Python Tutorial
Pyhton - Introduction
Pyhton - First Program
Pyhton - Comments
Pyhton - Lines / Indent
Pyhton - Multiple lines
Pyhton - Data Types
Pyhton - Variables
Pyhton - Type Conversion
Pyhton - Control Flows
Pyhton - Loops
Pyhton - Command Line Args
Pyhton - Basic Operators
Pyhton - Functions
Pyhton - String Methods
Pyhton - Files IO
Pyhton - REST API
Pyhton - Connect DB
Pyhton - Multithreading
Pyhton - Lists
Pyhton - Iterate Array
Pyhton - Exceptions
Pyhton - Lambdas
Pyhton - Modules
Pyhton - Invoke C
Pyhton - List Comprehensions
Pyhton - Generators
Pyhton - Class
Pyhton - Inheritance
Pyhton - Static & Class Methods
Pyhton - Decorators
Pyhton - pass
Pyhton - json
Pyhton - yaml
Pyhton - Socket
Pyhton - Logging
Pyhton - pint module
End of life Python 2
install python 3.8 on fedora 31
Python3.8 New Features
Python requests module error
Pyhton - Examples
Python installation
Python RESTful API Requests
REST (REpresentational State Transfer)
REST is emerged for standard design for creating web services and web APIs.REST Characteristics
- Client and Server: Separation between server (that offers a service) and client (that consumes the service).
- Stateless protocol: REST uses HTTP protocol, Server does not maintain information about client and client requests must contain required information to the server to process the request.
- Cacheable indicator: Server must inform to client whether requests can be cached or not.
- Layered System and Uniform Interface: Standardized and uniform communication between client and server
- Code on demand: This is optionsal, if needed, server can also provide executable code or scripts to the client to execute it.
HTTP methods
- GET: This method is used to obtain information about resources or particular resources
To get all employees information, GET request url may be like belowhttp://codingpointer.com/api/employees
To get particular employee information using employee id fieldhttp://codingpointer.com/api/employees/203
- POST:Creating new resource
http://codingpointer.com/api/employees //data (new employee information) will be provided with the request.
- PUT: Updating particular resource
http://codingpointer.com/api/employees/203 //updated data (employee information 203) will be provided in request.
- DELETE: Deleting particular resource
http://codingpointer.com/api/employees/203 //deletes employee #203)
Flask microframework
Flask microframework is very powerful python web framework.Before installing Flask, try to install virtualenv(Virtual Python Environment builder) on your machine.
$yum install virtualenvvirtualenv is a tool to create isolated python virtual environments.
Once installed, run this command to Install setuptools, pip, wheel for flask
$virtualenv flaskInstall flask on virtualenv
$flask/bin/pip install flaskCommand prompt:
Collecting flask
Downloading Flask-0.12.2-py2.py3-none-any.whl (83kB)
100% |████████████████████████████████| 92kB 753kB/s
Collecting itsdangerous>=0.21 (from flask)
Downloading itsdangerous-0.24.tar.gz (46kB)
100% |████████████████████████████████| 51kB 1.8MB/s
Collecting click>=2.0 (from flask)
Downloading click-6.7-py2.py3-none-any.whl (71kB)
100% |████████████████████████████████| 71kB 1.2MB/s
Collecting Jinja2>=2.4 (from flask)
Using cached Jinja2-2.9.6-py2.py3-none-any.whl
Collecting Werkzeug>=0.7 (from flask)
Downloading Werkzeug-0.12.2-py2.py3-none-any.whl (312kB)
100% |████████████████████████████████| 317kB 1.4MB/s
Collecting MarkupSafe>=0.23 (from Jinja2>=2.4->flask)
Building wheels for collected packages: itsdangerous
Running setup.py bdist_wheel for itsdangerous ... done
Stored in directory: /home/user_name/.cache/pip/wheels/fc/a8/66/24d655233c757e178d45dea2de22a04c6d92766abfb741129a
Successfully built itsdangerous
Installing collected packages: itsdangerous, click, MarkupSafe, Jinja2, Werkzeug, flask
Successfully installed Jinja2-2.9.6 MarkupSafe-1.0 Werkzeug-0.12.2 click-6.7 flask-0.12.2 itsdangerous-0.24
Simple web service using flask framework
# create file webservice.py
#!flask/bin/python
from flask import Flask
webservice = Flask(__name__)
@webservice.route('/')
def index():
return "Simple Web Service using Flask, Hello Python Flask Framwork!"
if __name__ == '__main__':
webservice.run(debug=True)
Execution steps:
$ chmod a+x webservice.py $./webservice.pyOutput:
* Running on http://127.0.0.1:5000/ (Press CTRL+C to quit) * Restarting with stat * Debugger is active! * Debugger PIN: 652-803-202Either http://127.0.0.1:5000/ or http://localhost:5000/ url can be used to view the webservice response as "Simple Web Service using Flask, Hello Python Flask Framwork!"
