A RESTAPI

Since version 19.5.10 pyDAL includes a restful API called RestAPI. It is inspired by GraphQL and while it’s not quite the same due to it being less powerful, it is in the spirit of py4web where it’s more practical and easier to use. Like GraphQL RestAPI allows a client to query for information using the GET method and allows to specify some details about the format of the response (which references to follow, and how to denormalize the data). Unlike GraphQL it allows the server to specify a policy and restrict which queries are allowed and which one are not. They can be evaluated dynamically per request based on the user and the state of the server. As the name implied RestAPI allows all standard methods: GET, POST, PUT, and DELETE. Each of them can be enabled or disabled based on the policy, for individual tables and individual fields.

Nota

Specifications might be subject to changes since this is a new feature.

Nos exemplos abaixo assumimos um aplicativo chamado “super-heróis” e o seguinte modelo:

db.define_table(
    'person',
    Field('name'),
    Field('job'))

db.define_table(
    'superhero',
    Field('name'),
    Field('real_identity', 'reference person'))

db.define_table(
    'superpower',
    Field('description'))

db.define_table(
    'tag',
    Field('superhero', 'reference superhero'),
    Field('superpower', 'reference superpower'),
    Field('strength', 'integer'))

We also assume the following controller:

from py4web import action, request
from .common import db
from pydal.restapi import RestAPI, Policy

policy = Policy()
policy.set('superhero', 'GET', authorize=True, allowed_patterns=['*'])
policy.set('*', 'GET', authorize=True, allowed_patterns=['*'])

# for security reasons we disabled here all methods but GET at the policy level, to enable any of them just set authorize = True
policy.set('*', 'PUT', authorize=False)
policy.set('*', 'POST', authorize=False)
policy.set('*', 'DELETE', authorize=False)

@action('api/<tablename>/', method = ['GET', 'POST'])
@action('api/<tablename>/<rec_id>', method = ['GET', 'PUT', 'DELETE'])
@action.uses(db)
def api(tablename, rec_id=None):
    return RestAPI(db, policy)(request.method,
                               tablename,
                               rec_id,
                               request.GET,
                               request.POST
                               )

A política é por tabela (ou * para todas as tabelas e por método. Autorizar pode ser verdade (permitir), False (negar) ou uma função com a assinatura (método, tablename, record_id, get_vars, post_vars) que retorna Verdadeiro / Falso . para a política GET pode especificar uma lista de padrões de consulta permitidos (* para todos). um padrão de consulta será comparado com as chaves na cadeia de consulta.

A acção acima referida é exposto como:

/superheroes/api/{tablename}
/superheroes/api/{tablename}/{rec_id}

Nota

Keep in mind that request.POST only contains the form data that is posted using a regular HTML-form or JavaScript FormData object. If you post just plain object (e.g. axios.post('path/to/api', {field:'some'})) you should pass request.json instead of request.POST, since the latter will contain just raw request-body which is string, not JSON. See Bottle documentation about request object.

RestAPI GET

A consulta geral tem a forma `` {} algo .eq = value`` onde `` eq = `` significa “igual”, `` gt = `` significa “maior que”, etc. A expressão pode ser prefixado por `` not.``.

{something} can be the name of a field in the table being queried as in:

** Todos os super-heróis chamado de “Superman” **

/superheroes/api/superhero?name.eq=Superman

It can be the name of a field of a table referred by the table being queried as in:

** Todos os super-heróis com a identidade real “Clark Kent” **

/superheroes/api/superhero?real_identity.name.eq=Clark Kent

It can be the name of a field of a table that refers to the table being queried as in:

** Todos os super-heróis com qualquer superpotência tag com força> 90 **

/superheroes/api/superhero?superhero.tag.strength.gt=90

(here tag is the name of the link table, the preceding superhero is the name of the field that refers to the selected table and strength is the name of the field used to filter)

Ele também pode ser um campo da tabela referenciada por uma tabela de muitos-para-muitos ligado como em:

** Todos os super-heróis com o poder de vôo **

/superheroes/api/superhero?superhero.tag.superpower.description.eq=Flight

A chave para entender a sintaxe acima é para quebrá-lo da seguinte forma:

superhero?superhero.tag.superpower.description.eq=Flight

e lê-lo como:

selecionar registros da tabela ** super-herói ** referido pelo campo ** super-herói ** da tabela ** tag ** quando a superpotência ** ** campo dos ditos pontos de mesa para um recorde com a descrição ** ** ** ** eq ual para “Flight”.

