feat(provider): add Authgear provider

.github/ISSUE_TEMPLATE/2_bug_provider.yml

@@ -29,6 +29,7 @@ body:
         - "Atlassian"
         - "Auth0"
         - "Authentik"
+        - "Authgear"
         - "Azure Active Directory"
         - "Azure Active Directory B2C"
         - "Azure DevOps"

packages/core/src/providers/authgear.ts

@@ -0,0 +1,81 @@
+/**
+ * <div class="provider" style={{backgroundColor: "#000", display: "flex", justifyContent: "space-between", color: "#fff", padding: 16}}>
+ * <span>Built-in <b>Authgear</b> integration.</span>
+ * <a href="https://authgear.com/">
+ *   <img style={{display: "block"}} src="https://authjs.dev/img/providers/authgear.svg" height="48" />
+ * </a>
+ * </div>
+ *
+ * @module providers/authgear
+ */
+import type { OAuthConfig, OAuthUserConfig } from "./index.js"
+
+export interface AuthgearProfile extends Record<string, any> {
+  sub: string
+  name: string
+  email: string
+  picture: string
+}
+
+/**
+ * Add Authgear login to your page.
+ *
+ * ### Setup
+ *
+ * #### Callback URL
+ * ```
+ * https://example.com/api/auth/callback/authgear
+ * ```
+ *
+ * #### Configuration
+ *```ts
+ * import { Auth } from "@auth/core"
+ * import Authgear from "@auth/core/providers/authgear"
+ *
+ * const request = new Request(origin)
+ * const response = await Auth(request, {
+ *   providers: [
+ *     Authgear({
+ *       clientId: YOUR_AUTHGEAR_CLIENT_ID,
+ *       clientSecret: YOUR_AUTHGEAR_CLIENT_SECRET,
+ *       issuer: YOUR_AUTHGEAR_ISSUER_OR_PROJECT_ENDPOINT,
+ *       client: {
+           token_endpoint_auth_method: "client_secret_post",
+         }
+ *     }),
+ *   ],
+ * })
+ * ```
+ *
+ * ### Resources
+ *
+ *  - [Authgear OAuth documentation](https://docs.authgear.com/get-started/regular-web-app)
+ *
+ * :::tip
+ *
+ * The Authgear provider comes with a [default configuration](https://github.com/nextauthjs/next-auth/blob/main/packages/core/src/providers/authgear.ts).
+ * To override the defaults for your use case, check out [customizing a built-in OAuth provider](https://authjs.dev/guides/configuring-oauth-providers).
+ *
+ * :::
+ *
+ * :::info **Disclaimer**
+ *
+ * If you think you found a bug in the default configuration, you can [open an issue](https://authjs.dev/new/provider-issue).
+ *
+ * Auth.js strictly adheres to the specification and it cannot take responsibility for any deviation from
+ * the spec by the provider. You can open an issue, but if the problem is non-compliance with the spec,
+ * we might not pursue a resolution. You can ask for more help in [Discussions](https://authjs.dev/new/github-discussions).
+ *
+ * :::
+ */
+export default function Authgear<P extends AuthgearProfile>(
+  options: OAuthUserConfig<P>
+): OAuthConfig<P> {
+  return {
+    id: "authgear",
+    name: "Authgear",
+    type: "oidc",
+    style: { bg: "#000", text: "#fff" },
+    options,
+  }
+}