Fix PathPattern encoding

[Tratcher]

Fixes #1307

Sample route from the issue:

      "CommonRestRoute": {
        "ClusterId": "cluster1",
        "Match": {
          "Path": "/service1/rest/{**remainder}"
        },
        "Transforms": [
          { "PathPattern": "/{remainder}" },
        ]
      },

PathPattern is supposed to take route parameters matched from the path and inject them into the given pattern. ** in the path pattern indicates a catch-all that will capture the remainder of the path.

Problem: When the catch-all captured multiple path segments the resulting path would have the /'s escaped as %2F. You should have been able to specify the PathPattern as { "PathPattern": "/{**remainder}" }, to avoid this, but it doesn't work with the RouteTemplate type we're using.

Solution: Use RoutePattern instead of RouteTemplate. This comes with a few usage differences.

• If you try to bind a value not present in the template it will be added as a query parameter. I had to filter these out.
• We had been passing the RouteParameters in to the defaults parameter to avoid the prior issue, but with RoutePattern it would cause default segments to be dropped. We no longer pass in the defaults collection.

[MihaZupan]

So aside from the change in undesired escaping, I take it the observable behavior from the user's perspective is the same here?

[Tratcher]

So aside from the change in undesired escaping, I take it the observable behavior from the user's perspective is the same here?

The biggest change is the clarification that the user needs to use the ** syntax in two places, in the route match and in the transform. Otherwise everything else should work as before.

[Tratcher]

Waiting on a review from Javier.