From 37936a450f8c75612feb739bdecb11c682e42c0e Mon Sep 17 00:00:00 2001
From: Niko Abeler <niko@rerere.org>
Date: Mon, 7 Nov 2022 19:44:10 +0100
Subject: [PATCH] indieauth-metadata

---
 cmd/owl/web/auth_test.go | 26 ++++++++++++++++++++++++++
 cmd/owl/web/handler.go   | 37 +++++++++++++++++++++++++++++++++++++
 cmd/owl/web/server.go    |  2 ++
 embed/initial/base.html  |  1 +
 user.go                  |  5 +++++
 5 files changed, 71 insertions(+)

diff --git a/cmd/owl/web/auth_test.go b/cmd/owl/web/auth_test.go
index 9ce37f9..844b598 100644
--- a/cmd/owl/web/auth_test.go
+++ b/cmd/owl/web/auth_test.go
@@ -399,3 +399,29 @@ func TestAccessTokenWithIncorrectCode(t *testing.T) {
 
 	assertions.AssertStatus(t, rr, http.StatusUnauthorized)
 }
+
+func TestIndieauthMetadata(t *testing.T) {
+	repo, user := getSingleUserTestRepo()
+	user.ResetPassword("testpassword")
+	req, _ := http.NewRequest("GET", user.IndieauthMetadataUrl(), nil)
+	rr := httptest.NewRecorder()
+	router := main.SingleUserRouter(&repo)
+	router.ServeHTTP(rr, req)
+
+	assertions.AssertStatus(t, rr, http.StatusOK)
+	// parse response as json
+	type responseType struct {
+		Issuer                        string   `json:"issuer"`
+		AuthorizationEndpoint         string   `json:"authorization_endpoint"`
+		TokenEndpoint                 string   `json:"token_endpoint"`
+		CodeChallengeMethodsSupported []string `json:"code_challenge_methods_supported"`
+		ScopesSupported               []string `json:"scopes_supported"`
+		ResponseTypesSupported        []string `json:"response_types_supported"`
+		GrantTypesSupported           []string `json:"grant_types_supported"`
+	}
+	var response responseType
+	json.Unmarshal(rr.Body.Bytes(), &response)
+	assertions.AssertEqual(t, response.Issuer, user.FullUrl())
+	assertions.AssertEqual(t, response.AuthorizationEndpoint, user.AuthUrl())
+	assertions.AssertEqual(t, response.TokenEndpoint, user.TokenUrl())
+}
diff --git a/cmd/owl/web/handler.go b/cmd/owl/web/handler.go
index 4cbf887..0bf1d22 100644
--- a/cmd/owl/web/handler.go
+++ b/cmd/owl/web/handler.go
@@ -60,6 +60,43 @@ func userIndexHandler(repo *owl.Repository) func(http.ResponseWriter, *http.Requ
 	}
 }
 
+func userAuthMetadataHandler(repo *owl.Repository) func(http.ResponseWriter, *http.Request, httprouter.Params) {
+	return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
+		user, err := getUserFromRepo(repo, ps)
+		if err != nil {
+			println("Error getting user: ", err.Error())
+			notFoundHandler(repo)(w, r)
+			return
+		}
+
+		type Response struct {
+			Issuer                        string   `json:"issuer"`
+			AuthorizationEndpoint         string   `json:"authorization_endpoint"`
+			TokenEndpoint                 string   `json:"token_endpoint"`
+			CodeChallengeMethodsSupported []string `json:"code_challenge_methods_supported"`
+			ScopesSupported               []string `json:"scopes_supported"`
+			ResponseTypesSupported        []string `json:"response_types_supported"`
+			GrantTypesSupported           []string `json:"grant_types_supported"`
+		}
+		response := Response{
+			Issuer:                        user.FullUrl(),
+			AuthorizationEndpoint:         user.AuthUrl(),
+			TokenEndpoint:                 user.TokenUrl(),
+			CodeChallengeMethodsSupported: []string{"S256", "plain"},
+			ScopesSupported:               []string{"profile"},
+			ResponseTypesSupported:        []string{"code"},
+			GrantTypesSupported:           []string{"authorization_code"},
+		}
+		jsonData, err := json.Marshal(response)
+		if err != nil {
+			println("Error marshalling json: ", err.Error())
+			w.WriteHeader(http.StatusInternalServerError)
+			w.Write([]byte("Internal server error"))
+		}
+		w.Write(jsonData)
+	}
+}
+
 func userAuthHandler(repo *owl.Repository) func(http.ResponseWriter, *http.Request, httprouter.Params) {
 	return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
 		user, err := getUserFromRepo(repo, ps)
diff --git a/cmd/owl/web/server.go b/cmd/owl/web/server.go
index 02937c1..7e75ac5 100644
--- a/cmd/owl/web/server.go
+++ b/cmd/owl/web/server.go
@@ -18,6 +18,7 @@ func Router(repo *owl.Repository) http.Handler {
 	router.POST("/user/:user/auth/", userAuthProfileHandler(repo))
 	router.POST("/user/:user/auth/verify/", userAuthVerifyHandler(repo))
 	router.POST("/user/:user/auth/token/", userAuthTokenHandler(repo))
+	router.GET("/user/:user/auth/indieauth-metadata", userAuthMetadataHandler(repo))
 	router.GET("/user/:user/media/*filepath", userMediaHandler(repo))
 	router.GET("/user/:user/index.xml", userRSSHandler(repo))
 	router.GET("/user/:user/posts/:post/", postHandler(repo))
@@ -35,6 +36,7 @@ func SingleUserRouter(repo *owl.Repository) http.Handler {
 	router.POST("/auth/", userAuthProfileHandler(repo))
 	router.POST("/auth/verify/", userAuthVerifyHandler(repo))
 	router.POST("/auth/token/", userAuthTokenHandler(repo))
+	router.GET("/auth/indieauth-metadata", userAuthMetadataHandler(repo))
 	router.GET("/media/*filepath", userMediaHandler(repo))
 	router.GET("/index.xml", userRSSHandler(repo))
 	router.GET("/posts/:post/", postHandler(repo))
diff --git a/embed/initial/base.html b/embed/initial/base.html
index ff99bb4..78ad250 100644
--- a/embed/initial/base.html
+++ b/embed/initial/base.html
@@ -28,6 +28,7 @@
     <link rel="stylesheet" href="/static/pico.min.css">
     <link rel="webmention" href="{{ .User.WebmentionUrl }}">
     {{ if .User.AuthUrl }}
+    <link rel="indieauth-metadata" href="{{ .User.IndieauthMetadataUrl }}">
     <link rel="authorization_endpoint" href="{{ .User.AuthUrl}}">
     <link rel="token_endpoint" href="{{ .User.TokenUrl}}">
     {{ end }}
diff --git a/user.go b/user.go
index ec0b2c3..6d1200a 100644
--- a/user.go
+++ b/user.go
@@ -78,6 +78,11 @@ func (user User) TokenUrl() string {
 	return url
 }
 
+func (user User) IndieauthMetadataUrl() string {
+	url, _ := url.JoinPath(user.AuthUrl(), "indieauth-metadata")
+	return url
+}
+
 func (user User) WebmentionUrl() string {
 	url, _ := url.JoinPath(user.FullUrl(), "webmention/")
 	return url