feat: add authentik provider

* feat: add authentik provider

* Update src/runtime/server/lib/oauth/authentik.ts

---------

Co-authored-by: Sébastien Chopin <seb@nuxtlabs.com>

Author: aoor9

README.md

@@ -205,6 +205,7 @@ It can also be set using environment variables:
 #### Supported OAuth Providers
 
 - Auth0
+- Authentik
 - AWS Cognito
 - Battle.net
 - Discord

playground/.env.example

@@ -81,3 +81,7 @@ NUXT_OAUTH_LINEAR_CLIENT_SECRET=
 NUXT_OAUTH_ZITADEL_CLIENT_ID=
 NUXT_OAUTH_ZITADEL_CLIENT_SECRET=
 NUXT_OAUTH_ZITADEL_DOMAIN=
+# Authentik
+NUXT_OAUTH_AUTHENTIK_CLIENT_ID=
+NUXT_OAUTH_AUTHENTIK_CLIENT_SECRET=
+NUXT_OAUTH_AUTHENTIK_DOMAIN=

playground/app.vue

@@ -153,6 +153,12 @@ const providers = computed(() =>
       disabled: Boolean(user.value?.zitadel),
       icon: 'i-gravity-ui-lock',
     },
+    {
+      label: user.value?.authentik || 'Authentik',
+      to: '/auth/authentik',
+      disabled: Boolean(user.value?.authentik),
+      icon: 'i-simple-icons-authentik',
+    },
   ].map(p => ({
     ...p,
     prefetch: false,

playground/auth.d.ts

@@ -28,6 +28,7 @@ declare module '#auth-utils' {
     dropbox?: string
     polar?: string
     zitadel?: string
+    authentik?: string
   }
 
   interface UserSession {

playground/server/routes/auth/authentik.get.ts

@@ -0,0 +1,12 @@
+export default defineOAuthAuthentikEventHandler({
+  async onSuccess(event, { user }) {
+    await setUserSession(event, {
+      user: {
+        authentik: user.preferred_username,
+      },
+      loggedInAt: Date.now(),
+    })
+
+    return sendRedirect(event, '/')
+  },
+})

src/module.ts

@@ -315,5 +315,12 @@ export default defineNuxtModule<ModuleOptions>({
       domain: '',
       redirectURL: '',
     })
+    // Authentik OAuth
+    runtimeConfig.oauth.authentik = defu(runtimeConfig.oauth.authentik, {
+      clientId: '',
+      clientSecret: '',
+      domain: '',
+      redirectURL: '',
+    })
   },
 })

