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Installation and Usage

Installation​

Option 1: Global installation​

Use the CLI command below to install Magic.jl globally.

$ julia -e 'using Pkg; Pkg.add("Magic")'

Option 2: Local project installation​

Initialize the REPL in the current project:

$ julia --project

Press ] in the Julia REPL to enter Pkg mode and enter this:

pkg> add MyPackage

Implementing Hello World​

Magic.jl web apps are julia scripts that run from top to bottom.

See below a simple Hello World script using Magic.jl saved with the name app.jl:

# app.jl
using Magic
if button("Click me")
    text("Hello World!")
end

Running a web app​

The previous example web app can be started in the following ways:

We use the start_app() function to start serving a web app from the REPL.

> using Magic
> start_app()

By default, start_app() will try to run a file named app.jl within the current directory, but you can give your script a different name and call start_app("my_app.jl"). You can also change some of the server settings, such as its port, via start_app() arguments. See start_app() to learn more.

The REPL is used just for starting the web app. Once it is started, the server loop will begin and the REPL will be blocked until the server is stopped with Ctrl+C.

✨ NOTE: You don't necessarily have to stop and restart the server after making changes to your web app. The wep app script is reloaded (via include) on every page refresh/interaction. One exception is if you make changes to @app_startup or @page_startup code blocks, because these blocks are only executed once, at the app startup.

In summary, this is the basic web app development workflow:

  1. Start the REPL and call start_app() (once).
  2. Open the browser (once).
  3. Make changes to the web app script.
  4. Refresh or interact with the page.
  5. Back to 3.

Option 2: From the terminal​

Starting from Julia 1.12, Magic.jl can be executed as a command line tool using the -m julia flag.

$ julia --project -m Magic

All of the arguments accepted by start_app() are accepted as command line argument. For instance, the command line below specifies the script that should be run and the port that the server should listen to:

$ julia --project -m Magic "my_app.jl" --port 443

Run julia -m Magic --help to learn more.

Starting the web app from the terminal is not recommended if you are developing the web app, because during development, you may need to restart the server to make your changes take effect. But restarting the server from the terminal can take more time than from restarting it from the REPL because both the julia runtime and your package dependencies will have to be reloaded. Nevertheless, this method works fine for running your app in production or running other people's app that you don't intend to change.

Check out our Demo Apps​

A great way to learn how to use Magic.jl is checking out our demo apps and exploring their source code.