Add functions to start/stop and ssh socks proxy

zsh/functions.zsh

@@ -66,6 +66,69 @@ function pr-checkout() {
     fi
 }
 
+# tail, but better
 function watch-file() {
     tail -f $1 | bat --paging=never -l log
 }
+
+# Get a temporary directory in a cross-platform manner
+# See https://unix.stackexchange.com/a/685873
+function get-temporary-directory() {
+    local temporary_directory=${XDG_RUNTIME_DIR:-${TMPDIR:-${TMP:-${TEMP:-/tmp}}}}
+
+    echo $temporary_directory
+}
+
+# Start an SSH SOCKS tunnel
+function start-proxy() {
+    if [ -z "$SSH_PROXY_HOST" ]; then
+        echo "SSH_PROXY_HOST is not set or empty"
+        
+        return
+    fi
+
+    local socket_dir=$(get-temporary-directory)
+
+    # Check if the last character of socket_dir is a directory separator character
+    if [[ $socket_dir[-1] == / ]]; then
+        # If yes, remove the directory separator character
+        socket_dir="${socket_dir%?}"
+    fi
+
+    echo "Opening proxy connection"
+
+    # Below we use -S and -M to help make closing the connection more reliable
+    # See this Stack Overflow answer for more info
+    # https://unix.stackexchange.com/a/525388
+
+    # -D 1337 opens up the SOXKS tunnel on localhost:1337
+    # -f Tells `ssh` to fork the ssh process in to the background
+    # -C Enables compression of data on the connections
+    # -q Uses quiet mode
+    # -N Do not execute a remote command on this connection 
+    # -S Set the ControlPath for this connection
+    # -M Place the client into `master` mode
+    ssh -D 1337 -f -C -q -N -S $socket_dir/ssh-proxy-control -M $SSH_PROXY_HOST
+}
+
+# Stop an open proxy connection
+function stop-proxy() {
+    if [ -z "$SSH_PROXY_HOST" ]; then
+        echo "SSH_PROXY_HOST is not set or empty"
+        
+        return
+    fi
+
+    local socket_dir=$(get-temporary-directory)
+
+    # Check if the last character of socket_dir is a directory separator character
+    if [[ $socket_dir[-1] == / ]]; then
+        # If yes, remove the directory separator character
+        socket_dir="${socket_dir%?}"
+    fi
+
+    echo "Closing proxy connection"
+
+    # See the comments in `start-proxy()` for more info
+    ssh -S $socket_dir/ssh-proxy-control -O exit $SSH_PROXY_HOST
+}