Note: This README applies to development branch. See the version for the latest stable release here.
Web player for terminal sessions (recorded with asciinema) you can use on your website.
asciinema player is an open-source terminal session player written in Javascript
and Rust. Unlike other video players asciinema player doesn't play
heavy-weight video files (.mp4, .webm etc) and instead plays light-weight
terminal session files called
asciicasts.
Asciicast is a capture of terminal's raw output, which needs to be interpreted during playback, therefore the player comes with its own interpreter based on Paul Williams' parser for ANSI-compatible video terminals. It's fully compatible with most widely used terminal emulators like xterm, Gnome Terminal, iTerm etc.
You can see the player in action on asciinema.org.
If you don't want to depend on asciinema.org and you prefer to host the player and the recordings yourself then read on, it's very simple.
- ability to copy-paste terminal content - it's just a text after all!,
- ultra smooth, timing-accurate playback,
- automatic font scaling to fit into container element in most efficient way,
- idle time optimization to skip longer periods of inactivity,
- predefined and custom font sizes,
- NPT-based or custom text poster,
- adjustable playback speed,
- looped playback, infinite or finite,
- starting playback at specific time,
- API for programmatic control,
- keyboard shortcuts,
- multiple color themes for standard 16 colors,
- full support for 256 color palette and 24-bit true color (ISO-8613-3),
- full-screen mode.
The following examples show how to use asciinema player on your own website.
It assumes you have obtained terminal session recording file by either:
- recording terminal session to a local file with
asciinema rec demo.cast(more details on recording), - downloading an existing recording from asciinema.org by appending
.castto the asciicast page URL (for example: https://asciinema.org/a/28307.cast).
Download latest version of the player bundle from
releases page. You
only need asciinema-player.min.js and asciinema-player.css files.
First, add asciinema-player.min.js, asciinema-player.cssand the .cast file of
your recording to your site's assets. The HTML snippet below assumes they're in
the web server's root directory.
Then add necessary includes to your HTML document and initialize the player
inside an empty <div> element:
<html>
<head>
...
<link rel="stylesheet" type="text/css" href="/asciinema-player.css" />
...
</head>
<body>
...
<div id="demo"></div>
...
<script src="/asciinema-player.min.js"></script>
<script>
AsciinemaPlayer.create('/demo.cast', document.getElementById('demo'));
</script>
</body>
</html>Add asciinema-player to your devDependencies:
npm install --save-dev asciinema-player@3.0.1Add empty <div id="demo"></div> element to your page to contain the player.
Import and use create function from asciinema-player module:
import * as AsciinemaPlayer from 'asciinema-player';
AsciinemaPlayer.create('/demo.cast', document.getElementById('demo'));Finally, include player's CSS file in your site CSS bundle. You'll find it in
the npm package at dist/bundle/asciinema-player.css.
To mount the player on your page use the create function exported by the
asciinema-player ES module with 2 arguments: the URL (or path) to the
asciicast file and the container DOM element to mount the player in.
AsciinemaPlayer.create(url, containerElement);You can tweak file fetching by passing { url: "...", fetchOpts: { ... } } as
the 1st argument to create. fetchOpts object is then passed to
fetch (as its 2nd
argument). This can be used to change HTTP method, configure credentials, etc.
If you'd like to inline the recording contents you can do so with Data URLs. For example:
AsciinemaPlayer.create(
'data:text/plain;base64,eyJ2ZXJzaW9uIjogMiwgIndpZHRoIjogODAsICJoZWlnaHQiOiAyNH0KWzAuMSwgIm8iLCAiaGVsbCJdClswLjUsICJvIiwgIm8gIl0KWzIuNSwgIm8iLCAid29ybGQhXG5cciJdCg==',
containerElement
);See Source for more ways of loading a recording into the player.
To pass additional options when mounting the player use 3 argument variant:
AsciinemaPlayer.create(url, containerElement, opts);For example, enable looping and select Solarized Dark theme:
AsciinemaPlayer.create('/demo.cast', document.getElementById('demo'), {
loop: true,
theme: 'solarized-dark'
});See Options for full list of available options.
If you'd like to control the player programatically then you can use the
functions exposed on the object returned from create function:
const player = AsciinemaPlayer.create(url, containerElement);
player.play();See API for details.
