View random ngrok URL when run in background

Question

When I start an ngrok client with ./ngrok tcp 22 it runs in the foreground and I can see the randoming generated forwarding URL, such as tcp://0.tcp.ngrok.io:

Answer 1

A Node.js solution.

Bonus: It copies the url to the clipboard in Windows, Mac and Linux¹

const http = require("http");
const { execSync } = require("child_process");

const callback = (res) => {
    let data = "";
    res.on("data", (chunk) => (data += chunk));
    res.on("end", () => {
        const resJSON = JSON.parse(data);
        const tunnels = resJSON.tunnels;

        const { public_url: url } = tunnels.find(({ proto }) => proto === "https");

        console.log(url);

        // Copy to clipboard
        switch (process.platform) {
            case "win32":
                execSync(`echo ${url} | clip`);
                break;
            
            case "darwin":
                execSync(`echo ${url} | pbcopy`);
                break;
                
            case "linux":
                // NOTE: this requires xclip to be installed
                execSync(`echo ${url} | xclip -selection clipboard`);
                break;
                
            default:
                break;
        }
    });
};

http.get("http://localhost:4040/api/tunnels", callback);

[1] You need to install xclip first:

sudo apt-get install xclip

Answer 2

import json
import requests


def get_ngrok_url():
    url = "http://localhost:4040/api/tunnels/"
    res = requests.get(url)
    res_unicode = res.content.decode("utf-8")
    res_json = json.loads(res_unicode)
    for i in res_json["tunnels"]:
        if i['name'] == 'command_line':
            return i['public_url']
            break

This is an edit of JUN_NETWORKS python 3 code. It outputs the HTTPS URL only. I find Ngrok will randomly change the order of which is URL is displayed first sometimes outputting HTTP. The additional loop will consistently look for the 'tunnel' named 'command_line' which is the HTTPS URL.

Answer 3

There are a couple of ways.

You can either:

1) Visit localhost:4040/status in your browser to see a bunch of information, or

2) Use curl to hit the API: localhost:4040/api/tunnels

Answer 4

If you love PowerShell, here it is in variables.

$ngrokOutput = ConvertFrom-Json (Invoke-WebRequest -Uri http://localhost:4040/api/tunnels).Content
$httpsUrl = $ngrokOutput.tunnels.public_url[0]
$httpUrl = $ngrokOutput.tunnels.public_url[1]

Answer 5

Run ./ngrok http & This runs the ngrok tunnel as a background process. Ngrok usually opens a window showing the assigned URL but since we are using the nohup command this is not visible.

Thus, then run curl http://127.0.0.1:4040/api/tunnels too see the URL assigned by ngrok

Answer 6

May be I'm a little too late in answering but would be glad if it is helpful for anyone visiting the question.

***Above answers are solutions to see/check the redirection URL. However to run ngrok in background, you could try using screen in linux . Incase you need help here a quick reference

Steps: 1. Just run the ngrok in screen and then detach. 2. Use the python script given by Gerard above to see the URL.

I have followed the same process and it works!