Community post tags (part 1) (LemmyNet#4997)

* partial post tags implementation

* fixes

* fix lints

* schema fix

* chore: restructure / rename tag tables

* chore: fix post view tests

* format

* lint

* expect used

* chore: update code to maybe final version

* add ts-rs optionals

* remove error context

* clippy

crates/api_common/src/post.rs

@@ -1,5 +1,5 @@
 use lemmy_db_schema::{
-  newtypes::{CommentId, CommunityId, DbUrl, LanguageId, PostId, PostReportId},
+  newtypes::{CommentId, CommunityId, DbUrl, LanguageId, PostId, PostReportId, TagId},
   ListingType,
   PostFeatureType,
   PostSortType,
@@ -37,6 +37,8 @@ pub struct CreatePost {
   /// Instead of fetching a thumbnail, use a custom one.
   #[cfg_attr(feature = "full", ts(optional))]
   pub custom_thumbnail: Option<String>,
+  #[cfg_attr(feature = "full", ts(optional))]
+  pub tags: Option<Vec<TagId>>,
   /// Time when this post should be scheduled. Null means publish immediately.
   #[cfg_attr(feature = "full", ts(optional))]
   pub scheduled_publish_time: Option<i64>,
@@ -164,6 +166,8 @@ pub struct EditPost {
   /// Instead of fetching a thumbnail, use a custom one.
   #[cfg_attr(feature = "full", ts(optional))]
   pub custom_thumbnail: Option<String>,
+  #[cfg_attr(feature = "full", ts(optional))]
+  pub tags: Option<Vec<TagId>>,
   /// Time when this post should be scheduled. Null means publish immediately.
   #[cfg_attr(feature = "full", ts(optional))]
   pub scheduled_publish_time: Option<i64>,

crates/db_schema/src/impls/mod.rs

@@ -35,4 +35,5 @@ pub mod private_message_report;
 pub mod registration_application;
 pub mod secret;
 pub mod site;
+pub mod tag;
 pub mod tagline;

crates/db_schema/src/impls/tag.rs

@@ -0,0 +1,53 @@
+use crate::{
+  newtypes::TagId,
+  schema::{post_tag, tag},
+  source::tag::{PostTagInsertForm, Tag, TagInsertForm},
+  traits::Crud,
+  utils::{get_conn, DbPool},
+};
+use diesel::{insert_into, result::Error, QueryDsl};
+use diesel_async::RunQueryDsl;
+use lemmy_utils::error::LemmyResult;
+
+#[async_trait]
+impl Crud for Tag {
+  type InsertForm = TagInsertForm;
+
+  type UpdateForm = TagInsertForm;
+
+  type IdType = TagId;
+
+  async fn create(pool: &mut DbPool<'_>, form: &Self::InsertForm) -> Result<Self, Error> {
+    let conn = &mut get_conn(pool).await?;
+    insert_into(tag::table)
+      .values(form)
+      .get_result::<Self>(conn)
+      .await
+  }
+
+  async fn update(
+    pool: &mut DbPool<'_>,
+    pid: TagId,
+    form: &Self::UpdateForm,
+  ) -> Result<Self, Error> {
+    let conn = &mut get_conn(pool).await?;
+    diesel::update(tag::table.find(pid))
+      .set(form)
+      .get_result::<Self>(conn)
+      .await
+  }
+}
+
+impl PostTagInsertForm {
+  pub async fn insert_tag_associations(
+    pool: &mut DbPool<'_>,
+    tags: &[PostTagInsertForm],
+  ) -> LemmyResult<()> {
+    let conn = &mut get_conn(pool).await?;
+    insert_into(post_tag::table)
+      .values(tags)
+      .execute(conn)
+      .await?;
+    Ok(())
+  }
+}

crates/db_schema/src/newtypes.rs

@@ -283,3 +283,9 @@ impl InstanceId {
     self.0
   }
 }
+
+#[derive(Debug, Copy, Clone, Hash, Eq, PartialEq, Default, Serialize, Deserialize)]
+#[cfg_attr(feature = "full", derive(DieselNewType, TS))]
+#[cfg_attr(feature = "full", ts(export))]
+/// The internal tag id.
+pub struct TagId(pub i32);

crates/db_schema/src/schema.rs

@@ -826,6 +826,14 @@ diesel::table! {
     }
 }
 
+diesel::table! {
+    post_tag (post_id, tag_id) {
+        post_id -> Int4,
+        tag_id -> Int4,
+        published -> Timestamptz,
+    }
+}
+
 diesel::table! {
     private_message (id) {
         id -> Int4,
@@ -951,6 +959,18 @@ diesel::table! {
     }
 }
 
