Overview

This article walks you through the steps of a beginner developing a coupon distribution service for the iPhone with a RESTful API and swift. It is a very detour implementation because it was implemented while examining the technical elements one by one.

In the previous Customize TableView freely using Swift's TableViewCell, the app acquires the coupon information managed in the database through the API and displays it in list format. I created it to the point where it is done.

Next, we will modify this API into a RESTful API. In order to change the code drastically when remodeling, we will implement an API that only responds to all coupon information with GET once, and then modify it so that it will respond to the coupon information according to the request.

reference

environment

Mac OS 10.15 VSCode 1.39.2 pipenv 2018.11.26 Python 3.7.4 Django 2.2.6

procedure

Install Django Rest Framework
Incorporate Django Rest Framework
Define Serializer
Modify View.py
Define URL_pattern
Check the operation using the curl command

Install Django Rest Framework

I'm creating a python project (virtual environment) with pipenv, so install the django rest framework there. Enter the pipenv shell and run the install command.

$ pipenv shell  #Enter the shell
$ pipenv install djangorestframework #Installation execution

Terminal being installed ...

If you look inside the Pipfile after the installation is complete, you will see that djangorest framework has been added to[packages].


[[source]]
name = "pypi"
url = "https://pypi.org/simple"
verify_ssl = true

[dev-packages]

[packages]
django = "*"
djangorestframework = "*"

[requires]
python_version = "3.7"

Incorporate the Django Rest Framework

Just add the installed rest_framework to ʻINSTALLED_APPS = { in setting.py` under the project name directory.


INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'coupon',
    'rest_framework', #add to
]

You're ready to use the Django Rest Framework.

Define Serializer

To use Rest Framework, you need a module called Serializer. Create and implement the Serializer file by yourself under the application directory.

I implemented it as follows.

`coupon/serializer.py`



from rest_framework import serializers #Import Django Rest Framework
from .models import Coupon # models.Import py coupon class

class CouponSerializer(serializers.ModelSerializer):
    class Meta:
        model = Coupon #Set the model name to be handled
        fields = '__all__'

In the code above, fields specifies the model fields (here coupon information) you want to respond to. If you want to respond to all items without specifying anything, use '__ all__'.

Modify View.py

Modify views.py for use with the Django Rest Framework.

Import rest_framework viewsets and filters
Import CouponSerializer of serializer defined above
Changed to queryset that responds to all coupon information
If you use rest_framework, it seems that the process of converting data to json format, dumping, and responding with HTTP is done automatically, so delete those unnecessary processes
Call CouponSerializer in serializer.py defined above.

The code looks like this: It's very simple.

`views.py`


from django.shortcuts import render
from .models import Coupon
from rest_framework import viewsets, filters
from .serializer import CouponSerializer


class CouponViewSet(viewsets.ModelViewSet):
    queryset = Coupon.objects.all() #Get all data
    serializer_class = CouponSerializer

Define URL_pattern

Edit ʻami_coupon_api / urls.pyandcoupon / urls.py. As a matter of fact, it seems better to edit from coupon / urls.py`.

The edited contents of coupon / urls.py are as follows.

Import routers for rest_framework
Import CouponViewSet defined in views.py
Define router and associate the URL with the view.py class (CouponViewSet in this case) that is called when the URL is requested to router.register.

`coupon/urls.py`


from django.urls import path
from . import views
from rest_framework import routers
from .views import CouponViewSet

router = routers.DefaultRouter()
router.register(r'coupons', CouponViewSet)

In the above, the 'coupons' part of r'coupons' is added after the request URL.

The edited contents of ʻami_coupon_api / urls.py` are as follows.

Import the url and include of django.conf.urls
Import the router defined in coupon / urls.py as coupon_router
Define URL and callee in urlpatterns
If the URL is ʻadmin / `, set it to go to the django console
In case of ʻapi / `, set to proceed to the object set by router

`ami_coupon_api/urls.py`


from django.contrib import admin
from django.urls import path,include
from django.conf.urls import url, include
from coupon.urls import router as coupon_router

urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^api/', include(coupon_router.urls)),
]

Check the operation using the curl command

Open a new terminal and try GET, POST, PUT requests. How to write a request is as follows. -X is an option to specify HTTP methods (GET, POST, PUT, etc.). Note that GET and POST could be executed without specifying.

