opener

opener

Open URL in your local web browser from the SSH-connected remote environment.

How does opener work?

opener is a daemon process that runs locally. When you send a URL to the process, it will execute a command tailored to your local environment (open on macOS, xdg-open on Linux) with the URL as an argument. As a result, the URL will be opened in your favorite web browser.

You remotely forward the socket file of the opener daemon, ~/.opener.sock, when you log in to the remote environment via SSH. In a remote environment, you use fake open command or xdg-open command to send the URL to ~/.opener.sock being forwarded from your local environment. The result is as if URL was sent to the local opener daemon, which opens the URL in your local web browser.

┌────────────────────┐                 ┌────────────────────┐
│                    │                 │                    │
│ ┌────────────────┐ │                 │ ┌────────────────┐ │
│ │   Web Browser  │ │                 │ │  open command  │ │
│ └─▲──────────────┘ │                 │ │     (fake)     │ │
│   │ Open URL       │                 │ └─┬──────────────┘ │
│ ┌─┴──────────────┐ │                 │   │                │
│ │  opener daemon │ │                 │   │ Send URL       │
│ └─┬──────────────┘ │                 │   │                │
│   │                │                 │   │                │
│ ┌─┴──────────────┐ │ SSH connection  │ ┌─▼──────────────┐ │
│ │ ~/.opener.sock │ ├─────────────────► │ ~/.opener.sock │ │
│ └────────────────┘ │ Remote forward  │ └────────────────┘ │
│                    │                 │                    │
│      localhost     │                 │    remote server   │
└────────────────────┘                 └────────────────────┘

Setup

Local environment

You can install opener with Homebrew. Since opener is a daemon, it is managed by Homebrew-services.

$ brew install superbrothers/opener/opener
$ brew services start opener

Set ssh config to forward ~/.opener.sock to the remote environment.

Host host.example.org
  RemoteForward /home/me/.opener.sock /Users/me/.opener.sock

Remote environment

Install a fake open or xdg-open command. Please choose your preference either way.

$ mkdir ~/bin
# open command
$ curl -L -o ~/bin/open https://raw.githubusercontent.com/superbrothers/opener/master/bin/open
$ chmod 755 ~/bin/open
# xdg-open command
$ curl -L -o ~/bin/xdg-open https://raw.githubusercontent.com/superbrothers/opener/master/bin/xdg-open
$ chmod 755 ~/bin/xdg-open
# Add ~/bin to $PATH and enable it
$ echo 'export PATH="$HOME/bin:$PATH"' >>~/.bashrc
$ source ~/.bashrc

Fake commands use nc command, so install it if you don't have it.

# Ubuntu 20.04
$ sudo apt install netcat

Add the following settings to sshd. This is an option to delete the socket file when you lose the connection to the remote environment.

# Add a configuration file
$ echo "StreamLocalBindUnlink yes" | sudo tee /etc/ssh/sshd_config.d/opener.conf
# Restart ssh service
$ sudo systemctl restart ssh

How to use it

If set up correctly, the following command in a remote environment will send the URL through opener and open the URL in your local web browser.

$ open https://www.google.com/

Configuration

You can configure opener with a config file. By default, it should be located at ~/.config/opener/config.yaml. You can also specify a config file with --config option.

# The network to use opener daemon.
# Allowed networks are: unix or tcp. (defaults to unix)
network: unix

# The address to listen on. (defaults to ~/.opener.sock)
address: ~/.opener.sock

Example: Open a URL from inside a container

If you want to open a URL from inside a container, you can use tcp network instead of unix.

┌─────────────────────────────────────────────────────────┐
│                                                         │
│ ┌────────────────┐                                      │
│ │   Web Browser  │                                      │
│ └─▲──────────────┘                 ┌──────────────────┐ │
│   │                                │     container    │ │
│   │ Open URL                       │                  │ │
│   │                                │ ┌──────────────┐ │ │
│ ┌─┴──────────────┐    Send a URL   │ │ open command │ │ │
│ │  opener daemon │◄────────────────┼─┤    (fake)    │ │ │
│ └────────────────┘   (TCP request) │ └──────────────┘ │ │
│   127.0.0.1:9999                   │                  │ │
│                                    └──────────────────┘ │
│                       localhost                         │
└─────────────────────────────────────────────────────────┘

Create the following config at ~/.config/opener/config.yaml:

network: tcp
address: 127.0.0.1:9999

Restart the opener daemon:

$ brew services restart opener

Send a URL to the opener daemon from inside a container:

$ docker run --rm -it busybox /bin/sh
# echo https://www.google.com/ | nc host.docker.internal 9999

The following script is useful as a fake open command.

#!/bin/sh
echo "$@" | nc host.docker.internal 9999

License

MIT License