+diesel::table! {
+    tag (id) {
+        id -> Int4,
+        ap_id -> Text,
+        name -> Text,
+        community_id -> Int4,
+        published -> Timestamptz,
+        updated -> Nullable<Timestamptz>,
+        deleted -> Bool,
+    }
+}
+
 diesel::table! {
     tagline (id) {
         id -> Int4,
@@ -1032,13 +1052,16 @@ diesel::joinable!(post_aggregates -> instance (instance_id));
 diesel::joinable!(post_aggregates -> person (creator_id));
 diesel::joinable!(post_aggregates -> post (post_id));
 diesel::joinable!(post_report -> post (post_id));
+diesel::joinable!(post_tag -> post (post_id));
+diesel::joinable!(post_tag -> tag (tag_id));
 diesel::joinable!(private_message_report -> private_message (private_message_id));
 diesel::joinable!(registration_application -> local_user (local_user_id));
 diesel::joinable!(registration_application -> person (admin_id));
 diesel::joinable!(site -> instance (instance_id));
 diesel::joinable!(site_aggregates -> site (site_id));
 diesel::joinable!(site_language -> language (language_id));
 diesel::joinable!(site_language -> site (site_id));
+diesel::joinable!(tag -> community (community_id));
 
 diesel::allow_tables_to_appear_in_same_query!(
     admin_allow_instance,
@@ -1098,6 +1121,7 @@ diesel::allow_tables_to_appear_in_same_query!(
     post_actions,
     post_aggregates,
     post_report,
+    post_tag,
     private_message,
     private_message_report,
     received_activity,
@@ -1108,5 +1132,6 @@ diesel::allow_tables_to_appear_in_same_query!(
     site,
     site_aggregates,
     site_language,
+    tag,
     tagline,
 );

crates/db_schema/src/source/mod.rs

@@ -40,6 +40,7 @@ pub mod private_message_report;
 pub mod registration_application;
 pub mod secret;
 pub mod site;
+pub mod tag;
 pub mod tagline;
 
 /// Default value for columns like [community::Community.inbox_url] which are marked as serde(skip).

crates/db_schema/src/source/tag.rs

@@ -0,0 +1,57 @@
+use crate::newtypes::{CommunityId, DbUrl, PostId, TagId};
+#[cfg(feature = "full")]
+use crate::schema::{post_tag, tag};
+use chrono::{DateTime, Utc};
+use serde::{Deserialize, Serialize};
+use serde_with::skip_serializing_none;
+#[cfg(feature = "full")]
+use ts_rs::TS;
+
+/// A tag that can be assigned to a post within a community.
+/// The tag object is created by the community moderators.
+/// The assignment happens by the post creator and can be updated by the community moderators.
+///
+/// A tag is a federatable object that gives additional context to another object, which can be
+/// displayed and filtered on currently, we only have community post tags, which is a tag that is
+/// created by post authors as well as mods  of a community, to categorize a post. in the future we
+/// may add more tag types, depending on the requirements, this will lead to either expansion of
+/// this table (community_id optional, addition of tag_type enum) or split of this table / creation
+/// of new tables.
+#[skip_serializing_none]
+#[derive(Debug, PartialEq, Serialize, Deserialize, Clone)]
+#[cfg_attr(feature = "full", derive(TS, Queryable, Selectable, Identifiable))]
+#[cfg_attr(feature = "full", diesel(table_name = tag))]
+#[cfg_attr(feature = "full", diesel(check_for_backend(diesel::pg::Pg)))]
+#[cfg_attr(feature = "full", ts(export))]
+pub struct Tag {
+  pub id: TagId,
+  pub ap_id: DbUrl,
+  pub name: String,
+  /// the community that owns this tag
+  pub community_id: CommunityId,
+  pub published: DateTime<Utc>,
+  #[cfg_attr(feature = "full", ts(optional))]
+  pub updated: Option<DateTime<Utc>>,
+  pub deleted: bool,
+}
+
+#[derive(Debug, Clone)]
+#[cfg_attr(feature = "full", derive(Insertable, AsChangeset))]
+#[cfg_attr(feature = "full", diesel(table_name = tag))]
+pub struct TagInsertForm {
+  pub ap_id: DbUrl,
+  pub name: String,
+  pub community_id: CommunityId,
+  // default now
+  pub published: Option<DateTime<Utc>>,
+  pub updated: Option<DateTime<Utc>>,
+  pub deleted: bool,
+}
+
+#[derive(Debug, Clone)]
+#[cfg_attr(feature = "full", derive(Insertable, AsChangeset))]
+#[cfg_attr(feature = "full", diesel(table_name = post_tag))]
+pub struct PostTagInsertForm {
+  pub post_id: PostId,
+  pub tag_id: TagId,
+}

