How to connect to emulators?

[l2aelba]

I was wondering about does it possible to connect to emulators like Bluestack / Nox / LD Player or something?

Or any trick for it? like by installed some program or something to fake it.

Thanks

[yume-chan]

I don't know about those third-party emulators, but at least for the official Android Emulator, it's possible, with some help of websockify.

If the ones you have mentioned can also be automatically picked up by a normal adb, then this method will also apply to them.

It's a little complex and requires some programming skill, please tell me if you want to know the details, then I will find some spare time to organize the steps and post here.

[yume-chan]

I added detection for WebSocket backend in ae1f9a2 to make it easier.

---

Some background information:

1. adb connects to AVD (Android Virtual Device, the official emulator) using TCP sockets.
2. AVD may choose any odd port number between 5555 and 5587 (even numbers are for serial connection), adb devices will scan all ports in that range to detect emulators.

So you need to firstly find out which port your emulator is currently using.

Run adb devices, emulators have serial numbers in form of "emulator-55XX" (where XX is two digits), add 1 to that number, that's the emulator's ADB port.

PS E:\AndroidSDK\platform-tools> ./adb devices
List of devices attached
emulator-5554   device

Or you may just try 5555, normally emulator starts at this port.

---

1. Web browsers can't open TCP sockets.
2. Web browsers can use WebSocket, which is similar to TCP socket, so a native program can convert between TCP socket and WebSocket to bridge the gap.

I use websockify-js here, other similar programs should also work.

1. Install Node.js
2. Clone (if you have Git) or download the source code of novnc/websockify-js repository
3. In a terminal, navigate to the websockify folder, run npm i (this command only needs to be run once)

Every time you want to connect to your emulators, in the websockify folder, run node websockify.js 15555 localhost:5555, replace 5555 to the port you found previously, but DO NOT change 15555. The output should be like

PS E:\git\novnc\websockify-js\websockify> node .\websockify.js 15555 localhost:5555
WebSocket settings:
    - proxying from :15555 to localhost:5555
    - Running in unencrypted HTTP (ws://) mode

Open my demo in browser or run it yourself, wait a few seconds, you should see ws://localhost:15555 in available devices

Click Connect, the confirmation dialog should display on your emulator screen.

In my testing the confirmation dialog sometimes closes by its own after a brief period. The only solution I found was simply click Allow fast enough.

---

Bouns:

adb connect command (ADB over Wi-Fi) also uses TCP sockets to connect to devices wirelessly. So this method also applies to ADB over Wi-Fi.

[guanzhangrtk]

I still didn't get you. This error message is from native ADB server, but since you are using websockify that connects to your device directly, there is no ADB server (the part on your device is called ADB daemon, ADB client/server are both the adb binary running on your computer). So I have no idea where you got this.

From your GUI, the error message was simply "more than one device/emulator". The three line error message I posted above I copied and pasted from scrcpy's FAQ to illustrate that potentially the message was truncated in your GUI. So are you saying in your implementation of adb it just has that one line error message?

In any case that was the only issue I had, everything else worked perfectly and is good enough for demonstration purposes. The only suggestion I have is perhaps having the GUI remember that setting (at least for that session) such that if I switch to the shell mode and back I don't have to re-enable that feature again, but those are minor stuff.

tinyh264 does use up quite a bit of CPU cycles as well as RAM, but not sure if there are better alternatives.

Thanks for the response.

[yume-chan]

[...] potentially the message was truncated in your GUI

Those two lines are from scrcpy. ADB daemon only returns the first line.

This issue had been fixed in Android 9, so I don't have a device to reproduce and fix it. If you have any methods to reliably detect Android < 9 or this error message when initiating the scrcpy module, and automatically switch to forward connection, PRs are welcomed.

The upstream issue is https://issuetracker.google.com/issues/37066218

The only suggestion I have is perhaps having the GUI remember that setting (at least for that session) such that if I switch to the shell mode and back I don't have to re-enable that feature again

Maybe I will add that when I have time.

[pr4x77]

I cant get this work. Getting the following error:

Error:

Error: Failed to construct 'WebSocket': An insecure WebSocket connection may not be initiated from a page loaded over HTTPS.
    at w.connect (https://yume-chan.github.io/ya-webadb/_next/static/chunks/pages/_app-7d11a706073519ba.js:1:1700)
    at Object.onClick (https://yume-chan.github.io/ya-webadb/_next/static/chunks/pages/_app-7d11a706073519ba.js:1:4708)
    at r._onClick (https://yume-chan.github.io/ya-webadb/_next/static/chunks/pages/_app-7d11a706073519ba.js:1:126599)
    at Object.eU (https://yume-chan.github.io/ya-webadb/_next/static/chunks/framework-e1850a8151a6a66f.js:9:14912)
    at eH (https://yume-chan.github.io/ya-webadb/_next/static/chunks/framework-e1850a8151a6a66f.js:9:15066)
    at https://yume-chan.github.io/ya-webadb/_next/static/chunks/framework-e1850a8151a6a66f.js:9:33374
    at re (https://yume-chan.github.io/ya-webadb/_next/static/chunks/framework-e1850a8151a6a66f.js:9:33473)
    at rn (https://yume-chan.github.io/ya-webadb/_next/static/chunks/framework-e1850a8151a6a66f.js:9:33887)
    at https://yume-chan.github.io/ya-webadb/_next/static/chunks/framework-e1850a8151a6a66f.js:9:39345
    at oP (https://yume-chan.github.io/ya-webadb/_next/static/chunks/framework-e1850a8151a6a66f.js:9:96345)

If I use encrypted websockets I get the following error:

Error: WebSocket connect failed at e.onerror (https://yume-chan.github.io/ya-webadb/_next/static/chunks/pages/_app-7d11a706073519ba.js:1:1808)

Any solution for this?

