An interesting Restlet Attribute behavior

Question

Using Restlet 2.1 for Java EE, I am discovering an interesting problem with its ability to handle attributes.

Suppose you have code like the following:

cmp.getDefaultHost().attach("/testpath/{attr}",SomeServerResource.class);

and on your browser you provide the following URL:

http://localhost:8100/testpath/command

then, of course, the attr attribute gets set to "command".

Unfortunately, suppose you want the attribute to be something like command/test, as in the following URL:

http://localhost:8100/testpath/command/test

or if you want to dynamically add things with different levels, like:

http://localhost:800/testpath/command/test/subsystems/network/security

in both cases the attr attribute is still set to "command"!

Is there some way in a restlet application to make an attribute that can retain the "slash", so that one can, for example, make the attr attribute be set to "command/test"? I would like to be able to just grab everything after testpath and have the entire string be the attribute.

Is this possible? Someone please advise.

score 1 · Answer 1 · answered Dec 06 '12 at 19:31

You can do this by using url encoding.

I made the following attachment in my router:

router.attach("/test/{cmd}", TestResource.class);

My test resource class looks like this, with a little help from Apache Commons Codec URLCodec

@Override
protected Representation get() {
    try {
    String raw = ResourceWrapper.get(this, "cmd");
    String decoded = new String(URLCodec.decodeUrl(raw.getBytes()));
    return ResourceWrapper.wrap(raw + " " + decoded);
    } catch(Exception e) { throw new RuntimeException(e); }
}

Note my resource wrapper class is simply utility methods. The get returns the string of the url param, and the wrap returns a StringRepresentation.

Now if I do something like this:

http://127.0.0.1/test/haha/awesome

I get a 404.

Instead, I do this:

http://127.0.0.1/test/haha%2fawesome

I have URLEncoded the folder path. This results in my browser saying:

haha%2fawesome haha/awesome

The first is the raw string, the second is the result. I don't know if this is suitable for your needs as it's a simplistic example, but as long as you URLEncode your attribute, you can decode it on the other end.

Thanks. This is a great solution for situations where the client application is generating the URL... — Factor Three, Dec 18 '12 at 15:39
I think the idea of users entering their own urls for commands is a bad idea, personally. But if you got the problem solved, that's great! — corsiKa, Dec 18 '12 at 21:42

score 1 · Accepted Answer · answered Dec 18 '12 at 00:42

1

For the same case I usually change the type of the variable :

Route route = cmp.getDefaultHost().attach("/testpath/{attr}",SomeServerResource.class);
route.getTemplate().getVariables().get("attr") = new Variable(Variable.TYPE_URI_PATH);

answered Dec 18 '12 at 00:42

vhardion

199
2
5

Though both solutions work, I like yours better because I'd hate to use the former in situations where users might have to enter a URL. Both solutions are good, though. – Factor Three Dec 18 '12 at 15:38

An interesting Restlet Attribute behavior

2 Answers2