A consulta permite modificadores adicionais, por exemplo

@offset=10
@limit=10
@order=name
@model=true
@lookup=real_identity

The first 3 are obvious. @model returns a JSON description of database model. @lookup denormalizes the linked field.

Aqui estão alguns exemplos práticos:

URL:

/superheroes/api/superhero

RESULTADO:

{
    "count": 3,
    "status": "success",
    "code": 200,
    "items": [
        {
            "real_identity": 1,
            "name": "Superman",
            "id": 1
        },
        {
            "real_identity": 2,
            "name": "Spiderman",
            "id": 2
        },
        {
            "real_identity": 3,
            "name": "Batman",
            "id": 3
        }
    ],
    "timestamp": "2019-05-19T05:38:00.132635",
    "api_version": "0.1"
}

URL:

/superheroes/api/superhero?@model=true

RESULTADO:

{
    "count": 3,
    "status": "success",
    "code": 200,
    "items": [
        {
            "real_identity": 1,
            "name": "Superman",
            "id": 1
        },
        {
            "real_identity": 2,
            "name": "Spiderman",
            "id": 2
        },
        {
            "real_identity": 3,
            "name": "Batman",
            "id": 3
        }
    ],
    "timestamp": "2021-01-04T07:03:38.466030",
    "model": [
        {
            "regex": "[1-9]\\d*",
            "name": "id",
            "default": null,
            "required": false,
            "label": "Id",
            "post_writable": true,
            "referenced_by": [
                "tag.superhero"
            ],
            "unique": false,
            "type": "id",
            "options": null,
            "put_writable": true
        },
        {
            "regex": null,
            "name": "name",
            "default": null,
            "required": false,
            "label": "Name",
            "post_writable": true,
            "unique": false,
            "type": "string",
            "options": null,
            "put_writable": true
        },
        {
            "regex": null,
            "name": "real_identity",
            "default": null,
            "required": false,
            "label": "Real Identity",
            "post_writable": true,
            "references": "person",
            "unique": false,
            "type": "reference",
            "options": null,
            "put_writable": true
        }
    ],
    "api_version": "0.1"
}

URL:

/superheroes/api/superhero?@lookup=real_identity

RESULTADO:

{
    "count": 3,
    "status": "success",
    "code": 200,
    "items": [
        {
            "real_identity": {
                "name": "Clark Kent",
                "job": "Journalist",
                "id": 1
            },
            "name": "Superman",
            "id": 1
        },
        {
            "real_identity": {
                "name": "Peter Park",
                "job": "Photographer",
                "id": 2
            },
            "name": "Spiderman",
            "id": 2
        },
        {
            "real_identity": {
                "name": "Bruce Wayne",
                "job": "CEO",
                "id": 3
            },
            "name": "Batman",
            "id": 3
        }
    ],
    "timestamp": "2019-05-19T05:38:00.178974",
    "api_version": "0.1"
}

URL:

/superheroes/api/superhero?@lookup=identity:real_identity

(Desnormalizar o real_identity e renomeá-lo de identidade)

RESULTADO:

{
    "count": 3,
    "status": "success",
    "code": 200,
    "items": [
        {
            "real_identity": 1,
            "name": "Superman",
            "id": 1,
            "identity": {
                "name": "Clark Kent",
                "job": "Journalist",
                "id": 1
            }
        },
        {
            "real_identity": 2,
            "name": "Spiderman",
            "id": 2,
            "identity": {
                "name": "Peter Park",
                "job": "Photographer",
                "id": 2
            }
        },
        {
            "real_identity": 3,
            "name": "Batman",
            "id": 3,
            "identity": {
                "name": "Bruce Wayne",
                "job": "CEO",
                "id": 3
            }
        }
    ],
    "timestamp": "2019-05-19T05:38:00.123218",
    "api_version": "0.1"
}

