Code for link preview images?

[astime8]

Hi,

Since the link preview images still aren't working properly ( ref #3793 ), I figured I'd ask how they're made.

Is it this code file under the path bookwyrm/preview_images.py ?

How would I generate an image with this code for a particular review? (Apart from needing the direct link to a review, which I already have.)
(I have no experience with python and am relatively a noob when it comes to coding – I know a bit of html)

[mouse-reeve]

Hi, I'm not sure there's a bug here. When preview images aren't available, the cover is used instead. There are a number of reasons why there isn't a cover image available:

• The preview wasn't done generating when the link was posted
• A cached version is being used, either by bookwyrm or by the client, which doesn't have a newly-generated preview image
• A transient error (like a timeout) caused the preview generation to fail
• The bookwyrm instance has not enable preview image generation

These all resolve over time, as images get re-generated for books and caches get cleared. Sometimes it's really out of our control, and other times it's too big a cost in terms of performance to prioritizing always having the preview image available.

[astime8]

oh okay, understandable! I'll edit the thread title then. :)

[mouse-reeve]

But to actually answer your question, that is the code that generates preview images. For preview images for books, you can search the code for generate_edition_preview_image_task.delay to see places where the celery background task that generates the images is called (here, for example)

[astime8]

hmm is there a way i can run the code on a single review? Paste it to a python program, "here's the link, now run the code for it", to get the preview image? Like, "run the code for this link specifically"? Hope that makes sense … :')

[mouse-reeve]

You can call generate_edition_preview_image_task directly and pass in the id of the book you want to generate it for. Something like (and this is just off the top of my head):

from bookwyrm import preview_images

preview_images.generate_edition_preview_image_task(<ediition id>)

That will call it synchronously, without using Celery.

[astime8]

thanks! but where would i paste the code into?

[mouse-reeve]

If you have a docker development environment, you can run ./bw-dev shell to access the application python shell