[CAMEL-9281] Http4 component removes trailing slashes from http requests (producer)

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.15.4, 2.16.1
• Fix Version/s: 2.16.2, 2.17.0
• Component/s: camel-http, camel-http4
• Estimated Complexity: Unknown
• Assignee: Claus Ibsen
• Reporter: Edward Welch
• Created: 01/Nov/15 15:21
• Updated: 09/Jan/16 14:38
• Resolved: 09/Jan/16 14:38

Description

I have created a scenario which seems to exploit a bug in the HttpHelper createURL method.

My use case:

Using http4 component in an http proxy with bridgeEndpoint true

Send a request such as http://somesite/contextpath

Request is forwarded by my proxy to a tomcat server. Tomcat will reply with a 302 and a new Location of http://somesite/contextpath/ as this is a built in behavior of tomcat to redirect the caller to the contextpath INCLUDING the trailing slash

I have http client configured with httpClient.redirectsEnabled=false
Therefore the 302 is sent back through my proxy to the caller.

The caller then makes the call to http://somesite/contextpath/

This is where the problem occurs, within the createUrl method:

        String path = exchange.getIn().getHeader(Exchange.HTTP_PATH, String.class);
        // NOW the HTTP_PATH is just related path, we don't need to trim it
        if (path != null) {
            if (path.startsWith("/")) {
                path = path.substring(1);
            }
            if (path.length() > 0) {
                // make sure that there is exactly one "/" between HTTP_URI and
                // HTTP_PATH
                if (!uri.endsWith("/")) {
                    uri = uri + "/";
                }
                uri = uri.concat(path);
            }
        }

When the second request is made with the trailing slash, the string "path" is / (just a single forward slash)

This hits the first conditional and results in true, which the following substring then removes this slash.

Now path.length() is not > 0 so the second conditional evaluates false.

And we end up with a uri returned that no longer has the trailing slash.

This is sent to Tomcat, Tomcat then promptly returns another 302 and a redirect loop is created.

I think the intent of this block of code is to combine the uri and path and make sure there isn't a duplicate forward slash?

So the simplest fix I can suggest would be something like

        String path = exchange.getIn().getHeader(Exchange.HTTP_PATH, String.class);
        // NOW the HTTP_PATH is just related path, we don't need to trim it
        if (path != null && ! path.equals("/")) {
            if (path.startsWith("/")) {
                path = path.substring(1);
            }
            if (path.length() > 0) {
                // make sure that there is exactly one "/" between HTTP_URI and
                // HTTP_PATH
                if (!uri.endsWith("/")) {
                    uri = uri + "/";
                }
                uri = uri.concat(path);
            }
        }

Where we would just check for this case explicitly with:

if (path != null && ! path.equals("/")) {

Thoughts?

I could probably put together a PR and add some test cases