Adding your existing Julia code into Genie apps

If you have existing Julia code (modules and files) which you'd like to quickly integrate into a web app, Genie provides an easy way to add and load your code.

Adding your Julia code to the lib/ folder

If you have some Julia code which you'd like to integrate in a Genie app, the simplest thing is to add the files to the lib/ folder. The files (and folders) in the lib/ folder are automatically loaded by Genie recursively. This means that you can also add folders under lib/, and they will be recursively loaded (included) into the app. Beware though that this only happens when the Genie app is initially loaded. Hence, an app restart will be required if you add files and folders after the app is started.

HEADS UP

Genie won't create the lib/ folder by default. If the lib/ folder is not present in the root of the app, just create it yourself:

julia> mkdir("lib")

Once your code is added to the lib/ folder, it will become available in your app's environment. For example, say we have a file called lib/MyLib.jl:

# lib/MyLib.jl
module MyLib

using Dates

function isitfriday()
  Dates.dayofweek(Dates.now()) == Dates.Friday
end

end

Assuming that the name of your Genie app (which is also the name of your main module in src/) is MyGenieApp, the modules loaded from lib/ will be available under the MyGenieApp namespace as MyGenieApp.MyLib.

HEADS UP

Instead of using the actual Genie app (main module) name, we can also use the alias ..Main.UserApp.

So we can reference and use our modules in lib/ in routes.jl as follows:

# routes.jl
using Genie
using MyGenieApp.MyLib # or using ..Main.UserApp.MyLib

route("/friday") do
  MyLib.isitfriday() ? "Yes, it's Friday!" : "No, not yet :("
end

Use the lib/ folder to host your Julia code so that Genie knows where to look in order to load it and make it available throughout the application.