add backend support for Apple auth provider

It's a bit different from other OAuth providers and requires a
different set of options and a private key file.

backend/app/cmd/server.go

@@ -96,16 +96,17 @@ type ServerCommand struct {
 		SendJWTHeader bool   `long:"send-jwt-header" env:"SEND_JWT_HEADER" description:"send JWT as a header instead of cookie"`
 		SameSite      string `long:"same-site" env:"SAME_SITE" description:"set same site policy for cookies" choice:"default" choice:"none" choice:"lax" choice:"strict" default:"default"` // nolint
 
-		Google    AuthGroup `group:"google" namespace:"google" env-namespace:"GOOGLE" description:"Google OAuth"`
-		Github    AuthGroup `group:"github" namespace:"github" env-namespace:"GITHUB" description:"Github OAuth"`
-		Facebook  AuthGroup `group:"facebook" namespace:"facebook" env-namespace:"FACEBOOK" description:"Facebook OAuth"`
-		Microsoft AuthGroup `group:"microsoft" namespace:"microsoft" env-namespace:"MICROSOFT" description:"Microsoft OAuth"`
-		Yandex    AuthGroup `group:"yandex" namespace:"yandex" env-namespace:"YANDEX" description:"Yandex OAuth"`
-		Twitter   AuthGroup `group:"twitter" namespace:"twitter" env-namespace:"TWITTER" description:"Twitter OAuth"`
-		Patreon   AuthGroup `group:"patreon" namespace:"patreon" env-namespace:"PATREON" description:"Patreon OAuth"`
-		Telegram  bool      `long:"telegram" env:"TELEGRAM" description:"Enable Telegram auth (using token from telegram.token)"`
-		Dev       bool      `long:"dev" env:"DEV" description:"enable dev (local) oauth2"`
-		Anonymous bool      `long:"anon" env:"ANON" description:"enable anonymous login"`
+		Apple     AppleGroup `group:"apple" namespace:"apple" env-namespace:"APPLE" description:"Apple OAuth"`
+		Google    AuthGroup  `group:"google" namespace:"google" env-namespace:"GOOGLE" description:"Google OAuth"`
+		Github    AuthGroup  `group:"github" namespace:"github" env-namespace:"GITHUB" description:"Github OAuth"`
+		Facebook  AuthGroup  `group:"facebook" namespace:"facebook" env-namespace:"FACEBOOK" description:"Facebook OAuth"`
+		Microsoft AuthGroup  `group:"microsoft" namespace:"microsoft" env-namespace:"MICROSOFT" description:"Microsoft OAuth"`
+		Yandex    AuthGroup  `group:"yandex" namespace:"yandex" env-namespace:"YANDEX" description:"Yandex OAuth"`
+		Twitter   AuthGroup  `group:"twitter" namespace:"twitter" env-namespace:"TWITTER" description:"Twitter OAuth"`
+		Patreon   AuthGroup  `group:"patreon" namespace:"patreon" env-namespace:"PATREON" description:"Patreon OAuth"`
+		Telegram  bool       `long:"telegram" env:"TELEGRAM" description:"Enable Telegram auth (using token from telegram.token)"`
+		Dev       bool       `long:"dev" env:"DEV" description:"enable dev (local) oauth2"`
+		Anonymous bool       `long:"anon" env:"ANON" description:"enable anonymous login"`
 		Email     struct {
 			Enable       bool          `long:"enable" env:"ENABLE" description:"enable auth via email"`
 			From         string        `long:"from" env:"FROM" description:"from email address"`
@@ -133,6 +134,14 @@ type ImageProxyGroup struct {
 	CacheExternal bool `long:"cache-external" env:"CACHE_EXTERNAL" description:"enable caching for external images"`
 }
 
+// AppleGroup defines options for Apple auth params
+type AppleGroup struct {
+	CID                string `long:"cid" env:"CID" description:"Apple client ID"`
+	TID                string `long:"tid" env:"TID" description:"Apple service ID"`
+	KID                string `long:"kid" env:"KID" description:"Private key ID"`
+	PrivateKeyFilePath string `long:"private-key-filepath" env:"PRIVATE_KEY_FILEPATH" description:"Private key file location" default:"/var/apple.p8"`
+}
+
 // AuthGroup defines options group for auth params
 type AuthGroup struct {
 	CID  string `long:"cid" env:"CID" description:"OAuth client ID"`
@@ -835,6 +844,20 @@ func (s *ServerCommand) addAuthProviders(authenticator *auth.Service) error {
 		providersCount++
 	}
 
