Introduction

Editing in Notepad

#A simple program.
print "Mary had a little lamb,"
print "it's fleece was white as snow;"
print "and everywhere that Mary went",
print "her lamb was sure to go."

Using the IDLE Environment

Mary had a little lamb,
it's fleece was white as snow;
and everywhere that Mary went her lamb was sure to go.

• First of all, the comment wasn't shown. That is good, because remember - comments aren't compiled. (try compiling it after removing the # - it comes out messy)
• Second, is that the 3rd and 4th line got joined. This is because there is a comma just outside the inverted commas that surround the text. In the 'print' command, this stops the program from starting a new line on the screen when showing text.
• You can also run the program from your command line program (e.g. MSDOS) - Open the prompt up, type 'cd path\to\your\file' then type 'python mary.py'. Your program will now execute in the command line.

Variables

#variables demonstrated
print "This program is a demo of variables"
v = 1
print "The value of v is now", v
v = v + 1
print "v now equals itself plus one, making it worth", v
v = 51
print "v can store any numerical value, to be used elsewhere."
print "for example, in a sentence. v is now worth", v
print "v times 5 equals", v*5
print "but v still only remains", v
print "to make v five times bigger, you would have to type v = v * 5"
v = v * 5
print "there you go, now v equals", v, "and not", v / 5

Strings

#giving variables text, and adding text.
word1 = "Good"
word2 = "Morning"
word3 = "to you too!"
print word1, word2
sentence = word1 + " " + word2 + " " +word3
print sentence

Good Morning
Good Morning to you too!

Conclusion

What is Requests?

Requests is an Apache2 Licensed HTTP library, written in Python, for human beings

Requests allow you to send HTTP/1.1 requests. 

You can add headers, form data, multipart files, and parameters with simple
Python dictionaries, and access the response data in the same way.

Install Requests

There are a few ways to install Requests. Either use pip, easy_install,
or get the tarball.

You can also get the code through GitHub, if you prefer that. 

To see the full list of options, please consult the install documentation here.

We are using pip to install, simply type in: 

pip install requests

Importing the module

To import the Requests module, put this command at the beginning of your script.

import requests

Making a request

Note, I will sometimes use http://httpbin.org/ throughout this article. 

It supports most of the common HTTP verbs and mostly return the variables you
send in, which is sometimes very useful when you are writing a (HTTP) script. 

# Get a webpage, this creates a Response object called "r"

r = requests.get('https://github.com/timeline.json')

Response Code

We can check the response status code, and do a status code lookup with the
dictionary look-up object. 

r = requests.get('https://github.com/timeline.json')
r.status_code
>>200

r.status_code == requests.codes.ok
>>> True

requests.codes['temporary_redirect']
>>> 307

requests.codes.teapot
>>> 418

requests.codes['\o/']
>>> 200

Get the content

Get the content of the server's response.

import requests
r = requests.get('https://github.com/timeline.json')
print r.text

# Requests also comes with a builtin JSON decoder, 
# in case you’re dealing with JSON data
import requests
r = requests.get('https://github.com/timeline.json')
print r.json

Headers

We can view the server’s response headers using a Python dictionary, and we can 
access the headers using any capitalization we want.

If a header doesn't exist in the Response, its value defaults to None

r.headers
{
    'status': '200 OK',
    'content-encoding': 'gzip',
    'transfer-encoding': 'chunked',
    'connection': 'close',
    'server': 'nginx/1.0.4',
    'x-runtime': '148ms',
    'etag': '"e1ca502697e5c9317743dc078f67693f"',
    'content-type': 'application/json; charset=utf-8'
}

r.headers['Content-Type']
>>>'application/json; charset=utf-8'

r.headers.get('content-type')
>>>'application/json; charset=utf-8'

r.headers['X-Random']
>>>None

# Get the headers of a given URL
resp = requests.head("http://www.google.com")
print resp.status_code, resp.text, resp.headers

Encoding

Requests will automatically decode content from the server. 

Most Unicode charsets are seamlessly decoded.

When you make a request, Requests makes educated guesses about the encoding
of the response based on the HTTP headers.

The text encoding guessed by Requests is used when you access r.text.

You can find out what encoding Requests is using, and change it, using the
r.encoding property:

If you change the encoding, Requests will use the new value of r.encoding
whenever you call r.text.

print r.encoding
>> utf-8

>>> r.encoding = 'ISO-8859-1'

Custom Headers

If you’d like to add HTTP headers to a request, simply pass in a dict to the
headers parameter.

import json
url = 'https://api.github.com/some/endpoint'
payload = {'some': 'data'}
headers = {'content-type': 'application/json'}

r = requests.post(url, data=json.dumps(payload), headers=headers)

Redirection and History

Requests will automatically perform location redirection while using the GET
and OPTIONS verbs.

GitHub redirects all HTTP requests to HTTPS. 

We can use the history method of the Response object to track redirection. 

r = requests.get('http://github.com')
r.url
>>> 'https://github.com/'

r.status_code
>>> 200

r.history
>>> []

Make a HTTP Post request

With Requests you can of course also do post requests.

r = requests.post("http://httpbin.org/post")

You can use other HTTP requests types as well (PUT, DELETE, HEAD and OPTIONS)

r = requests.put("http://httpbin.org/put")
r = requests.delete("http://httpbin.org/delete")
r = requests.head("http://httpbin.org/get")
r = requests.options("http://httpbin.org/get")

# This small script creates a Github repo.

import requests, json

github_url = "https://api.github.com/user/repos"
data = json.dumps({'name':'test', 'description':'some test repo'}) 
r = requests.post(github_url, data, auth=('user', '*****'))

print r.json

Errors and Exceptions

In the event of a network problem (e.g. DNS failure, refused connection, etc),
Requests will raise a ConnectionError exception.

In the event of the rare invalid HTTP response, Requests will raise an HTTPError
exception.

If a request times out, a Timeout exception is raised.

If a request exceeds the configured number of maximum redirections, a
TooManyRedirects exception is raised.

All exceptions that Requests explicitly raises inherit from
requests.exceptions.RequestException.

Types of Operator

• Arithmetic Operators
• Comparison (Relational) Operators
• Assignment Operators
• Logical Operators
• Bitwise Operators
• Membership Operators
• Identity Operators

Python Arithmetic Operators

Python Comparison Operators

Python Assignment Operators

Python Bitwise Operators

Python Logical Operators

Python Membership Operators

Python Identity Operators

Python Operators Precedence