Django: Creating PDF , writing content and returning as a downloaded file

Hi guys,

It took me hours to make it finally work but working with PDFs is a pain. I want to share what worked for me.

The canvas should be thought of as a sheet of white paper with points on the sheet identified using Cartesian (X,Y) coordinates which by default have the (0,0) origin point at the lower left corner of the page.

from reportlab.pdfgen import canvas
import io

pdf_buffer = io.BytesIO()
p = canvas.Canvas(pdf_buffer)
p.drawString(0, 100, "Hello People")
p.showPage()
p.save()

response = HttpResponse(content_type='application/pdf')
response['Content-Disposition'] = 'attachment; filename="some_file.pdf"'
pdf_value = pdf_buffer.getvalue()
response.write(pdf_value)
return response

Above code , generates a pdf with the words "Hello People" written in it. 

PyCharms Handy short cuts

Hi friends. Today we are going to see some extremely useful (and must know) shortcuts for PyCharms .

Moving to last working point:

Ctrl+Shift+Backspace

How and when to use *args and **kwargs in Python

args and kwargs are special arguments (the words itself are just convention) which can be passed to a function.

Python Special Methods : __call__

Python has some methods that are special in a way . If  these methods are created inside a class, they can bring in some unique behaviors . We will talk about the method '__call__' today.

Examples of Super method in Classes

Hi all. We are going to see some examples of usage of keyword 'super' here . 

Python Global Variables

The keyword "global" has a special purpose . If you look into the help docstring of this keyword, you must notice this line :

 It would be impossible to assign to a global variable without "global " 

The word to note is "Assign"

Now . In python , if you declare a variable outside the scope of all functions or classes, it is AVAILABLE GLOBALLY. Meaning I can use it anywhere anytime.

But what is NOT clear , is , you CANNOT change the value\contents of this variable.

Bringing statefulness into your program (e.x an integrating counter ), might need you to keep updating some variable's value . That means, functions must be able to change that value.

Hence, the keyword "global" .

Production server launch using Django and Apache and mod wsgi

Some of us develop Django applications which can be used inside Intranet for various purposes.
Some ideas are:

• HRMS apps
• Interview Management Tools
• Grievance Management Tool
• Financial Report Generators. 

These apps running on intranet, generally don't face too much traffic at a time, but they do need to compute or face heavy queries which is why, it's a good idea to release them on a proper environment . Typically they are light on UI. I choose to use bootstrap which is enough to achieve a decent look . 

Still you should serve them using something which is good at serving static content. So I chose Apache. Lets get started.