+	if s.Auth.Apple.CID != "" && s.Auth.Apple.TID != "" && s.Auth.Apple.KID != "" {
+		err := authenticator.AddAppleProvider(
+			provider.AppleConfig{
+				ClientID: s.Auth.Apple.CID,
+				TeamID:   s.Auth.Apple.TID,
+				KeyID:    s.Auth.Apple.KID,
+			},
+			provider.LoadApplePrivateKeyFromFile(s.Auth.Apple.PrivateKeyFilePath),
+		)
+		if err != nil {
+			return err
+		}
+		providersCount++
+	}
 	if s.Auth.Google.CID != "" && s.Auth.Google.CSEC != "" {
 		authenticator.AddProvider("google", s.Auth.Google.CID, s.Auth.Google.CSEC)
 		providersCount++

backend/app/cmd/server_test.go

@@ -758,6 +758,8 @@ func prepServerApp(t *testing.T, fn func(o ServerCommand) ServerCommand) (*serve
 	cmd.Avatar.FS.Path, cmd.Avatar.Type, cmd.BackupLocation, cmd.Image.FS.Path = "/tmp/remark42_test", "fs", "/tmp/remark42_test", "/tmp/remark42_test"
 	cmd.Store.Bolt.Path = fmt.Sprintf("/tmp/%d", cmd.Port)
 	cmd.Store.Bolt.Timeout = 10 * time.Second
+	cmd.Auth.Apple.CID, cmd.Auth.Apple.KID, cmd.Auth.Apple.TID = "cid", "kid", "tid"
+	cmd.Auth.Apple.PrivateKeyFilePath = "testdata/apple.p8"
 	cmd.Auth.Github.CSEC, cmd.Auth.Github.CID = "csec", "cid"
 	cmd.Auth.Google.CSEC, cmd.Auth.Google.CID = "csec", "cid"
 	cmd.Auth.Facebook.CSEC, cmd.Auth.Facebook.CID = "csec", "cid"

backend/app/cmd/testdata/apple.p8

@@ -0,0 +1,6 @@
+-----BEGIN PRIVATE KEY-----
+MIGTAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBHkwdwIBAQQgGH2MylyZjjRdauTk
+xxXW6p8VSHqIeVRRKSJPg1xn6+KgCgYIKoZIzj0DAQehRANCAAS/mNzQ7aBbIBr3
+DiHiJGIDEzi6+q3mmyhH6ZWQWFdFei2qgdyM1V6qtRPVq+yHBNSBebbR4noE/IYO
+hMdWYrKn
+-----END PRIVATE KEY-----

backend/go.mod

@@ -11,7 +11,7 @@ require (
 	github.com/go-chi/chi/v5 v5.0.7
 	github.com/go-chi/cors v1.2.1
 	github.com/go-chi/render v1.0.2
-	github.com/go-pkgz/auth v1.20.1-0.20221226231300-65f433fba0f1
+	github.com/go-pkgz/auth v1.20.1-0.20230103203948-168bd5a101b7
 	github.com/go-pkgz/jrpc v0.3.0
 	github.com/go-pkgz/lcw v1.0.3-0.20221226231215-a66ea7c4aff7
 	github.com/go-pkgz/lgr v0.10.4

backend/go.sum

@@ -142,6 +142,8 @@ github.com/go-oauth2/oauth2/v4 v4.5.1 h1:3vxp+cjLqDe1TbogbwtMyeHRHr1tD+ksrK7xNpp
 github.com/go-oauth2/oauth2/v4 v4.5.1/go.mod h1:wk/2uLImWIa9VVQDgxz99H2GDbhmfi/9/Xr+GvkSUSQ=
 github.com/go-pkgz/auth v1.20.1-0.20221226231300-65f433fba0f1 h1:MJA4rZAwjd+KpaR2PqrxeDPloNu9Wml1UVQjL2fOtVM=
 github.com/go-pkgz/auth v1.20.1-0.20221226231300-65f433fba0f1/go.mod h1:fG1CP4+LDPnebYeO1BAZg/euTQQ8cnGn+5ZrXvJfckA=
+github.com/go-pkgz/auth v1.20.1-0.20230103203948-168bd5a101b7 h1:ktKI3Y3UytkBLL1cOEzJmAi3nNKeaRGOzDj51Kgqp6M=
+github.com/go-pkgz/auth v1.20.1-0.20230103203948-168bd5a101b7/go.mod h1:fG1CP4+LDPnebYeO1BAZg/euTQQ8cnGn+5ZrXvJfckA=
 github.com/go-pkgz/email v0.3.1-0.20221002173339-19d25a20d99c/go.mod h1:TpnmSLkQW3FyICit2hn7WIhCUDrhCX6btzz5wS3wHRI=
 github.com/go-pkgz/email v0.4.1 h1:2vtP2gibsSzqhz6eD5DklSp11m657XEVf17fuXaxMvk=
 github.com/go-pkgz/email v0.4.1/go.mod h1:BdxglsQnymzhfdbnncEE72a6DrucZHy6I+42LK2jLEc=

