envoyproxy/envoy

URL Rewriting inside the response body

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#21,403 opened on May 23, 2022

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area/http_filterenhancementhelp wanted

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Description

Was attempting to see if a reverse proxy configuration with Envoy can ensure URL rewriting inside the response body.

Use case in question would be that a website exists inside a corp network but needs to be exposed to internet via a reverse proxy. If the website hardcodes links to other resources, the browser accessing from internet will not be able to fetch the content that is located internally. If reverse proxy is able to parse the response content and translate hardcoded links to internet facing endpoints, browser would be able to render the website as needed.

Nginx solves this with module ngx_http_sub_module and Apache does it with mod_proxy_html. Not sure what is the right approach to take with Envoy. If not supported yet, is it in pipeline to build such feature?

Contributor guide

Research direction
Explore Envoy's HTTP filter API for body rewrite capabilities. Look at existing filters like the header mutation filter or the Lua filter for inspiration. Consider implementing a new filter that uses regex substitution on the response body, similar to Nginx's sub filter.
Tech stack
cpp
Domain
backendapiinfrastructure
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Over 1 week
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C++HTTPEnvoy filter development
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
20