Update federated posts to not cache sensitive images if not allow by local site (#3253)

* Update federated posts to not cache sensitive images if not allow by local site

* Refactor thumbnail match to simplify logic

crates/api_common/src/request.rs

@@ -193,6 +193,7 @@ pub async fn fetch_site_data(
   client: &ClientWithMiddleware,
   settings: &Settings,
   url: Option<&Url>,
+  include_image: bool,
 ) -> (Option<SiteMetadata>, Option<DbUrl>) {
   match &url {
     Some(url) => {
@@ -200,6 +201,9 @@ pub async fn fetch_site_data(
       // Ignore errors, since it may be an image, or not have the data.
       // Warning, this may ignore SSL errors
       let metadata_option = fetch_site_metadata(client, url).await.ok();
+      if !include_image {
+        return (metadata_option, None);
+      }
 
       let missing_pictrs_file =
         |r: PictrsResponse| r.files.first().expect("missing pictrs file").file.clone();

crates/api_common/src/utils.rs

@@ -428,6 +428,13 @@ pub fn local_site_opt_to_slur_regex(local_site: &Option<LocalSite>) -> Option<Re
     .unwrap_or(None)
 }
 
+pub fn local_site_opt_to_sensitive(local_site: &Option<LocalSite>) -> bool {
+  local_site
+    .as_ref()
+    .map(|site| site.enable_nsfw)
+    .unwrap_or(false)
+}
+
 pub fn send_application_approved_email(
   user: &LocalUserView,
   settings: &Settings,

crates/api_crud/src/post/create.rs

@@ -79,7 +79,7 @@ impl PerformCrud for CreatePost {
 
     // Fetch post links and pictrs cached image
     let (metadata_res, thumbnail_url) =
-      fetch_site_data(context.client(), context.settings(), data_url).await;
+      fetch_site_data(context.client(), context.settings(), data_url, true).await;
     let (embed_title, embed_description, embed_video_url) = metadata_res
       .map(|u| (u.title, u.description, u.embed_video_url))
       .unwrap_or_default();

crates/api_crud/src/post/update.rs

@@ -69,7 +69,7 @@ impl PerformCrud for EditPost {
     // Fetch post links and Pictrs cached image
     let data_url = data.url.as_ref();
     let (metadata_res, thumbnail_url) =
-      fetch_site_data(context.client(), context.settings(), data_url).await;
+      fetch_site_data(context.client(), context.settings(), data_url, true).await;
     let (embed_title, embed_description, embed_video_url) = metadata_res
       .map(|u| (Some(u.title), Some(u.description), Some(u.embed_video_url)))
       .unwrap_or_default();

crates/apub/src/objects/post.rs

@@ -25,7 +25,7 @@ use html2md::parse_html;
 use lemmy_api_common::{
   context::LemmyContext,
   request::fetch_site_data,
-  utils::{is_mod_or_admin, local_site_opt_to_slur_regex},
+  utils::{is_mod_or_admin, local_site_opt_to_sensitive, local_site_opt_to_slur_regex},
 };
 use lemmy_db_schema::{
   self,
@@ -197,18 +197,33 @@ impl Object for ApubPost {
       } else {
         None
       };
+
+      let local_site = LocalSite::read(context.pool()).await.ok();
+      let allow_sensitive = local_site_opt_to_sensitive(&local_site);
+      let page_is_sensitive = page.sensitive.unwrap_or(false);
+      let include_image = allow_sensitive || !page_is_sensitive;
+
       // Only fetch metadata if the post has a url and was not seen previously. We dont want to
       // waste resources by fetching metadata for the same post multiple times.
-      let (metadata_res, thumbnail_url) = match &url {
+      // Additionally, only fetch image if content is not sensitive or is allowed on local site.
+      let (metadata_res, thumbnail) = match &url {
         Some(url) if old_post.is_err() => {
-          fetch_site_data(context.client(), context.settings(), Some(url)).await
+          fetch_site_data(
+            context.client(),
+            context.settings(),
+            Some(url),
+            include_image,
+          )
+          .await
         }
-        _ => (None, page.image.map(|i| i.url.into())),
+        _ => (None, None),
       };
+      // If no image was included with metadata, use post image instead when available.
+      let thumbnail_url = thumbnail.or_else(|| page.image.map(|i| i.url.into()));
+
       let (embed_title, embed_description, embed_video_url) = metadata_res
         .map(|u| (u.title, u.description, u.embed_video_url))
         .unwrap_or_default();
-      let local_site = LocalSite::read(context.pool()).await.ok();
       let slur_regex = &local_site_opt_to_slur_regex(&local_site);
 
       let body_slurs_removed =