Django Rest Framework vs Django TastyPie

transcript

RESTful APIs in Django: Library Face-Off!

TastyPie vs Django REST Framework

Scope of Discussion

● Introduction to REST● Review of Django’s Flow● Demo Structure Overview● Demo of TastyPie● Demo of Django Rest Framework● Demo of SQLAlchemy in both Frameworks● Conclusion

Introduction to REST● REST - Representational State Transfer● REST is a philosophy, not a communication protocol.

o An architectural style for distributed systems just like the web

o REST is not tied to the web, but it's almost always implemented as such, and was inspired by HTTP

o Majority of RESTful APIs use HTTP serving JSON or XML.

Examples of REST Systems

● Google Glass API● Twitter API● Amazon Web Services● Atom (RESTful alternative to RSS)● Tesla Model S

o Uses RESTful calls to communicate between mobile devices and car: http://docs.timdorr.apiary.io/

REST Characteristics● The term was introduced by Roy Fielding in 2000 for

his in his doctoral dissertation at UC Irvine

● 6 Constraints proposed by Roy Fielding

o Client-Server

o Stateless Server

o Cache

o Uniform Interface

o Layered System

o Code-On-Demand

REST Characteristics● Client-Server Model: Pull Based (not event driven) system

o Client - Sends requests to a server and awaits a response from the server.

o Server - Provides a service to multiple clients. Receives requests and provides a response for the information that the client requested.

REST Characteristics● Stateless Server

o Each request to the server must contain all of the

information necessary for the server to understand the

request.

o Server cannot take advantage of any server-side stored

context.

● Ex: Server cannot know user’s profile before the request is

REST Characteristics● Cacheable Responses

o Responses from the server have to be capable of being

cached by the client (though this doesn’t need to be used).

● Ex: Client stores locally the employee’s id for each

consequent request after the initial request to login was

successful.

REST Characteristics● Uniform Interface

o Resource Identifier - URL / URI

http://twitter.com/#!/jack/status/20

o Resource Representation and Manipulation

Whatever comes back that represents the resource identified by

the URL. We can manipulate the resource directly from the URL.

o Self-Descriptive Messages

Self-descriptive messages contain metadata to describe the

meaning of the message. The methods used to invoke the message

must be standard and agreeable between the first three

constraints - client-server, stateless server, and cache.

REST Characteristics● Uniform Interface

o HATEOAS - Hypermedia as

the engine of application

User requests resource

Resource has

transitions (or

hyperlinks) to go to a

new state (new

resources)

REST Characteristics● Layered System

o Should be able to

accommodate extra

layers like proxy

servers, firewalls,

gateways, caching

system

o (this is why HTTP is

most often used)

REST Characteristics● Code-on-Demand

o The optional code-on-

demand constraint

allows clients to request

and execute code from

servers. This, in turn,

allows the server to

deploy new features to

clients.

● API Design: Ruminating Over RESTo https://blog.apigee.com/detail/api_design_ruminat

ing_over_rest

● A Beginner's Guide to HTTP and RESTo http://code.tutsplus.com/tutorials/a-beginners-

guide-to-http-and-rest--net-16340

● HATEOASo https://www.youtube.com/watch?v=6UXc71O7htc

More Information

● Hypertext Transfer Protocolo Roy Fielding used REST to implement HTTP 1.1o The protocol that is used to manipulate remote

resources. o We can use HTTP Verbs to manipulate these

resources.

CRUD (Create, Read, Update, Delete)

Operation HTTP Verb

Get an element by it’s ID GET

Get a list of elements GET

Insert a new element POST or PUT (usually POST)

Update an existing element PUT

Delete an element DELETE

Basic Operations for Manipulating Data over HTTP

To most people, REST just means...

● Expose directory-structure-like URLS

● Use HTTP methods correctly / consistently

● Transfer XML or JSON

● Be stateless

o The same call should always yield the same result

regardless of server state / previous calls made

What are the Benefits?● Separation of frontend and backend logic

o easy to change your frontend client without touching your APIo can add multiple clients (web, mobile, desktop app, batch

process, etc) with no logic changeso gives a clear API layer to document.

● Only one protocol for accessing backend logic: changes only need to be made in one place.

● Predictable since it is stateless

What are the Benefits?● You can make good use of HTTP caching and proxy

servers / load balancers to help you handle high load.

