Make URL joining more robust

server/src/lib.rs

@@ -5,7 +5,7 @@ pub mod nm;
 
 use css_inline::{CSSInliner, InlineError, InlineOptions};
 use linkify::{LinkFinder, LinkKind};
-use log::error;
+use log::{error, info};
 use lol_html::{element, errors::RewritingError, rewrite_str, RewriteStrSettings};
 use maplit::{hashmap, hashset};
 use thiserror::Error;
@@ -50,31 +50,15 @@ pub fn linkify_html(text: &str) -> String {
 pub fn sanitize_html(
     html: &str,
     cid_prefix: &str,
-    base_url: &Url,
+    base_url: &Option<Url>,
 ) -> Result<String, SanitizeError> {
-    let element_content_handlers = vec![
+    let mut element_content_handlers = vec![
         // Open links in new tab
         element!("a[href]", |el| {
             el.set_attribute("target", "_blank").unwrap();
 
             Ok(())
         }),
-        // Make links with relative URLs absolute
-        element!("a[href]", |el| {
-            if let Some(Ok(href)) = el.get_attribute("href").map(|href| base_url.join(&href)) {
-                el.set_attribute("href", &href.as_str()).unwrap();
-            }
-
-            Ok(())
-        }),
-        // Make images with relative srcs absolute
-        element!("img[src]", |el| {
-            if let Some(Ok(src)) = el.get_attribute("src").map(|src| base_url.join(&src)) {
-                el.set_attribute("src", &src.as_str()).unwrap();
-            }
-
-            Ok(())
-        }),
         // Replace mixed part CID images with URL
         element!("img[src]", |el| {
             let src = el
@@ -98,6 +82,30 @@ pub fn sanitize_html(
             Ok(())
         }),
     ];
+    if let Some(base_url) = base_url {
+        element_content_handlers.extend(vec![
+            // Make links with relative URLs absolute
+            element!("a[href]", |el| {
+                if let Some(Ok(href)) = el.get_attribute("href").map(|href| {
+                    info!("href {href:?}");
+                    base_url.join(&href)
+                }) {
+                    el.set_attribute("href", &href.as_str()).unwrap();
+                }
+
+                Ok(())
+            }),
+            // Make images with relative srcs absolute
+            element!("img[src]", |el| {
+                if let Some(Ok(src)) = el.get_attribute("src").map(|src| base_url.join(&src)) {
+                    info!("src {src:?}");
+                    el.set_attribute("src", &src.as_str()).unwrap();
+                }
+
+                Ok(())
+            }),
+        ]);
+    }
 
     let inline_opts = InlineOptions {
         inline_style_tags: true,