Modificateurs de thème : une brève introduction

Alors que les thèmes deviennent plus ambitieux, nous cherchons des moyens de leur permettre de manipuler le comportement principal côté serveur. Bien qu’ils ne disposeront jamais du même niveau de contrôle que les plugins, nous pouvons fournir quelques points d’accroche prédéfinis que les thèmes peuvent manipuler.

Voici : les modificateurs de thème :partying_face:

Ils sont spécifiés en utilisant la clé modifiers dans le fichier about.json de votre thème.

Pour une liste 100 % à jour des modificateurs, consultez le schéma de la base de données au bas de theme_modifier_set.rb, mais voici un bref résumé de ce que nous avons jusqu’à présent :

  • serialize_topic_excerpts booléen (par défaut false) - inclure toujours des extraits lors de la sérialisation des listes de sujets

  • csp_extensions tableau de chaînes - ajouter des directives au CSP. Fonctionne de la même manière que l’ancienne méthode de réglage de thème « extend_content_security_policy ». Mais rappelez-vous, les balises \u003cscript src=\"\"\u003e simples sont autorisées automatiquement.

  • svg_icons tableau de chaînes - une liste d’icônes qui doivent être incluses dans le sous-ensemble d’icônes

  • topic thumbnails tableau de dimensions - demander des résolutions supplémentaires dans l’ensemble des vignettes de sujet. Notez qu’elles sont générées de manière asynchrone, vous devez donc revenir à l’image d’origine si la taille demandée n’est pas fournie. Plus d’informations disponibles dans le message de commit

  • serialize_post_user_badges tableau de chaînes - une liste de noms de badges (correspondant aux entrées de la table des badges) à sérialiser avec les données de publication. Lorsqu’il est configuré, le système inclut les badges d’utilisateur spécifiés avec chaque publication pour le rendu côté client.

Un thème qui utilise intensivement ces nouveaux points d’accroche est Topic List Thumbnails - consultez le code pour voir comment cela fonctionne.

Modificateurs dépendant des paramètres

Les modificateurs de thème peuvent également être configurés pour extraire leur valeur d’un paramètre de thème, permettant aux opérateurs de site de remplacer le comportement du modificateur sans modifier le code du thème. Pour qu’un modificateur dépende d’un paramètre, utilisez cette syntaxe dans votre about.json :

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

Par exemple, si vous avez un paramètre de thème appelé show_excerpts et que vous souhaitez qu’il contrôle le modificateur serialize_topic_excerpts :

Dans settings.yml :

show_excerpts:
  default: false

Dans about.json :

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

Lorsque le paramètre show_excerpts est modifié, la valeur du modificateur se mettra automatiquement à jour pour correspondre. Cela offre une flexibilité aux opérateurs de site pour personnaliser le comportement du thème via l’interface d’administration.


Ce document est contrôlé par version - suggérez des modifications sur github.

35 « J'aime »

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.

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There isn’t at the moment, but I’ll look into it :eyes:

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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!

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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.

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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

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

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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!

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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:

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? …

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

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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:

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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.

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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

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Excellent. Just added it to TLP and looks like it’s working! Thanks for your help!

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4 posts were split to a new topic: Getting thumbnails from json endpoints

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.

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.

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Hi David, anything special one needs to do to ensure Pro icons can be used in a TC?

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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:

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

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