Kotlin is a statically-typed programming language that runs on the JVM and can also be compiled to JavaScript or native code. It is an open-source, pragmatic language that combines features of both functional and object-oriented programming.
Flask is a Python web framework built with a small core and easy-to-extend philosophy. Flask is a popular choice for building microservices due to its lightweight nature.
In this article, we'll see how to use Kotlin and Flask to build a simple web application. We'll start by setting up our development environment and then we'll create a Kotlin class and a Flask route to display a simple message.
Before we can start coding, we need to set up our development environment. We'll need to install the Kotlin compiler and the Flask web framework.
You can install the Kotlin compiler from the official Kotlin website. There are instructions for installing Kotlin on Windows, macOS, and Linux.
Flask can be installed from the Python Package Index using the pip package manager.
$ pip install flask
Now that we have our development environment set up, let's write some Kotlin code. We'll start by creating a Kotlin file named Hello.kt
.
fun main(args: Array<String>) {
println("Hello, Kotlin!")
}
We can compile this Kotlin code to JavaScript using the kotlinc
compiler.
$ kotlinc Hello.kt -output hello.js
We can also compile it to native code using the kotlinc-native
compiler.
$ kotlinc-native Hello.kt -o hello
Now that we have our Kotlin file, let's write a Flask route to display a simple message. We'll create a file named app.py
and import the Flask
class.
from flask import Flask
Next, we'll create an instance of the Flask
class. We need to pass in a name for our application.
app = Flask(__name__)
Now, we can create a route. A route is a function that is decorated with the @app.route
decorator. The @app.route
decorator takes a path as an argument. This is the path that will be associated with the function.
@app.route('/')
def index():
return 'Hello, Flask!'
Finally, we need to tell Flask to run our application. We do this by calling the run
method.
if __name__ == '__main__':
app.run()
We can run our Flask application using the flask
command.
$ flask run
* Serving Flask app "app"
* Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
We can now access our application at http://127.0.0.1:5000/.
In this article, we've seen how to use Kotlin and Flask to build a simple web application. We've started by setting up our development environment and then we've created a Kotlin file and a Flask route to display a simple message.