テーマモディファイア：簡単な紹介

ドキュメント 開発者ガイド
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テーマがより野心的になるにつれて、テーマがコアのサーバーサイドの動作を操作できるようにする方法を探してきました。プラグインほどの制御レベルが与えられることはありませんが、テーマが操作するためのいくつかの定義済みのフックを提供できます。

テーマモディファイアの紹介 :partying_face:

これらは、テーマの about.json ファイルの modifiers キーを使用して指定されます。

100%最新のモディファイアのリストについては、theme_modifier_set.rb の最後にあるデータベーススキーマを確認してください。しかし、ここまでの簡単な要約を以下に示します。

  • serialize_topic_excerpts boolean (デフォルト false) - トピックリストをシリアル化する際に常に抜粋を含めます

  • csp_extensions string 配列 - CSP にディレクティブを追加します。古い「extend_content_security_policy」テーマ設定メソッドと同じように機能します。ただし、単純な <script src=""> タグは自動的に許可されていることを忘れないでください。

  • svg_icons string 配列 - アイコンサブセットに含めるべきアイコンのリスト

  • topic thumbnails 寸法の配列 - トピックサムネイルセットで追加の解像度を要求します。これらは非同期で生成されるため、要求したサイズが提供されない場合は、元の画像にフォールバックする必要があります。詳細についてはコミットメッセージを参照してください。

  • serialize_post_user_badges string 配列 - 投稿データと一緒にシリアル化するバッジ名（badges テーブルのエントリと一致）のリスト。設定すると、システムはクライアントサイドのレンダリングのために、各投稿に指定されたユーザーバッジを含めます。

これらの新しいフックを多用しているテーマの例として、Topic List Thumbnails があります。動作を確認するためにコードをチェックしてください。

設定依存のモディファイア

テーマモディファイアは、その値をテーマ設定から取得するように構成することもできます。これにより、サイトオペレーターはテーマのコードを編集せずにモディファイアの動作をオーバーライドできます。モディファイアを設定に依存させるには、about.json で次の構文を使用します。

{
  "modifiers": {
    "modifier_name": {
      "type": "setting",
      "value": "setting_name"
    }
  }
}

たとえば、show_excerpts というテーマ設定があり、それが serialize_topic_excerpts モディファイアを制御するようにしたい場合：

settings.yml で：

show_excerpts:
  default: false

about.json で：

{
  "modifiers": {
    "serialize_topic_excerpts": {
      "type": "setting",
      "value": "show_excerpts"
    }
  }
}

show_excerpts 設定が変更されると、モディファイアの値は自動的にそれに一致するように更新されます。これにより、サイトオペレーターが管理 UI を通じてテーマの動作をカスタマイズするための柔軟性が提供されます。

このドキュメントはバージョン管理されています - 変更の提案はgithubで行ってください。

「いいね！」 35
Is it possible to fetch image Urls array for every post in latest.json?
Topic List Previews (legacy)
Discourse 2.5.0.beta5 Release Notes
Theme Developer Quick Reference Guide
Customizing the topic list
Topic List Previews (legacy)
Get excerpt for regular topics
Topic List Previews (legacy)
'Always include topic excerpt' setting
Adding statcounter code
Topic List Previews (legacy)
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David, probably a bit lazy of me to ask but is there any way to access this in a plugin:

Themes can request additional thumbnail sizes by using a modifier in their about.json file:

I will be attempting to migrate the TLP plugin to this new schema and it would be good to have the same access to features from a plugin, at least in the meantime.

「いいね！」 2
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There isn’t at the moment, but I’ll look into it :eyes:

「いいね！」 6
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David, what’s the right approach for BULK recreation of thumbnails?

I’ve just tried utilising on one of my sites and it seems to have processed about 10% of the Topics … then given up (or turned its nose up at the rest). Why I think it’s the former is that the Topics for whom Thumbnails were produced were the latest 10%.

Rebaking posts doesn’t seem to cut it. In fact, I did run a bulk rebake and wonder if that upset it …

I notice that image_url can be populated, but there are no thumbnails.

Any advice, appreciated!

「いいね！」 1
7

That column doesn’t do anything, and will be dropped very soon. image_upload_id is the one you want.