RESTful API Using Python and Flask Framework
Get request for getting all employees information
# Create file rest-service.py
#!flask/bin/python
from flask import Flask, jsonify, abort
rest_api = Flask(__name__)
employees = [
{
'id': 1,
'name': 'employee 1',
'designation': 'supervisor'
},
{
'id': 2,
'name': 'employee 2',
'designation': 'labour'
}
]
@rest_api.route('/codingpointer/api/employees', methods=['GET'])
def get_employees():
return jsonify({'employees': employees})
@rest_api.route('/codingpointer/api/employees/', methods=['GET'])
def get_employee(id):
employee = [employee for employee in employees if employee['id'] == id]
if len(employee) == 0:
abort(404)
return jsonify({'employee': employee[0]})
if __name__ == '__main__':
rest_api.run(debug=True)
Execution steps:
$chmod a+x rest-service.py $./rest-service.pyTo run and test the RESTful service, we can use curl command or just place the url in browser: http://localhost:5000/codingpointer/api/employees
$ curl -i http://localhost:5000/codingpointer/api/employeesOutput:
HTTP/1.0 200 OK
Content-Type: application/json
Content-Length: 205
Server: Werkzeug/0.12.2 Python/2.7.13
Date: Fri, 08 Sep 2017 18:32:08 GMT
{
"employees": [
{
"designation": "supervisor",
"id": 1,
"name": "employee 1"
},
{
"designation": "labour",
"id": 2,
"name": "employee 2"
}
]
}
To get particular employee information
$ curl -i http://localhost:5000/codingpointer/api/employees/1Output:
HTTP/1.0 200 OK
Content-Type: application/json
Content-Length: 97
Server: Werkzeug/0.12.2 Python/2.7.13
Date: Sat, 09 Sep 2017 03:12:12 GMT
{
"employee": {
"designation": "supervisor",
"id": 1,
"name": "employee 1"
}
}
Employee id is not found
displays below error if employee record is not found for particular employee id$ curl -i http://localhost:5000/codingpointer/api/employees/3 HTTP/1.0 404 NOT FOUND Content-Type: text/html Content-Length: 233 Server: Werkzeug/0.12.2 Python/2.7.13 Date: Sat, 09 Sep 2017 20:02:43 GMT <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> <title>404 Not Found</title> <h1>Not Found</h1> <p>The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.</p>
Creating customized error message
#!flask/bin/python
from flask import Flask, jsonify,make_response,abort
rest_api = Flask(__name__)
employees = [
{
'id': 1,
'name': 'employee 1',
'designation': 'supervisor'
},
{
'id': 2,
'name': 'employee 2',
'designation': 'labour'
}
]
@rest_api.errorhandler(404)
def get_not_found(error):
return make_response(jsonify({'error': 'Not found'}), 404)
@rest_api.route('/codingpointer/api/employees', methods=['GET'])
def get_employees():
return jsonify({'employees': employees})
@rest_api.route('/codingpointer/api/employees/', methods=['GET'])
def get_employee(id):
employee = [employee for employee in employees if employee['id'] == id]
if len(employee) == 0:
abort(404)
return jsonify({'employee': employee[0]})
if __name__ == '__main__':
rest_api.run(debug=True)
Execution step:
$ ./rest-service2.py * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit) * Restarting with stat * Debugger is active! * Debugger PIN: 742-803-202 127.0.0.1 - - [10/Sep/2017 01:35:26] "GET /codingpointer/api/employees/3 HTTP/1.1" 404 -Output:
$ curl -i http://localhost:5000/codingpointer/api/employees/3
HTTP/1.0 404 NOT FOUND
Content-Type: application/json
Content-Length: 27
Server: Werkzeug/0.12.2 Python/2.7.13
Date: Sat, 09 Sep 2017 20:05:26 GMT
{
"error": "Not found"
}
RESTful API POST Method
POST method is used to create or insert a new record in the database.
