyone know of any libraries or routines that do Host replacement in an url correctly?
EDIT: For my use case, I want my host replacement to match what a java servlet would respond with. I tried this out by running a local java web server, and then tested it using curl -H 'Host:superduper.com:80' 'http://localhost:8000/testurl' and having that endpoint simply return the url from request.getRequestURL().toString(), where request is a HttpServletRequest. It returned http://superduper.com/testurl, so it removed the default port for http, so that's what I'm striving for as well.
I quickly tried using java.net.URI, javax.ws.rs.core.UriBuilder, and org.apache.http.client.utils.URIBuilder, and none of them seemed to get the idea of a host header possibly including a port, so they all needed some extra logic from what I could see to make it happen correctly, without the port being "doubled up" at times, and not replaced correctly at other times.
Since java.net.URL doesnt require any extra libs, I used it. I do know that if I was using URL.equals somewhere, that could be a problem as it does DNS lookups possibly, but I'm not so I think it's good, as this covers my use cases, as displayed by the pseudo unit test.
I put together this way of doing it, which you can test it out online here at repl.it !
import java.net.URL;
import java.net.MalformedURLException;
class Main
{
public static void main(String[] args)
{
testReplaceHostInUrl();
}
public static void testReplaceHostInUrl()
{
assertEquals("http://myserver:20000/me/out?it=5", replaceHostInUrl("http://localhost/me/out?it=5","myserver:20000"));
assertEquals("http://myserver:20000/me/out?it=5", replaceHostInUrl("http://localhost:19000/me/out?it=5","myserver:20000"));
assertEquals("http://super/me/out?it=5", replaceHostInUrl("http://localhost:19000/me/out?it=5","super"));
assertEquals("http://super/me/out?it=5", replaceHostInUrl("http://www.test.com/me/out?it=5","super"));
assertEquals("https://myserver:20000/me/out?it=5", replaceHostInUrl("https://localhost/me/out?it=5","myserver:20000"));
assertEquals("https://myserver:20000/me/out?it=5", replaceHostInUrl("https://localhost:19000/me/out?it=5","myserver:20000"));
assertEquals("https://super/me/out?it=5", replaceHostInUrl("https://www.test.com/me/out?it=5","super"));
assertEquals("https://super/me/out?it=5", replaceHostInUrl("https://www.test.com:4300/me/out?it=5","super"));
assertEquals("https://super/me/out?it=5", replaceHostInUrl("https://www.test.com:4300/me/out?it=5","super:443"));
assertEquals("http://super/me/out?it=5", replaceHostInUrl("http://www.test.com:4300/me/out?it=5","super:80"));
assertEquals("http://super:8080/me/out?it=5", replaceHostInUrl("http://www.test.com:80/me/out?it=5","super:8080"));
assertEquals("http://super/me/out?it=5&test=5", replaceHostInUrl("http://www.test.com:80/me/out?it=5&test=5","super:80"));
assertEquals("https://super:80/me/out?it=5&test=5", replaceHostInUrl("https://www.test.com:80/me/out?it=5&test=5","super:80"));
assertEquals("https://super/me/out?it=5&test=5", replaceHostInUrl("https://www.test.com:80/me/out?it=5&test=5","super:443"));
assertEquals("http://super:443/me/out?it=5&test=5", replaceHostInUrl("http://www.test.com:443/me/out?it=5&test=5","super:443"));
assertEquals("http://super:443/me/out?it=5&test=5", replaceHostInUrl("HTTP://www.test.com:443/me/out?it=5&test=5","super:443"));
assertEquals("http://SUPERDUPER:443/ME/OUT?IT=5&TEST=5", replaceHostInUrl("HTTP://WWW.TEST.COM:443/ME/OUT?IT=5&TEST=5","SUPERDUPER:443"));
assertEquals("https://SUPERDUPER:23/ME/OUT?IT=5&TEST=5", replaceHostInUrl("HTTPS://WWW.TEST.COM:22/ME/OUT?IT=5&TEST=5","SUPERDUPER:23"));
assertEquals(null, replaceHostInUrl(null, null));
}
public static String replaceHostInUrl(String url, String newHost)
{
if (url == null || newHost == null)
{
return url;
}
try
{
URL originalURL = new URL(url);
boolean hostHasPort = newHost.indexOf(":") != -1;
int newPort = originalURL.getPort();
if (hostHasPort)
{
URL hostURL = new URL("http://" + newHost);
newHost = hostURL.getHost();
newPort = hostURL.getPort();
}
else
{
newPort = -1;
}
// Use implicit port if it's a default port
boolean isHttps = originalURL.getProtocol().equals("https");
boolean useDefaultPort = (newPort == 443 && isHttps) || (newPort == 80 && !isHttps);
newPort = useDefaultPort ? -1 : newPort;
URL newURL = new URL(originalURL.getProtocol(), newHost, newPort, originalURL.getFile());
String result = newURL.toString();
return result;
}
catch (MalformedURLException e)
{
throw new RuntimeException("Couldnt replace host in url, originalUrl=" + url + ", newHost=" + newHost);
}
}
public static void assertEquals(String expected, String actual)
{
if (expected == null && actual == null)
{
System.out.println("TEST PASSED, expected:" + expected + ", actual:" + actual);
return;
}
if (! expected.equals(actual))
throw new RuntimeException("Not equal! expected:" + expected + ", actual:" + actual);
System.out.println("TEST PASSED, expected:" + expected + ", actual:" + actual);
}
}