src/runtime/server/lib/oauth/authentik.ts

@@ -0,0 +1,113 @@
+import type { H3Event } from 'h3'
+import { eventHandler, getQuery, sendRedirect } from 'h3'
+import { withQuery } from 'ufo'
+import { defu } from 'defu'
+import { handleMissingConfiguration, handleAccessTokenErrorResponse, getOAuthRedirectURL, requestAccessToken } from '../utils'
+import { useRuntimeConfig, createError } from '#imports'
+import type { OAuthConfig } from '#auth-utils'
+
+export interface OAuthAuthentikConfig {
+  /**
+   * Authentik OAuth Client ID
+   * @default process.env.NUXT_OAUTH_AUTHENTIK_CLIENT_ID
+   */
+  clientId?: string
+  /**
+   * Authentik OAuth Client Secret
+   * @default process.env.NUXT_OAUTH_AUTHENTIK_CLIENT_SECRET
+   */
+  clientSecret?: string
+  /**
+   * Authentik OAuth Domain
+   * @example https://<your-authentik-instance>
+   * @default process.env.NUXT_OAUTH_AUTHENTIK_DOMAIN
+   */
+  domain?: string
+  /**
+   * Redirect URL to allow overriding for situations like prod failing to determine public hostname
+   * @default process.env.NUXT_OAUTH_AUTHENTIK_REDIRECT_URL or current URL
+   */
+  redirectURL?: string
+}
+
+export function defineOAuthAuthentikEventHandler({ config, onSuccess, onError }: OAuthConfig<OAuthAuthentikConfig>) {
+  return eventHandler(async (event: H3Event) => {
+    config = defu(config, useRuntimeConfig(event).oauth?.authentik) as OAuthAuthentikConfig
+
+    const query = getQuery<{ code?: string, error?: string }>(event)
+
+    if (query.error) {
+      const error = createError({
+        statusCode: 401,
+        message: `Authentik login failed: ${query.error || 'Unknown error'}`,
+        data: query,
+      })
+      if (!onError) throw error
+      return onError(event, error)
+    }
+
+    if (!config.clientId || !config.clientSecret || !config.domain) {
+      return handleMissingConfiguration(event, 'authentik', ['clientId', 'clientSecret', 'domain'], onError)
+    }
+
+    const authorizationURL = `https://${config.domain}/application/o/authorize/`
+    const tokenURL = `https://${config.domain}/application/o/token/`
+    const redirectURL = config.redirectURL || getOAuthRedirectURL(event)
+
+    if (!query.code) {
+      // Redirect to Authentik OAuth page
+
+      return sendRedirect(
+        event,
+        withQuery(authorizationURL, {
+          response_type: 'code',
+          client_id: config.clientId,
+          redirect_uri: redirectURL,
+          scope: ['openid', 'profile', 'email'].join(' '),
+        }),
+      )
+    }
+
+    const tokens = await requestAccessToken(tokenURL, {
+      headers: {
+        'Authorization': `Basic ${Buffer.from(`${config.clientId}:${config.clientSecret}`).toString('base64')}`,
+        'Content-Type': 'application/x-www-form-urlencoded',
+      },
+      body: {
+        grant_type: 'authorization_code',
+        client_id: config.clientId,
+        redirect_uri: redirectURL,
+        code: query.code,
+      },
+    })
+
+    if (tokens.error) {
+      return handleAccessTokenErrorResponse(event, 'authentik', tokens, onError)
+    }
+
+    const accessToken = tokens.access_token
+    // Fetch user info
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    const user: any = await $fetch(`https://${config.domain}/application/o/userinfo/`, {
+      headers: {
+        Authorization: `Bearer ${accessToken}`,
+        Accept: 'application/json',
+      },
+    })
+
+    if (!user) {
+      const error = createError({
+        statusCode: 500,
+        message: 'Could not get Authentik user',
+        data: tokens,
+      })
+      if (!onError) throw error
+      return onError(event, error)
+    }
+
+    return onSuccess(event, {
+      user,
+      tokens,
+    })
+  })
+}

src/runtime/types/oauth-config.ts

@@ -1,6 +1,6 @@
 import type { H3Event, H3Error } from 'h3'
 
-export type OAuthProvider = 'auth0' | 'battledotnet' | 'cognito' | 'discord' | 'dropbox' | 'facebook' | 'github' | 'gitlab' | 'google' | 'instagram' | 'keycloak' | 'linear' | 'linkedin' | 'microsoft' | 'paypal' | 'polar' | 'spotify' | 'steam' | 'tiktok' | 'twitch' | 'vk' | 'x' | 'xsuaa' | 'yandex' | 'zitadel' | (string & {})
+export type OAuthProvider = 'auth0' | 'authentik' | 'battledotnet' | 'cognito' | 'discord' | 'dropbox' | 'facebook' | 'github' | 'gitlab' | 'google' | 'instagram' | 'keycloak' | 'linear' | 'linkedin' | 'microsoft' | 'paypal' | 'polar' | 'spotify' | 'steam' | 'tiktok' | 'twitch' | 'vk' | 'x' | 'xsuaa' | 'yandex' | 'zitadel' | (string & {})
 
 export type OnError = (event: H3Event, error: H3Error) => Promise<void> | void