Need URL rewrite to add trailing slash

[javefang]

I have a simple app, which has the following file structure at root

• script.js
• style.css
• index.html (load the other two files using relative path script.js and style.css)

Since I want to access the app via URL http://example/app, I proxied the web app with rule PathStripPrefix:/app. The problem is when I try to access URL http://example/app (without trailing slash), it will load "index.html" fine, but not the JS and CSS file. When I look into the debugger, it tries to load:

• http://example/script.js
• http://exmaple/style.css

Instead of (the correct one):

• http://example/app/script.js
• http://example/app/style.css

It only works when I type the original URL with a trailing slash, so http://example/app/. This is not a big deal for me but users sometimes find it annoying since we used to use Nginx, who sends an "301 Moved Permanently" to a URL with trailing slash when it's not there. I wonder if it is possible / makes sense to implement this in Traefik?

Thank you!

[godliness]

same issue
version: v1.0.3

@emilevauge is this a bug?

[javefang]

Think should be a feature. Although you.probably want it most of the time, and begins does it by default if you use it as reverse proxy.

Expected behaviour is explained in my original post.

[royjs]

I also have the same issue

[emilevauge]

Hi, this is due to the underlying muxer used in traefik http://www.gorillatoolkit.org/pkg/mux#Router.StrictSlash. We use it with StrictSlash enabled but there is an exception:

Special case: when a route sets a path prefix using the PathPrefix() method, strict slash is ignored for that route because the redirect behavior can't be determined from a prefix alone. However, any subrouters created from that route inherit the original StrictSlash setting.

We need to work on this indeed...
As a workaround for now, I suggest to use Host rules instead of Path based rules if possible.
Any help on this is welcome ;)

[ThinkBriK]

I was able to workaround this issue using the regex on the entrypoint:

defaultEntryPoints = ["http"]
[entryPoints]
  [entryPoints.http]
  address = ":80"
    [entryPoints.http.redirect]
      regex = "(http:\\/\\/[^\\/]+\\/([^\\?]+)[^\\/])$"
      replacement = "$1/"

The redirection is fine but I ran into #679 :(

[pascalandy]

I have a similar issue here: #1123

[juanpaps03]

same issue #1106

[pascalandy]

Many issues are related to this.

[markhowells]

@emilevauge I hate to just add noise to this issue - but host based routing isn't really an option for us. Our customers have too many http proxy/firewalls in the way... Certainly we can organise html data such that the webserver container responds correctly with the full path but it pollutes the deployment - adding 'brittleness' since if we change the deployment path we have to change the data organisation to reflect the path and/or add configuration to what would otherwise be a trivial deployment...

[ldez]

Closed by #1638, in the version 1.3.0-rc3.

[kachkaev]

@ldez could you please clarify how to achieve a 301/302 redirect from http://example/app to http://example/app/, as @javefang is asking? Still facing the problem he described, i.e. when I open http://example/app, the browser tries to load css and js from http://example/static/main.(js|css)instead of http://example/app/static/main.(js|css), because asset paths in index.html are relative. What I'm looking for is some easy way to automatically add a trailing slash to /app if it's not entered.

My current igress spec:

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: my-app
  annotations:
    kubernetes.io/ingress.class: traefik
    traefik.frontend.rule.type: PathPrefixStrip
    # need something else here?
spec:
  rules:
  - host: example
    http:
      paths:
      - path: /app
        backend:
          serviceName: my-app
          servicePort: http

There is a dirty workaround for nginx in kubernetes-retired/contrib#1884 (comment), but I haven't found anything similar for traefik. Could not understand what to add to my spec after reading the docs and #1638.

When I use - path: /app/, going to /app returns 404 from another container. Also not something I'm looking for.

[pascalandy]

I confirm this was resolve when Emile officially released the fix about 3 months ago.
I run v1.3.3 and it's all good.

[kachkaev]

@pascalandy do you mean that traefik automatically redirects from /app to /app/ in your case? If yes, what does your config look like?