URL:

/superheroes/api/superhero?@lookup=identity!:real_identity[name,job]

(Desnormalizar o real_identity [mas apenas campos nome e trabalho], recolher a com o prefixo de identidade)

RESULTADO:

{
    "count": 3,
    "status": "success",
    "code": 200,
    "items": [
        {
            "name": "Superman",
            "identity.job": "Journalist",
            "identity.name": "Clark Kent",
            "id": 1
        },
        {
            "name": "Spiderman",
            "identity.job": "Photographer",
            "identity.name": "Peter Park",
            "id": 2
        },
        {
            "name": "Batman",
            "identity.job": "CEO",
            "identity.name": "Bruce Wayne",
            "id": 3
        }
    ],
    "timestamp": "2021-01-04T07:03:38.559918",
    "api_version": "0.1"
}

URL:

/superheroes/api/superhero?@lookup=superhero.tag

RESULTADO:

{
    "count": 3,
    "status": "success",
    "code": 200,
    "items": [
        {
            "real_identity": 1,
            "name": "Superman",
            "superhero.tag": [
                {
                    "strength": 100,
                    "superhero": 1,
                    "id": 1,
                    "superpower": 1
                },
                {
                    "strength": 100,
                    "superhero": 1,
                    "id": 2,
                    "superpower": 2
                },
                {
                    "strength": 100,
                    "superhero": 1,
                    "id": 3,
                    "superpower": 3
                },
                {
                    "strength": 100,
                    "superhero": 1,
                    "id": 4,
                    "superpower": 4
                }
            ],
            "id": 1
        },
        {
            "real_identity": 2,
            "name": "Spiderman",
            "superhero.tag": [
                {
                    "strength": 50,
                    "superhero": 2,
                    "id": 5,
                    "superpower": 2
                },
                {
                    "strength": 75,
                    "superhero": 2,
                    "id": 6,
                    "superpower": 3
                },
                {
                    "strength": 10,
                    "superhero": 2,
                    "id": 7,
                    "superpower": 4
                }
            ],
            "id": 2
        },
        {
            "real_identity": 3,
            "name": "Batman",
            "superhero.tag": [
                {
                    "strength": 80,
                    "superhero": 3,
                    "id": 8,
                    "superpower": 2
                },
                {
                    "strength": 20,
                    "superhero": 3,
                    "id": 9,
                    "superpower": 3
                },
                {
                    "strength": 70,
                    "superhero": 3,
                    "id": 10,
                    "superpower": 4
                }
            ],
            "id": 3
        }
    ],
    "timestamp": "2019-05-19T05:38:00.201988",
    "api_version": "0.1"
}

URL:

/superheroes/api/superhero?@lookup=superhero.tag.superpower

RESULTADO:

{
    "count": 3,
    "status": "success",
    "code": 200,
    "items": [
        {
            "real_identity": 1,
            "name": "Superman",
            "superhero.tag.superpower": [
                {
                    "strength": 100,
                    "superhero": 1,
                    "id": 1,
                    "superpower": {
                        "id": 1,
                        "description": "Flight"
                    }
                },
                {
                    "strength": 100,
                    "superhero": 1,
                    "id": 2,
                    "superpower": {
                        "id": 2,
                        "description": "Strength"
                    }
                },
                {
                    "strength": 100,
                    "superhero": 1,
                    "id": 3,
                    "superpower": {
                        "id": 3,
                        "description": "Speed"
                    }
                },
                {
                    "strength": 100,
                    "superhero": 1,
                    "id": 4,
                    "superpower": {
                        "id": 4,
                        "description": "Durability"
                    }
                }
            ],
            "id": 1
        },
        {
            "real_identity": 2,
            "name": "Spiderman",
            "superhero.tag.superpower": [
                {
                    "strength": 50,
                    "superhero": 2,
                    "id": 5,
                    "superpower": {
                        "id": 2,
                        "description": "Strength"
                    }
                },
                {
                    "strength": 75,
                    "superhero": 2,
                    "id": 6,
                    "superpower": {
                        "id": 3,
                        "description": "Speed"
                    }
                },
                {
                    "strength": 10,
                    "superhero": 2,
                    "id": 7,
                    "superpower": {
                        "id": 4,
                        "description": "Durability"
                    }
                }
            ],
            "id": 2
        },
        {
            "real_identity": 3,
            "name": "Batman",
            "superhero.tag.superpower": [
                {
                    "strength": 80,
                    "superhero": 3,
                    "id": 8,
                    "superpower": {
                        "id": 2,
                        "description": "Strength"
                    }
                },
                {
                    "strength": 20,
                    "superhero": 3,
                    "id": 9,
                    "superpower": {
                        "id": 3,
                        "description": "Speed"
                    }
                },
                {
                    "strength": 70,
                    "superhero": 3,
                    "id": 10,
                    "superpower": {
                        "id": 4,
                        "description": "Durability"
                    }
                }
            ],
            "id": 3
        }
    ],
    "timestamp": "2019-05-19T05:38:00.322494",
    "api_version": "0.1"
}

URL (it’s a single line, split for readability):

/superheroes/api/superhero?
@lookup=powers:superhero.tag[strength].superpower[description]

RESULTADO:

{
    "count": 3,
    "status": "success",
    "code": 200,
    "items": [
        {
            "real_identity": 1,
            "name": "Superman",
            "powers": [
                {
                    "strength": 100,
                    "superpower": {
                        "description": "Flight"
                    }
                },
                {
                    "strength": 100,
                    "superpower": {
                        "description": "Strength"
                    }
                },
                {
                    "strength": 100,
                    "superpower": {
                        "description": "Speed"
                    }
                },
                {
                    "strength": 100,
                    "superpower": {
                        "description": "Durability"
                    }
                }
            ],
            "id": 1
        },
        {
            "real_identity": 2,
            "name": "Spiderman",
            "powers": [
                {
                    "strength": 50,
                    "superpower": {
                        "description": "Strength"
                    }
                },
                {
                    "strength": 75,
                    "superpower": {
                        "description": "Speed"
                    }
                },
                {
                    "strength": 10,
                    "superpower": {
                        "description": "Durability"
                    }
                }
            ],
            "id": 2
        },
        {
            "real_identity": 3,
            "name": "Batman",
            "powers": [
                {
                    "strength": 80,
                    "superpower": {
                        "description": "Strength"
                    }
                },
                {
                    "strength": 20,
                    "superpower": {
                        "description": "Speed"
                    }
                },
                {
                    "strength": 70,
                    "superpower": {
                        "description": "Durability"
                    }
                }
            ],
            "id": 3
        }
    ],
    "timestamp": "2019-05-19T05:38:00.309903",
    "api_version": "0.1"
}

URL (it’s a single line, split for readability):

/superheroes/api/superhero?
@lookup=powers!:superhero.tag[strength].superpower[description]

RESULTADO:

{
    "count": 3,
    "status": "success",
    "code": 200,
    "items": [
        {
            "real_identity": 1,
            "name": "Superman",
            "powers": [
                {
                    "strength": 100,
                    "description": "Flight"
                },
                {
                    "strength": 100,
                    "description": "Strength"
                },
                {
                    "strength": 100,
                    "description": "Speed"
                },
                {
                    "strength": 100,
                    "description": "Durability"
                }
            ],
            "id": 1
        },
        {
            "real_identity": 2,
            "name": "Spiderman",
            "powers": [
                {
                    "strength": 50,
                    "description": "Strength"
                },
                {
                    "strength": 75,
                    "description": "Speed"
                },
                {
                    "strength": 10,
                    "description": "Durability"
                }
            ],
            "id": 2
        },
        {
            "real_identity": 3,
            "name": "Batman",
            "powers": [
                {
                    "strength": 80,
                    "description": "Strength"
                },
                {
                    "strength": 20,
                    "description": "Speed"
                },
                {
                    "strength": 70,
                    "description": "Durability"
                }
            ],
            "id": 3
        }
    ],
    "timestamp": "2019-05-19T05:38:00.355181",
    "api_version": "0.1"
}

