subfilter is a middleware plugin for Traefik which rewrites the HTTP response body by replacing a search
regex by a replacement string. Subfilter was directly cloned from
plugin-rewritebody and modified (keeping all git history) to address issues not resolved in the upstream
repository
[pilot]
token = "xxxx"
[experimental.plugins.subfilter]
modulename = "github.com/DirtyCajunRice/subfilter"
version = "v0.5.0"To configure the subfilter plugin, create a middleware in your configuration as explained here. The
following examples create and use subfilter to replace all foo occurrences by bar in the HTTP response body.
If you want to apply some limits on the response body, you can chain this middleware plugin with the Buffering middleware from Traefik.
[http.routers]
[http.routers.my-router]
rule = "Host(`localhost`)"
middlewares = ["subfilter-foo"]
service = "my-service"
[http.middlewares]
[http.middlewares.subfilter-foo.plugin.subfilter]
# Keep Last-Modified header returned by the HTTP service.
# By default, the Last-Modified header is removed.
lastModified = true
# Rewrites all "foo" occurences by "bar"
[[http.middlewares.subfilter-foo.plugin.subfilter.filters]]
regex = "foo"
replacement = "bar"
[http.services]
[http.services.my-service]
[http.services.my-service.loadBalancer]
[[http.services.my-service.loadBalancer.servers]]
url = "http://127.0.0.1"extraArgs
...
- "--experimental.plugins.subfilter.modulename=github.com/DirtyCajunRice/subfilter"
- "--experimental.plugins.subfilter.version=v0.5.0"
...Middleware CRD
apiVersion: traefik.containo.us/v1alpha1
kind: Middleware
metadata:
name: subfilter-foo
spec:
plugin:
subfilter:
lastModified: true
filters:
- regex: foo
replacement: barsubfilter uses golang's regexp package. You can use The Go Playground to test your regex.
Here is a minimally viable example:
package main
import (
"fmt"
"regexp"
)
func main() {
r := regexp.MustCompile(`((href|src)=")/`)
body := []byte("<html><head><link rel=\"stylesheet\" href=\"/style.css\"></head></html>")
replace :=[]byte("${1}/subdomain/")
fmt.Printf("%s\n", r.ReplaceAll(body, replace))
}