Python Rest API Example using Bottle Framework

Hi friends, here is another useful post where I will show you a simple Python Rest API Example. In this tutorial we will learn about what is REST API and how to build it in python.So let’s start the tutorial.First of all we will learn  what is REST API.

What is REST API

• It stands for Representational State Transfer.
• Roy Fielding defined  REST API in 2000.
• It is an architectural design that have many constraints for designing web applications.

Architectural Constraints Of REST API

• Client-Server Architecture – Client is responsible for handling front-end and server for back-end.They work separately without depending to each other.
• Statelessness – It means server will not store any information about the latest HTTP request that the client has sended.Therefore each request is treated as new request every time.
• Cacheability – It saves times and improve scalability and performance.
• Layered system – It means that , there may be intermediary things like Proxies,Gateways and another REST APIs between the client and the server.
• Uniform Interface – The interaction of all components in a REST API will have the same interface. It will have the same set of protocols, uniform resource identifiers (URI), methods, and representations.

Real world concept of REST API

• Furthermore we can understand the concept of REST API clearly in addition to take an example.
• So take an example from real world . Let’s consider  we are going to book flight tickets.Hence there is two method for booking. First one is to book tickets directly from flight’s website and second one is via some travel agencies.
• In case of travel agencies rather to  flight’s websites , they keep records about different flights simultaneously .They are connected with the database of all flights.
• Booking through travel agencies, we need not go to websites of several flights because they keeps records of all flights  in one place.
• Hence the travel agencies play the role as a REST API.
• So i hope  REST API concept is cleared to all of you.

Real world example of REST APIs

• Instagram
• facebook
• Twitter
• Gmail
• GitHub
• Weather Underground etc

RESTful web services

Consequently Designing of REST API is based on HTTP protocol. It also provides some methods such as  –

• GET – to read data from database
• POST – to insert new data in database
• PUT – to update data in database
• DELETE – to delete data from database

HTTP Status Codes

Whenever client make request to the server , server send status code as a result i.e., response to the client.In addition Some of Status Codes are following –

Status code	Meaning
100	continue
102	processing
200	ok
201	created
202	accepted
302	found
304	not modified
403	forbidden
404	not found
503	Service unavailable

Building our Python Rest API Example

So, now we will start building REST API in Python. Here I am using BOTTLE framework rather than any others because of its simplicity. Before proceeding to coding. First of all we will understand what is BOTTLE framework.

BOTTLE Framework

In this tutorial, i am using BOTTLE framework because it is especially relevant.So the first question is – what is BOTTLE .

• BOTTLE is nothing but a simple, fast and light weight micro web framework for python programming language.
• Most python standard library have many dependencies but BOTTLE has no  dependencies. It is distributed as a single file module.
• it helps in developing web applications easily and fastly.

Overview

Now start to building Rest Api.

• First we create a dictionary  that stores informations about employees.
• Implement get service for displaying all the employee’s informations.
• Implement get service for displaying only a particular employee’s information according to name.
• create post service for adding information in employee’s database.
• create delete service for deleting employee’s informations.

Stuffs Required

• PyCharm IDE (i preferred PyCharm but you can use anyone)
• BOTTLE framework
• POSTMAN REST client for testing
• knowledge of python

Let the Code Begin

First of all create a project and name it. Create a python file inside the project. I hope you know about creating project.

Installing BOTTLE module

Go to File menu and click on Setting, as a result a window appears like below.

Furthermore expand Project:RestApi option and select Project Interpreter.As a result a window will appear.Then search the bottle module and click on Install Package.

Finally Bottle has been  successfully installed.

Importing Bottle

Bottle library have run() method.This method starts a server instance.Here run() method contain two parameters:

reloader : whenever we changes in our code we have to restart the server.Reloader start auto-reloading server.It’s default value is False.

debug : It is very helpful in early development.It provides a complete informations whenever an error occurred.

Creating a dictionary

Here i am creating a dictionary that stores informations of employees.

So the Dictionary name is employee. It have three items name, address and Dept.I am taking details of three employees but you can take more than that.

Get All Employee Details

first we need to import get service.

It means any get request will come in between will be passes in the function underneath the decorator.

•  Create a @get()  decorator.
• Decorator is any python object for modifying a function or a class.
• Furthermore for a huge list of decorators  check the link  Python Decorator Library
• we passes a null point called employee.
• Then call a function getAllEmployee() .And simply returns the dictionary  with a key employees and value employee.
• This will return all the items stored in dictionary.The complete code is –

Testing the API

Hence On running above code we get an url like below.

Here i am using POSTMAN REST client for testing  API. This is  POSTMAN screen.

Now type the URL and click send button, we get following output.

Get a particular employee details

We can also get a particular employee’s details rather than to get all employees.Here i am doing so according to employee’s name.

• Again take a decorator and pass a variable name.
• Define a method  get_Emp_by_name(name). It takes the parameter what the variable passed to the decorator .
• Create a variable that search the dictionary by name.
• Return the selected employee.

Now run the application.Pass the url along with employee name. It will display the details of passed employee.

Add the employee

Furthermore i am going to add an element. It is pretty simple.first of all import the post and request method.

• Create a post decorator .
• Call a function add_emp(). This function is going to take JSON object with the information given in dictionary.
• Create a variable new_emp to add the employee details.
• request is a HTTP library .It allows  us to send HTTP/1.1 requests using Python.It is used to add  data via simple Python libraries
• append() method add the new employee in existing list.

Now run the code. Insert url , select post from dropdown. Click on Body select raw and in text select JSON(application/json).Insert the employee’s details as follows –

On clicking send button we will get the following output as a result.

We can see the new data is added to the existing employee’s list.

Deleting the employee details

Hence the last thing is to delete employee.For this write the following code.First import the delete library.

Now create a delete decorator. The code is seems like the code of getting a particular employee.But it have  a little bit change.

• Call a method remove_emp() and pass the parameter name i.e., employee name.
• create a variable for searching the selected element in dictionary .
• remove() method delete the  selected object from the employee list.
• return the updated list of employee.

Hence run the code.Select delete from dropdown. Enter url along with employee name(i am taking employee Arsh ) and click send button.The output will be as follows –

Finally the employee Arsh is successfully  removed from the employee list.

So  this is a tutorial of Building REST API in Python . In conclusion, this is a helpful post for creating REST API . If you have any query regarding to this post you can comment freely. Thank You.