Generate post thumbnail/metadata in background (ref #4529)

crates/api_common/src/post.rs

@@ -30,9 +30,6 @@ pub struct CreatePost {
   pub honeypot: Option<String>,
   pub nsfw: Option<bool>,
   pub language_id: Option<LanguageId>,
-  #[cfg_attr(feature = "full", ts(type = "string"))]
-  /// Instead of fetching a thumbnail, use a custom one.
-  pub custom_thumbnail: Option<Url>,
 }
 
 #[derive(Debug, Serialize, Deserialize, Clone)]
@@ -122,9 +119,6 @@ pub struct EditPost {
   pub alt_text: Option<String>,
   pub nsfw: Option<bool>,
   pub language_id: Option<LanguageId>,
-  #[cfg_attr(feature = "full", ts(type = "string"))]
-  /// Instead of fetching a thumbnail, use a custom one.
-  pub custom_thumbnail: Option<Url>,
 }
 
 #[derive(Debug, Serialize, Deserialize, Clone, Copy, Default, PartialEq, Eq, Hash)]

crates/api_common/src/request.rs

@@ -1,16 +1,22 @@
 use crate::{
   context::LemmyContext,
+  lemmy_db_schema::traits::Crud,
   post::{LinkMetadata, OpenGraphData},
-  utils::proxy_image_link,
+  utils::{local_site_opt_to_sensitive, proxy_image_link},
 };
 use encoding::{all::encodings, DecoderTrap};
 use lemmy_db_schema::{
   newtypes::DbUrl,
-  source::images::{LocalImage, LocalImageForm},
+  source::{
+    images::{LocalImage, LocalImageForm},
+    local_site::LocalSite,
+    post::{Post, PostUpdateForm},
+  },
 };
 use lemmy_utils::{
   error::{LemmyError, LemmyErrorType},
   settings::structs::{PictrsImageMode, Settings},
+  spawn_try_task,
   version::VERSION,
   REQWEST_TIMEOUT,
 };
@@ -83,6 +89,37 @@ pub async fn fetch_link_metadata_opt(
   }
 }
 
+/// Generate post thumbnail in background task, because some sites can be very slow to respond.
+pub fn generate_post_link_metadata(
+  post: Post,
+  local_site: Option<LocalSite>,
+  context: LemmyContext,
+) {
+  spawn_try_task(async move {
+    let allow_sensitive = local_site_opt_to_sensitive(&local_site);
+    let allow_generate_thumbnail = allow_sensitive || !post.nsfw;
+    let url: Option<Url> = post.url.map(Into::into);
+    let metadata = fetch_link_metadata_opt(url.as_ref(), allow_generate_thumbnail, &context).await;
+    let thumbnail_url = if let Some(thumbnail_url_) = metadata.thumbnail {
+      Some(Some(
+        proxy_image_link(thumbnail_url_.into(), &context).await?,
+      ))
+    } else {
+      None
+    };
+    let form = PostUpdateForm {
+      embed_title: Some(metadata.opengraph_data.title),
+      embed_description: Some(metadata.opengraph_data.description),
+      embed_video_url: Some(metadata.opengraph_data.embed_video_url),
+      thumbnail_url,
+      url_content_type: Some(metadata.content_type),
+      ..Default::default()
+    };
+    Post::update(&mut context.pool(), post.id, &form).await?;
+    Ok(())
+  });
+}
+
 /// Extract site metadata from HTML Opengraph attributes.
 fn extract_opengraph_data(html_bytes: &[u8], url: &Url) -> Result<OpenGraphData, LemmyError> {
   let html = String::from_utf8_lossy(html_bytes);

crates/api_crud/src/post/create.rs

@@ -4,7 +4,7 @@ use lemmy_api_common::{
   build_response::build_post_response,
   context::LemmyContext,
   post::{CreatePost, PostResponse},
-  request::fetch_link_metadata_opt,
+  request::generate_post_link_metadata,
   send_activity::{ActivityChannel, SendActivityData},
   utils::{
     check_community_user_action,
@@ -67,14 +67,12 @@ pub async fn create_post(
   let body = process_markdown_opt(&data.body, &slur_regex, &url_blocklist, &context).await?;
   let data_url = data.url.as_ref();
   let url = data_url.map(clean_url_params); // TODO no good way to handle a "clear"
-  let custom_thumbnail = data.custom_thumbnail.as_ref().map(clean_url_params);
 
   is_valid_post_title(&data.name)?;
   is_valid_body_field(&body, true)?;
   is_valid_alt_text_field(&data.alt_text)?;
   is_url_blocked(&url, &url_blocklist)?;
   check_url_scheme(&url)?;
-  check_url_scheme(&custom_thumbnail)?;
 
   check_community_user_action(
     &local_user_view.person,
@@ -97,18 +95,7 @@ pub async fn create_post(
       Err(LemmyErrorType::OnlyModsCanPostInCommunity)?
     }
   }
-
-  // Only generate the thumbnail if there's no custom thumbnail provided,
-  // otherwise it will save it in pictrs
-  let generate_thumbnail = custom_thumbnail.is_none();
-
-  // Fetch post links and pictrs cached image
-  let metadata = fetch_link_metadata_opt(url.as_ref(), generate_thumbnail, &context).await;
   let url = proxy_image_link_opt_apub(url, &context).await?;
-  let thumbnail_url = proxy_image_link_opt_apub(custom_thumbnail, &context)
-    .await?
-    .map(Into::into)
-    .or(metadata.thumbnail);
 