backend/vendor/modules.txt

@@ -65,7 +65,7 @@ github.com/go-chi/render
 github.com/go-oauth2/oauth2/v4
 github.com/go-oauth2/oauth2/v4/errors
 github.com/go-oauth2/oauth2/v4/server
-# github.com/go-pkgz/auth v1.20.1-0.20221226231300-65f433fba0f1
+# github.com/go-pkgz/auth v1.20.1-0.20230103203948-168bd5a101b7
 ## explicit; go 1.17
 github.com/go-pkgz/auth
 github.com/go-pkgz/auth/avatar

site/src/docs/configuration/authorization/index.md

@@ -6,6 +6,23 @@ title: Authorization
 
 Authentication handled by external providers. You should set up OAuth2 for at least one of them to allow users to make comments. It is not mandatory to have all of them, but one should be correctly configured.
 
+### Apple
+
+1. Log in [to the developer account](https://developer.apple.com/account).
+1. If you don't have an App ID yet, [create one](https://developer.apple.com/account/resources/identifiers/add/bundleId). Later on, you'll need **TeamID**, which is an "App ID Prefix" value.
+1. Enable the "Sign in with Apple" capability for your App ID in [the Certificates, Identifiers & Profiles](https://developer.apple.com/account/resources/identifiers/list) section.
+1. Create [Service ID](https://developer.apple.com/account/resources/identifiers/list/serviceId) and bind with App ID from the previous step. Apple will display the description field value to end-users on sign-in. You'll need that service **Identifier as a ClientID** later on**.**
+1. Configure "Sign in with Apple" for created Service ID. Add domain where you will use that auth on to "Domains and subdomains" and its main page URL (like `https://example.com/` to "Return URLs".
+1. Register a [New Key](https://developer.apple.com/account/resources/authkeys/list) (private key) for the "Sign in with Apple" feature and download it. Write down the **Key ID**. This key will be used to create [JWT](https://developer.apple.com/documentation/sign_in_with_apple/generate_and_validate_tokens#3262048) Client Secret.
+1. Add your Remark42 domain name and sender email in the Certificates, Identifiers & Profiles >> [More](https://developer.apple.com/account/resources/services/configure) section as a new Email Source.
+
+After completing the previous steps, you can proceed with configuring the Apple auth provider. You'll need to set the following environment variables:
+
+- `AUTH_APPLE_CID` (**required**) - Apple client ID
+- `AUTH_APPLE_TID` (**required**) - Apple service ID
+- `AUTH_APPLE_KID` (**required**) - Private key ID
+- `AUTH_APPLE_PRIVATE_KEY_FILEPATH` (default `/var/apple.p8`) - Private key file location
+
 ### Facebook
 
 1. Open the list of apps on the [Facebook Developers Platform](https://developers.facebook.com/apps)

site/src/docs/configuration/parameters/index.md

@@ -80,6 +80,10 @@ services:
 | auth.ttl.cookie                | AUTH_TTL_COOKIE                | `200h`                   | cookie TTL                                                |
 | auth.send-jwt-header           | AUTH_SEND_JWT_HEADER           | `false`                  | send JWT as a header instead of a cookie                  |
 | auth.same-site                 | AUTH_SAME_SITE                 | `default`                | set same site policy for cookies (`default`, `none`, `lax` or `strict`) |
+| auth.apple.cid                 | AUTH_APPLE_CID                 |                          | Apple client ID                                           |
+| auth.apple.tid                 | AUTH_APPLE_TID                 |                          | Apple service ID                                          |
+| auth.apple.kid                 | AUTH_APPLE_KID                 |                          | Private key ID                                            |
+| auth.apple.private-key-filepath | AUTH_APPLE_PRIVATE_KEY_FILEPATH | `/var/apple.p8`        | Private key file location                                 |
 | auth.google.cid                | AUTH_GOOGLE_CID                |                          | Google OAuth client ID                                    |
 | auth.google.csec               | AUTH_GOOGLE_CSEC               |                          | Google OAuth client secret                                |
 | auth.facebook.cid              | AUTH_FACEBOOK_CID              |                          | Facebook OAuth client ID                                  |

site/src/pages/index.md

@@ -8,7 +8,7 @@ title: Remark42 – Privacy-focused lightweight commenting engine
 
 Remark42 allows you to have a self-hosted, lightweight, and simple (yet functional) comment engine, which doesn't spy on users. It can be embedded into blogs, articles or any other place where readers add comments.
 
-* Social login via Google, Twitter, Facebook, Microsoft, GitHub, Yandex, Patreon and Telegram
+* Social login via Google, Twitter, Facebook, Microsoft, GitHub, Apple, Yandex, Patreon and Telegram
 * Login via email
 * Optional anonymous access
 * Multi-level nested comments with both tree and plain presentations