Can traefik rewrite the location header of redirect responses (302) - reverse-proxy

Question

I am using traefik 2.0.2 as reverse proxy in front of some services. One backend services is returning a redirect response (302), where the location header contains the absolute redirected url. The url of the backend is not reachable from the outside, how can I rewrite the location to go through the reverse proxy again?
E.g. a client requests http://my-domain/foo and receives a 302 response with location header containing http://backend:8080/foo/bar/, which of course will not work.
I am looking for something similar to ProxyPassReverse of apache mod_proxy. I have read through the available middlewares of traefik, but nothing seems to fit my requirement.
My simplified configuration:
# traefik.yml
entryPoints:
web:
address: ":80"
providers:
file:
filename: "dynamic-conf.yml"
# dynamic-conf.yml
http:
routers:
router1:
entryPoints:
- web
service: service1
rule: "PathPrefix(`/foo`)"
services:
service1
loadBalancer:
servers:
- url: http://backend:8080

Answer 1

I did not find an option to rewrite the location header of a service response using traefik.
A feature request to replaceResponseHeaders exists.
My (temporary) solution is to perform the redirection in traefik using the RedirectRegex middleware, such that the backend service does not need to response with a redirect.
The updated configuration would look like this:
# dynamic-conf.yml
http:
routers:
router1:
entryPoints:
- web
service: service1
rule: "PathPrefix(`/foo`)"
middlewares:
- my-redirect
middlewares:
my-redirect: # Workaround for service1 redirection
redirectRegex:
regex: "^https?://[^/]+/foo/?$"
replacement: "/foo/webapp/"
services:
service1
loadBalancer:
servers:
- url: http://backend:8080

Answer 2

I had the same issue as you, could not resolve it with your solution, but now, with the traefik plugins, we can:
Static config:
pilot:
token: "xxxx"
experimental:
plugins:
rewriteHeaders:
modulename: "github.com/XciD/traefik-plugin-rewrite-headers"
version: "v0.0.2"
Dynamic config:
http:
routes:
my-router:
rule: "Host(`localhost`)"
service: "my-service"
middlewares :
- "rewriteHeaders"
services:
my-service:
loadBalancer:
servers:
- url: "http://127.0.0.1"
middlewares:
rewriteHeaders:
plugin:
rewriteHeaders:
header: "Location"
regex: "^http://(.+)$"
replacement: "https://$1"
Disclaimer: I'm the author of the plugin