$ curl -X [HTTP method] [URL] [Request parameters]

Try GET. Request parameters are not attached.

$ curl -X GET http://127.0.0.1:8000/api/coupons/

This json is returned.

[{"id": 1, "code": "0001", "benefit": "1,000 yen discount from payment", "explanation": "Limited to customers using 5,000 yen or more. Cannot be used with other coupons. "," store ":" All stores "," start ":" 2019-10-01 "," deadline ":" 2019-12-31 "," status ": true}, {" id ": 2," code ":" 0002 "," benefit ":" 10% off payment! "," explanation ":" Cannot be combined with other coupons "," store ":" Yurakucho store "," start ":" 2019-10 -01 "," deadline ":" 2019-12-31 "," status ": true}, {"id ": 3," code ":" 0003 "," benefit ":" [Halloween only] Disguise 30% off when you come to the store "," explanation ":" Only for customers who are disguised as 50% or more of the whole body (judgment is the feeling of the staff). Cannot be used with other coupons "," store ":" Kanda store "," start ":" 2019-10-31 "," deadline ":" 2019-10-31 "," status ": true}, {"id ": 4," code ":" 0004 ", "benefit": "[September only] Moon-viewing dumpling service", "explanation": "Given a moon-viewing dumpling to customers who wish! Can be used with other coupons!", "Store": "All stores" , "start": "2019-09-01", "deadline": "2019-09-30", "status": true}, {"id": 5, "code": "0005", "benefit" : "[Rainy days only] 15% off payment", "explanation": "Available only when coupons are delivered. Cannot be combined with other coupons", "store": "All stores", "start" ":" 2019-10-01 "," deadline ":" 2019-12-31 "," status ": false}, {" id ": 6," code ":" 0006 "," benefit ":" [ Sunday only] Cheers Tequila Service "," explanation ":" We will serve Tequila for the number of people. Can be used with other coupons. "," store ":" Kanda Store "," start ":" 2019-11-03 " , "d eadline ":" 2019-12-01 "," status ": true}]

Try POST.

curl -X POST http://127.0.0.1:8000/api/coupons/ -d "code=0007" -d "benefit=From checkout 19%pull" -d "explanation=Limited to December 29th-December 31st." -d "store=Kanda store" -d "start=2019-12-29" -d "deadline=2019-12-31" -d "status=true"

If it goes well, the POSTed data will be returned in json.

{"id": 7, "code": "0007", "benefit": "19% discount from checkout", "explanation": "December 29-31 only.", "Store": "Kanda store", "start": "2019-12-29", "deadline": "2019-12-31", "status": true}

Try PUT. At the time of PUT, it is necessary to specify the HTTP method. More importantly, you need to ** specify the table's primary key in the URL **. In the coupon model, "id" is the primary key, so specify the id of the data you want to overwrite (7 in this case) at the end of the URL.

curl -X PUT http://127.0.0.1:8000/api/coupons/7/ -d "code=0007" -d "benefit=From checkout 19%pull" -d "explanation=Limited to December 29th-December 31st. Cannot be used with other coupons" -d "store=Kanda store" -d "start=2019-12-29" -d "deadline=2019-12-31" -d "status=true"

If all goes well, the overwritten data will be returned in json.

{"id": 7, "code": "0007", "benefit": "19% discount from checkout", "explanation": "December 29-31 only. Combined with other coupons Impossible "," store ":" Kanda store "," start ":" 2019-12-29 "," deadline ":" 2019-12-31 "," status ": true}

Try DELETE. Execute the POST request again to create a coupon with id = 8. Make sure you've added a coupon with id = 8 on your GET request or on the Django server console.

Next, delete the coupon with id = 8 in the request below. As with PUT, you need to specify the primary key of the coupon to be deleted.

curl -X DELETE http://127.0.0.1:8000/api/coupons/8/

If all goes well, nothing will be returned. Make sure the coupon with id = 8 has been deleted in your GET request or in the Django server console.

So far, you have a basic Rest Framework. From here, Add filters and authentication functions to get only coupons that meet the conditions.

Create RESTful APIs with Django Rest Framework