Mine does! https://github.com/spieglt/flyingcarpet

Thanks for the link. Looking through the Github, this appears to be close to what I'm looking for on my own project. Namely, being able to share files automatically with nearby devices when they move within range.

I thought Bluetooth might be viable, as beacons and GattServers seem to be designed for this purpose. Android's implementation was painful, yet doable. However, after wading into Microsoft's codebase, I suspect it will be slog.

Question: With an agreed upon network name or configuration, and agreed upon access parameters, how much change do you think it would take for FlyingCarpet to instead by used as a semi-anonymous, dynamic membership mesh network?

Ex: A laptop and a phone get near each other, they recognize their proximity, and that they are both offering the known network, they then check for the presence of known filetypes in a known folder location, and exchange small updates with each other. The same with any number of desktops, laptops, or phones that get near each other. If I was in a mall with 11 other similarly configured phones nearby, and 5 people working on laptops, then my phone would call the 16 other devices, and they would each get a file from my phone, and I would get a file from their phones.

It's a very cool idea, but the first barrier that comes to mind would be that when the clients join the hotspots, they don't have internet access, so joining the network would mean losing internet, for laptops and phones without cellular data. I know the LocalOnlyHotspot API I use on Android doesn't offer internet tethering. I'm not sure how possible it is to ensure that on Windows and Linux devices that host hotspots. Also, the device that offers the hotspot in Flying Carpet is pretty much acting like a normal WiFi access point in infrastructure mode, so a real mesh network would probably look a lot different.

Thanks. Those are the kind of issues I was worried about with a superficial glance. The general idea looks tempting ("send files to nearby devices"). However, dropping connectivity every time would probably be a deal breaker. I was hoping you might be able to connect for like 10-20 seconds, grab a few kB of files, and then continue on your way, having a spotty, partial connectivity to other devices while wandering the above mall scenario.

Great project! Thank you for building it.

If the UI was simpler and more "Apple-like" (hate to say this) I could convince my non-tech coworkers/family/friends to use it.

Also, could you auto detect the other peer's OS? You could skip an extra step and UI element. Do you need it to know which WiFi bandwidth to use?

Thank you! Yeah, obviously the UI is a weak part. I'd like to improve it eventually but as a one-person project I don't want it to have as minimal of an interface as AirDrop. With all the ways transfers can go wrong, I want that information to be in the user's face so they can submit issues and I can help debug easily.

And no, it can't detect anything about the other device until they're on a WiFi network together, and that can't happen until it knows the peer's OS because it has to know whether it or the peer should be hosting the hotspot. Windows has precedence, then Linux, then Android. (The iOS version doesn't need to know the peer's OS because iOS and macOS can't stand up a hotspot programmatically anymore, so it always has to join.)

So how would a transfer between two iOS devices work? Neither would be able to create the hotspot, right?

Correct, Flying Carpet doesn't work for Apple-to-Apple transfers, but AirDrop already fills this need.

Thank you for the detailed explanation, it's not my specialty yet really fun to scratch a bit of the surface in other aspects :)

Excellent work.

Haven't tried yet but this is really cool. Nice job.

I used this a while ago, thanks!

Great to hear, thanks for letting me know it worked!

This serves the purpose of cross-platform file sharing. Great job.

This. Airdrop is actually viable for transferring huge files, like RAW photos or ProRes footage. I've had video engineering professionals ask me if it's viable to implement Airdrop support in something like a camera or a recorder, not because it's pretty or doesn't need cables, but because it would save them time in a media workflow (they are busy people).

Resilio Sync's pretty fast and less fussy than AirDrop, I also don't like keeping AirDrop running chronically

I have been using Resilio Sync between my Mac, Synology and an android e-ink tablet. Everything was working fine when I set it up, then a few months later when I wanted to transfer something I discovered that Resilio Sync on the Android e-ink tablet had forgotten about the shared folder. Trying to set it up again is a pain. I would prefer AirDrop over Resilio Sync any day of the week.

Resilio Sync is also incredibly slow when the two devices are not connected to the same network. Like kb/s slow.

> I also don't like keeping AirDrop running chronically

Why?

It’s better now that you can choose only to expose it to contacts, and only enable it for “everyone” for a limited time. I seem to remember in the past you could leave “everyone” enabled indefinitely, evident anytime you stood in a crowd.

