Image preview of mapillary link

mariotomo · August 29, 2022, 2:46pm

in a topic, linking a mapillary image gives link, not the image.

for example, the topic How to tag an arch symbolising entry to area holds links to images on different platforms, only the ones on mapillary do not get rendered as images.

habi · August 30, 2022, 6:40am

I think this is because Mapillary does not follow the https://oembed.com/ specification, e.g. no preview image can be loaded by the Discourse server.

cbeddow · September 1, 2022, 7:11pm

I’ll ask the team what we might need to do to get this to work!

cbeddow · September 5, 2022, 12:31pm

@habi @mariotomo as far as we can tell, Meta/Mapillary has everything needed. So it should work on Discord but it’s not clear why:

Meta tags are here: HEY META - Website Meta Tag Check

mariotomo · September 5, 2022, 1:52pm

… so, where’s the ball now? can I do something to put it back to rolling?

stephankn · September 5, 2022, 8:04pm

I see at least in the preview an image embedded

I use this link:

https://www.mapillary.com/app/?lat=18.785124499999995&lng=98.99314630000003&z=17&pKey=204383767969703

which results in this preview box having the small version of the image visible.

Is this the missing preview? Then it works for me…

mariotomo · September 5, 2022, 10:57pm

let me see …

or does one need the whole link, not just the pKey?

no, it works just fine, just the pKey, then wait a bit until you get the miniature.

would it be possible, a just slightly larger miniature? possibly through an extra parameter besides the pKey, like width or height?

and what must we do, to get the preview in an old message? re-editing it?

re-editing helped. a larger picture would be nice.

stephankn · September 6, 2022, 7:09am

I guess this should be possible. The image link in the meta header is this:

  <meta name="og:image" content="https://scontent.ffra1-1.fna.fbcdn.net/m1/v/t6/An-8E3Rj9NjUSg83IO89mifvraL4Wjc3lzAnxf5KUz3XSG8HL0IBkfvQCFLYoECR-4F1nY2AbQFLjzssbRUx5U3vMG4PbYRgZyEShfXU4-Lz_Yf4OU9JE_NSmUZJzsVUiAT2mVNJQ02zXNLG9oTbjw?stp=s1024x576&ccb=10-5&oh=00_AT_5ihVTfFZB0gKVQ_wAoS5QE7EVU8jFWtFMizygABnn9Q&oe=631CD3AE&_nc_sid=122ab1">

This will load a 1024x576 pixel version of the image.

The relevant code to create it is IMHO this:

github.com

discourse/discourse/blob/1472e47aae5bfdfb6fd9abfe89beb186c751f514/lib/onebox/engine/opengraph_image.rb#L9


      
          # frozen_string_literal: true
          
          module Onebox
            module Engine
              module OpengraphImage
          
                def to_html
                  og = get_opengraph
                  "<img src='#{og.image}' width='#{og.image_width}' height='#{og.image_height}' class='onebox' #{og.title_attr}>"
                end
              end
            end
          end

GitHub search does not show me any related location where the image_height property is set. Maybe someone more familiar with Ruby and the code can have a closer look.I guess there is a location where it is capped. Also somewhere must be code which transferred the resized preview image to the uploads folder of discourse.

Maybe a better way for us would be to create a specific onebox handler for mapillary and not use the generic handler. That way you have more control over the final layout.

Image preview of mapillary link

in a topic, linking a mapillary image gives link, not the image.

for example, the topic How to tag an arch **symbolising** entry to area holds links to images on different platforms, only the ones on mapillary do not get rendered as images.

for example, the topic How to tag an arch symbolising entry to area holds links to images on different platforms, only the ones on mapillary do not get rendered as images.