Added first draft of versions to schema

README.md

@@ -1,3 +1,38 @@
 # blog
 
-Handles the contents of the blogging section.
+Handles the contents of the blogging section.
+
+## Schema & Data Objects
+
+All objects have a personal UUID ID, generated automatically by PostgreSQL.
+
+### Sections
+
+Sections group posts according to a common subject or some other metric by
+which they could be grouped. They can be seen as sub-blogs within the larger
+system. Each post can be part of only one section, & posts not part of a
+section will not be shown in the public UI.
+
+A section has a title & optional description, along with a shortname. The
+shortname is what will be used inside URLs for routing.
+
+A section can be part of the default posts list, meaning all posts created in
+this section will be shown on the homepage. The default list is an aggregated
+list containing all default sections.
+
+A section can be private, meaning all posts created in this section will not be
+shown on the any public page without authentification. Furthermore, it can
+specify wether posts should have titles, or are not allowed to. This is to
+allow for creating microblogs, which do not require titles.
+
+### Posts & Versions
+
+A post represents a publication in a specific section. The posts table itself
+only specifies which section a post belongs to & wether or not the post is
+private. Any content of the actual post is stored a a version. A private post
+can only be seen by logged-in users with the right authorization.
+
+Each version has its own publication date, with the last publication being
+shown when visiting the post. The UI however should also expose a way to show
+previous versions of the post. Each version has its own title (if allowed) &
+content. A version can be a draft. This means that the version will not be shown in the public UI, allowing the user to finish it at a later time.

migrations/2021-09-13-143540_sections/down.sql

@@ -1,7 +1,8 @@
 -- This file should undo anything in `up.sql`
-drop trigger insert_enforce_post_titles on posts;
+drop trigger insert_enforce_version_titles on versions;
-drop trigger update_enforce_post_titles on posts;
+drop trigger update_enforce_version_titles on versions;
-drop function enforce_post_titles;
+drop function enforce_version_titles;
 
+drop table versions cascade;
 drop table posts cascade;
 drop table sections cascade;

migrations/2021-09-13-143540_sections/up.sql

@@ -1,4 +1,3 @@
--- Your SQL goes here
 create table sections (
     id uuid DEFAULT gen_random_uuid() PRIMARY KEY,
 
@@ -11,48 +10,80 @@ create table sections (
     -- Wether to show the section in the default list on the homepage
     is_default boolean NOT NULL DEFAULT false,
     -- Wether the posts should contain titles or not
-    has_titles boolean NOT NULL DEFAULT true
+    has_titles boolean NOT NULL DEFAULT true,
+    -- Wether posts in this section should be shown publicly
+    is_private boolean NOT NULL DEFAULT false
 );
 
 create table posts (
     id uuid DEFAULT gen_random_uuid() PRIMARY KEY,
 
-    section_id uuid NOT NULL REFERENCES sections(id) ON DELETE CASCADE,
+    -- Posts shouldn't get deleted when we delete a section, as they're the
-    -- Title of the post
+    -- most valuable part of a blog
-    -- Wether this is NULL or not is enforced using the enforce_post_titles trigger
+    section_id uuid NOT NULL REFERENCES sections(id) ON DELETE SET NULL,
-    title varchar(255),
+
-    -- Post date, defaults to today
+    -- Wether a post should be private
-    publish_date date NOT NULL DEFAULT now(),
+    is_private boolean NOT NULL DEFAULT false,
-    -- Content of the post
+    -- Wether the post is archived
-    content text NOT NULL
+    is_archived boolean NOT NULL DEFAULT false
 );
 
-create function enforce_post_titles() returns trigger as $enforce_post_titles$
+create table versions (
+    id uuid DEFAULT gen_random_uuid() PRIMARY KEY,
+
+    -- A version should be deleted when its referenced post is deleted
+    post_id uuid NOT NULL REFERENCES posts(id) ON DELETE CASCADE,
+
+    -- Title of the post. Wether this is NULL or not is enforced using the
+    -- enforce_post_titles trigger.
+    title varchar(255),
+    -- Publish date
+    publish_date date,
+    -- Content of the post, in Markdown
+    content text NOT NULL DEFAULT '',
+    -- Wether the version is still a draft
+    is_draft boolean NOT NULL default true,
+
+    -- This check allows draft posts to be created without having to enter a
+    -- publish date, but forces them to have one if they're not a draft.
+    CHECK (is_draft OR publish_date IS NOT NULL)
+);
+
+create function enforce_version_titles() returns trigger as $$
     begin
+        -- Draft versions shouldn't be evaluated.
+        if new.is_draft then
+            return new;
+        end if;
+
         -- Check for a wrongfully null title
         if new.title is null and exists (
-            select 1 from sections where id = new.section_id and has_titles
+            select 1 from posts 
+                inner join sections on posts.section_id = sections.id
+                where posts.id = new.post_id and sections.has_titles
         ) then
             raise exception 'Expected a post title, but got null.';
         end if;
 
         if new.title is not null and exists (
-            select 1 from sections where id = new.section_id and not has_titles
+            select 1 from posts 
+                inner join sections on posts.section_id = sections.id
+                where posts.id = new.post_id and not sections.has_titles
         ) then
             raise exception 'Expected an empty post title, but got a value.';
         end if;
 
         return new;
     end;
-$enforce_post_titles$ language plpgsql;
+$$ language plpgsql;
 
-create trigger insert_enforce_post_titles
+create trigger insert_enforce_version_titles
-    before insert on posts
+    before insert on versions
     for each row
-    execute function enforce_post_titles();
+    execute function enforce_version_titles();
 
-create trigger update_enforce_post_titles
+create trigger update_enforce_version_titles
-    before update of title on posts
+    before update of title on versions
     for each row
     when (old.title is distinct from new.title)
-    execute function enforce_post_titles();
+    execute function enforce_version_titles();

src/schema.rs

@@ -2,9 +2,8 @@ table! {
     posts (id) {
         id -> Uuid,
         section_id -> Uuid,
-        title -> Nullable<Varchar>,
+        is_private -> Bool,
-        publish_date -> Date,
+        is_archived -> Bool,
-        content -> Text,
     }
 }
 
@@ -16,12 +15,26 @@ table! {
         description -> Nullable<Text>,
         is_default -> Bool,
         has_titles -> Bool,
+        is_private -> Bool,
+    }
+}
+
+table! {
+    versions (id) {
+        id -> Uuid,
+        post_id -> Uuid,
+        title -> Nullable<Varchar>,
+        publish_date -> Nullable<Date>,
+        content -> Text,
+        is_draft -> Bool,
     }
 }
 
 joinable!(posts -> sections (section_id));
+joinable!(versions -> posts (post_id));
 
 allow_tables_to_appear_in_same_query!(
     posts,
     sections,
+    versions,
 );