A self-hostable WebSocket based tunneling solution to expose your localhost. 🚀

This is Surang client repository. Check out surang-server for server code.

Surang allows you to expose your localhost server to the world through WebSocket based one-to-one tunnel. Surang is created to be easy to host on most of the hosting platforms that support NodeJS (read more at How is Surang different from localtunnel? ).

Note: There are no public Surang servers (and there cannot be as surang-server only supports one client at a time for now.) You are supposed to host your own surang-server. (PS: It's as simple as a single mouse click.)

Installation

1. Host your surang-server:

Head over to surang-server repository for step-by-step instructions on hosting your surang-server.

2. Install surang client:

npm install -g surang

CLI usage

Configure surang:

surang config

This will configure your Surang client for once and all, so that you don't have to pass command line options every time. (You can run this again to update global configuration if needed.)

Start:

surang start --port 8000

As you guessed, this will connect to configured surang-server and start tunneling traffic to your local server on given port.

Additional command line options:

Apart from --port, following options can also be used with surang start command.

Options passed through command line will take precedence over respective global options.

Argument		Type	Description	Required (default)
--port	-p	number	port on which local HTTP server is running	Yes
--host	-h	string	upstream surang-server address (without protocol prefix)	Yes*
--auth-key	-a	string	auth key to be used for authenticating to surang-server	Yes*
--secure	-s	boolean	set this to "false" if your surang-server doesn't support https & wss traffic	No (true)*
--verbose	-v	boolean	set this to "false" to disable logging of incoming requests	No (true)*
--version		boolean	show surang client version	No (false)
--help		boolean	show help on CLI usage	No (false)

*Host, Auth key, Security protocol & Logging options can be set in global config through surang config command.

--auth-key is used by surang client to authenticate itself to surang-server. You can set this to any secret string on your surang-server as an environment variable. This prevents other people from using your server even if they know the server url. Check out instructions at surang-server for detailed info.

Disabling --secure flag is not recommended. Exposing your localhost server to internet over non-secure protocols is never a good idea.

Errors you can encounter when trying to connect to Surang server:

Unauthorized: This can happen when AUTH_KEY configured at client doesn't match with the one configured at server. Make sure both the AUTH_KEYs are same. Server can also reject with this error if AUTH_KEY is not defined on server. Follow instructions here to set it up properly.
Version mismatch: This happens if your Surang client's version doesn't match with that of Surang server. Make sure to use client & server releases having same major version.
Already connected with another client: Surang server can tunnel to only one client at a time. If the server is connected to some other Surang client, it will reply with this error. Make sure you are not connecting to same server again without stopping pervious client. If you think someone else has connected to your Surang server (which means your AUTH_KEY is probably compromised), change the AUTH_KEY and restart the server.
Unknown error: Most of the time this will happen because of network failures and connection breakdowns. If this happens frequently, raise an issue here.

Known issues & limitations:

As WebSocket messages are used to transfer request & response information, response data with 'chunked transfer encoding' can not be handled correctly. To overcome this, Surang client will always send Accept-Encoding: identity header to local server, overriding any encoding headers from original client.
Large binary resources (like images & other media files) will probably fail to load over tunneled connection.
As Surang client itself connects to surang-server through WebSocket connection, trying to use WebSockets over the tunnel will probably not work.

How is Surang different from localtunnel?

'localtunnel' is great. It's open-source, free, supports multiple clients at once, and you can host your own localtunnel server too. Unfortunately, localtunnel uses TCP connections over non-root TCP ports. This can be troublesome if you want to host your own server, as most of the cloud platforms with free tiers don't give this much freedom to us (and our servers). On the other hand WebSockets are now widely supported on cloud hosting platforms.

(PS: I got inspired to write this library, when I realised that localtunnel can not be hosted on Heroku's free tier.)

localtunnel uses TCP connections, surang uses WebSocket connection to do the trick.
localtunnel cannot be hosted on platforms which don't support it's requirements, surang should be easier to host as WebSockets are widely supported nowadays.
localtunnel allows multiple client connections with single server, surang doesn't (yet). Everyone is supposed to host their own surang-server.
localtunnel is mature and has great community, surang is in early phase and might not work for all types of requests yet.

anilmkadam/surang