#!flask/bin/python
from flask import Flask, jsonify, request
rest_api = Flask(__name__)
employees = [
{
'id': 1,
'name': 'employee 1',
'designation': 'supervisor'
},
{
'id': 2,
'name': 'employee 2',
'designation': 'labour'
}
]
@rest_api.route('/codingpointer/api/employees', methods=['POST'])
def create_new_employee():
if not request.json or not 'name' in request.json:
abort(400)
employee = {
'id': employees[-1]['id'] + 1,
'name': request.json['name'],
'designation': request.json['designation']
}
employees.append(employee)
return jsonify({'employee': employee}), 201
if __name__ == '__main__':
rest_api.run(debug=True)
Execution steps:
$ chmod a+x rest-service.py ]$ ./rest-service1.py * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit) * Restarting with stat * Debugger is active! * Debugger PIN: 742-803-202 127.0.0.1 - - [10/Sep/2017 00:11:32] "POST /codingpointer/api/employees HTTP/1.1" 201 -Output:
$ curl -i -H "Content-Type: application/json" -X POST -d '{"name":"employee 3", "designation":"manager"}' http://localhost:5000/codingpointer/api/employees
HTTP/1.0 201 CREATED
Content-Type: application/json
Content-Length: 94
Server: Werkzeug/0.12.2 Python/2.7.13
Date: Sat, 09 Sep 2017 18:41:32 GMT
{
"employee": {
"designation": "manager",
"id": 3,
"name": "employee 3"
}
}
RESTful API Error codes
Some Error codes which are mostly used in REST API's| Error Code | Description |
|---|---|
| 200 | HTTP code 'OK'- Send back status code as OK to the client. Mostly used for PUT and DELETE methods. |
| 201 | HTTP code 'Created'- Send back status code as Created to the client. |
| 400 | HTTP code 'bad request' - Send back status code as bad request to the client. |
| 404 | HTTP code 'Not Found' - Send back status code as Not Found to the client. |
RESTful API PUT Method
PUT method is used to update a particular record in the database objects.
#!flask/bin/python
from flask import Flask, jsonify, request, abort
rest_api = Flask(__name__)
employees = [
{
'id': 1,
'name': 'employee 1',
'designation': 'supervisor'
},
{
'id': 2,
'name': 'employee 2',
'designation': 'labour'
}
]
@rest_api.route('/codingpointer/api/employees/', methods=['PUT'])
def update_employee(id):
employee = [employee for employee in employees if employee['id'] == id]
if len(employee) == 0:
abort(404)
if not request.json:
abort(400)
employee[0]['designation'] = request.json.get('designation', employee[0]['designation'])
return jsonify({'employee': employee[0]})
if __name__ == '__main__':
rest_api.run(debug=True)
Execution step:
$ ./rest-service3.py * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit) * Restarting with stat * Debugger is active! * Debugger PIN: 742-803-202 127.0.0.1 - - [10/Sep/2017 02:14:18] "PUT /codingpointer/api/employees/2 HTTP/1.1" 200 -Output:
$ curl -i -H "Content-Type: application/json" -X PUT -d '{"designation":"supervisor-II"}' http://localhost:5000/codingpointer/api/employees/2
HTTP/1.0 200 OK
Content-Type: application/json
Content-Length: 100
Server: Werkzeug/0.12.2 Python/2.7.13
Date: Sat, 09 Sep 2017 20:44:18 GMT
{
"employee": {
"designation": "supervisor-II",
"id": 2,
"name": "employee 2"
}
}
RESTful API DELETE Method
DELETE method is used to delete a particular record in the database objects.
#!flask/bin/python
from flask import Flask, jsonify, abort
rest_api = Flask(__name__)
employees = [
{
'id': 1,
'name': 'employee 1',
'designation': 'supervisor'
},
{
'id': 2,
'name': 'employee 2',
'designation': 'labour'
}
]
@rest_api.route('/codingpointer/api/employees/', methods=['DELETE'])
def delete_employee(id):
employee = [employee for employee in employees if employee['id'] == id]
if len(employee) == 0:
abort(404)
employees.remove(employee[0])
return jsonify({'result': True})
if __name__ == '__main__':
rest_api.run(debug=True)
Execution steps:
$ ./rest-service4.py * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit) * Restarting with stat * Debugger is active! * Debugger PIN: 742-803-202 127.0.0.1 - - [10/Sep/2017 02:22:39] "GET /codingpointer/api/employees/2 HTTP/1.1" 405 - 127.0.0.1 - - [10/Sep/2017 02:26:04] "DELETE /codingpointer/api/employees/2 HTTP/1.1" 200 -Output:
$ curl -i -H "Content-Type: application/json" -X DELETE http://localhost:5000/codingpointer/api/employees/2
HTTP/1.0 200 OK
Content-Type: application/json
Content-Length: 21
Server: Werkzeug/0.12.2 Python/2.7.13
Date: Sat, 09 Sep 2017 20:56:04 GMT
{
"result": true
}
Secure RESTful API's
Simplest method to secure RESTful API is to ensure clients to provide username and password.In HTTP context, two authentication types are Basic and Digest.
