> Wifi got a bunch of ambient discovery capabilities a bit back that seems exactly targeted to this stuff. Neighbor Awareness Networking, or WiFi Aware for the trademarked industry packaging there-of. It was built into Android 8. There's also even older wifi-p2p/wifi direct (again, spec vs industry branding for the same thing).

The problem with these is that interop is a nightmare. And interop is exactly what you want to get 99.9% working, otherwise the tech is moot.

Apple, and to an extent Google, can do it thanks to their control of the vertical stack. Open-source... has a harder time about it.

How exactly is Apple good at Interop?

Their whole market strategy is the exact opposite. They only implement standards when forced by regulations or overwhelming market forces.

You're not wrong, but I meant interop within their ecosystem. The walled garden is a very comfortable place.

If you're operating between your devices, that's not interoperability.

Homekit is one

If you can call a purely apple designed protocol as Interop. Its no different to the lightning connector. Apple designed it, and trademarked it. If you want to play ball you need to pay apple a licensing cut.

EDIT: I have just seen they have recently introduced matter support for iot devices. This is a big step in the right direction!

Also good luck finding a NAN-capable WiFi adaptor that you can plug in to your regular Linux PC, Raspberry Pi, etc.

Nearby Share isn't locked down and, in fact, works just fine with zero Google involvement. Google only needs to be involved for limited device visibility and all the phone number stuff that entails.

Here's the protocol docs — both devices just tell each other that they're "unable" to do "paired key encryption" and the connection continues: https://github.com/grishka/NearDrop/blob/master/PROTOCOL.md

> Wi-Fi NAN

I have been very interested in this. Sadly, finding hardware that supports it (both HW and SW) seems quite hard at the moment. This stackoverflow answer mentions a few, but I have no idea about software support: https://stackoverflow.com/a/54214808/3795597

I tried poking around the Linux drivers and userspace tools (which required reading some source code, the documentation is pretty bad), I summed up some of my finding there: https://superuser.com/a/1786039

So far, I only encountered two phone series that supported NAN: POCO and Google Pixel. So much for interoperability. I still wonder if it's possible to build a compatible implementation leveraging Monitor mode. This is how Owl (open source "Airdrop"/ADWL implementation) does it: https://github.com/seemoo-lab/owl

ESP32 also seems to support Wi-Fi NAN: https://docs.espressif.com/projects/esp-idf/en/latest/esp32/...

> Still hoping for some alternatives that can do ad-hoc communication, without any network infrastructure.

That’s the real benefit of Airdrop. It’s so nice when you’re traveling to be able to share photos with someone you just met without worrying about WiFi hotspots, mobile data plans or any of that. You can be out in the middle of the ocean and it just works.

We used plain ol bluetooth for this 20 or so years ago. I haven't used AirDrop but assume it's got better UX, but otherwise, what makes it special?

Speed, mostly. Ad-hoc wifi can push tens of MB/s, which matters when sharing photos and videos at today's sizes.

Yup, I use fsquirt.exe to transfer small files between my phone and laptop. But I have to grab a usb cable for anything bigger than a low-res picture.

AirDrop uses Bluetooth for local device discovery and then attempts a send over the following protocols:

1. local IP network, if available

2. ad hoc WiFi, if possible

3. the Bluetooth connection

4. fallback via Apple's servers (newest iOS only)

It's primary advantage is its ability to negotiate over a number of different interfaces and protocols, as needed.

You’re free to swap files via regular Bluetooth with an app that supports it.

AirDrop is fast (actual transfer happens over WiFi) and easy - makes it so you don’t need to know anything about Bluetooth to use it. It’s a challenge to find an alternative app with the same level of functionality.

Better UX that makes it actually usable

4k video isn’t exactly quick to transfer over Bluetooth

literally nothing, they just disabled blue tooth transfers on iOS and came up with airdrop as if it was something novel

There is nothing disabled, AirDrop just works so well. And AirDrop is novel, because still, there is nothing like it.

Except android nearby share. Still closed standard sadly, but at least works on Windows.

I'm not sure that the benefit really pays off. AirDrop doesn't need network infrastructure but it does need a wi-fi adapter needs to support active monitor mode (it's extremely common for hardware to lack support for this).

The requirement for network infrastructure can be worked around by creating an ad-hoc wifi network.

> The requirement for network infrastructure can be worked around by creating an ad-hoc wifi network.

Unfortunately for 95% of people that you want want to share files with, that’s a total dealbreaker.

If you don't have a network connection, you can setup an adhoc hotspot on any Android 9+ (Settings > Network & internet > Hotspot & tethering https://support.google.com/android/answer/9059108) or iPhone (Settings > Personal Hotspot), then connect to it using any WiFi-enabled device.

A useful filesharing utility that a friend wrote is https://github.com/akovacs/uploadserver - it's basically a nicer version of:

    python -m http.server 8000

Download prebuilt binaries for Linux, Windows, Mac OS from https://github.com/akovacs/uploadserver/releases/ or install from source if you prefer

Determine your machine's IP address using:

    # Linux
    hostname -I

    # Mac
    ifconfig

    # Windows
    ipconfig

Start the file server, and then navigate to it using the web browser of your choice on any device connected to the WiFi network (no need for a client application).

    chmod +x upload_server
    ./upload_server

Navigate to the server's ip address (indicated by the hostname -I command you ran earlier) port 8000 in the browser of your choice and upload files using the web UI or directly via curl:

    curl -X POST --data-binary @file_to_upload.txt http://192.168.1.X:8000/uploaded_file.txt

Then download the file to another machine or mobile device either from your web browser or via a commandline tool:

    curl http://192.168.1.X:8000/uploads/uploaded_file.txt --output downloaded_file.txt

I use qweborf. Just right click "share this over http". Then it has some settings where I can put a password.

This fits the bill, but it's noisy https://github.com/ggerganov/wave-share

I thought "noisy" was about extra traffic, or cluttered UI, but wow, it uses actual sound.