   // Only need to check if language is allowed in case user set it explicitly. When using default
   // language, it already only returns allowed languages.
@@ -134,24 +121,25 @@ pub async fn create_post(
 
   let post_form = PostInsertForm::builder()
     .name(data.name.trim().to_string())
-    .url_content_type(metadata.content_type)
     .url(url)
     .body(body)
     .alt_text(data.alt_text.clone())
     .community_id(data.community_id)
     .creator_id(local_user_view.person.id)
     .nsfw(data.nsfw)
-    .embed_title(metadata.opengraph_data.title)
-    .embed_description(metadata.opengraph_data.description)
-    .embed_video_url(metadata.opengraph_data.embed_video_url)
     .language_id(language_id)
-    .thumbnail_url(thumbnail_url)
     .build();
 
   let inserted_post = Post::create(&mut context.pool(), &post_form)
     .await
     .with_lemmy_type(LemmyErrorType::CouldntCreatePost)?;
 
+  generate_post_link_metadata(
+    inserted_post.clone(),
+    Some(local_site),
+    context.app_data().clone(),
+  );
+
   let inserted_post_id = inserted_post.id;
   let protocol_and_hostname = context.settings().get_protocol_and_hostname();
   let apub_id = generate_local_apub_endpoint(

crates/api_crud/src/post/update.rs

@@ -4,7 +4,7 @@ use lemmy_api_common::{
   build_response::build_post_response,
   context::LemmyContext,
   post::{EditPost, PostResponse},
-  request::fetch_link_metadata,
+  request::generate_post_link_metadata,
   send_activity::{ActivityChannel, SendActivityData},
   utils::{
     check_community_user_action,
@@ -51,7 +51,6 @@ pub async fn update_post(
   // TODO No good way to handle a clear.
   // Issue link: https://github.com/LemmyNet/lemmy/issues/2287
   let url = data.url.as_ref().map(clean_url_params);
-  let custom_thumbnail = data.custom_thumbnail.as_ref().map(clean_url_params);
 
   let url_blocklist = get_url_blocklist(&context).await?;
 
@@ -67,7 +66,6 @@ pub async fn update_post(
   is_valid_alt_text_field(&data.alt_text)?;
   is_url_blocked(&url, &url_blocklist)?;
   check_url_scheme(&url)?;
-  check_url_scheme(&custom_thumbnail)?;
 
   let post_id = data.post_id;
   let orig_post = Post::read(&mut context.pool(), post_id).await?;
@@ -84,40 +82,11 @@ pub async fn update_post(
     Err(LemmyErrorType::NoPostEditAllowed)?
   }
 
-  // Fetch post links and thumbnail if url was updated
-  let (embed_title, embed_description, embed_video_url, metadata_thumbnail, metadata_content_type) =
-    match &url {
-      Some(url) => {
-        // Only generate the thumbnail if there's no custom thumbnail provided,
-        // otherwise it will save it in pictrs
-        let generate_thumbnail = custom_thumbnail.is_none() || orig_post.thumbnail_url.is_none();
-
-        let metadata = fetch_link_metadata(url, generate_thumbnail, &context).await?;
-        (
-          Some(metadata.opengraph_data.title),
-          Some(metadata.opengraph_data.description),
-          Some(metadata.opengraph_data.embed_video_url),
-          Some(metadata.thumbnail),
-          Some(metadata.content_type),
-        )
-      }
-      _ => Default::default(),
-    };
-
   let url = match url {
     Some(url) => Some(proxy_image_link_opt_apub(Some(url), &context).await?),
     _ => Default::default(),
   };
 
-  let custom_thumbnail = match custom_thumbnail {
-    Some(custom_thumbnail) => {
-      Some(proxy_image_link_opt_apub(Some(custom_thumbnail), &context).await?)
-    }
-    _ => Default::default(),
-  };
-
-  let thumbnail_url = custom_thumbnail.or(metadata_thumbnail);
-
   let language_id = data.language_id;
   CommunityLanguage::is_allowed_community_language(
     &mut context.pool(),
@@ -129,15 +98,10 @@ pub async fn update_post(
   let post_form = PostUpdateForm {
     name: data.name.clone(),
     url,
-    url_content_type: metadata_content_type,
     body: diesel_option_overwrite(body),
     alt_text: diesel_option_overwrite(data.alt_text.clone()),
     nsfw: data.nsfw,
-    embed_title,
-    embed_description,
-    embed_video_url,
     language_id: data.language_id,
-    thumbnail_url,
     updated: Some(Some(naive_now())),
     ..Default::default()
   };
@@ -147,6 +111,12 @@ pub async fn update_post(
     .await
     .with_lemmy_type(LemmyErrorType::CouldntUpdatePost)?;
 