There should be no need for this. I deliberately designed it so that people can install new themes without having to mess around on the console. Thumbnails are generated asynchronously when needed. For example:

  • you add a new theme, which requests new resolutions
  • a user requests a topic, we serve the thumbnails that exist. If any sizes don’t exist, we schedule a sidekiq job.
  • next time someone requests the topic, the correct thumbnails will exist

If the requested thumbnail size is larger than the original, we won’t bother generate the thumbnail.

So the critical thing to bear in mind for this to work is:

There’s an example of this fallback logic in the thumbnail theme component I made - feel free to steal logic from there.

「いいね！」 5
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The fallback is serialised as thumbnailsl[0]? Yes, I’m already handling that. (nice implementation btw, very easy to handle)

Is it possible some images are ‘not making the grade’ or fitting the criteria?

The behaviour we have in the TLP plugin will pick up one-box thumbnails. That’s not happening in every case here I think.

For example, if you get time, take a look at these examples:

I don’t think these thumbnails make the cut. The thumbnails are serialized as null

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Yes that’s deliberate - we had a number of requests to remove small onebox thumbnails. For example, people were ending up with their github avatar as a topic thumbnail - which is rarely intended

https://github.com/discourse/discourse/commit/956d15d13fd8056cbf60ca64ebbd1edca00d0125

Note that for oneboxes where the image is the actual content (such as instagram/twitter/etc photos), they will be selected.

As for the youtube video, I fixed that yesterday.

https://github.com/discourse/discourse/commit/0c6f30d92a4090aa7447e2e579a17a180e49ce17

「いいね！」 5
10

Ah great, thanks for confirmation.

That’s odd, build was more recent, but some still seem to be being overlooked.

Yeah, that’s partly why I ended up implementing a thumbnail picker for the situations where the automated choice wasn’t optimal. I may still want to modify that behaviour, but I will try to do so in the plugin.

Thanks for your time David!

「いいね！」 2
11

OK, I’ve worked it out. After a somewhat fruitless byebug session I could not work out why older YT posts were not getting thumbnails.

Then is dawned on me. It’s because of this:

image
image1278×164 16.3 KB

So I suggest that actually it might be necessary to rebake after setting this to a rather larger number (365?).

I think I’m right in saying that if something is not uploaded locally, it won’t have a thumbnail created? …

「いいね！」 4
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:+1: correct, this only works for local uploads… we may need to rethink that “max days old” setting :thinking:

「いいね！」 8
15

I have a plan, will try and get it implemented this week. One question - do you need the values to be dynamic?

i.e. Will the resolutions be defined at boot? Or at runtime (e.g. via site settings)?

The former is easier… but the latter might be possible as well :thinking:

「いいね！」 2
16

Thanks for taking a look.

I just need a fixed way, exactly like the theme component.

A site setting would be nice though.

I will add for full disclosure: id like to migrate away from the plugin so parity with theme component solution would be more than enough.

「いいね！」 2
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@merefield here you go:

Hopefully the commit message explains how it works, but let me know if you have any questions

「いいね！」 7
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Excellent. Just added it to TLP and looks like it’s working! Thanks for your help!

「いいね！」 4
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4 posts were split to a new topic: Getting thumbnails from json endpoints

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Can we make it work for images from remote server as well? For example, images from Blogger, Picasa, or Amazon S3?

Because Discourse supports hosting on Amazon S3 for big and large image site, now if everything needs to be hosted on the local server directly then this design methodology seems to be a drawback.

With this update, it’s not an easy fix for my site since we’re using other server to host the images. Now it’s too difficult to move to an affiliated server with many posts, while it’s too big for hosting on local sever.

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This is only designed to work on Discourse ‘uploads’. Those can be on S3, or some other service, if you use

We recommend using the download_remote_images site setting to automatically download images which are hotlinked from other sites.

「いいね！」 4
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Hi David, anything special one needs to do to ensure Pro icons can be used in a TC?

「いいね！」 1
23

Nothing special, no. It should work just the same as using pro icons elsewhere in Discourse. I guess you are using this plugin to enable pro icons?

If it doesn’t work let me know and I’ll take a look :eyes:

「いいね！」 2
24

Yep we are. We’ll have another dig. Thanks for response late your eve!

「いいね！」 2