In the most common case the recording to be played is fetched from a URL. If
you'd like to load it from a different source you can pass it to create as { data: data } where data can be one of:
- a string containing asciicast in v1 or v2 format
- an object representing asciicast in v1 format
- an array representing asciicast in v2 format
- a function which when invoked returns any of the above (may be async)
For example:
AsciinemaPlayer.create({ data: data }, containerElement);data value is defined in one of the following ways:
// object representing asciicast in v1 format
{version: 1, width: 80, height: 24, stdout: [[1.0, "hello "], [1.0, "world!"]]};// string representing asciicast in v1 format (json)
'{"version": 1, "width": 80, "height": 24, "stdout": [[1.0, "hello "], [1.0, "world!"]]}';// array representing asciicast in v2 format
[
{version: 2, width: 80, height: 24},
[1.0, "o", "hello "],
[2.0, "o", "world!"]
]// string representing asciicast in v2 format (ndjson)
'{"version": 2, "width": 80, "height": 24}\n[1.0, "o", "hello "]\n[2.0, "o", "world!"]';// function returning a string representing asciicast in v2 format (ndjson)
() => '{"version": 2, "width": 80, "height": 24}\n[1.0, "o", "hello "]\n[2.0, "o", "world!"]';If data is a function then the player invokes the function when playback is
started by a user. If preload: true option is used then the function is
invoked during player initialization.
The following options can be used to tweak player's look and feel:
Type: number
Number of columns of player's terminal.
When not set it defaults to 80 (until asciicast gets loaded) and to terminal width saved in the asciicast file (after it gets loaded).
It's recommended to set it to the same value as in asciicast file to prevent player to resize itself from 80x24 to the actual dimensions of the asciicast when it gets loaded.
Type: number
Number of lines of player's terminal.
When not set it defaults to 24 (until asciicast gets loaded) and to terminal height saved in the asciicast file (after it gets loaded).
Same recommendation as for cols applies here.
Type: boolean
Set this option to true if playback should start automatically.
Defaults to false - no auto play.
Type: boolean
Set this option to true if the recording should be preloaded on player's
initialization.
Defaults to false - no preload.
Type: boolean or number
Set this option to either true or a number if playback should be looped. When
set to a number (e.g. 3) then the recording will be re-played given number of
times and stopped after that.
Defaults to false - no looping.
Type: number or string
Start playback at a given time.
Supported formats:
123(number of seconds)"2:03"("mm:ss")"1:02:03"("hh:mm:ss")
Defaults to 0.
Type: number
Playback speed. The value of 2 means 2x faster.
Defaults to 1 - normal speed.
Type: number
Limit terminal inactivity to a given number of seconds.
For example, when set to 2 any inactivity longer than 2 seconds will be
"compressed" to 2 seconds.
Defaults to:
idle_time_limitfrom asciicast header (saved when passing-i <sec>toasciinema rec),- no limit, when it was not specified at the time of recording.
Type: string
Terminal color theme.
One of:
"asciinema""monokai""tango""solarized-dark""solarized-light"
Defaults to "asciinema".
You can also use a custom theme.
Type: string
Poster (a preview frame) to display until the playback is started.
The following poster specifications are supported:
npt:1:23- display recording "frame" at given time using NPT ("Normal Play Time") notationdata:text/plain,Poster text- print given text
The easiest way of specifying a poster is to use NPT format. For example,
npt:1:23 will preload the recording and display terminal contents at 1 min 23
sec.
Example:
AsciinemaPlayer.create('/demo.cast', document.getElementById('demo'), {
poster: 'npt:1:23'
});Alternatively, a poster value of data:text/plain,This will be printed as poster\n\rThis in second line will display arbitrary text. All ANSI escape
codes can be used to add color
and move the cursor around to produce good looking poster.
Example of using custom text poster with control sequences (aka escape codes):
AsciinemaPlayer.create('/demo.cast', document.getElementById('demo'), {
poster: "data:text/plain,I'm regular \x1b[1;32mI'm bold green\x1b[3BI'm 3 lines down"
});Defaults to blank terminal or, when startAt is specified, to screen contents
at time specified by startAt.
Type: string
Controls the player's fitting (sizing) behaviour inside its container element.
