Blog plugin events

A blog event is named blog:<resource>:<phase>_<action>. The resource is the last part of the module name, in snake case: MishkaBlog.BlogPost is blog_post, MishkaBlog.PostRating is post_rating. The action is the Ash action that ran, such as publish. The action of a master, such as master_publish, fires its own event.

Fired after the action's transaction commits. The plugin receives the saved record and a read-only meta of %{actor:, site_id:}. The reply does not change the action.

These resources fire them: blog_post, collection, tag, blogger, team, comment, auto_posting, post_rating, post_bookmark, comment_vote, blogger_follower, team_follower, post_view, post_blogger, post_collection, post_tag, team_member and team_permission.

Fired before the action runs. The plugin receives the changeset. It returns the changeset, changed or not, or the changeset with Ash.Changeset.add_error/2 to reject the action.

Fired before a read runs. The plugin receives the Ash.Query and returns it, usually with an added filter or sort.

Fired when the rendered_content calculation of a post or comment is loaded, which blog-post-detail and blog-post-comments do. The plugin receives %{html: raw, record: record} and returns %{html: changed}.

This plugin refuses a reader's comment that contains a phrase. Start it in your application's supervision tree.

defmodule MyApp.Plugins.RejectComment do
  use MishkaInstaller.Event.Hook, event: "blog:comment:before_create_public"

  @impl true
  def call(changeset, _meta) do
    content = Ash.Changeset.get_attribute(changeset, :content) || ""

    if String.contains?(content, "buy now") do
      {:reply, Ash.Changeset.add_error(changeset, field: :content, message: "Rejected")}
    else
      {:reply, changeset}
    end
  end
end

An after event listens by name too. MishkaCmsCore.Runtime.Resources.Notifiers.PluginHook.event_name/2 builds the name, so the plugin cannot misspell it.

alias MishkaCmsCore.Runtime.Resources.Notifiers.PluginHook

use MishkaInstaller.Event.Hook,
  event: PluginHook.event_name(MishkaBlog.BlogPost, :publish)

The blog starts 24 plugins of its own. These are the events they listen on.

Three plugins read a blog page once and frame it. A request runs PageSource first, then PageFrame, then the blog's PageSeo, which builds the head from the same rows. PageSource and PageFrame answer only for their own pages and hand every other page back untouched before they read anything. TranslationKeys runs when the CMS works out which translation keys a site still uses. All three run at priority 50.

What the source holds

The source is read in handle_params/3, as the signed-in visitor or as a guest, through the same public actions the blocks read with. A record that visitor may not open is nil in the struct.

• A post is read with its text as the site draws it, its readers' rating, its count of approved comments, its categories and tags, its authors with their teams, and its other editions.
• A category and a tag are read with the number of posts their own page lists and their other editions. The page of their post list that the address names is read with them.
• A blogger is read with their teams. A team is read with its members and how many posts each has.
• The front page holds the featured posts of its strip, how many posts the visitor may open in the page's language, and the page of the list that the address names.

A list the reader narrows with a search, or on the front page with a tag, reads for itself. A live patch that stays on the same record, such as another page of a list, takes from the read of the address before it what the new address left unchanged. A block takes rows from the source only when it declares the page_source attribute and the source was read for the same site, visitor, language and page. See Page source: read a page's rows once.

What the frame holds

• The bar shows the blog's name, which leads to the front page, and four places (Posts, Categories, Tags and People). The place the reader is in is marked. A post, a category and a tag are in Posts, and a blogger and a team are in People.
• The bar's words are the site's translations in the response's language. A word nobody translated shows as its key.
• For a post, a category and a tag, the languages are every published edition the visitor may open, each at its own slug. A blogger and a team are one record in every language, so each language the site publishes in is offered at the same slug. A list page keeps the layout's own list: the same path in each language.

See Page frame: languages and the section bar for the shape of both entries.

What the translation keys name

The five words are Blog, Posts, Categories, Tags and People. No template holds them, because a plugin draws the bar. Without TranslationKeys, Remove unused on the Translations screen would delete them and what a translator wrote for them. Setting the blog up registers the same words for each language of the site. See Translate an extension's words.

• How the blog works.
• Blog JSON:API.
• Blog admin screens: the settings the blog registers.
• Plugin events: every event the CMS fires.