[keycloak-dev] Client Adapters for Golang

[Thomas Darimont]

Hello Bela,

what framework or library are you using in your Go Web App? The thing is,
there is no such thing as a "single" Keycloak integration,
due to the myriads of web frameworks available for Go.

Of course most of them support a Servlet Filter like middleware pattern (as
shown below) that could be implemented somewhat generic but in the end you
probably
need an integration that is custom to your framework.

I just started to adding support for Keycloak to
https://github.com/stretchr/gomniauth but the library is missing a bit of
functionality such as logout etc.
There is https://github.com/gambol99/keycloak-proxy where you could look
for the OIDC protocol interaction create your own implementation.

Another option would be to just use an OIDC go client implementation like:
https://github.com/coreos/go-oidc or https://github.com/ericchiang/oidc

Cheers,
Thomas


package main

import (
"flag"
"fmt"
"github.com/gorilla/mux"
"log"
"net/http"
"net/http/httputil"
"os"
"time"
)

var greeting string

func main() {

flag.StringVar(&greeting, "g", "Hello", "The greeting message, defaults to
'Hello'")
flag.Parse()

logger := *log.New(os.Stdout, "logger: ", log.Lshortfile)

router := mux.NewRouter()
router.Handle("/greet", http.HandlerFunc(greet))

//for all routes apply the follwing list of handlers
http.Handle("/", Adapt(router,
WithLogger(&logger),
WithRequestTracing(),
WithHeaders(map[string]string{"foo": "42", "bar": "1337"}),
))

http.ListenAndServe(":8080", nil)
}

// Adapter wraps an http.Handler with Additional functionality.
type Adapter func(http.Handler) http.Handler

// Adapt h with all specified adapters.
func Adapt(h http.Handler, adapters ...Adapter) http.Handler {

// apply handler backwards so that they are executed in declared order
for i := len(adapters) - 1; i >= 0; i-- {
h = adapters[i](h)
}

return h
}

// curl -v http://localhost:8080/greet
func greet(w http.ResponseWriter, r *http.Request) {

w.WriteHeader(http.StatusOK)
fmt.Fprintf(w, greeting+" %v\n", time.Now().String())
}

func WithRequestTracing() Adapter {
return func(h http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {

dump, err := httputil.DumpRequest(r, true)
if err != nil {
http.Error(w, fmt.Sprint(err), http.StatusInternalServerError)
return
}

fmt.Printf("Request Dump:\n%q\n", dump)

h.ServeHTTP(w, r)
})
}
}

func WithHeaders(headers map[string]string) Adapter {
return func(h http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {

for key, value := range headers {
w.Header().Add(key, value)
}

h.ServeHTTP(w, r)
})
}
}

func WithLogger(l *log.Logger) Adapter {
return func(h http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {

l.Println(r.Method, r.URL.Path)

h.ServeHTTP(w, r)
})
}
}


2018-03-05 0:48 GMT+01:00 Bela Berde <bela.berde at gmail.com>:

> Hi,
> Is there someone who successfully connected Keycloak to a Golang
> Frontend-Backend?
> Many thanks.
> Cheers
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> keycloak-dev at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/keycloak-dev
>