Function for Retrieving Own Ip Address from Within R

Function for retrieving own ip address from within R?

You can issue a system() command to your operating system:

In Windows you can use ipconfig
In Linux, use ifconfig

For example, on Windows try calling system() with the argument intern=TRUE to return the results to R:

x <- system("ipconfig", intern=TRUE)

This returns:

x
 [1] ""                                                                   
 [2] "Windows IP Configuration"                                           
 [3] ""                                                                   
 [4] ""                                                                   
 [5] "Wireless LAN adapter Wireless Network Connection:"                  
 [6] ""                                                                   
 [7] "   Connection-specific DNS Suffix  . : tbglondon.local"             
 [8] "   Link-local IPv6 Address . . . . . : fe80::c0cb:e470:91c7:abb9%14"
 [9] "   IPv4 Address. . . . . . . . . . . : 10.201.120.184"              
[10] "   Subnet Mask . . . . . . . . . . . : 255.255.255.0"               
[11] "   Default Gateway . . . . . . . . . : 10.201.120.253"              
[12] ""                                                                   
[13] "Ethernet adapter Local Area Connection:"                            
[14] ""                                                                   
[15] "   Connection-specific DNS Suffix  . : tbglondon.local"             
[16] "   Link-local IPv6 Address . . . . . : fe80::9d9b:c44c:fd4d:1c77%11"
[17] "   IPv4 Address. . . . . . . . . . . : 10.201.120.157"              
[18] "   Subnet Mask . . . . . . . . . . . : 255.255.255.0"               
[19] "   Default Gateway . . . . . . . . . : 10.201.120.253"              
[20] ""                                                                   
[21] "Tunnel adapter Local Area Connection* 13:"                          
[22] ""                                                                   
[23] "   Media State . . . . . . . . . . . : Media disconnected"          
[24] "   Connection-specific DNS Suffix  . : "                            
[25] ""                                                                   
[26] "Tunnel adapter isatap.tbglondon.local:"                             
[27] ""                                                                   
[28] "   Media State . . . . . . . . . . . : Media disconnected"          
[29] "   Connection-specific DNS Suffix  . : tbglondon.local"             
[30] ""                                                                   
[31] "Tunnel adapter Teredo Tunneling Pseudo-Interface:"                  
[32] ""                                                                   
[33] "   Media State . . . . . . . . . . . : Media disconnected"          
[34] "   Connection-specific DNS Suffix  . : "

Now you can use grep to find the lines with IPv4:

x[grep("IPv4", x)]
[1] "   IPv4 Address. . . . . . . . . . . : 10.201.120.184"
[2] "   IPv4 Address. . . . . . . . . . . : 10.201.120.157"

And to extract just the ip address:

z <- x[grep("IPv4", x)]
gsub(".*? ([[:digit:]])", "\\1", z)
"10.201.120.184" "10.201.120.157"

How to get client IP address in R Plumber

To close out the question, I'll restate the comment:

Since plumber uses httpuv, it's possible you can reach the req$REMOTE_ADDR property of the request handle.

Get local IP address in Node.js

This information can be found in os.networkInterfaces(), — an object, that maps network interface names to its properties (so that one interface can, for example, have several addresses):

'use strict';

const { networkInterfaces } = require('os');

const nets = networkInterfaces();
const results = Object.create(null); // Or just '{}', an empty object

for (const name of Object.keys(nets)) {
    for (const net of nets[name]) {
        // Skip over non-IPv4 and internal (i.e. 127.0.0.1) addresses
        // 'IPv4' is in Node <= 17, from 18 it's a number 4 or 6
        const familyV4Value = typeof net.family === 'string' ? 'IPv4' : 4
        if (net.family === familyV4Value && !net.internal) {
            if (!results[name]) {
                results[name] = [];
            }
            results[name].push(net.address);
        }
    }
}

// 'results'
{
  "en0": [
    "192.168.1.101"
  ],
  "eth0": [
    "10.0.0.101"
  ],
  "<network name>": [
    "<ip>",
    "<ip alias>",
    "<ip alias>",
    ...
  ]
}

// results["en0"][0]
"192.168.1.101"

Function for Retrieving Own Ip Address from Within R