Sometimes it is very useful to share a local port in your computer over the Internet

localhost.run

It is a free service that allow an user to share local URL as a public available URL.

For example:

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$ PORT=8080 ./yourapp &
Serving on port 8080 ...
$ ssh -R 80:localhost:8080 ssh.localhost.run
Connect to http://yourproject.localhost.run or https://yourproject.localhost.run

This allows a user to access a service running in your computer on port 80

How does it works

It uses the SSH protocol to forward the requests made the the public URL to the configured local port.

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-R port:host:hostport
             Specifies that connections to the given TCP port or Unix socket
             on the remote (server) host are to be forwarded to the local
             side.

This way, then doing this:

ssh localhost.run -R 80:localhost:80

Requests to this public URL will be forwarded to the given local port

To share a different local port you can change localhost:80 to localhost:4000

ssh localhost.run -R 80:localhost:4000

this way, conections will be forwarded to port 4000 on localhost

You can even allow a connection to another host on your network. Do not worry about firewall or NAT/port forwarding.

ssh localhost.run -R 80:otherhost:80

To generate a custom public URL you can use a different username on the ssh connection:

ssh somecustomname@localhost.run -R 80:localhost:4000

This way, the generated URL will be: http://somecustomname.localhost.run (if no one is using this username already)

Use Cases

Allow access to a service listening on 127.0.0.1

I think this is the default use case for this service, I usually use it to access some unpublished pages of this blog on my phone

Since the bundle exec jekyll serve command will listen on 127.0.0.1:4000

I could’n access it from my phone, even on the same network.

I can change jekyll configuration to listen on 0.0.0.0, but I still need to be in the same network. (if my phone is using mobile data it won’t work)

Testing a webhook in a local environment

When testing a webhook, it is useful to get the requests on your local machine

This can be a bit hard when working in closed networks, with private IP ranges.

With localhost.run you can create a public URL to your local development project.

Share a local file

You can also use this service to share local files over the Internet.

With the default nginx instalation you can put some files on the webserver root folder:

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rafael@tyr:/var/www/html$ cat test.txt 
This is a test document.

rafael@tyr:/var/www/html$ sudo service nginx start 
rafael@tyr:/var/www/html$ ssh localhost.run -R 80:localhost:80 
Connect to http://rafael.localhost.run or https://rafael.localhost.run

In another machine:

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rafael@tyr:~$ curl https://rafael.localhost.run/test.txt
This is a test document.

Now you can access these files anywhere: