支持列表级和项目级CRUD操作

作者：张约翰

这是一个如何实现简单的项目列表的示例，该列表同时支持列表级和项目级CRUD操作。

具体来说，应该可以使用单个GET获取整个列表（包括所有项目），也可以使用单个POST附加项目（而不是修补列表）。

解决方案是通过数据库事件挂钩插入嵌入的子文档 (items ）在父列表返回到客户端之前将其删除，并在父列表被删除时删除子项。虽然这会导致两个数据库查询，但它仍然有效。

main.py

from eve import Eve
from bson.objectid import ObjectId

app = Eve()
mongo = app.data.driver


def after_fetching_lists(response):
    list_id = response['_id']
    f = {'list_id': ObjectId(list_id)}
    response['items'] = list(mongo.db.items.find(f))


def after_deleting_lists(item):
    list_id = item['_id']
    f = {'list_id': ObjectId(list_id)}
    mongo.db.items.delete_many(f)

app.on_fetched_item_lists += after_fetching_lists
app.on_deleted_item_lists += after_deleting_lists

app.run()

settings.py

import os

DEBUG = True

MONGO_HOST = os.environ.get('MONGO_HOST', 'localhost')
MONGO_PORT = os.environ.get('MONGO_PORT', 27017)
MONGO_USERNAME = os.environ.get('MONGO_USERNAME', 'user')
MONGO_PASSWORD = os.environ.get('MONGO_PASSWORD', 'user')
MONGO_DBNAME = os.environ.get('MONGO_DBNAME', 'listtest')

RESOURCE_METHODS = ['GET', 'POST', 'DELETE']
ITEM_METHODS = ['GET', 'PUT', 'PATCH', 'DELETE']

DOMAIN = {
    'lists': {
        'schema': {
            'title': {
                'type': 'string'
            }
        }
    },
    'items': {
        'url': 'lists/<regex("[a-f0-9]{24}"):list_id>/items',
        'schema': {
            'list_id': {
                'type': 'objectid',
                'data_relation': {
                    'resource': 'lists',
                    'field': '_id'
                }
            },
            'name': {
                'type': 'string',
                'required': True
            }
        }
    }
}

使用

$ curl -i -X POST http://127.0.0.1:5000/lists -d title="My List"
HTTP/1.0 201 CREATED

{
    "_id": "58960f83a663e2e6746dfa6a",
    :
}

$ curl -i -X POST http://127.0.0.1:5000/lists/58960f83a663e2e6746dfa6a/items -d 'name=Alice'
HTTP/1.0 201 CREATED

$ curl -i -X POST http://127.0.0.1:5000/lists/58960f83a663e2e6746dfa6a/items -d 'name=Bob'
HTTP/1.0 201 CREATED

$ curl -i -X GET http://127.0.0.1:5000/lists/58960f83a663e2e6746dfa6a
HTTP/1.0 200 OK

{
    "_created": "Sat, 04 Feb 2017 17:29:39 GMT",
    "_etag": "01799f6be25a044ab95cfeb2dc0f834d11b796d8",
    "_id": "58960f83a663e2e6746dfa6a",
    "_updated": "Sat, 04 Feb 2017 17:29:39 GMT",
    "items": [
        {
            "_created": "Sat, 04 Feb 2017 17:30:06 GMT",
            "_etag": "72ad9248ad5bf45c7bfe3e03a1b9bc384d94572f",
            "_id": "58960f9ea663e2e6746dfa6b",
            "_updated": "Sat, 04 Feb 2017 17:30:06 GMT",
            "list_id": "58960f83a663e2e6746dfa6a",
            "name": "Alice",
            "quantity": 1
        },
        {
            "_created": "Sat, 04 Feb 2017 17:30:13 GMT",
            "_etag": "447f51b057fb5e0a70472e96ff883c64b5e2e308",
            "_id": "58960fa5a663e2e6746dfa6c",
            "_updated": "Sat, 04 Feb 2017 17:30:13 GMT",
            "list_id": "58960f83a663e2e6746dfa6a",
            "name": "Bob",
            "quantity": 1
        }
    ],
    "title": "My List"
}

$ curl -i -X DELETE http://127.0.0.1:5000/lists/58960f83a663e2e6746dfa6a/items/58960f9ea663e2e6746dfa6b -H "If-Match: 72ad9248ad5bf45c7bfe3e03a1b9bc384d94572f"
HTTP/1.0 204 NO CONTENT

$ curl -i -X GET http://127.0.0.1:5000/lists/58960f83a663e2e6746dfa6a
HTTP/1.0 200 OK

{
    "_created": "Sat, 04 Feb 2017 17:29:39 GMT",
    "_etag": "01799f6be25a044ab95cfeb2dc0f834d11b796d8",
    "_id": "58960f83a663e2e6746dfa6a",
    "_updated": "Sat, 04 Feb 2017 17:29:39 GMT",
    "items": [
        {
            "_created": "Sat, 04 Feb 2017 17:30:13 GMT",
            "_etag": "447f51b057fb5e0a70472e96ff883c64b5e2e308",
            "_id": "58960fa5a663e2e6746dfa6c",
            "_updated": "Sat, 04 Feb 2017 17:30:13 GMT",
            "list_id": "58960f83a663e2e6746dfa6a",
            "name": "Bob",
            "quantity": 1
        }
    ],
    "title": "My List"
}