Getting started

Create Project & Application

mkdir tutorial
cd tutorial
django-admin startproject tutorial .
python manage.py startapp snippets

Add our snippets application and rest_framework at tutorial/settings.py

INSTALLED_APPS = [
    ...
    'rest_framework',
    'snippets.apps.SnippetsConfig',
]

Creating a model to work with

コードセグメントを保存するSnippetモデル(=ORM object)を作成します.

# /snippets/models.py
from django.db import models
from pygments.lexers import get_all_lexers
from pygments.styles import get_all_styles

LEXERS = [item for item in get_all_lexers() if item[1]]
LANGUAGE_CHOICES = sorted([(item[1][0], item[0]) for item in LEXERS])
STYLE_CHOICES = sorted([(item, item) for item in get_all_styles()])


class Snippet(models.Model):
    created = models.DateTimeField(auto_now_add=True)
    title = models.CharField(max_length=100, blank=True, default='')
    code = models.TextField()
    linenos = models.BooleanField(default=False)
    language = models.CharField(choices=LANGUAGE_CHOICES, default='python', max_length=100)
    style = models.CharField(choices=STYLE_CHOICES, default='friendly', max_length=100)

    class Meta:
        ordering = ['created']

migrateコマンドでDBにSnippetテーブルを作成する

❯ python manage.py makemigrations snippets
❯ python manage.py migrate
Operations to perform:
  Apply all migrations: admin, auth, contenttypes, sessions, snippets
Running migrations:
  Applying contenttypes.0001_initial... OK
  Applying auth.0001_initial... OK
  Applying admin.0001_initial... OK
  Applying admin.0002_logentry_remove_auto_add... OK
  Applying admin.0003_logentry_add_action_flag_choices... OK
  Applying contenttypes.0002_remove_content_type_name... OK
  Applying auth.0002_alter_permission_name_max_length... OK
  Applying auth.0003_alter_user_email_max_length... OK
  Applying auth.0004_alter_user_username_opts... OK
  Applying auth.0005_alter_user_last_login_null... OK
  Applying auth.0006_require_contenttypes_0002... OK
  Applying auth.0007_alter_validators_add_error_messages... OK
  Applying auth.0008_alter_user_username_max_length... OK
  Applying auth.0009_alter_user_last_name_max_length... OK
  Applying auth.0010_alter_group_name_max_length... OK
  Applying auth.0011_update_proxy_permissions... OK
  Applying auth.0012_alter_user_first_name_max_length... OK
  Applying sessions.0001_initial... OK
  Applying snippets.0001_initial... OK

生成されたSnipetオブジェクトをシーケンス化/逆シーケンス化するには、シーケンス化器を設定する必要があります.rest_framework.serializers.Serializerを使用してモデルにフィールドを定義するように、serializerフィールド(Creating a Serializer class)を定義できます.ただし、定義したモデルはModelSerializerを使用して再使用できます.

# /snippets/serializers.py
class SnippetSerializer(serializers.ModelSerializer):
    class Meta:
        model = Snippet
        fields = ['id', 'title', 'code', 'linenos', 'language', 'style']

ModelSerializerは、Snippetモデルの「id」、「title」、「code」、「linenos」、「language」および「style」フィールドをインポートし、reprで検証できるシーケンス化フィールドを自動的に設定します.

# Get into shell `python manage.py shell`
from snippets.serializers import SnippetSerializer
serializer = SnippetSerializer()
print(repr(serializer))
# SnippetSerializer():
#    id = IntegerField(label='ID', read_only=True)
#    title = CharField(allow_blank=True, max_length=100, required=False)
#    code = CharField(style={'base_template': 'textarea.html'})
#    linenos = BooleanField(required=False)
#    language = ChoiceField(choices=[('Clipper', 'FoxPro'), ('Cucumber', 'Gherkin'), ('RobotFramework', 'RobotFramework'), ('abap', 'ABAP'), ('ada', 'Ada')...
#    style = ChoiceField(choices=[('autumn', 'autumn'), ('borland', 'borland'), ('bw', 'bw'), ('colorful', 'colorful')...

ModelSerializerを整理する作業は以下の通りです.

モデル内のフィールドをインポートし、serializerフィールドを自動的に設定します.

create()、update()Methodsの基本実装

Writing regular Django views using our Serializer

Serializerを使用するAPIエンドポイントを作成します.

snippets/views.py:要求を処理するためのトラフィックコードを実装するビュー

from django.http import HttpResponse, JsonResponse
from django.views.decorators.csrf import csrf_exempt
from rest_framework.parsers import JSONParser
from snippets.models import Snippet
from snippets.serializers import SnippetSerializer


@csrf_exempt
def snippet_list(request):
    """
    List all code snippets, or create a new snippet.
    """
    if request.method == 'GET':
        snippets = Snippet.objects.all()
        serializer = SnippetSerializer(snippets, many=True)
        return JsonResponse(serializer.data, safe=False)

    elif request.method == 'POST':
        data = JSONParser().parse(request)
        serializer = SnippetSerializer(data=data)
        if serializer.is_valid():
            serializer.save()
            return JsonResponse(serializer.data, status=201)
        return JsonResponse(serializer.errors, status=400)


@csrf_exempt
def snippet_detail(request, pk):
    """
    Retrieve, update or delete a code snippet.
    """
    try:
        snippet = Snippet.objects.get(pk=pk)
    except Snippet.DoesNotExist:
        return HttpResponse(status=404)

    if request.method == 'GET':
        serializer = SnippetSerializer(snippet)
        return JsonResponse(serializer.data)

    elif request.method == 'PUT':
        data = JSONParser().parse(request)
        serializer = SnippetSerializer(snippet, data=data)
        if serializer.is_valid():
            serializer.save()
            return JsonResponse(serializer.data)
        return JsonResponse(serializer.errors, status=400)

    elif request.method == 'DELETE':
        snippet.delete()
        return HttpResponse(status=204)

snippets/urls.py - endpoint : view mapping

from django.urls import path
from snippets import views

urlpatterns = [
    path('snippets/', views.snippet_list),
    path('snippets/<int:pk>/', views.snippet_detail),
]

tutorial/urls.py - register endpoints

from django.urls import path, include

urlpatterns = [
    path('', include('snippets.urls')),
]

Testing our first attempt at a Web API

python manage.py runserver

Validating models...

0 errors found
Django version 1.11, using settings 'tutorial.settings'
Development server is running at http://127.0.0.1:8000/
Quit the server with CONTROL-C.

❯ curl -X POST http://localhost:8000/snippets/ -d '{"code": "print"}'
{"id": 1, "title": "", "code": "print", "linenos": false, "language": "python", "style": "friendly"}%
❯ curl -X POST http://localhost:8000/snippets/ -d '{"code": "foo = \"bar\""}'
{"id": 2, "title": "", "code": "foo = \"bar\"", "linenos": false, "language": "python", "style": "friendly"}%

❯ curl http://localhost:8000/snippets/
[{"id": 1, "title": "", "code": "print", "linenos": false, "language": "python", "style": "friendly"}, {"id": 2, "title": "", "code": "foo = \"bar\"", "linenos": false, "language": "python", "style": "friendly"}]%
❯ curl http://localhost:8000/snippets/1/
{"id": 1, "title": "", "code": "print", "linenos": false, "language": "python", "style": "friendly"}%
❯ curl http://localhost:8000/snippets/2/
{"id": 2, "title": "", "code": "foo = \"bar\"", "linenos": false, "language": "python", "style": "friendly"}%

Refs

Code repo : Github
Tutorial 1: Serialization