[pascalandy]

Enjoy this setup :)
https://github.com/pascalandy/docker-stack-this/tree/master/traefik_stack5

[ldez]

@pascalandy I don't know if you have see: we created https://github.com/containous/traefik/wiki/Awesome-Traefik.
We will very happy if you want to share your repositories in this wiki 😃

[kachkaev]

Thanks for the links guys. Not sure my kubernetes-specific question is answered in that material though :–)

[martinbaillie]

Not sure this was answered either. Did you find a way to go from http://example/app to http://example/app/ @kachkaev?

[kachkaev]

No, unfortunately. I still can't configure a separate backend at /app/ and make a rule that would redirect /app to /app/. Wondering if this issue should be reopened.

[kachkaev]

Any ideas?

[kachkaev]

Here is my current solution for k8s until I find something better 😆

Meet namespace redirects!

## add-trailing-slash.yaml
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: add-trailing-slash
  namespace: redirects
data:
  default.conf: |
    server {
      server_name $host;
      rewrite ^(.*) $scheme://$host$1/ permanent;
    }
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: add-trailing-slash
  namespace: redirects
  labels:
    part: add-trailing-slash
spec:
  replicas: 1
  template:
    metadata:
      labels:
        part: add-trailing-slash
    spec:
      containers:
      - name: main
        image: nginx:1.13.6-alpine
        volumeMounts:
        - name: nginx-config
          mountPath: /etc/nginx/conf.d/
      volumes:
      - name: nginx-config
        configMap:
          name: add-trailing-slash
---
apiVersion: v1
kind: Service
metadata:
  name: add-trailing-slash
  namespace: redirects
  labels:
    part: add-trailing-slash
spec:
  ports:
  - port: 80
    name: http
  selector:
    part: add-trailing-slash

kubectl apply -f add-trailing-slash.yaml

CASES=(
example.com/path1
another.example.com/path2
)

for CASE in "${CASES[@]}"; do
IFS='/' read CASE_DOMAIN CASE_PATH <<< "$CASE"

echo "
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: add-trailing-slash-for-${CASE_DOMAIN}--${CASE_PATH//\//-}
  namespace: redirects
spec:
  rules:
  - host: ${CASE_DOMAIN}
    http:
      paths:
      - path: /${CASE_PATH}
        backend:
          serviceName: add-trailing-slash
          servicePort: http
" | kubectl apply -f -;
done;

Thankfully I don't have that many client-facing microsercices that start with example.com/some-path. I know the solution is too bulky, so if anyone has any better suggestions, I'll be happy throw away all of the above manifests!

[pascalandy]

Thanks @MindTooth

@jvenezia you're sure about your latest config?

[jvenezia]

@MindTooth I should have told I was using Ansible, not docker compose. The syntax is a bit different.

With docker-compose, it should look like that:

labels:
- "traefik.frontend.redirect.regex=^(.*)/portainer$"
- "traefik.frontend.redirect.replacement=$1/portainer/"
- "traefik.frontend.rule=PathPrefix:/portainer;ReplacePathRegex: ^/portainer/(.*) /$1"

As you mentioned, you maybe need double the $'s. I don't have to do that, probably because of Ansible.

Did that work for you @pascalandy? Working like a charm form me!

[MindTooth]

No worries. Works like a champ AFAIK. Thanks to the both of you.

[pascalandy]

I tried few possibilities and still have the same error:

"traefik.frontend.rule=PathPrefix:/portainer;ReplacePathRegex: ^/portainer/(.*) /$1"
invalid interpolation format for services.portainer.deploy.labels.[]: "traefik.frontend.redirect.regex=^(.*)/portainer$". You may need to escape any $ with another $.

"traefik.frontend.rule=PathPrefix:/portainer;ReplacePathRegex: ^/portainer/(.*) /#$1"
invalid interpolation format for services.portainer.deploy.labels.[]: "traefik.frontend.redirect.regex=^(.*)/portainer$". You may need to escape any $ with another $.

"traefik.frontend.rule=PathPrefix:/portainer;ReplacePathRegex: ^/portainer/(.*) /$$1"
invalid interpolation format for services.portainer.deploy.labels.[]: "traefik.frontend.redirect.regex=^(.*)/portainer$". You may need to escape any $ with another $.

