Google Maps embeded links sometimes work, sometimes don't (onebox 404)

Canapin · November 2, 2022, 11:57am

I’m facing a weird behavior with Google Maps link.

Sometimes, they properly embed, and sometimes the onebox request returns a 404. I couldn’t find a way to reproduce the issue consistently, but it’s very often. Just try to paste links, move the google maps camera or cropping, try again, etc…

I first thought about a rate limit, but it’s not. The links that work and those that don’t are the same here or on my forum. Example:

Does anyone have an idea about where this issue comes from? Google side? Discourse side? Should it be moved to Contribute > Bug?

awesomerobot · February 21, 2023, 9:07pm

This is kind of weird, I just happened to notice the pattern… but I think it has something to do with the zoom level in the link?

15.5z

15z

16.75z

17z

An entirely different location…

15.38z

15z

My guess is that it’s a Google Maps onebox engine issue on our end?

Falco · February 21, 2023, 10:02pm

Nice sleuthing @awesomerobot !

Looks like our regex for zoom level doesn’t allow dots here:

github.com/discourse/discourse

lib/onebox/engine/google_maps_onebox.rb

main


      
              break if type != :standard
              sleep 0.1
            end
          end
          
          case type
          when :standard
            # Fallback for map URLs that don't resolve into an easily embeddable old-style URI
            # Roadmaps use a "z" zoomlevel, satellite maps use "m" the horizontal width in meters
            # TODO: tilted satellite maps using "a,y,t"
            match = @url.match(/@(?<lon>[\d.-]+),(?<lat>[\d.-]+),(?<zoom>\d+)(\.\d+)?(?<mz>[mz])/)
            raise "unexpected standard url #{@url}" unless match
            zoom = match[:mz] == "z" ? match[:zoom] : Math.log2(57280048.0 / match[:zoom].to_f).round
            location = "#{match[:lon]},#{match[:lat]}"
            url = "https://maps.google.com/maps?ll=#{location}&z=#{zoom}&output=embed&dg=ntvb"
            url += "&q=#{$1}" if match = @url.match(%r{/place/([^/\?]+)})
            url += "&cid=#{($1 + $2).to_i(16)}" if @url.match(/!3m1!1s0x(\h{16}):0x(\h{16})/)
            @url = url
            @placeholder =
              "https://maps.googleapis.com/maps/api/staticmap?maptype=roadmap&center=#{location}&zoom=#{zoom}&size=690x400&sensor=false"
          when :custom

Quite an easy fix.

Canapin · February 22, 2023, 12:01am

What a catch

Thanks for figuring it out!

zogstrip · February 28, 2023, 9:36pm

@loic can you have a quick look at this one?

loic · March 1, 2023, 8:07am

Sure, I’ll take a look

loic · March 1, 2023, 11:46am

Fixed here:
https://github.com/discourse/discourse/pull/20497

zogstrip · March 2, 2023, 9:39am

Rebuilding @awesomerobot’s post and all the Google Maps links are now working

Closing this.

Topic		Replies	Views
Google Maps Onebox Issue Product Support	4	2384	May 3, 2019
Google Maps onebox issues Bug	15	3901	January 1, 2016
Embedding google maps short urls is broken Feature	9	7152	March 22, 2015
Embedded google map stopped working Product Support	10	4904	September 30, 2020
Google maps link not embedding anymore Product Support	2	697	September 12, 2022

Google Maps embeded links sometimes work, sometimes don't (onebox 404)

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