[yume-chan]

The error message is very clear. Either run WebSockify on the same device where you run Tango, or add a valid HTTPS certificate to the WebSockify server.

[1234567890nevver]

devices attached
emulator-5554 device
Or you may just try 5555,

[yume-chan]

Now it's possible to connect to emulators and ADB over WiFi without webscokify. See #349.

[ubipo]

Is it possible to connect to an adb server (e.g. started with adb -a -P 5037 nodaemon server start) with this technique? I get a 'Connection closed unexpectedly' error. The adb server outputs the following:

adb D 04-16 19:05:07 111186 111186 fdevent_epoll.cpp:174] (fdevent 2: fd 10 R) got events 0x1
adb D 04-16 19:05:07 111186 111186 sockets.cpp:457] LS(3): created (fd=11)
adb D 04-16 19:05:07 111186 111186 sockets.cpp:973] Connecting to smart socket
adb D 04-16 19:05:07 111186 111186 sockets.cpp:961] Creating smart socket
adb D 04-16 19:05:07 111186 111186 sockets.cpp:968] SS(0)
adb D 04-16 19:05:07 111186 111186 fdevent_epoll.cpp:174] (fdevent 8: fd 11 R) got events 0x1
adb D 04-16 19:05:07 111186 111186 sockets.cpp:386] LS(3): event_func(fd=11(==11), ev=0001)
adb D 04-16 19:05:07 111186 111186 sockets.cpp:187] LS(3): post adb_read(fd=11,...) r=24 (errno=0) avail=1048576
adb D 04-16 19:05:07 111186 111186 sockets.cpp:187] LS(3): post adb_read(fd=11,...) r=-1 (errno=11) avail=1048552
adb D 04-16 19:05:07 111186 111186 sockets.cpp:203] LS(3): fd=11 post avail loop. r=-1 is_eof=0 forced_eof=0
adb D 04-16 19:05:07 111186 111186 sockets.cpp:792] SS(0): enqueue 24
adb D 04-16 19:05:07 111186 111186 sockets.cpp:808] SS(0): bad size (4294967295)
adb D 04-16 19:05:07 111186 111186 sockets.cpp:951] SS(0): closed
adb D 04-16 19:05:07 111186 111186 sockets.cpp:347] entered local_socket_close. LS(3) fd=11
adb D 04-16 19:05:07 111186 111186 sockets.cpp:333] LS(3): destroying fde.fd=11
adb D 04-16 19:05:07 111186 111186 sockets.cpp:369] LS(3): closed
adb D 04-16 19:05:07 111186 111186 sockets.cpp:219] LS(3): fd=11 post peer->enqueue(). r=-1
adb D 04-16 19:05:07 111186 111186 fdevent_epoll.cpp:174] (fdevent 9: fd 11 R) got events 0x5

For context: connecting via USB does work and I tried websockify-js, the original Python websockify, and websocat, but none of them seem to work.

[ubipo]

Ah huh I might be confusing adb over usb and the communication with the adb daemon server (https://gist.github.com/hfutxqd/a5b2969c485dabd512e543768a35a046). I might look into implementing the latter if those really are separate things.

[yume-chan]

No, Tango implements the protocol between ADB server and ADB daemon. I believe it's possible to create a "fake" backend to parse and re-package messages to be sent to ADB server.

First it should query the ADB server for connected devices. Because ADB server has already authenticated with the devices, this backend doesn't need Adb.authenticate(), but should use new Adb() directly.

Then it acts as a backend, but instead of forwarding packages blindly, it needs to parse those packages and translate them to the protocol the other end can understand.

It may itself accepts another backend for communicating with ADB server (net module in Node.js or Direct Sockets API in browsers).

The forward and reverse tunnels are extra tricky:

Tango doesn't need forward tunnel registration, the users can connect to forward tunnels using adb.createSocket("tcp:8080"). This package needs to call adb forward tcp:0 tcp:8080, connect to the returned port, then remove the tunnel.

Same for reverse tunnel, Tango allows any string for local address, but this package needs to choose a port, listen on it, call adb reverse tcp:1234 tcp:8080, and generate fake ADB sockets for each incoming connections.

[yume-chan]

Now Tango supports the protocol between ADB client and ADB server: https://tango-adb.github.io/docs/tango/server/connection. I only have a server connection that based on Node.js net module. A WebSocket server connection class (similar to WebSocket daemon connection) is required if you want to use WebSocket.

[iamqiqi1017]

Why not integrate the method of connecting AVD into your project instead of installing another project separately, which is easier to deploy and apply.