From 7667190a9c417fb8de8dc459619feaa67cd4013f Mon Sep 17 00:00:00 2001
From: Niko Abeler <niko@rerere.org>
Date: Wed, 19 Oct 2022 21:14:31 +0200
Subject: [PATCH] added some OpenGraph meta tags

---
 embed/initial/base.html | 13 +++++++++++++
 post.go                 | 21 ++++++++++++---------
 renderer.go             | 32 ++++++++++++++++++++++----------
 renderer_test.go        | 37 +++++++++++++++++++++++++++++++++++++
 4 files changed, 84 insertions(+), 19 deletions(-)

diff --git a/embed/initial/base.html b/embed/initial/base.html
index 307b405..3bf225e 100644
--- a/embed/initial/base.html
+++ b/embed/initial/base.html
@@ -6,6 +6,19 @@
     <meta http-equiv="X-UA-Compatible" content="IE=edge">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>{{ .Title }} - {{ .User.Config.Title }}</title>
+
+    <meta property="og:title" content="{{ .Title }}" />
+    {{ if .Description }}
+    <meta name="description" content="{{ .Description }}">
+    <meta property="og:description" content="{{ .Description }}" />
+    {{ end }}
+    {{ if .Type }}
+    <meta property="og:type" content="{{ .Type }}" />
+    {{ end }}
+    {{ if .SelfUrl }}
+    <meta property="og:url" content="{{ .SelfUrl }}" />
+    {{ end }}
+
     <link rel="stylesheet" href="/static/pico.min.css">
     <link rel="webmention" href="{{ .User.WebmentionUrl }}">
     <style>
diff --git a/post.go b/post.go
index cef26c9..f88b9cd 100644
--- a/post.go
+++ b/post.go
@@ -32,11 +32,12 @@ type Reply struct {
 }
 
 type PostMeta struct {
-	Title   string    `yaml:"title"`
-	Aliases []string  `yaml:"aliases"`
-	Date    time.Time `yaml:"date"`
-	Draft   bool      `yaml:"draft"`
-	Reply   Reply     `yaml:"reply"`
+	Title       string    `yaml:"title"`
+	Description string    `yaml:"description"`
+	Aliases     []string  `yaml:"aliases"`
+	Date        time.Time `yaml:"date"`
+	Draft       bool      `yaml:"draft"`
+	Reply       Reply     `yaml:"reply"`
 }
 
 func (pm PostMeta) FormattedDate() string {
@@ -45,10 +46,11 @@ func (pm PostMeta) FormattedDate() string {
 
 func (pm *PostMeta) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	type T struct {
-		Title   string   `yaml:"title"`
-		Aliases []string `yaml:"aliases"`
-		Draft   bool     `yaml:"draft"`
-		Reply   Reply    `yaml:"reply"`
+		Title       string   `yaml:"title"`
+		Description string   `yaml:"description"`
+		Aliases     []string `yaml:"aliases"`
+		Draft       bool     `yaml:"draft"`
+		Reply       Reply    `yaml:"reply"`
 	}
 	type S struct {
 		Date string `yaml:"date"`
@@ -64,6 +66,7 @@ func (pm *PostMeta) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	}
 
 	pm.Title = t.Title
+	pm.Description = t.Description
 	pm.Aliases = t.Aliases
 	pm.Draft = t.Draft
 	pm.Reply = t.Reply
diff --git a/renderer.go b/renderer.go
index 9e9224c..8a9d5fd 100644
--- a/renderer.go
+++ b/renderer.go
@@ -7,8 +7,11 @@ import (
 )
 
 type PageContent struct {
-	Title   string
-	Content template.HTML
+	Title       string
+	Description string
+	Content     template.HTML
+	Type        string
+	SelfUrl     string
 }
 
 type PostRenderData struct {
@@ -46,13 +49,19 @@ func renderIntoBaseTemplate(user User, data PageContent) (string, error) {
 	}
 
 	full_data := struct {
-		Title   string
-		Content template.HTML
-		User    User
+		Title       string
+		Description string
+		Content     template.HTML
+		Type        string
+		SelfUrl     string
+		User        User
 	}{
-		Title:   data.Title,
-		Content: data.Content,
-		User:    user,
+		Title:       data.Title,
+		Description: data.Description,
+		Content:     data.Content,
+		Type:        data.Type,
+		SelfUrl:     data.SelfUrl,
+		User:        user,
 	}
 
 	var html bytes.Buffer
@@ -78,8 +87,11 @@ func RenderPost(post *Post) (string, error) {
 	}
 
 	return renderIntoBaseTemplate(*post.user, PageContent{
-		Title:   post.Title(),
-		Content: template.HTML(postHtml),
+		Title:       post.Title(),
+		Description: post.Meta().Description,
+		Content:     template.HTML(postHtml),
+		Type:        "article",
+		SelfUrl:     post.FullUrl(),
 	})
 }
 
diff --git a/renderer_test.go b/renderer_test.go
index 46f255f..f0f2d1d 100644
--- a/renderer_test.go
+++ b/renderer_test.go
@@ -323,3 +323,40 @@ func TestRenderReplyWithText(t *testing.T) {
 		t.Error("Reply text not rendered. Got: " + result)
 	}
 }
+
+func TestOpenGraphTags(t *testing.T) {
+	user := getTestUser()
+	post, _ := user.CreateNewPost("testpost", false)
+
+	content := "---\n"
+	content += "title: The Rock\n"
+	content += "description: Dwayne Johnson\n"
+	content += "date: Wed, 17 Aug 2022 10:50:02 +0000\n"
+	content += "---\n"
+	content += "\n"
+	content += "Hi \n"
+
+	err := os.WriteFile(post.ContentFile(), []byte(content), 0644)
+	if err != nil {
+		t.Error(err)
+	}
+	post, _ = user.GetPost(post.Id())
+
+	result, _ := owl.RenderPost(post)
+
+	if !strings.Contains(result, "<meta property=\"og:title\" content=\"The Rock\" />") {
+		t.Error("incorrent og:title . Got: " + result)
+	}
+
+	if !strings.Contains(result, "<meta property=\"og:description\" content=\"Dwayne Johnson\" />") {
+		t.Error("incorrent og:description . Got: " + result)
+	}
+
+	if !strings.Contains(result, "<meta property=\"og:type\" content=\"article\" />") {
+		t.Error("incorrent og:type . Got: " + result)
+	}
+	if !strings.Contains(result, "<meta property=\"og:url\" content=\""+post.FullUrl()+"\" />") {
+		t.Error("incorrent og:url . Got: " + result)
+	}
+
+}