● It helps you organize very complex applications into simple resources.

● It makes it easy for new clients to use your application, even if you haven’t designed it specifically for them.

Why is this example #1 not RESTful?

Bret lives in Oregon. His address is part of his user profile – not sent with every API call

When he performs a GET call on the URL /cars/used/9000/12000/To search for used cars in his price range, he gets back only results for within 50 miles of his address.

Request:Method: GETRequest Payload:{

"username" : "bobschmoe",

"query" : "nearby"

Example 1: Find Cars for User

URL: http://foo.bar.com/cars/used/

Response:{

"results” : [{

"car_id" : "ABC001”,

"make” : "Honda”,

"model” : "Accord” }, {

"car_id” : "ABC001”,

"make” : "Honda”,

"model” : "Accord”

"zip": "11040"

Example 1: Find Cars for User

It is NOT RESTful since it is not stateless.● The server some how knew the user’s zip

code. The client didn’t provide this information to the server.

Request:Method: POSTRequest Payload:{

"resource" : "vehicle",

"method" : "addVehicle",

"year" : "2014",

"make" : "Honda",

"model" : "Accord",

"trim" : "EX-L",

Example 2: Add Vehicle to Company Profile

URL: http://profile.mycompany.com/api/

Response:{

"resource_id" : "ABC00234",

Example 2: Add Vehicle to Company Profile

It is NOT RESTful since the URI is not unique.● Unique resources are not tied to a unique

URI. They all share one.● Due to all requests being routed through one

URI (/api/), no results have the ability to be cachable.

Request:Method: POSTRequest Payload:{

"address" : "123 Main Street",

"city" : "Lake Success",

"state" : "NY",

Example #3: Modifying Patient Information

URL: http://mymeds.com/patients?method=updateAddress&patient_id=3254

Response:{

"success" : "true"

This is NOT RESTful because the resource has state information.● The client is making this call in order to change the state of the _

data on the server. But the client is using the GET method instead of the PUT method.

● REST specifies that A resource is uniquely tied to a single URI and that the correct method is used to create, read, update, or delete it.

This is NOT RESTful because the resource has state information.● Tunneling all calls through GET is the primary REST anti-pattern!

The base URI here - /patients/ - is not uniquely tied to a resource.

● /patient/address/32543/ used together with PUT would be better.

Django Request-Response Cycle

Browser

Django

urlpatterns = patterns(

# Examples:

# url(r'^$', 'notematic3000.views.home', name='home'),

url(r'^note/(?P<pk>\d+)/update/(?P<params>.+)',

views.UpdateNote.as_view(), name='update'),

url(r'^note/(?P<pk>\d+)/delete',

views.DeleteNote.as_view(), name='delete'),

url(r'^note/(?P<%s>\d+)' % PK,

views.DisplayNote.as_view(), name=DISPLAY),

url(r'^new/(?P<params>.+)',

views.CreateNote.as_view(), name='create'),

url(r'^(all)?', views.AllNotes.as_view(), name=GETALL),

Selected view

● Receives request object

● Responsible for all

processing of request

● One view will process

different methods

● Performs database

interactions using ORM

● Creates response

● Returns response

object

GET note/3

Response - (e.g. JSON text)

Demo Structure Overview

Project Structurenotematic3000

|----------------------------------------------- notes

|-- Makefile |----------------------------- api

|-- manage.py |-- admin.py |-- __init__.py

|-- notematic3000 |-- alchemy |-- rest

|-- settings `-- rest.py |-- models.py | `-- viewsets.py

| |-- base.py |-- tests.py `-- tastypie

| |-- default.py |-- urls.py |-- api.py

| |-- __init__.py `-- views.py |-- __init__.py

| |-- pie.py -̀- sqlalchemy_api.py

| `-- rest.py

`-- wsgi.py

Project Settingsfrom base import *

# MODIFY INSTALLED APPS

INSTALLED_APPS = INSTALLED_APPS + ('rest_framework',)

# MODIFY URLS

ROOT_URLCONF = 'notematic3000.urls.rest'