URL (it’s a single line, split for readability):

/superheroes/api/superhero?
@lookup=powers!:superhero.tag[strength].superpower[description],
identity!:real_identity[name]

RESULTADO:

{
    "count": 3,
    "status": "success",
    "code": 200,
    "items": [
        {
            "name": "Superman",
            "identity.name": "Clark Kent",
            "powers": [
                {
                    "strength": 100,
                    "description": "Flight"
                },
                {
                    "strength": 100,
                    "description": "Strength"
                },
                {
                    "strength": 100,
                    "description": "Speed"
                },
                {
                    "strength": 100,
                    "description": "Durability"
                }
            ],
            "id": 1
        },
        {
            "name": "Spiderman",
            "identity.name": "Peter Park",
            "powers": [
                {
                    "strength": 50,
                    "description": "Strength"
                },
                {
                    "strength": 75,
                    "description": "Speed"
                },
                {
                    "strength": 10,
                    "description": "Durability"
                }
            ],
            "id": 2
        },
        {
            "name": "Batman",
            "identity.name": "Bruce Wayne",
            "powers": [
                {
                    "strength": 80,
                    "description": "Strength"
                },
                {
                    "strength": 20,
                    "description": "Speed"
                },
                {
                    "strength": 70,
                    "description": "Durability"
                }
            ],
            "id": 3
        }
    ],
    "timestamp": "2021-01-04T07:31:34.974953",
    "api_version": "0.1"
}

URL:

/superheroes/api/superhero?name.eq=Superman

RESULTADO:

{
    "count": 1,
    "status": "success",
    "code": 200,
    "items": [
        {
            "real_identity": 1,
            "name": "Superman",
            "id": 1
        }
    ],
    "timestamp": "2019-05-19T05:38:00.405515",
    "api_version": "0.1"
}

URL:

/superheroes/api/superhero?real_identity.name.eq=Clark Kent

RESULTADO:

{
    "count": 1,
    "status": "success",
    "code": 200,
    "items": [
        {
            "real_identity": 1,
            "name": "Superman",
            "id": 1
        }
    ],
    "timestamp": "2019-05-19T05:38:00.366288",
    "api_version": "0.1"
}

URL:

/superheroes/api/superhero?not.real_identity.name.eq=Clark Kent

RESULTADO:

{
    "count": 2,
    "status": "success",
    "code": 200,
    "items": [
        {
            "real_identity": 2,
            "name": "Spiderman",
            "id": 2
        },
        {
            "real_identity": 3,
            "name": "Batman",
            "id": 3
        }
    ],
    "timestamp": "2019-05-19T05:38:00.451907",
    "api_version": "0.1"
}

URL:

/superheroes/api/superhero?superhero.tag.superpower.description=Flight

RESULTADO:

{
    "count": 1,
    "status": "success",
    "code": 200,
    "items": [
        {
            "real_identity": 1,
            "name": "Superman",
            "id": 1
        }
    ],
    "timestamp": "2019-05-19T05:38:00.453020",
    "api_version": "0.1"
}

All RestAPI response have the fields:

api_version

RestAPI version.

timestamp

Datetime in ISO 8601 format.

status

RestAPI status (i.e. «success» or «error»).

code

HTTP status.

Other optional fields are:

count

Total matching (not total returned), for GET.

items

In response to a GET.

errors

Usually a validation error.

models

Usually if status != «success».

message

For error details.