feat: support custom OIDC token endpoint URL

credentials/credentials.ts

@@ -37,6 +37,8 @@ interface ClientAssertionRequest {
   audience: string;
 }
 
+export const DEFAULT_TOKEN_ENDPOINT_PATH = "oauth/token";
+
 export class Credentials {
   private accessToken?: string;
   private accessTokenExpiryDate?: Date;
@@ -93,9 +95,9 @@ export class Credentials {
       assertParamExists("Credentials", "config.apiAudience", authConfig.config?.apiAudience);
       assertParamExists("Credentials", "config.clientSecret or config.clientAssertionSigningKey", (authConfig.config as ClientSecretConfig).clientSecret || (authConfig.config as PrivateKeyJWTConfig).clientAssertionSigningKey);
 
-      if (!isWellFormedUriString(`https://${authConfig.config?.apiTokenIssuer}`)) {
+      if (!isWellFormedUriString(this.buildApiTokenUrl(authConfig.config?.apiTokenIssuer))) {
         throw new FgaValidationError(
-          `Configuration.apiTokenIssuer does not form a valid URI (https://${authConfig.config?.apiTokenIssuer})`);
+          `Configuration.apiTokenIssuer does not form a valid URI (${authConfig.config?.apiTokenIssuer})`);
       }
       break;
     }
@@ -138,13 +140,38 @@ export class Credentials {
     }
   }
 
+  /**
+   * Constructs the token endpoint URL from the provided API token issuer.
+   * Defaults to https:// scheme if none provided and appends the default
+   * token endpoint path when the issuer has no path or only a root path.
+   * 
+   * @param apiTokenIssuer
+   * @return string The constructed token endpoint URL, or empty string if invalid
+   */
+  private buildApiTokenUrl(apiTokenIssuer: string): string {
+    let url = URL.parse(apiTokenIssuer);
+    if (!url && !apiTokenIssuer.startsWith("https://") && !apiTokenIssuer.startsWith("http://")) {
+      url = URL.parse(`https://${apiTokenIssuer}`);
+    }
+
+    if (url) {
+      if (url.pathname === "" || url.pathname === "/") {
+        url.pathname = `/${DEFAULT_TOKEN_ENDPOINT_PATH}`;
+      }
+
+      return url.toString();
+    }
+
+    return "";
+  }
+
   /**
    * Request new access token
    * @return string
    */
   private async refreshAccessToken() {
     const clientCredentials = (this.authConfig as { method: CredentialsMethod.ClientCredentials; config: ClientCredentialsConfig })?.config;
-    const url = `https://${clientCredentials.apiTokenIssuer}/oauth/token`;
+    const url = this.buildApiTokenUrl(clientCredentials.apiTokenIssuer);
     const credentialsPayload = await this.buildClientAuthenticationPayload();
 
