xplr/docs/en/src/message.md

Message

You can think of xplr as a server. Just like web servers listen to HTTP requests, xplr listens to messages.

See the full list of messages that xplr can handle.

You can send messages to an xplr session in the following ways:

• Via key bindings
• Via Lua function calls
• Via shell command using the input pipe

Format

To send messages using the key bindings or Lua functions calls, messages are represented in Lua syntax. For example:

• "Quit"
• { FocusPath = "/path/to/file" }
• { Call = { command = "bash", args = { "-c", "read -p test" } } }

However, to send messages using the input pipe, they need to be represented using YAML (or JSON) syntax. For example:

• Quit
• FocusPath: "/path/to/file"
• Call: { command: bash, args: ["-c", "read -p test"] }

Lua Function Calls

xplr allows users to define lua functions using the xplr.fn.custom Lua API.

These functions can be called using messages like CallLua, CallLuaSilently.

When called the function receives a special argument that contains some useful information. The function can optionally return a list of messages which will be handled by xplr.

CallLua Argument

This is a special argument passed to the lua functions when called using the CallLua, CallLuaSilently messages.

It contains the following information:

• version
• config
• pwd
• focused_node
• directory_buffer
• selection
• mode
• layout
• input_buffer
• pid
• session_path
• explorer_config
• history
• last_modes

TODO: Document each. For now, refer to the rust doc.

Example:

-- Define the function
xplr.fn.custom.ask_name_and_greet = function(app)
  print("What's your name?")

  local name = io.read()
  local greeting = "Hello " .. name .. "!"
  local message = greeting .. " You are inside " .. app.pwd

  return {
    { LogSuccess = message },
  }
end

-- Map the function to a key (space)
xplr.config.modes.builtin.default.key_bindings.on_key.space = {
  help = "ask name and greet",
  messages = {
    { CallLua = "custom.ask_name_and_greet" }
  }
}

-- Now, when you press "space" in default mode, you will be prompted for your
-- name. Enter your name to receive a nice greeting and to know your location.

Environment Variables and Pipes

Alternative to CallLua, CallLuaSilently messages that call Lua functions, there are Call, CallLuaSilently, BashExec, BashExecSilently messages that call shell commands.

However, unlike the Lua functions, these shell commands have to read the useful information and send messages via environment variables and temporary files called "pipe"s. These environment variables and files are only available when a command is being executed.

Visit the fzf integration tutorial for example.

Environment variables

To see the environment variables, invoke the shell by typing :! in default mode and run the following command:

env | grep ^XPLR_

You will see something like:

XPLR_FOCUS_INDEX=0
XPLR_MODE=action to
XPLR_PIPE_SELECTION_OUT=/run/user/1000/xplr/session/122278/pipe/selection_out
XPLR_INPUT_BUFFER=
XPLR_PIPE_GLOBAL_HELP_MENU_OUT=/run/user/1000/xplr/session/122278/pipe/global_help_menu_out
XPLR_PID=122278
XPLR_PIPE_MSG_IN=/run/user/1000/xplr/session/122278/pipe/msg_in
XPLR_PIPE_LOGS_OUT=/run/user/1000/xplr/session/122278/pipe/logs_out
XPLR_PIPE_RESULT_OUT=/run/user/1000/xplr/session/122278/pipe/result_out
XPLR_PIPE_HISTORY_OUT=/run/user/1000/xplr/session/122278/pipe/history_out
XPLR_FOCUS_PATH=/home/sayanarijit/Documents/GitHub/xplr/docs/en/book
XPLR_SESSION_PATH=/run/user/1000/xplr/session/122278
XPLR_APP_VERSION=0.14.3
XPLR_PIPE_DIRECTORY_NODES_OUT=/run/user/1000/xplr/session/122278/pipe/directory_nodes_out

The environment variables starting with XPLR_PIPE_ are the temporary files called "pipe"s.

Input pipe

Current there is only one input pipe.

• XPLR_PIPE_MSG_IN

Output pipes

XPLR_PIPE_*_OUT are the output pipes that contain data which cannot be exposed directly via environment variables, like multi-line string.

• XPLR_PIPE_SELECTION_OUT
• XPLR_PIPE_GLOBAL_HELP_MENU_OUT
• XPLR_PIPE_LOGS_OUT
• XPLR_PIPE_RESULT_OUT
• XPLR_PIPE_HISTORY_OUT
• XPLR_PIPE_DIRECTORY_NODES_OUT

XPLR_PIPE_MSG_IN

Append new-line delimited messages to this pipe in YAML (or JSON) syntax. These messages will be read and handled by xplr after the command execution.

XPLR_PIPE_SELECTION_OUT

New-line delimited list of selected paths.

XPLR_PIPE_GLOBAL_HELP_MENU_OUT

The full help menu.

XPLR_PIPE_LOGS_OUT

New-line delimited list of logs.

XPLR_PIPE_RESULT_OUT

New-line delimited result (selected paths if any, else the focused path)

XPLR_PIPE_HISTORY_OUT

New-line delimited list of last visited paths (similar to jump list in vim).

XPLR_PIPE_DIRECTORY_NODES_OUT

New-line delimited list of paths, filtered and sorted as displayed in the files table.

Example:

xplr.config.modes.builtin.default.key_bindings.on_key.space = {
  help = "ask name and greet",
  messages = {
    {
      BashExec = [===[
      echo "What's your name?"

      read name
      greeting="Hello $name!"
      message="$greeting You are inside $PWD"
    
      echo LogSuccess: '"'$message'"' >> "${XPLR_PIPE_MSG_IN:?}"
      ]===]
    }
  }
}

-- Now, when you press "space" in default mode, you will be prompted for your
-- name. Enter your name to receive a nice greeting and to know your location.