# DJANGO REST FRAMEWORK SETTINGS

REST_FRAMEWORK = {

'DEFAULT_RENDERER_CLASSES' : (

'rest_framework.renderers.BrowsableAPIRenderer',

'rest_framework.renderers.JSONRenderer',

'rest_framework.renderers.XMLRenderer', ) }

Project Structurenotematic3000

|----------------------------------------------- notes

|-- Makefile |----------------------------- api

|-- manage.py |-- admin.py |-- __init__.py

|-- notematic3000 |-- alchemy |-- rest

|-- settings `-- rest.py |-- models.py | `-- viewsets.py

| |-- base.py |-- tests.py `-- tastypie

| |-- default.py |-- urls.py |-- api.py

| |-- __init__.py `-- views.py |-- __init__.py

| |-- pie.py -̀- sqlalchemy_api.py

| `-- rest.py

`-- wsgi.py

Introduction to DRF

Django REST framework is a powerful and flexible toolkit that makes it easy to build Web APIs.

DRF - Routers● REST framework adds support for automatic URL

routing to Django, and provides you with a simple, quick and consistent way of wiring your view logic to a set of URLs.

● Types of Routerso SimpleRoutero DefaultRoutero CustomRouters

DRF - Parsers● REST framework includes a number of built in Parser

classes, that allow you to accept requests with various media types. There is also support for defining your own custom parsers, which gives you the flexibility to design the media types that your API accepts.

● Types of Parserso Built-In:

JSONParser, YAMLParser, XMLParser, FormParser, MultiPartParser, FileUploadParser

o You can build your own custom parser

DRF - ViewSets● Django REST framework allows you to combine the

logic for a set of related views in a single class, called a ViewSet. In other frameworks you may also find conceptually similar implementations named something like 'Resources' or 'Controllers'.

● Types of ViewSets:o Built-In:

GenericViewSet, ModelViewSet, ReadOnlyModelViewSet

o You can build your own custom ViewSet

● REST framework includes a number of built in Renderer classes, that allow you to return responses with various media types.

DRF - Renderers

● Built-in Rendererso JSONRenderer, UnicodeJSONRenderer,

JSONPRenderer, YAMLRenderer, XMLRenderer, TemplateHTMLRenderer, StaticHTMLRenderer,HTMLFormRenderer, BrowsableAPIRenderer, MultiPartRenderer

o Custom Renderers

DRF - Renderers

Other Features

● Authorizationo BasicAuthorization, TokenAuthorization,

SessionAuthorization, OAuthAuthorization, OAuth2Authorization, CustomAuthorization

● Permissions● Throttling● Filtering● Pagination

DEMO TIME

Introduction to Tastypie● Tastypie is a framework providing boilerplate code to

create RESTful APIs● Depends on Django - cannot stand alone● Basically involves creating ‘Resource’ oriented classes● Resources are intermediary between end-user and

Django models● Provides out-of-box authentication, authorization,

caching, throttling and serialization

Tastypie Request Flow

Django URL Resolver check

HTTP Request

Lookup view for match

Check for serialization errors

call dispatch

dispatch method call

HTTP method in allowed list?

Authenticate/Authorize

Throttle check

call actual method

Advanced Tastypie● Bundles - Abstraction to pass data between resources ● Api - Collection of resources● Resource Fields - Representation of resource (just like

Django Fields)● You can customize authentication, authorization,

caching, throttling, validation, serialization ● Learn more at http://django-tastypie.readthedocs.org/

DEMO TIME

Non-Django ORM sources

● What if - we cannot use Django ORM and we need something more advanced?

● Both frameworks have hooks to replace Django ORM

● Tastypie - Extend and override ‘Resource’ methods

● DRF - Extend and override ‘ViewSet’ methods

Conclusion (1)

● REST is now the standard for open APIs● REST is best summed up as verbs + nouns in

URLS● Django app is structured as urls + views +

models + stuff to make it easier● Provides ORM ● Lots of libraries which build off it

Conclusion (2)

● DRF documentation is better and well-structured

● DRF is modular, pluggable, easy to understand● DRF supports web-browsable APIs and oAuth2● DRF has better integration with Swagger

● TastyPie is older, can do anything, but is less Django-style

The VerdictDescription DRF TastyPie

Git Commits

Web-browsable APIs Yes No

Throttling Yes Yes

Caching Yes Yes

Form Validation No Yes

oAuth2 Yes No

Documentation Well-structured, easy to find Good, but not good enough

Ease of use APIs are Django-like, easier to

understand and hence use

APIs hard to understand and

hence use

Swagger Better integration Does integrate, but takes effort

Django Rest Framework vs Django TastyPie

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