     try {

tests/credentials.test.ts

@@ -0,0 +1,120 @@
+import * as nock from "nock";
+import { Credentials, CredentialsMethod, DEFAULT_TOKEN_ENDPOINT_PATH } from "../credentials";
+import { AuthCredentialsConfig } from "../credentials/types";
+import { TelemetryConfiguration } from "../telemetry/configuration";
+import {
+  OPENFGA_API_AUDIENCE,
+  OPENFGA_CLIENT_ID,
+  OPENFGA_CLIENT_SECRET,
+} from "./helpers/default-config";
+
+nock.disableNetConnect();
+
+describe("Credentials", () => {
+  const mockTelemetryConfig: TelemetryConfiguration = new TelemetryConfiguration({});
+
+  describe("Refreshing access token", () => {
+    interface TestCase {
+      description: string;
+      apiTokenIssuer: string;
+      expectedBaseUrl: string;
+      expectedPath: string;
+      queryParams?: Record<string, string>;
+    }
+
+    const testCases: TestCase[] = [
+      {
+        description: "should use default scheme and token endpoint path when apiTokenIssuer has no scheme and no path",
+        apiTokenIssuer: "issuer.fga.example",
+        expectedBaseUrl: "https://issuer.fga.example",
+        expectedPath: `/${DEFAULT_TOKEN_ENDPOINT_PATH}`,
+      },
+      {
+        description: "should use default token endpoint path when apiTokenIssuer has root path and no scheme",
+        apiTokenIssuer: "https://issuer.fga.example/",
+        expectedBaseUrl: "https://issuer.fga.example",
+        expectedPath: `/${DEFAULT_TOKEN_ENDPOINT_PATH}`,
+      },
+      {
+        description: "should preserve custom token endpoint path when provided",
+        apiTokenIssuer: "https://issuer.fga.example/some_endpoint",
+        expectedBaseUrl: "https://issuer.fga.example",
+        expectedPath: "/some_endpoint",
+      },
+      {
+        description: "should preserve custom token endpoint path with nested path when provided",
+        apiTokenIssuer: "https://issuer.fga.example/api/v1/oauth/token",
+        expectedBaseUrl: "https://issuer.fga.example",
+        expectedPath: "/api/v1/oauth/token",
+      },
+      {
+        description: "should add https:// prefix when apiTokenIssuer has no scheme",
+        apiTokenIssuer: "issuer.fga.example/some_endpoint",
+        expectedBaseUrl: "https://issuer.fga.example",
+        expectedPath: "/some_endpoint",
+      },
+      {
+        description: "should preserve http:// scheme when provided",
+        apiTokenIssuer: "http://issuer.fga.example/some_endpoint",
+        expectedBaseUrl: "http://issuer.fga.example",
+        expectedPath: "/some_endpoint",
+      },
+      {
+        description: "should use default path when apiTokenIssuer has https:// scheme but no path",
+        apiTokenIssuer: "https://issuer.fga.example",
+        expectedBaseUrl: "https://issuer.fga.example",
+        expectedPath: `/${DEFAULT_TOKEN_ENDPOINT_PATH}`,
+      },
+      {
+        description: "should preserve custom path with query parameters",
+        apiTokenIssuer: "https://issuer.fga.example/some_endpoint?param=value",
+        expectedBaseUrl: "https://issuer.fga.example",
+        expectedPath: "/some_endpoint",
+        queryParams: { param: "value" },
+      },
+      {
+        description: "should preserve custom path with port number",
+        apiTokenIssuer: "https://issuer.fga.example:8080/some_endpoint",
+        expectedBaseUrl: "https://issuer.fga.example:8080",
+        expectedPath: "/some_endpoint",
+      },
+    ];
+
+    test.each(testCases)("$description", async ({ apiTokenIssuer, expectedBaseUrl, expectedPath, queryParams }) => {
+      const scope = queryParams
+        ? nock(expectedBaseUrl)
+          .post(expectedPath)
+          .query(queryParams)
+          .reply(200, {
+            access_token: "test-token",
+            expires_in: 300,
+          })
+        : nock(expectedBaseUrl)
+          .post(expectedPath)
+          .reply(200, {
+            access_token: "test-token",
+            expires_in: 300,
+          });
+
+      const credentials = new Credentials(
+        {
+          method: CredentialsMethod.ClientCredentials,
+          config: {
+            apiTokenIssuer,
+            apiAudience: OPENFGA_API_AUDIENCE,
+            clientId: OPENFGA_CLIENT_ID,
+            clientSecret: OPENFGA_CLIENT_SECRET,
+          },
+        } as AuthCredentialsConfig,
+        undefined,
+        mockTelemetryConfig,
+      );
+
+      await credentials.getAccessTokenHeader();
+
+      expect(scope.isDone()).toBe(true);
+      nock.cleanAll();
+    });
+  });
+});
+

tests/index.test.ts

@@ -61,15 +61,30 @@ describe("OpenFGA SDK", function () {
       ).not.toThrowError();
     });
 
-    it("should validate apiTokenIssuer in configuration (should not allow scheme as part of the apiTokenIssuer)", () => {
+    it.each(["https://", "http://", ""])("should allow valid schemes as part of the apiTokenIssuer in configuration (%s)", (scheme) => {
       expect(
         () => new OpenFgaApi({
           ...baseConfig,
           credentials: {
             method: CredentialsMethod.ClientCredentials,
             config: {
               ...(baseConfig.credentials as any).config,
-              apiTokenIssuer: "https://tokenissuer.fga.example"
+              apiTokenIssuer: `${scheme}tokenissuer.fga.example`
+            }
+          } as Configuration["credentials"]
+        })
+      ).not.toThrowError();
+    });
+
+    it.each(["tcp://", "grpc://", "file://"])("should not allow invalid schemes as part of the apiTokenIssuer in configuration (%s)", (scheme) => {
+      expect(
+        () => new OpenFgaApi({
+          ...baseConfig,
+          credentials: {
+            method: CredentialsMethod.ClientCredentials,
+            config: {
+              ...(baseConfig.credentials as any).config,
+              apiTokenIssuer: `${scheme}tokenissuer.fga.example`
             }
           } as Configuration["credentials"]
         })