+  generate_post_link_metadata(
+    updated_post.clone(),
+    Some(local_site),
+    context.app_data().clone(),
+  );
+
   ActivityChannel::submit_activity(SendActivityData::UpdatePost(updated_post), &context).await?;
 
   build_post_response(

crates/apub/src/objects/post.rs

@@ -24,10 +24,9 @@ use chrono::{DateTime, Utc};
 use html2text::{from_read_with_decorator, render::text_renderer::TrivialDecorator};
 use lemmy_api_common::{
   context::LemmyContext,
-  request::fetch_link_metadata_opt,
+  request::generate_post_link_metadata,
   utils::{
     get_url_blocklist,
-    local_site_opt_to_sensitive,
     local_site_opt_to_slur_regex,
     process_markdown_opt,
     proxy_image_link_opt_apub,
@@ -219,6 +218,8 @@ impl Object for ApubPost {
 
     let first_attachment = page.attachment.first();
 
+    let local_site = LocalSite::read(&mut context.pool()).await.ok();
+
     let form = if !page.is_mod_action(context).await? {
       let url = if let Some(attachment) = first_attachment.cloned() {
         Some(attachment.url())
@@ -231,21 +232,8 @@ impl Object for ApubPost {
       check_url_scheme(&url)?;
 
       let alt_text = first_attachment.cloned().and_then(Attachment::alt_text);
-      let local_site = LocalSite::read(&mut context.pool()).await.ok();
-      let allow_sensitive = local_site_opt_to_sensitive(&local_site);
-      let page_is_sensitive = page.sensitive.unwrap_or(false);
-      let allow_generate_thumbnail = allow_sensitive || !page_is_sensitive;
-      let mut thumbnail_url = page.image.map(|i| i.url);
-      let do_generate_thumbnail = thumbnail_url.is_none() && allow_generate_thumbnail;
-
-      // Generate local thumbnail only if no thumbnail was federated and 'sensitive' attributes allow it.
-      let metadata = fetch_link_metadata_opt(url.as_ref(), do_generate_thumbnail, context).await;
-      if let Some(thumbnail_url_) = metadata.thumbnail {
-        thumbnail_url = Some(thumbnail_url_.into());
-      }
-      let url = proxy_image_link_opt_apub(url, context).await?;
-      let thumbnail_url = proxy_image_link_opt_apub(thumbnail_url, context).await?;
 
+      let url = proxy_image_link_opt_apub(url, context).await?;
       let slur_regex = &local_site_opt_to_slur_regex(&local_site);
       let url_blocklist = get_url_blocklist(context).await?;
 
@@ -254,30 +242,22 @@ impl Object for ApubPost {
       let language_id =
         LanguageTag::to_language_id_single(page.language, &mut context.pool()).await?;
 
-      PostInsertForm {
-        name,
-        url: url.map(Into::into),
-        body,
-        alt_text,
-        creator_id: creator.id,
-        community_id: community.id,
-        removed: None,
-        locked: page.comments_enabled.map(|e| !e),
-        published: page.published.map(Into::into),
-        updated: page.updated.map(Into::into),
-        deleted: Some(false),
-        nsfw: page.sensitive,
-        embed_title: metadata.opengraph_data.title,
-        embed_description: metadata.opengraph_data.description,
-        embed_video_url: metadata.opengraph_data.embed_video_url,
-        thumbnail_url,
-        ap_id: Some(page.id.clone().into()),
-        local: Some(false),
-        language_id,
-        featured_community: None,
-        featured_local: None,
-        url_content_type: metadata.content_type,
-      }
+      PostInsertForm::builder()
+        .name(name)
+        .url(url.map(Into::into))
+        .body(body)
+        .alt_text(alt_text)
+        .creator_id(creator.id)
+        .community_id(community.id)
+        .locked(page.comments_enabled.map(|e| !e))
+        .published(page.published.map(Into::into))
+        .updated(page.updated.map(Into::into))
+        .deleted(Some(false))
+        .nsfw(page.sensitive)
+        .ap_id(Some(page.id.clone().into()))
+        .local(Some(false))
+        .language_id(language_id)
+        .build()
     } else {
       // if is mod action, only update locked/stickied fields, nothing else
       PostInsertForm::builder()
@@ -292,6 +272,8 @@ impl Object for ApubPost {
 
     let post = Post::create(&mut context.pool(), &form).await?;
 
+    generate_post_link_metadata(post.clone(), local_site, context.app_data().clone());
+
     // write mod log entry for lock
     if Page::is_locked_changed(&old_post, &page.comments_enabled) {
       let form = ModLockPostForm {