flask frameworkbasedonPython_microframework.pptx

flask frameworkbasedonPython_microframework.pptx

• 1.
  Topics to beCovered  Flask Framework
• 2.
  What is Flask Flaskis a web framework. This means flask provides you with tools, libraries and technologies that allow you to build a web application. This web application can be some web pages, a blog, a wiki or go as big as a web-based calendar application or a commercial website. Flask is part of the categories of the micro-framework. Micro-framework are normally framework with little to no dependencies to external libraries. Flask is a web application framework written in Python. It was developed by Armin Ronacher, who led a team of international Python enthusiasts called Poocco. Flask is based on the Werkzeg WSGI toolkit and the Jinja2 template engine.Both are Pocco projects.
• 3.
  WSGI The Web ServerGateway Interface (Web Server Gateway Interface, WSGI) has been used as a standard for Python web application development. WSGI is the specification of a common interface between web servers and web applications. Werkzeug Werkzeug is a WSGI toolkit that implements requests, response objects, and utility functions. This enables a web frame to be built on it. The Flask framework uses Werkzeg as one of its bases. jinja2 jinja2 is a popular template engine for Python.A web template system combines a template with a specific data source to render a dynamic web page.
• 4.
  Installation of flask Toinstall flask run the following command pip install Flask
• 5.
  First Flask application Openany text editor (notepad, notepad++ .etc) of your choice Write the following lines of code and save to a file named as filename.py Here we save it as a.py from flask import Flask app = Flask(__name__) #creating the Flask class object @app.route('/') #decorator defines the def home(): return "hello, this is our first flask website"; if __name__ =='__main__': app.run(debug = True)
• 6.
  run this pythoncode on the command line and check the result. Output:
• 7.
  To build thepython web application, we need to import the Flask module. An object of the Flask class is considered as the WSGI application. We need to pass the name of the current module, i.e. __name__ as the argument into the Flask constructor. The route() function of the Flask class defines the URL mapping of the associated function. The syntax is given below. Explanation app.route(rule, options) It accepts the following parameters. rule: It represents the URL binding with the function. options: It represents the list of parameters to be associated with the rule object As we can see here, the / URL is bound to the main function which is responsible for returning the server response. It can return a string to be printed on the browser's window or we can use the HTML template to return the HTML file as a response from the server. Finally, the run method of the Flask class is used to run the flask application on the local development server.The syntax is given below. app.run(host, port, debug, options)