Skip to main content

Flask and Replit - How to use it Together

Learn how to prepare Flask for production

Flask is a lightweight and flexible Python web framework that allows developers to easily build web applications. Flask is known for its simplicity and ease of use, making it a popular choice for building web apps of various sizes and complexities. Flask provides many built-in tools and libraries that make it easy to implement common web development features, such as routing, views, templates, and more.

Replit is an online integrated development environment (IDE) that allows developers to write, run, and collaborate on code in the cloud. Replit provides an easy-to-use interface that includes a code editor, a terminal, and a file manager, making it easy to create and manage Python projects without the need for local installations. Replit also offers a range of features and tools, such as version control, project sharing, and live coding sessions.

Running Flask on Replit allows developers to build and deploy web applications entirely in the cloud. This eliminates the need for local installations of Python or other dependencies, making it easy to get started with web development quickly and without any setup time. Flask apps can be run on Replit using a built-in server or deployed to a production environment using Replit's hosting capabilities.

By combining Flask and Replit, developers can easily build, test, and deploy web applications entirely in the cloud, without needing to worry about managing local installations or dealing with complex deployment processes.


✅ Setting up a Python Project in Replit​

Sure, here is a breakdown of the second subtopic, "Setting up a new Python project in Replit":

Creating a Replit Account

To create a new Python project in Replit, you'll first need to create a Replit account if you don't already have one. You can sign up for a free account by visiting the Replit website and following the on-screen instructions.

Creating a new Python Project

Once you've signed up for a Replit account, you can create a new Python project by clicking on the "Create repl" button on the Replit homepage. In the "Create repl" window, select "Python" as the language and give your project a name. For this tutorial, I'll be using flask-project.

Creating new replit project

Configuring the Environment

After creating the new Python project, you may want to configure the project environment to your specific needs. For example, you may want to install specific Python packages or configure environment variables. Replit provides a "Packages" tool and a "Secrets" tool that you can use to manage project dependencies and environment variables, respectively in the "Tools" pane on the left-hand sidebar.

Setting up Git integration

Replit provides Git integration that allows you to commit changes to your code and push them to a remote repository, such as GitHub. To set up Git integration, navigate to the "Git" tool in the "Tools" pane and follow the on-screen instructions to link your Replit account with your Git provider.

Adding code to the project

Once the project environment is configured, you can start writing Python code in the Replit editor. By default, Replit creates a main.py file that you can use to start building your Flask app.

With these steps, you can easily set up a new Python project in Replit and start building your Flask app. Replit provides a user-friendly interface that allows you to manage project dependencies, environment variables, and Git integration, making it easy to get started with web development quickly and efficiently. Below is a view of the project page and description.

Replit project page and description


✅ Installing Flask​

There are two ways to install packages on Replit. You can use the "Packages" tool in the "Tools" pane or use Replit built-in terminal (shell) also located in the "Tools" pane. To use the "Packages" tool, open the tools pane and click on packages.

A new "Packages" tab will be opened on your editor environment, from the tab search for the package you want to install and click on the "Install" button, to install the package. Alternatively, we can use the "Shell" tool (terminal) that is provided by Replit. The "Shell" tool is opened in a separate tab when a new project is started, but if you can find it, just check the "Tools" pane on the left-hand side of your editor.

Replit uses Poetry as the package manager, check the Basic Usage guide to get started. You can see all commands here. By using Poetry, you ensure that your project does not have broken dependencies and also gives you the chance to replicate your development environment (package-wise) outside Replit.

To install Flask in a Replit project using the terminal, you'll need to open the Replit Terminal. You can do this by clicking the "Shell" button in the left-hand sidebar of the Replit editor. Once the Replit Terminal is open, you can use the following command to install Flask in your Replit project:

$ poetry add flask

This command will download and install the latest version of Flask and its dependencies in your project's virtual environment.

Verifying the installation

After installing Flask, you may want to verify that the installation was successful. You can do this by importing Flask in your Python code and running a simple Flask app. For example, you can add the following code to your main.py file:

# main.py
from flask import Flask

app = Flask(__name__)

@app.route('/')
def hello():
    return 'Hello, World!'

if __name__ == '__main__':
    app.run(host='0.0.0.0')

This code defines a simple Flask app that responds with "Hello, World!" when accessed at the root URL. Adding host='0.0.0.0' gives you access to Replit "Webview" tool, which you can use to view your project when it is running. You can run the app by clicking the "Run" button in the Replit editor. The "Webview" tool opens automatically, but in the case where it does not, Click on "Webview" in the "Tools" pane.

Replit with webview and files

By following these steps, you can easily install Flask in a Replit project and start building your Flask app. Replit's built-in terminal and package management tools make it easy to install and manage project dependencies, allowing you to focus on developing your app.


✅ Using a Flask Template in Replit​

For this use-case, we will be using Soft UI Dashboard Flask a popular open-source starter. There are several ways to go about using the template, we can fork the repository, and then connect to GitHub from Replit and use the forked repository. For this section, we will be cloning the repository directly and starting it up in Replit.


Cloning Flask Soft UI Dashboard​

To clone the repository, open the "Shell" tool, and run the command

$ git clone https://github.com/app-generator/flask-soft-ui-dashboard.git

Once the repository is cloned, check the "Files" pane on the left-hand side, you will see the folder 'flask-soft-ui-dashboard`. Now we have the files for the template on Replit.


Installing Dependencies on Replit​

Inside flask-soft-ui-dashboard folder, there is a requirements.txt file that contains all the dependencies for the template. We can install them individually using the "Packages" tool or use a command that allows us to install them at once.

Note: Poetry does not have support for reading dependencies from requirements.txt files.

To install the dependencies for the template, open the "Shell" tool and run the command:

$ poetry add $(sed 's/#.*//' requirements.txt)

Using the sed command, we remove all the lines that are comments and send the others as multiple packages to poetry add command. Once this is executed completely we can start the Flask application.


Starting the Flask Template​

Before running the Flask template, we will be making some changes to the "run.py" file in the "flask-soft-ui-dashboard" directory.

# flask-soft-ui-dashboard/run.py
...
if __name__ == '__main__':
    app.run(host='0.0.0.0') # <-- Updated: host added

With host='0.0.0.0' we can make use of Replit "Webview" tool.

To start the Flask application, open the "Shell" tool and run the following command

$ python flask-soft-ui-dashboard/run.py

Once "Webview" is open, we can check the webpage from our browser using the link shown in the address bar of "Webview", it looks like https://<project-name>.<user-name.repl.co/. The start button is not used because it searches for "main.py" file in the root directory of the project.

Flask Soft Dashboard" opens the login page, create an account using the sign up page, then login to the account to see the homepage of the theme. Below is a picture showing the login page, signup page and homepage respectively.

Flask soft ui dashboard login page


Flask soft ui dashboard signup page


Flask soft ui dashboard homepage

Now we have a flask application that is using flask-soft-ui-dashboard. we can make changes to the files to fit our project needs.


✅ In Summary​

In this article, we have learned how to start Flask on Replit and use a Flask template. We first created a new Flask project on Replit, and then we cloned a Flask template from GitHub. We made some changes to the template, and then we ran the Flask application. We were able to successfully start the Flask application and view the dashboard.

✅ Resources​