adding slo request for saml in demo example

s2example/demo.go

@@ -15,13 +15,15 @@
 package main
 
 import (
+	"crypto/rsa"
 	"crypto/x509"
 	"fmt"
+	"io"
 	"net/http"
-
-	"io/ioutil"
+	"os"
 
 	"encoding/base64"
+	"encoding/pem"
 	"encoding/xml"
 
 	saml2 "github.com/russellhaering/gosaml2"
@@ -35,7 +37,7 @@ func main() {
 		panic(err)
 	}
 
-	rawMetadata, err := ioutil.ReadAll(res.Body)
+	rawMetadata, err := io.ReadAll(res.Body)
 	if err != nil {
 		panic(err)
 	}
@@ -82,16 +84,36 @@ func main() {
 		AudienceURI:                 "http://example.com/saml/acs/example",
 		IDPCertificateStore:         &certStore,
 		SPKeyStore:                  randomKeyStore,
+		IdentityProviderSLOURL: metadata.IDPSSODescriptor.SingleLogoutServices[0].Location,
+		ServiceProviderSLOURL: "http://localhost:8080/v1/_logout",
+	}
+
+
+//  generate sp private key, certificate this is used to sign the slo request for logout
+	keystore, err := loadKeystore("<private key path>","<certificate path>")
+	if err!=nil {
+		fmt.Printf("Error loading keystore")
 	}
 
+	sp.SetSPSigningKeyStore(keystore)
+
+	sessionIndex := ""
+	nameID := ""
+
 	http.HandleFunc("/v1/_saml_callback", func(rw http.ResponseWriter, req *http.Request) {
 		err := req.ParseForm()
+		rw.Header().Add("Content-Type", "text/html")
+
 		if err != nil {
 			rw.WriteHeader(http.StatusBadRequest)
 			return
 		}
 
 		assertionInfo, err := sp.RetrieveAssertionInfo(req.FormValue("SAMLResponse"))
+
+		sessionIndex = assertionInfo.SessionIndex
+		nameID = assertionInfo.NameID
+
 		if err != nil {
 			rw.WriteHeader(http.StatusForbidden)
 			return
@@ -119,6 +141,36 @@ func main() {
 
 		fmt.Fprintf(rw, "Warnings:\n")
 		fmt.Fprintf(rw, "%+v\n", assertionInfo.WarningInfo)
+
+		logoutRequest, err := sp.BuildLogoutRequestDocument(nameID, sessionIndex)
+
+		logouturl , _ := sp.BuildLogoutURLRedirect("", logoutRequest)
+
+		fmt.Fprintf(rw, " Click to logout <a href=%s> Logout </a>\n", logouturl)
+	})
+
+	http.HandleFunc("/v1/_logout", func(rw http.ResponseWriter, req *http.Request) {
+
+		err := req.ParseForm()
+		if err != nil {
+			rw.WriteHeader(http.StatusBadRequest)
+			return
+		}
+
+
+		response , err := sp.ValidateEncodedLogoutResponsePOST(req.FormValue("SAMLResponse"))
+		fmt.Printf("the logout response %v\n", response.Status.StatusCode.Value)
+
+
+		if err!=nil {
+			fmt.Printf("Failed to logout %s \n", err)
+			fmt.Fprintf(rw, "Couldn't log out %s due to some internal error",nameID)
+		}else if response.Status.StatusCode.Value != "urn:oasis:names:tc:SAML:2.0:status:Success"{
+			fmt.Fprintf(rw, "Couldn't log out %s due to invalid request", nameID)
+		}else{
+			fmt.Fprintf(rw, "%s logged out successfully",nameID)
+		}
+
 	})
 
 	println("Visit this URL To Authenticate:")
@@ -137,3 +189,41 @@ func main() {
 		panic(err)
 	}
 }
+
+
+func loadKeystore(privateKeyPath, publicCertificate string) (*saml2.KeyStore, error){
+	privateKeyBytes, err := os.ReadFile(privateKeyPath)
+
+	if err != nil {
+		fmt.Printf("There is some error reading the private key %v \n", err)
+		return nil, err
+	}
+
+	certBytes, err := os.ReadFile(publicCertificate)
+
+	if err != nil {
+		fmt.Printf("There is some error reading the cert key %v \n", err)
+		return nil, err
+	}
+
+	block, _ := pem.Decode(privateKeyBytes)
+
+	if block == nil {
+		fmt.Printf("Invalid Pem private key")
+		panic("Invalid Pem private key")
+	}
+
+	privateKey, err := x509.ParsePKCS8PrivateKey(block.Bytes)
+
+	if err!=nil {
+		fmt.Printf("There is some error signing parsing the private key: %v\n", err)
+		return nil, err
+	}
+
+	keystore := &saml2.KeyStore{
+		Signer: privateKey.(*rsa.PrivateKey),
+		Cert: certBytes,
+	}
+
+	return keystore, nil
+}