Client IP Address — Edge Functions

[WilliamScott-AdventGX]

As far as I can tell, an edge function can not obtain the IP address of the client who invoked it.

Headers X-Forwarded-From, host, and deno's STD serve function's parameter connInfo all return supabase related IP addresses or the local machine address of the edge function.

Is anyone aware if this is possible or impossible?
We are needing to keep a log of IP addresses that invoked the function.

Thanks

[nounder]

This is critical for many location-based app, such as commerce or content providers. Without access to client IP it is impossible to do any location-based features for the user, such as currency/country detection.

[nounder]

As a workaround, If you are using Next.js, you can implement your own Next.js edge API endpoint as following:

import type { NextRequest } from "next/server";

export const config = {
  runtime: "experimental-edge",
};

export default async function handler(req: NextRequest) {
  let ip = req.ip;

  // you can use req.geo on some hosted platform, like Vercel (only for paid plans)

  // IP not available probably because we're on our workstation.
  // Get its external IP to simulate real world.
  if (!ip) {
    const { origin } = await fetch("https://httpbin.org/ip").then((v) =>
      v.json()
    );

    ip = origin;
  }

  const ipInfo = await fetchIpInfo(ip);

  return json(ipInfo);
}

async function fetchIpInfo(ip) {
  // Use external API, like: ipregistry.co
}

function json(data) {
  return new Response(
    JSON.stringify({
      ...data,
    }),
    {
      status: 200,
      headers: {
        "content-type": "application/json",
      },
    }
  );
}

[laktek]

@WilliamScott-AdventGX @r-ae-i Thanks for bringing this up! We've made an update that should populate the X-Forwarded-For header with the request's client IP correctly.

Here's an example snippet on how you can detect user's location based on IP in an edge function:

import { serve } from "https://deno.land/std@0.131.0/http/server.ts"

function ips(req: Request) {
  return req.headers.get("x-forwarded-for")?.split(/\s*,\s*/);
}

serve(async (req) => {
  const clientIps = ips(req) || [''];
  const res = await fetch(`https://ipinfo.io/${clientIps[0]}?token=XXXX`, {
      headers: { 'Content-Type': 'application/json'}});
  const { city, country } = await res.json();

  return new Response(
    JSON.stringify(`You're accessing from ${city}, ${country}`),
    { headers: { "Content-Type": "application/json" } },
  )
})

[idevelop]

@laktek I think the header is X-Forwarded-For - it's written correctly in your code snippet but not in your first paragraph.

[laktek]

@idevelop Thanks! updated the comment.

[torkleyy]

I'm using exactly this code, but it seems the x-forwarded-for header isn't always set - half of the time it's just empty.