Link hashtags in posts to corresponding tag timeline pages

src/activitypub/activity.rs

@@ -3,6 +3,7 @@ use serde::{Deserialize, Serialize};
 use serde_json::{json, Value};
 use uuid::Uuid;
 
+use crate::frontend::get_tag_page_url;
 use crate::models::posts::types::Post;
 use crate::models::profiles::types::DbActorProfile;
 use crate::models::users::types::User;
@@ -186,10 +187,11 @@ pub fn create_note(
         tags.push(tag);
     };
     for tag_name in &post.tags {
+        let tag_page_url = get_tag_page_url(instance_url, tag_name);
         let tag = Tag {
             name: format!("#{}", tag_name),
             tag_type: HASHTAG.to_string(),
-            href: None,
+            href: Some(tag_page_url),
         };
         tags.push(tag);
     };

src/activitypub/views.rs

@@ -71,7 +71,7 @@ async fn actor_view(
     let db_client = &**get_database_client(&db_pool).await?;
     let user = get_user_by_name(db_client, &username).await?;
     if !is_activitypub_request(&request) {
-        let page_url = get_profile_page_url(&user.id, &config.instance_url());
+        let page_url = get_profile_page_url(&config.instance_url(), &user.id);
         let response = HttpResponse::Found()
             .header("Location", page_url)
             .finish();
@@ -203,7 +203,7 @@ pub async fn object_view(
         .find(|post| post.id == internal_object_id && post.author.is_local())
         .ok_or(HttpError::NotFoundError("post"))?;
     if !is_activitypub_request(&request) {
-        let page_url = get_post_page_url(&post.id, &config.instance_url());
+        let page_url = get_post_page_url(&config.instance_url(), &post.id);
         let response = HttpResponse::Found()
             .header("Location", page_url)
             .finish();

src/frontend.rs

@@ -2,10 +2,14 @@
 use uuid::Uuid;
 
 // Assuming frontend is on the same host as backend
-pub fn get_profile_page_url(profile_id: &Uuid, instance_url: &str) -> String {
+pub fn get_profile_page_url(instance_url: &str, profile_id: &Uuid) -> String {
     format!("{}/profile/{}", instance_url, profile_id)
 }
 
-pub fn get_post_page_url(post_id: &Uuid, instance_url: &str) -> String {
+pub fn get_post_page_url(instance_url: &str, post_id: &Uuid) -> String {
     format!("{}/post/{}", instance_url, post_id)
 }
+
+pub fn get_tag_page_url(instance_url: &str, tag_name: &str) -> String {
+    format!("{}/tag/{}", instance_url, tag_name)
+}

src/mastodon_api/statuses/views.rs

@@ -72,7 +72,11 @@ async fn create_status(
     post_data.mentions = mention_map.values()
         .map(|profile| profile.id).collect();
     post_data.tags = find_tags(&post_data.content);
-    post_data.content = replace_tags(&post_data.content, &post_data.tags);
+    post_data.content = replace_tags(
+        &instance.url(),
+        &post_data.content,
+        &post_data.tags,
+    );
     let post = create_post(db_client, &current_user.id, post_data).await?;
     // Federate
     let maybe_in_reply_to = match post.in_reply_to_id {

src/models/posts/tags.rs

@@ -1,6 +1,7 @@
 use regex::{Captures, Regex};
 
 use crate::errors::ConversionError;
+use crate::frontend::get_tag_page_url;
 
 const HASHTAG_RE: &str = r"(?m)(?P<before>^|\s)#(?P<tag>\S+)";
 const HASHTAG_SECONDARY_RE: &str = r"^(?P<tag>[0-9A-Za-z]+)(?P<after>(\.|<br>|\.<br>)?)$";
@@ -23,7 +24,7 @@ pub fn find_tags(text: &str) -> Vec<String> {
 }
 
 /// Replaces hashtags with links
-pub fn replace_tags(text: &str, tags: &[String]) -> String {
+pub fn replace_tags(instance_url: &str, text: &str, tags: &[String]) -> String {
     let hashtag_re = Regex::new(HASHTAG_RE).unwrap();
     let hashtag_secondary_re = Regex::new(HASHTAG_SECONDARY_RE).unwrap();
     let result = hashtag_re.replace_all(text, |caps: &Captures| {
@@ -33,10 +34,11 @@ pub fn replace_tags(text: &str, tags: &[String]) -> String {
             let tag_name = tag.to_lowercase();
             let after = secondary_caps["after"].to_string();
             if tags.contains(&tag_name) {
+                let tag_page_url = get_tag_page_url(instance_url, &tag_name);
                 format!(
-                    r#"{}<a class="hashtag" href="/tag/{}">#{}</a>{}"#,
+                    r#"{}<a class="hashtag" href="{}">#{}</a>{}"#,
                     before,
-                    tag_name,
+                    tag_page_url,
                     tag,
                     after,
                 )
@@ -63,6 +65,8 @@ pub fn normalize_tag(tag: &str) -> Result<String, ConversionError> {
 mod tests {
     use super::*;
 
+    const INSTANCE_URL: &str = "https://example.com";
+
     #[test]
     fn test_find_tags() {
         let text = concat!(
@@ -87,13 +91,13 @@ mod tests {
             "more text #tag2",
         );
         let tags = find_tags(text);
-        let output = replace_tags(&text, &tags);
+        let output = replace_tags(INSTANCE_URL, &text, &tags);
 
         let expected_output = concat!(
-            r#"@user1@server1 some text <a class="hashtag" href="/tag/testtag">#TestTag</a>."#, "\n",
-            r#"<a class="hashtag" href="/tag/tag1">#TAG1</a> <a class="hashtag" href="/tag/tag1">#tag1</a> "#,
+            r#"@user1@server1 some text <a class="hashtag" href="https://example.com/tag/testtag">#TestTag</a>."#, "\n",
+            r#"<a class="hashtag" href="https://example.com/tag/tag1">#TAG1</a> <a class="hashtag" href="https://example.com/tag/tag1">#tag1</a> "#,
             r#"#test_underscore #test*special "#,
-            r#"more text <a class="hashtag" href="/tag/tag2">#tag2</a>"#,
+            r#"more text <a class="hashtag" href="https://example.com/tag/tag2">#tag2</a>"#,
         );
         assert_eq!(output, expected_output);
     }