Flask-AutoCRUD

Inspired by: sandman2

based on: sqlalchemy-filters Flask-ResponseBuilder Flask-ErrorsHandler

Automatically generate a RESTful APIs for CRUD operation and advanced search on a database. If a list of Model is not provided, all tables are affected, otherwise you can customize:

• resource name
• fields name
• resource url
• allowed methods
• hidden fields

Features

• HATEOAS support
• conditional requests via ETag header
• full range of CRUD operations
• filtering, sorting and pagination
• customizable responses via query string
• custom FETCH method for advanced search
• content negotiation based on Accept header
• export to csv available
• meta resource description
• cli tool to run autocrud on a database

Quickstart

Install flask_autocrud using pip:

$ pip install Flask-AutoCRUD

Example usage

from flask import Flask

from flask_autocrud import AutoCrud
from flask_sqlalchemy import SQLAlchemy


app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite+pysqlite:///db.sqlite3'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
app.config['AUTOCRUD_METADATA_ENABLED'] = True

db = SQLAlchemy(app)
AutoCrud(app, db)

app.run(debug=True)

Go to http://127.0.0.1:5000/resources and see all available resources with its endpoint. NOTE: you must set SQLALCHEMY_DATABASE_URI with your database.

If you want to see an example use with Flask-Admin see in example folder.

Filtering and Sorting

Add filters as query string parameters, they are applied in AND, OR operator not supported.

You can use entity fields as parameter with the following placeholders in the value:

• null value: null
• in operator: list separated by ;
• not operator: ! means: not equal, not null, not in
• comparators: __gt__ (grater), __lt__ (lesser), __gte__ (grater-equal), __lte__ (lesser-equal)
• like operator: % for example: %%test%, %test% or %%test NOTE first % are not used in expression, it only indicated that value must be used with like operator.

Other parameters, note that all starts with _:

• Use _fields parameter to get only the fields listed as value, separated by ;.
• Use _limit and _page parameters for pagination.
• Sorting is implemented with _sort parameter. The value is a list of field separated by ; You can prepend - to reverse order.
• Use _export parameter to export data into csv format with file name passed as value or leave empty for default. You can also use Accept:text/csv header, but it has a different behavior because the transformation is applied at the end of response.
• Use _related in order to fetch data of related resources listed as value separated by ; or leave empty if you want all. Added in 2.2.0 in previous release use _extended with no filters.
• Use _as_table in order to flatten nested dict useful if you want render response as table in combination with response in html format or simply if you do not want nested json (no value required).
• With _no_links links of related data and pages are filtered (no value required).

Example requests:

• /invoice?InvoiceId=(35;344)
• /invoice?Total=__lte__10&_sort=Total
• /invoice?_fields=BillingCountry;Total;InvoiceId&InvoiceId=!355;344&_sort=-InvoiceId
• /invoice?_fields=Total;InvoiceId&BillingPostalCode=!null&BillingCountry=%%ermany
• /invoice?_fields=Total;InvoiceDate;InvoiceId;CustomerId&_page=2&_limit=10
• /invoice?InvoiceDate=(2009-01-01;2009-02-01 00:00:00)
• /track?_related=Album;Genre

Custom method FETCH

FETCH request is like a GET collection resources with a body that represents the filters to apply. It differs from filters in query string because there are used to reduce the response (filters are in AND), here are used to produce a search response, in fact you can request and filter data of combined related resources (like sql JOIN) and use OR operator with a simple syntax.

See: sqlalchemy-filters documentation for filters explanation and more examples.

If you are unable to use FETCH, you can use POST method with header: X-HTTP-Method-Override: FETCH. If you want only headers and not response use header: X-HTTP-Method-Override: HEAD.

The following is an example of body request on /customer:

{
    "fields": [
        "Address",
        "City"
    ],
    "related": {
        "Employee": [
            "FirstName",
            "LastName"
        ],
        "Invoice": ["*"]
    },
    "filters": [
        {
            "model": "Customer",
            "field": "SupportRepId",
            "op": "==",
            "value": 5
        },
        {
            "model": "Invoice",
            "field": "Total",
            "op": ">",
            "value": 6
        }
    ],
    "sorting": [
        {
            "model": "Invoice",
            "field": "Total",
            "direction": "asc"
        },
        {
            "model": "Customer",
            "field": "Address",
            "direction": "desc"
        }
    ]
}

AutoCRUD cli

You can use autocrud as a standalone application configurable via yaml file. Some options could be given via cli see: autocrud --help.

From release 2.2.0 multiple wsgi server can be used, instead in previous release only gunicorn or waitress can be used; in addition cli options are changed.

Configuration file contains 2 principal macro section:

• app: every configuration under it will be passed to Flask config object
• wsgi: every configuration under it will be passed to the chosen wsgi server

For example:

app:
  SQLALCHEMY_DATABASE_URI: sqlite+pysqlite:///examples/db.sqlite3
  SQLALCHEMY_TRACK_MODIFICATIONS: false
wsgi:
  bind: localhost:5000
  workers: 1
  threads: 1

Configuration

1. AUTOCRUD_METADATA_ENABLED: (default: True) enable metadata endpoint for a resource
2. AUTOCRUD_METADATA_URL: (default: '/meta) added at the end of url resource
3. AUTOCRUD_READ_ONLY: (default: False) enable only http GET method
4. AUTOCRUD_BASE_URL: (default: '') prefix url for resources
5. AUTOCRUD_RESOURCES_URL: (default: '/resources') url for all available resources
6. AUTOCRUD_RESOURCES_URL_ENABLED: (default: True) enable route for resources list
7. AUTOCRUD_SUBDOMAIN: (default: None) bind autocrud endpoints to a subdomain
8. AUTOCRUD_MAX_QUERY_LIMIT: (default 1000) max query limit, 0 means no limit
9. AUTOCRUD_FETCH_ENABLED: (default True) enable or disable FETCH method
10. AUTOCRUD_QUERY_STRING_FILTERS_ENABLED: (default True) enable or disable filters in querystring
11. AUTOCRUD_EXPORT_ENABLED: (default True) enable or disable export to csv
12. AUTOCRUD_DATABASE_SCHEMA: (default None) database schema to consider
13. AUTOCRUD_CONDITIONAL_REQUEST_ENABLED: (default True) allow conditional request

TODO

• automatic swagger ui or alternative api docs

Feedback and contributions are welcome.

License MIT