Install Flask-HTTPAuth
$ flask/bin/pip install flask-httpauth
Basic HTTP authentication in REST API
#!flask/bin/python
from flask import Flask, jsonify,make_response
rest_api = Flask(__name__)
employees = [
{
'id': 1,
'name': 'employee 1',
'designation': 'supervisor'
},
{
'id': 2,
'name': 'employee 2',
'designation': 'labour'
}
]
@rest_api.route('/codingpointer/api/employees', methods=['GET'])
def get_employees():
return jsonify({'employees': employees})
@rest_api.route('/codingpointer/api/employees/', methods=['GET'])
def get_task(id):
employee = [employee for employee in employees if employee['id'] == id]
if len(employee) == 0:
abort(404)
return jsonify({'employee': employee[0]})
if __name__ == '__main__':
rest_api.run(debug=True)
Execution step:
$ ./rest-service5.py * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit) * Restarting with stat * Debugger is active! * Debugger PIN: 742-803-202Invalid Credentials Output:
$ curl -i -u 'test-user:test-passwd1' http://localhost:5000/codingpointer/api/employees/2
HTTP/1.0 401 UNAUTHORIZED
Content-Type: application/json
WWW-Authenticate: Basic realm="Authentication Required"
Content-Length: 37
Server: Werkzeug/0.12.2 Python/2.7.13
Date: Sat, 09 Sep 2017 21:23:58 GMT
{
"error": "Unauthorized access"
}
Valid Credentials Output:
$ curl -i -u 'test-user:test-passwd' http://localhost:5000/codingpointer/api/employees/2
HTTP/1.0 200 OK
Content-Type: application/json
Content-Length: 93
Server: Werkzeug/0.12.2 Python/2.7.13
Date: Sat, 09 Sep 2017 21:24:02 GMT
{
"employee": {
"designation": "labour",
"id": 2,
"name": "employee 2"
}
}
REST API POST request to get the access token
import requests, urllib
import json
url="https://api.test.com/oauth/access_token"
CONSUMER_KEY="consumer_key"
CONSUMER_SECRET="consumer_secret_key"
headers={ 'User-Agent' : 'OAuth gem v0.4.4',
'Connection' : 'close',
'Content-type' : 'application/x-www-form-urlencoded',
'Content-Length' : '175' }
data={'grant_type' : 'client_credentials',
'client_id': CONSUMER_KEY ,
'client_secret' : CONSUMER_SECRET
}
response = requests.post(url, headers=headers, data=urllib.urlencode(data))
print "Post Request to : " +url
print response
print "Response Message: "+response.text
REST API POST Request to get data
import requests, urllib, json
url="https://api.testapi.com/method"
ACCESS_TOKEN="access_token"
headers={ 'User-Agent' : 'OAuth gem v0.4.4',
'Authorization' : ACCESS_TOKEN
}
input_data={ 'param1': 22}
response = requests.post(url, data=json.dumps(data),headers=headers)
print "Get Request to : " + url
#print response
#print "Response Message: "+response.text
json_data=response.json()
print json_data
#for person in json_data['data']:
# for key, value in json_data.iteritems():
# print key, 'is:', value
#print "\n"
« Previous Next »
Python Programming Language Examples
Fibonacci Series Python Program
Python Program To Calculate Gross Salary
Python Program To Calculate Simple Interest
Python Program To Convert Memory Size in MB
Python Program To Check Number Is Prime or Not
Python Program To Swap Two Numbers
Factorial Series Python Program
Python Program to find next polyndrome number
Singly Linked List Python Program
Double Linked List Python Program
Linear Search Python Program
Binary Search Python Program
Ternary Search Python Program
Bubble Sort Python Program
Selection Sort Python Program
Insertion Sort Python Program
Merge Sort Python Program
Quick Sort Python Program
Counting Sort Python Program
Radix Sort Python Program
Python Socket Program To Chat Between Server and Client
Python Program To Run Command Remotely using SSH
Python Program with Key Value Pair Arguments
Python Program with Key Value Pair Arguments Using argparse Module
Python Program to print lines in colors, bold, warning, failure and header indications
Python Program for remote directory exists or not using SSH
Python Program to Split String by Multiple Separators
Reads linux system memory and unit conversion in python program ( RHEL / Fedora / Centos )
Python Tutorial
2020 - All Rights Reserved. | 
