Updated April 19, 2023
Definition of Flask Server
Flask server is defined as server software that is capable of running HTTP requests on the public world wide web, private LAN, and private WANs and comprises of one or many computers bundled together and dedicatedly working for running the software application on the worldwide web. Flask has a built-in server, but options of using others are present for the convenience of the developers. The server is capable of handling requests from HTTP on one or more configured websites. In short, the working of a server is to receive the incoming HTTP request and send the processed HTTP request back to the client, details of the working we will understand in our upcoming sections!
Why do we need a Flask server?
When a Flask application is created it needs to be assisted in a way to make it successfully running it on the deployed side of the application. In this successful running of flask application, we need to make sure that the deployed side is running properly and there is a seamless connection between the client-side and the deployed side. The deployed is nothing, but software that runs and handles the HTTP requests and is known as the server. In this section, we would understand why we use Flask server specifically, and not just any random one.
Flask as software is based on WSGI toolkit and Jinja2 template engine. The WSGI is an acronym for Web Server Gateway Interface and is a server-side interface that enables the running of Python web applications. In a quest to understand the need of a flask server, we would also understand the role of WSGI so that the full picture is complete. In a traditional server, there is no provision of running Python applications and to be frank doesn’t understand Python and its applications. Hence, in late 1990s an apache module was created for executing arbitrary Python codes. This module was not a standard specification and was just a workaround to run Python codes on server. Since, not a standard one, there were many potential security vulnerabilities for which, the python community thought of a consistent way of executing Python codes. In this way WSGI was created, the interface, and hence gave rise to the concept of Flask server.
Now, with the need of having a standardized server, it came other benefits like:
- More provision of flexibility: The choice of what web component to be used for deploying the application is kept totally different from the application itself. This also enables the application developers and server developers to work independently yet making them come together.
- Better scaling functionalities: It is capable of supporting thousands of requests for dynamic content at once. These servers handle the requests and the choice of communication by efficiently managing the web traffic.
Now that we know the need, it is now important for us to know how it works. Let’s look at it in the next section!
How does Flask server work?
Flask has an in-built server, but that server is not suitable for production because of inability of making application very scalable, and hence there is a requirement of putting the Flask application behind the real web server so that there is effective communication with Flask through WSGI protocol. One such widely used server is Gunicorn!
Now there are different facets where it is used and here in this section, we will know about the working in the facts in detail.
- Handling static files: Web application requires a static file, for example, Javascript or CSS for rendering the display of the web page. The Web server has the role of configuring the static file where the object request of Data is sent to the server as a global request from the Client’s web page. The server helps in processing the request by importing the Flask module.
- Flask sessions: The server stores the data in a session. Here it holds the data temporarily in a temporary folder mapped to a specific Session ID.
- Uploading of File in Flask: Here the server holds the file temporarily before they move to the desired location.
- Sending Form data: The form in HTML collects the information of the required entries and then are forwarded and stored on the server.
With the various instances, we understand that mainly server helps in storing the required data before processing!
Advantages and Disadvantages
Not every concept is perfect and hence consists of pros and cons. Let’s review them here:
Advantages:
- Flask server enables developers with capability of building scalable solutions.
- With lesser dependency between server and application, it enables flexibility.
- Enables Flask to be more optimized in terms of performance.
- It enables developer to write more modular codes.
Disadvantages:
- Flask’s in-built server is single-threaded and hence, the requests are executed one by one serially. For this reason, there is a provision of other Flask servers.
- Flask’s in-built server has an issue with security which are taken care by alternate versions like Gunicorn, Waitress, etc.
Examples
Now that we have complete knowledge about the what’s the role of flask server, working of Flask server, and the advantages and disadvantages in this section we will look at some examples on how flask servers are implemented so that once can get some practical sense of how this server looks like and what’s the in-built server along with one of the other WSGI server i.e. Gunicorn.
Example #1
Running a local Flask server
Syntax
In the python code:
from flask import Flask
appFlask = Flask(__name__)
@appFlask.route('/index')
def index():
return "Hello World!"
if __name__ == "__main__":
appFlask.run(debug=True)Output:
Example #2
Running with Waitress server on Windows:
Syntax:
from flask import Flask
from waitress import serve
appFlask = Flask(__name__)
@appFlask.route('/index')
def index():
return "Hello World!"
serve(appFlask, host='0.0.0.0', port=8080, threads=1)Output:
Conclusion
Here with this article, we have got an essence of how important a server is for any Flask application and with that some of the advantages and disadvantages of the server. It is always recommended to use this for UNIX as support in windows is not extensive as in UNIX.
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