> I seem to remember in the past you could leave “everyone” enabled indefinitely, evident anytime you stood in a crowd.

er yes, Apple seemingly eliminated the "everyone/forever" option because it was being used to slightly-anonymously[0] spread stuff the chinese government didn't like [1]

0: https://arstechnica.com/security/2024/01/hackers-can-id-uniq... 1: https://techcrunch.com/2022/11/09/apple-limits-airdrop-every...

I was pleasantly pleased to recently learn Airdrop has no file size limitation! I needed to transfer several 7-9 GB files and thought for sure I'd run into issues but everything moved smooth (and quickly!).

This. Apple’s built in migration tool always (well, the last 3 years anyways) fails to move everything in my File’s app over to the new device.

I’ve moved ~500-800GB via air drop in one go before.

Apple usually does excellent integrations between their devices. But I haven't used AirDrop so I'm not familiar with how it works: in order to create an ad-hoc wireless connection, if the devices were already connected to some wifi access point, are they temporarily disconnected for the duration of the ad-hoc connection?

If not, I'd guess that Apple devices maybe come with 2 WiFi adapters inside?

Neither — frequency hopping is used so that the device can establish AWDL connectivity directly with nearby devices while maintaining a connection to an access point, while still only having a single Wi-Fi adapter.

> frequency hopping

That this is possible, and allows to maintain a dual connection to an AP and an ad-hoc connection to another device for AirDrop, sounds amazing. Now I want to learn more about that technique and where/how it can be applied to non-Apple devices!

Bluetooth does it too!

It's hard enough to get Bluetooth to connect to one device!

To be fair it’s great at connecting to every device within 100 meters other than the one in your hand.

The next version fixes this problem and uses less power.

And yes, I’m being sarcastic.

Honestly, I've been having excellent experience with BT (and headphones) with modern devices.

For example, my Lenovo T14s (2023 AMD version running the latest kernel) connects to my (5.2 version of BT) headphones really well. Similarly, my android phone connects to the same headphones and whatever device sends data, that's what I hear.

Similarly, my Steam Deck connects to two of the headphones I'm using (Sennheiser and Apple Airpods) seamlessly.

At first, I thought you were alluding to Bluetooth file sharing, which Apple doesn’t support.

I was referring to frequency hopping. In any case Apple does support Bluetooth file transfer on macOS, just not on iOS.

AirPlay and Miracast both rely on WiFi (in case of Miracast it's WiFi Direct, for AirPlay I'm not sure), so it's not uncommon for WiFi chips to maintain 2 connections at once.

No they don’t disconnect from WiFi and as of the latest iOS you can now leave airdrop radius and it will use the internet to continue transfer. Its magic

IIRC Apple uses some proprietary radio protocol (or maybe it’s just Bluetooth) to discover and communicate with nearby Apple products.

It uses Bonjour [1], which has an LGPL reimplementation named Avahi [2]

[1]: https://en.m.wikipedia.org/wiki/Bonjour_(software)

[2]: https://en.m.wikipedia.org/wiki/Avahi_(software)

For the sake of being picky, Bonjour is not a radio protocol (Layer 1), it’s a set of tools which enable zero config networking (Layer 2/3)

I agree, it's not a radio protocol and I wasn't trying to imply that it was. The person I was responding to posited it might be one and I pointed them to the protocol that's used without explicitly correcting them on that point.

Makes sense.

It can’t use just bonjour.

Apple devices can detect out of network devices as well.

You can create a hotspot and start a HTTP server. Scan a QR code to connect to the hotspot, then a QR code for the file URL. It's easy and works with any device with Wifi access.

For the server, on Android I use "Share via HTTP". On desktop running a lightweight HTTP server is easy too.

Edit:

Apparently that sounded complicated, here is how I can share a file from my phone to any other phone in the same Wifi.

- Click Share -> Share with HTTP.

- The app opens and shows a QR code.

- Other person scans the code. Their browser opens the file and they can do whatever they want with it.

If you have no Wifi:

- Open QR code for hotspot

- Other person scans QR code for hotspot, then for file.

If you still think it is too complicated, surely there is an opportunity create a simpler UI! From a technology perspective it does not have to be complicated.