crates/db_schema/src/utils.rs

@@ -547,6 +547,11 @@ pub mod functions {
 
   // really this function is variadic, this just adds the two-argument version
   define_sql_function!(fn coalesce<T: diesel::sql_types::SqlType + diesel::sql_types::SingleValue>(x: diesel::sql_types::Nullable<T>, y: T) -> T);
+
+  define_sql_function! {
+    #[aggregate]
+    fn json_agg<T: diesel::sql_types::SqlType + diesel::sql_types::SingleValue>(obj: T) -> Json
+  }
 }
 
 pub const DELETED_REPLACEMENT_TEXT: &str = "*Permanently Deleted*";

crates/db_views/Cargo.toml

@@ -35,6 +35,7 @@ diesel-async = { workspace = true, optional = true }
 diesel_ltree = { workspace = true, optional = true }
 serde = { workspace = true }
 serde_with = { workspace = true }
+serde_json = { workspace = true }
 tracing = { workspace = true, optional = true }
 ts-rs = { workspace = true, optional = true }
 actix-web = { workspace = true, optional = true }
@@ -46,3 +47,4 @@ serial_test = { workspace = true }
 tokio = { workspace = true }
 pretty_assertions = { workspace = true }
 url = { workspace = true }
+test-context = "0.3.0"

crates/db_views/src/lib.rs

@@ -14,6 +14,8 @@ pub mod local_user_view;
 #[cfg(feature = "full")]
 pub mod post_report_view;
 #[cfg(feature = "full")]
+pub mod post_tags_view;
+#[cfg(feature = "full")]
 pub mod post_view;
 #[cfg(feature = "full")]
 pub mod private_message_report_view;

crates/db_views/src/post_tags_view.rs

@@ -0,0 +1,30 @@
+//! see post_view.rs for the reason for this json decoding
+use crate::structs::PostTags;
+use diesel::{
+  deserialize::FromSql,
+  pg::{Pg, PgValue},
+  serialize::ToSql,
+  sql_types::{self, Nullable},
+};
+
+impl FromSql<Nullable<sql_types::Json>, Pg> for PostTags {
+  fn from_sql(bytes: PgValue) -> diesel::deserialize::Result<Self> {
+    let value = <serde_json::Value as FromSql<sql_types::Json, Pg>>::from_sql(bytes)?;
+    Ok(serde_json::from_value::<PostTags>(value)?)
+  }
+  fn from_nullable_sql(
+    bytes: Option<<Pg as diesel::backend::Backend>::RawValue<'_>>,
+  ) -> diesel::deserialize::Result<Self> {
+    match bytes {
+      Some(bytes) => Self::from_sql(bytes),
+      None => Ok(Self { tags: vec![] }),
+    }
+  }
+}
+
+impl ToSql<Nullable<sql_types::Json>, Pg> for PostTags {
+  fn to_sql(&self, out: &mut diesel::serialize::Output<Pg>) -> diesel::serialize::Result {
+    let value = serde_json::to_value(self)?;
+    <serde_json::Value as ToSql<sql_types::Json, Pg>>::to_sql(&value, &mut out.reborrow())
+  }
+}