Creating Web Application in python

Web Application : 

Web Application is an application software that runs in web browser . Software programs will run on operating system. Whereas Web Applications will run on World Wide Web ( WWW ) with an internet connection. We Application is directly connected with the users. Web Application includes online forms, sheets, photo and video editing, file conversion, and also scanning.

  Web Application is mainly designed to interaction with the clients or end users. It contains static content. The user of web application can read the content in the web application and also manage the content in the web application but the user of website can only read the content in the web application but they cannot change the content in the web application.

 Python web applications are platform independent and they can be run by anyone who can access the internet. It mainly focuses on back end development. Python web applications are mainly built using python web frame works. Web Applications are also known as static because the content cannot be changed by the website user.

 Python-driven web applications use Python code to figure out what moves to make and what content to show. Your code is controlled by the web server that has your site, and that implies that your clients don't have to introduce anything. All they need to cooperate with your code is a program and an Internet association.

Types of Web Application :

->Static Web Application

->Dynamic Web Application

->E-commerce Web Application

->Single-page Web Application

->Portal Web Application

->Content management system web application

->Animated Web Application

->Rich Internet Web Application

Python Web Applications:

 We can create web applications using different frame works such as Flask,  Django, Web2Py etc.

 We mainly use python web applications using flask to do handle the application in an easy manner. Flask is a most important frame work that is used in python. It is a light frame work that provides tools and features to create Web Applications. It gives more flexibility to developers. It also acts as accessible frame work for new developers.

Whereas Django is more popular framework in python. It also provides many features. Along with this it is also used to reduce the time to build complex applications.

Python web application step by step procedure using flask :

Inorder to create a web application using python we should contain the following prerequisites such as python 3 programming and environment of python should be known clearly , and the one should have basic python 3 concepts such as packages , libraries , data types , lists , tuples , dictionary and etc, and should also have basic concepts of HTML.

Step – 1: Installing flask

Inorder to create a web application first we have to install the frame work with what we are working. So the first step that should be done is installation of the flask. First we have to activate the python environment. And then we have to install the flask using pip. Flask can be installed using pip by using the following command.

pip install Flask

After completion of installing the Flask we can also see that there are also many other packages that are invoked in Flask. So we can see all the list of installed packages that are invoked in Flask. These packages that are  invoked in flask are used to perform different functions.

Step – 2: Creating simple application

Now we have our programming environment set up, we will start using Flask. In this step, we will make a mini Flask web application in a Python file which consists of HTML code that displays on browser. In our flask_app directory, we should open a file named app.py to edit and then use nano to edit the code.

After completion of writing the code save and close the file. That becomes a mini web application. Now we have a simple flask web application saved in python file with name app.py.

Step – 3: Running the application

After creating the file which consists of Flask application, we should run it using the Flask command line interface.In our flask_app directory we should tell flask to find the application app.py by using the flask app using following command :

export FLASK_APP = app

After completing of finding the flask application the next step is to run the application. We can run the mini flask we application using the following command :

flask run

After completion of running of the application we may see the output of the above written code.

Step – 4: Routes and View Functions

Route to an application displays different kind of data based on the URL. Routes are mainly considered for URL. It is used to determine what does an user receives when they visit the web application on their respective browsers or systems.

Let us see the following URL ‘ s as an example. ( http : / / 127 . 0 . 0 . 1 : 5000 / ) is used to show the main route that displays index page. There are many other URL ‘ s that mainly work on the routes.

We have to open app.py file for editing. After opening the code we have we have added a new function called about ( ) . This function is mainly focused on the routes, and also we will use hello ( ) function which is a kind of view function to edit the given code in app.py . After completion of editing the file we need to save and close the file.

Step – 5: Dynamic Routes

In the above step we have just created a route but in this step we may create route in such a way that an end user can interact with it.

In this step we may use the methods like capitalize() , escape() and format() for editing the code in app.py file same as shown above we need to create the routes for the given code.

Step – 6: Debugging a Flask Application

After completing the creation of a web application it may consists of errors where the user may feel some difficulty to login or to access the data.

So inorder to debug the errors we can use the method named greet_user to debug the user defined errors in the code. So that the code can run without any errors and so users may not face any difficulty in accessing the data.