Yeah! Just like Dropbox can trivially be replaced by FTP, FUSE mounts and CVS……

I'll just tap share -> person

Can't agree more. Users don't want to run a server or figure any of that out. There is a person near them and they want to share a file quickly.

I am not sure you understand. You click share, then Share via HTTP, the other person scans the QR code, they have the file. Setting up the server is no effort at all.

Only if you are outside without Wifi you have to do another step, setting up a Wifi hotspot, but that is not hard. And in most situations I have been in both devices were in the same network anyways.

But that's 80% of why AirDrop is so great. Exchanging files/photos/videos when you're not home and sometimes with strangers / acquaintances.

> Setting up the server is no effort at all.

This assumes that the user has a level of technical knowledge that most people don’t have.

Which of the steps that I described required advanced technical knowledge?

Edit: Ah maybe you thought setting up the server is an additional step. It is not. Share via HTTP is the server. It runs directly on your phone. The URL points directly to your device.

And the remote user's authentication is handled, how? And the routing, NAT, and discovery of your server's private IP address is handled?

None of that is necessary because you are not exposing anything to the internet. We are still talking about local sharing. Android does not have a firewall so there really is nothing to configure. But if you think it cannot be possible, try it for yourself.

You seem confidently oblivious of security concerns, almost as if you're just here to shill for a janky app.

Ok, let's paint this picture:

You scan a QR code to connect to someone's wifi.

All your traffic can now be captured. DNS requests will be logged. Some traffic might be redirected. When will the connection be closed? What if someone shows you a different QR code, and you're not that tech-savvy. For example a phishing webpage which asks for the user's password. Many many many people will still just enter their single-password-for-everything. What if the QR code is a deeplink to an app.. for example to a conversation on or whatever. Or maybe someone was previously logged in into some account.

Let me just teach my mum how to run a HTTP server and generate QR codes to send me photos of our lunch /s

It's the same difficulty. They used techy terms because we know that's what's happening, but your mom doesn't need to know those terms or anything like that.

Thank you, I think I didn't get the idea across properly.

An app like "Share via HTTP" does that for you.

https://play.google.com/store/apps/details?id=com.MarcosDiez...

It's literally click in the share icon and choose "Share over QR".

The device then will do the "run a server with the file, create the QR Code for access, display it". Your mum has no need to learn how to run it, just how she doesn't need to know anything about how airdrop works to use it.

> here is how I can share a file from my phone to any other phone in the same Wifi.

This will not work on many public and corporate networks. A common place where you’d want to share.

> surely there is an opportunity create a simpler UI!

It’ll still suck compared to Airdrop. Apple has gone to a lot of trouble to make that work as well as it does. Trying to setup something relying on temporary hotspots will be sub par UX. (And a nonstarter for Apple devices - user apps can’t touch the WiFi settings).

I did this in public networks and it did work, but I am not an expert in how they are set up. When do you think it would not work?

Wireless Client Isolation.

Here is but one vendor doc. https://documentation.meraki.com/MR/Firewall_and_Traffic_Sha...

It is standard practice to enable this these days in public networks and it is so common that even consumer grade shit router now come with an option to enable.

  > create an ad-hoc wireless connection.

Every Android device I've used has had "Send via Bluetooth" functionality built in. Is the WiFi connection just significantly faster or does it provide other additional benefits?

Significantly faster

For large files, less power will be used for WiFi versus Bluetooth.

You would need to use "Nearby Share" for that. But it's also Standard with Androif

Sure now walk away from the person while the file is transfering... on airdrop it finishes over the internet after you walk out of range :)

Nearby Share can also use the internet to transfer it

WiFi is massively faster.

Apple Watches used to update over Bluetooth and it would take hours, literally. And someone discovered a trick to turn off Bluetooth to force it to update over Wi-Fi, and then the download took just minutes.

most wifi is probably 2 orders of magnitude faster than bluetooth transfer. Syncthing is great if you're looking for multiplatform syncing of files. It takes a little playing around though, the interface is not what I would call beginner friendly, but it's not too bad, and has been very dependable in my experience

I admit the convenience is not the same, but this was already possible with my first Android phone (2011/12ish).

There was an app called "Wifi File Transfer" which would expose a web UI in the local network to download and upload files to the phone's storage.

First I only used it to upload music to my phone (faster than USB1.1 or even USB2).