[pascalandy]

You can easily try my configs here

[MindTooth]

@pascalandy: Care to try with "traefik.frontend.redirect.regex=^(.*)/portainer$$"? Seems to missing a $.

[pascalandy]

FULL PROJET

error:

invalid interpolation format for services.portainer.deploy.labels.[]: "traefik.frontend.redirect.replacement=$1/portainer/". You may need to escape any $ with another $.

config:

- "traefik.frontend.redirect.regex=^(.*)/portainer$$"
- "traefik.frontend.redirect.replacement=$1/portainer/"
- "traefik.frontend.rule=PathPrefix:/portainer;ReplacePathRegex: ^/portainer/(.*) /$$1"

[hartzell]

What happens if you change the second line of your config from:

- "traefik.frontend.redirect.replacement=$1/portainer/"

to:

- "traefik.frontend.redirect.replacement=$$1/portainer/"

(escaping the $ with a second $)?

[pascalandy]

works!!!

- "traefik.frontend.redirect.regex=^(.*)/portainer$$"
- "traefik.frontend.redirect.replacement=$$1/portainer/"
- "traefik.frontend.rule=PathPrefix:/portainer;ReplacePathRegex: ^/portainer/(.*) /$$1"

[hartzell]

Woo hoo!

[pascalandy]

Thank you so much guys! @hartzell @MindTooth @jvenezia

I merged/squashed this change to master :)
Enjoy: https://github.com/pascalandy/docker-stack-this/tree/master/traefik_stack5

[pascalandy]

@ldez I believe this trailing "/" issue should be part of the docs as an example. Cheers!

[ldez]

@pascalandy maybe your first first pull request 😃 ?

[pascalandy]

Sure, please point me in which section should this doc appear and I'll do it!
I looked into https://github.com/containous/traefik/tree/master/docs and I don't see examples for docker-compose. Let's me know :)

[ldez]

I think you can add a new section here https://github.com/containous/traefik/blob/master/docs/user-guide/examples.md

[pascalandy]

See PR here: #3891

[nyurik]

I created a docs issue #4221 with a similar problem - i think we should document, as a table, all the variations of each matcher and replacer, and when they would apply, and how they would change the request on the backend. Would love to get feedback from the experts here :)

[tiagoefreitas]

How to do this using file config instead of docker-compose? Doesn't seem to work due to different variables

[romprod]

Ditto, would be interesting to do this using file config

[hartzell]

@romprod, @tiagoefreitas -- What have you tried? Can you show us a nearly working example?

[romprod]

I have this working now, I'll post my config when I get back after the weekend hopefully

[romprod]

Working code to translate 192.168.0.1:9000 to 123.co.uk/portainer

[backends.portainer]
    [backends.portainer.servers.portainer]
    url = "http://192.168.0.1:9000"

[frontends.portainer]
  backend = "portainer"
  passHostHeader = true

    [frontends.portainer.routes.portainer]
    rule = "Host:123.co.uk; PathPrefix:/portainer;ReplacePathRegex: ^/portainer/(.*) /$1"

[frontends.portainer.redirect]
      regex = "^(.*)/portainer$"
	  replacement = "$1/portainer/"

[richardburakowski]

I needed something backward compatible to 1.4 - Tested on 1.4.6 and 1.6.6
Adding a trailing slash while keeping the path prefix:
- traefik.frontend.rule=PathPrefixStripRegex:/api{u:$$},/api/;AddPrefix:/api/

regex matches and strips on/apiand/api/and puts back/api/so there's always at least/api/

Alternately,
- traefik.frontend.rule=PathPrefixStrip:/api;AddPrefix:/api
if you can handle/api123rewriting as/api/123

similarly to drop the prefix:
- traefik.frontend.rule=PathPrefixStripRegex:/api{u:$$},/api/;AddPrefix:/

[gerroon]

This is killing me. How am I supposed to employ this kind of rewriting site wide? I do not want to create regex for tens of apps. I am wondering why this is still not considered an optional thing.