How to URL encode query strings using request transformer

[rhargreaves]

We're using the request-transformer plugin as so:

- name: some-route
  url: https://some-url
  routes:
    - name: some-route
      paths:
        - /some-url/?$
      methods:
        - GET
  plugins:
    - name: request-transformer
      config:
        replace:
          uri: /foo/$(query_params.foo)/bar/$(query_params.bar)/

However, there doesn't seem to be a way to properly URL encode the query_params.foo or query_params.bar variables. This means it cannot be used with any query string which might contain Unicode characters. We've tried using untrusted_lua but it doesn't seem to allow us to access any global variables (such as require or ngx)

As such, we've had to make a custom plugin to solve this particular issue, but its not a generic solution.

We're using version 2.5.0.

[StarlightIbuki]

Actually, the URI will always be URL encoded to make sure it contains no illegal characters.
However, your concern about URL encoding is right. If the query arguments contain slashes, question marks, or anything related to URL semantics, it can be a problem (we did introduce a new implementation of encoding/decoding with more careful handling, but it's not used here).

Quick thought:

1. We could let replace.uri always handle the template as a segment, escaping all of those "reserved" characters;
2. We could expose more functions to the advanced template, allowing users to do more with request variables.