Then I found out it also works fine when creating a WiFI AP/Hotspot and allowing other peers to connect to it.

So Wi-Fi Direct?

With WiFi direct, the devices must pair in a manner similar to an initial Bluetooth pairing.

Apple simplifies this stage.

ISTR around something like the Galaxy Nexus Google doing demos of beaming files between devices via WiFi Direct after having exchanged info with an NFC tap.

But that was just before they decided everything had to go via their cloud.

Curiously if you used a London bus in around 2005 with bluetooth on you would experience a lot of files being sent to you via ad hoc networks.

I think the modern alternative is Nearby Share which works via BLE or WiFi with Android / Windows / ChromeOS

this also gives you wifi speed actually. thanks for webrtc.

Many things give you wifi speed, if you're connected to wifi.

With Airdrop, if you are on the moon and meet a stranger there who also has an iphone, you can perform the high-speed transfer of large files.

Will an iPhone work in a vacuum?

You’re kidding, but a working phone was found on the ground after the panel blew out of the Boeing a few weeks ago.

https://www.theverge.com/2024/1/8/24029806/boeing-737-max-9-...

I don’t think there’s anything in a phone that’d stop its core functions in a vacuum. The human trying to use it, not so much.

I was kind of kidding, but I was also kind of intrigued by the idea. My instinct is that it would work in a vacuum, but that is just a gut feeling. But I also could not think of why one could not.

Overheating could be a problem. cooling by thermal radiation alone maybe isn't enough

wouldn't it use bluetooth in that case? Or does it create adhoc wifi connections somehow?

It will use bluetooth for discovery and then establish an adhoc wifi connection between the two devices.

So Apple.com has built a connection that doesn't adhere to TCP/IP standards. Great engineering, people!

How do you figure that? I don't know anything about how this works, but ad-hoc Wi-Fi connections are a thing, and they use good ol' TCP/IP. It just means you don't connect to some pre-existing Wi-Fi network managed by some third party (from the exchanging terminals' perspective).

1. How do you know this? 2. Even if it's the case, why would it be wrong if it's the best choice for the requirements? (incredibly simple, fast, reliable local file sharing). TCP/IP isn't the end-all be-all.

It's a peer-to-peer wireless connection that doesn't go over the internet at all. Why does it matter (and how would you even know) if they use TCP/IP?

snapdrop.net does. It works locally in your network Peer2Peer

It doesn't do what airdrop does, although it is a step better than Sharedrop, in that it doesn't require the data be sent over the internet. But it still has a lot of extra hassle that airdrop doesn't have. If you're away from home, you first have to enable Mobile Hotspot to create a wifi network (and pay your carrier for the right, since it's usually locked down in Android), then manually connect your other device to that wifi. Airdrop skips all of that. If Airdrop is open, it's scanning via bluetooth for another device with Airdrop enabled (it doesnt even have to be open). Then they instantly agree on an ad-hoc network and connect, all invisibly to the user. So you don't do anything at all. I wish a Android developer could accomplish this.

I see your point now. Here no phone with a Contract is locked anymore, and certainly no Bullshit like "locked Functions" that you have to pay extra for like Tethering. So it's not a huge hassle to quickly spin up a hotspot.

But Android offers a Airdrop-Like-Feature natively called "Nearby Share" but what still sucks in my POV that there is still no Cross-Plattform-Solution between iPhones and Android out there

I routinely use airdrop to transfer mapping data when fighting bushfires in remote areas. There’s no network of any kind on most of these, but with a geocoded PDF map and Avenza we can still plot going edges, mark hotspots and dangerous trees, etc.

Being able to quickly squirt all of that, including photos, to another crew is a literal lifesaver.

"All of these "alternatives to airdop" don't seem to actually do what airdrop does, which is create an ad-hoc wireless connection."

Not all of them.

"Airdrop isn't just a nice UI for sending files between people, it allows a wi-fi speed transfer between two [Apple] devices that aren't connected to an existing network of that speed."

More precisely, WiFi Direct allows it.

There is no reason why one should not be able to use WiFi Direct to transfer files between Apple hardware and non-Apple hardware.

But Apple and Google, via iOS and Android, stop users from using WiFi Direct to do it.

WiFi Direct does not belong to Apple.

https://en.wikipedia.org/wiki/Wi-Fi_Direct