Possible values:
"width"- scale to full width of the container"height"- scale to full height of the container (requires the container element to have fixed height)"both"- scale to either full width or height, maximizing usage of available space (requires the container element to have fixed height)false/"none"- don't scale, use fixed size font (also seefontSizeoption below)
Defaults to "width".
Version 2.x of the player supported only the behaviour represented by the
falsevalue. If you're upgrading from v2 to v3 and want to preserve the sizing behaviour then includefit: falseoption.
Type: string
Size of the terminal font.
Possible values:
"small""medium""big"- any valid CSS
font-sizevalue, e.g."15px"
Defaults to "small".
This option is effective only when
fit: falseoption is specified as well (see above).
Type: string
Terminal font-family override.
Use any valid CSS font-family value, e.g "'JetBrains Mono', Consolas, Menlo, 'Bitstream Vera Sans Mono', monospace".
Type: number
Terminal line height override.
The value is relative to the font size (like em unit in CSS). For example a
value of 1 makes the line height equal to the font size, leaving no space
between lines. A value of 2 makes it double the font size, etc.
Defaults to 1.33333333.
import * as AsciinemaPlayer from 'asciinema-player';
// skip the above import when using standalone player bundle
const player = AsciinemaPlayer.create(url, containerElement);The object returned by create function (saved as player const above)
contains several functions that can be used to control the player from
your code.
For example, initiate playback and print the recording duration when it starts:
player.play().then(() => {
console.log(`started! duration: ${player.getDuration()}`);
});The following functions are available on the player object:
Returns the current playback time in seconds.
player.getCurrentTime(); // => 1.23Returns the length of the recording in seconds, or null if the recording is
not loaded yet.
player.getDuration(); // => 123.45Initiates playback of the recording. If the recording hasn't been preloaded then it's loaded, and playback is started.
player.play();This function returns a promise which is fulfilled when the playback actually starts.
player.play().then(() => {
console.log(`started! duration: ${player.getDuration()}`);
});If you want to synchronize asciinema player with other elements on the page (for
example <audio> element) then you can use this promise for coordination.
Alternatively you can add event listener for play event (see below).
Pauses playback.
player.pause();The playback is paused immediately.
Changes the playback location to time t given in seconds (e.g. 15) or
percentage (e.g '50%').
This function returns a promise which is fulfilled when the location actually changes.
player.seek(15).then(() => {
console.log(`current time: ${player.getCurrentTime()}`);
});Adds event listener, binding handler's this to the player object.
The play event is dispatched when playback starts or resumes from pause.
player.addEventListener('play', () => {
console.log(`playing! we're at: ${this.getCurrentTime()}`);
})The pause event is dispatched when playback is paused.
player.addEventListener('pause', () => {
console.log("paused!");
})The ended event is dispatched when playback stops after reaching the end of
the recording.
player.addEventListener('ended', () => {
console.log("ended!");
})Use this function to dispose of the player, i.e. to shut it down, release all resources and remove it from DOM.
The following keyboard shortcuts are currently available (when the player element is focused):
- space - play / pause
- f - toggle fullscreen mode
- ← / → - rewind by 5 seconds / fast-forward by 5 seconds
- Shift + ← / Shift + → - rewind by 10% / fast-forward by 10%
- 0, 1, 2 ... 9 - jump to 0%, 10%, 20% ... 90%
The project requires Node.js, npm and Rust for development and build related tasks so make sure you have the latest versions installed.
To build the project:
git clone https://github.com/asciinema/asciinema-player
cd asciinema-player
git submodule update --init
rustup target add wasm32-unknown-unknown
npm install
npm run build
npm run bundle
This produces:
dist/index.js- ES module, to beimport-ed in your JS bundledist/bundle/asciinema-player.js- standalone player script, to be linked directly from a websitedist/bundle/asciinema-player.min.js- minimized version of the abovedist/bundle/asciinema-player.css- stylesheet, to be linked directly from a website or included in a CSS bundle
If you want to contribute to this project check out Contributing page.
Developed with passion by Marcin Kulik and great open source contributors.
Copyright © 2011-2022 Marcin Kulik.
All code is licensed under the Apache License, Version 2.0. See LICENSE file for details.