Terence Eden
🆕 blog! “Rebuilding FourSquare for ActivityPub using OpenStreetMap”
I used to like the original FourSquare. The "mayor" stuff was a bit silly, and my friends never left that many reviews, but I loved being able to signal to my friends "I am at this cool museum" or "We're at this pub if you want to meet" or "Spendi…
👀 Read more: https://shkspr.mobi/blog/2024/01/rebuilding-foursquare-for-activitypub-using-openstreetmap/
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#ActivityPub #fediverse #FOURSQUARE #geolocation #OpenStreetMap
Evan Prodromou 🇨🇦🇺🇸🇬🇷🇵🇸
@Edent so, I strongly recommend looking at the full Activity Vocabulary. There are several activities specifically for check-ins. I'm excited about this project.
Evan Prodromou 🇨🇦🇺🇸🇬🇷🇵🇸
@Edent I'll put it on my list! I've got a deadline for my book on the 31st and I'm trying not to get distracted. I'll check this week. The big thing is: use `Arrive` for check-ins! And include a `summary` for servers that don't know what to do with them.
Terence Eden
@evan Thanks Evan, I really appreciate that!
I've got the bare-bones working. I can now post a location. Let me know if you want to take a look at the account.
Evan Prodromou 🇨🇦🇺🇸🇬🇷🇵🇸
@bobwyman @Edent let's make an extension for lunar Place objects!
Bob Wyman
@evan @Edent Unfortunately, the Place object is under-specified. While this doesn't impact most AS/AP users today, humans will soon return to the Moon and when they do, they won't be able to use AS Place objects to check-in or state their current location.
The problem is that AS Place doesn't allow specifying a coordinate system for Lat/Long. Thus, one can't use locations using the Lunar Coordinate System or any non-Earth Planetary Coordinate System.
We should fix this.
https://lunar.gsfc.nasa.gov/library/451-SCI-000958.pdf
Terence Eden
I've just reposted a public status from my new location check-in service.
It doesn't handle replies or likes, but you can follow it.
Expect buggy and untested weirdness 🙂
Terence Eden
OK gang! I now have an *extremely* basic ActivityPub server which can send messages to its follower!
Next steps:
* Record who is following it.
* Post to all followers (not just me).
* Stable URl for posts.
* Front end for picking locations nearby.
* About a dozen other things!
Terence Eden
Nice! My toy server can now:
✅ Record who is following it.
✅ Post to multiple inboxes.
✅ Generate a permalink for its posts.
It doesn't do:
❌ Signature verification
❌ Handling replies, likes, or unfollows (it is a read-only account)
❌ Showing number of followers, posts, etc.
Pretty happy with that.
Next step - a UI so I can actually send custom posts.
Terence Eden
Not the prettiest page on the web, but I can now Geolocate my phone and find the 25 nearest named places on #OSM.
Next stage is making a button to send that location to my ActivityPub server to send out a message.
(This is crappy code, poorly architected. Just a Proof of Concept.)
Terence Eden
It's all working!
You can follow @edent_location for my "FourSquare-style" check-ins to locations.
TODO:
📸 Upload and store photos.
🔣 Set the language text to prevent spurious "Translate" options.
🖼 Make the interface look nice.
🔒 Better security
👨💻 Tidy up the source code.
Eugen Rochko
@Edent TODO for us: Display the location metadata when it's provided 😅
Terence Eden
@Gargron 🥰
Yes please!
Terence Eden
Image upload works! And those photos percolate through the #fediverse!
I still need to add proper alt text (just a static description for now).
And the UI is 💩
But I'm pretty pleased with how far I've got in a few hours of hacking away.
It is *totally* possible to build a location-based service on top of #OSM and #ActivityPub!
Terence Eden
Goodness me! The ActivityPub network is chatty.
In the last 6 hours, I've received 371 different messages to my single-user inbox.
Most of which seem to be from servers announcing users have been deleted. They're not users or servers I've seen before.
Is this normal?
Eugen Rochko
@Edent Yes
Terence Eden
I've added a feature request to #Mastodon to display geotags.
Terence Eden
@Gargron haha! Fair enough.
Evan Prodromou 🇨🇦🇺🇸🇬🇷🇵🇸
Bob Wyman
@evan @Edent An extension for Lunar Place objects would be unnecessarily specific and would leave unaddressed the need for extensions allowing Place objects to describe locations on Mars, Io, Neptune, etc.
Given that Latitude/Longitude/Altitude is relevant to most celestial bodies, it would be more effective to add to Place objects a field for specifying the Coordinate System that should be used in interpreting the Latitude/Longitude, etc.
silverpill
@Edent This actor doesn't have the outbox property, which is required by ActivityPub standard
Terence Eden
I've built an ersatz FourSquare clone for the Fediverse!
For now it is single user instance (me) and runs on a simple server with no database - just a couple of PHP files.
It geolocates my phone's web browser, shows nearby Points of Interest using OpenStreetMap, lets me attach a short message & an image with alt text.
Then it posts it to its Fediverse followers. The post contains geotags which *some* ActivityPub clients can see.
Sample post:
https://location.edent.tel/posts/65b8f590-f308-d472-82c5-92a9f227c641.json
Follow: @edent_location
Terence Eden
Hmmm. Either I don't understand the #ActivityStreams spec, or Mastodon doesn't.
According to:
https://www.w3.org/TR/activitystreams-core/#defaultlangcontext
I *should* be able to specify the language in the `@ context`. Might have to go for the slightly more verbose `contentMap` instead.
Terence Eden
OK, if you'd like to play about with a *very* basic front-end for my Fediverse-location-foursquare-check-in thing, please visit:
SUPER bare-bones. Just a proof of concept.
Terence Eden
Here's my blog post about building a personal #Fediverse server in #PHP.
https://shkspr.mobi/blog/2024/02/a-tiny-incomplete-single-user-write-only-activitypub-server-in-php/
It was surprisingly simple. You can *publish* #ActivityPub with very modest computing resources.
If you can see the geotags on @edent_location please send me a screenshot 🙂
Terence Eden
Yesterday I went out into the real world and used my self-built FourSquare-forFediverse clone for the first time!
You can see the results by following @edent_location
✅ Location metadata attached
✅ Images with alt text
✅ Links to OSM
❌ No parsing of URls or Hashtags
❌ Location accuracy still a bit dodgy
❌ UI very bare-bones
Pretty good result for half-a-dozen PHP files.
Terence Eden
Hmmm. Converting my #ActivityPub posts to #GeoJSON was pretty straightforward.
Here's what a map of my recent check-in activity looks like:
Terence Eden
Source code is at https://github.com/edent/location-activitypub-symfony
Very much a Minimum Viable Product. Will blog about how it works this weekend.
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