Send extra parameters with client credentials request (#354)

Co-authored-by: Ewan Harris <ewan.harris@okta.com>

README.md

@@ -30,7 +30,7 @@
 
 This library follows the [same support policy as Go](https://go.dev/doc/devel/release#policy). The last two major Go releases are actively supported and compatibility issues will be fixed. While you may find that older versions of Go may work, we will not actively test and fix compatibility issues with these versions.
 
-- Go 1.20+
+- Go 1.21+
 
 ### Installation
 

authentication/oauth.go

@@ -148,6 +148,10 @@ func (o *OAuth) LoginWithClientCredentials(ctx context.Context, body oauth.Login
 		data.Set("organization", body.Organization)
 	}
 
+	for k, v := range body.ExtraParameters {
+		data.Set(k, v)
+	}
+
 	err = o.authentication.addClientAuthenticationToURLValues(body.ClientAuthentication, data, true)
 
 	if err != nil {

authentication/oauth_test.go

@@ -207,6 +207,26 @@ func TestLoginWithClientCredentials(t *testing.T) {
 		assert.Equal(t, "Bearer", tokenSet.TokenType)
 	})
 
+	t.Run("Should allow sending extra parameters", func(t *testing.T) {
+		skipE2E(t)
+		configureHTTPTestRecordings(t, authAPI)
+
+		tokenSet, err := authAPI.OAuth.LoginWithClientCredentials(context.Background(), oauth.LoginWithClientCredentialsRequest{
+			ClientAuthentication: oauth.ClientAuthentication{
+				ClientSecret: clientSecret,
+				ClientID:     "test-other-clientid",
+			},
+			Audience: "test-audience",
+			ExtraParameters: map[string]string{
+				"test": "value",
+			},
+		}, oauth.IDTokenValidationOptions{})
+
+		assert.NoError(t, err)
+		assert.NotEmpty(t, tokenSet.AccessToken)
+		assert.Equal(t, "Bearer", tokenSet.TokenType)
+	})
+
 	t.Run("Should support using private key jwt auth", func(t *testing.T) {
 		skipE2E(t)
 

go.mod

@@ -1,6 +1,6 @@
 module github.com/auth0/go-auth0
 
-go 1.20
+go 1.21
 
 require (
 	github.com/PuerkitoBio/rehttp v1.3.0

test/data/recordings/authentication/TestLoginWithClientCredentials/Should_allow_sending_extra_parameters.yaml

@@ -0,0 +1,46 @@
+---
+version: 2
+interactions:
+    - id: 0
+      request:
+        proto: HTTP/1.1
+        proto_major: 1
+        proto_minor: 1
+        content_length: 170
+        transfer_encoding: []
+        trailer: {}
+        host: go-auth0-dev.eu.auth0.com
+        remote_addr: ""
+        request_uri: ""
+        body: audience=test-audience&client_id=test-other-clientid&client_secret=test-client_secret&grant_type=client_credentials&test=value
+        form:
+            client_id:
+                - test-other-clientid
+            client_secret:
+                - test-client_secret
+            audience:
+                - test-audience
+            grant_type:
+                - client_credentials
+            test:
+                - value
+        headers:
+            Content-Type:
+                - application/x-www-form-urlencoded
+        url: https://go-auth0-dev.eu.auth0.com/oauth/token
+        method: POST
+      response:
+        proto: HTTP/2.0
+        proto_major: 2
+        proto_minor: 0
+        transfer_encoding: []
+        trailer: {}
+        content_length: -1
+        uncompressed: true
+        body: '{"access_token":"test-other-access-token","expires_in":86400,"token_type":"Bearer"}'
+        headers:
+            Content-Type:
+                - application/json
+        status: 200 OK
+        code: 200
+        duration: 145.095875ms