server: add link to news posts back to original article

server/src/lib.rs

@@ -116,6 +116,29 @@ impl Transformer for InlineStyle {
     }
 }
 
+struct AddOutlink(Option<url::Url>);
+
+impl Transformer for AddOutlink {
+    fn should_run(&self, _: &str) -> bool {
+        self.0
+            .as_ref()
+            .map(|l| l.scheme().starts_with("http"))
+            .unwrap_or(false)
+    }
+    fn transform(&self, html: &str) -> Result<String, TransformError> {
+        if let Some(url) = &self.0 {
+            Ok(format!(
+                r#"
+                {html}
+                <div><a href="{}">View on site</a></div>
+                "#,
+                url
+            ))
+        } else {
+            Ok(html.to_string())
+        }
+    }
+}
 pub fn linkify_html(text: &str) -> String {
     let mut finder = LinkFinder::new();
     let finder = finder.url_must_have_scheme(false).kinds(&[LinkKind::Url]);

server/src/newsreader.rs

@@ -13,7 +13,7 @@ use crate::{
     compute_offset_limit,
     error::ServerError,
     graphql::{Body, Email, Html, Message, Tag, Thread, ThreadSummary},
-    EscapeHtml, InlineStyle, SanitizeHtml, StripHtml, Transformer,
+    AddOutlink, EscapeHtml, InlineStyle, SanitizeHtml, StripHtml, Transformer,
 };
 
 pub fn is_newsreader_search(query: &str) -> bool {
@@ -191,7 +191,8 @@ pub async fn thread(pool: &PgPool, thread_id: String) -> Result<Thread, ServerEr
     // TODO: add site specific cleanups. For example:
     // * Grafana does <div class="image-wrapp"><img class="lazyload>"<img src="/media/...>"</img></div>
     // * Some sites appear to be HTML encoded, unencode them, i.e. imperialviolent
-    let body_tranformers: Vec<Box<dyn Transformer>> = vec![
+    let mut body_tranformers: Vec<Box<dyn Transformer>> = vec![
+        Box::new(AddOutlink(link.clone())),
         Box::new(EscapeHtml),
         Box::new(InlineStyle),
         Box::new(SanitizeHtml {