subgrounds.transform module

Subgrounds request/response transformation layers module

This module defines interfaces (abstract classes) for transformation layers. Transformation layers, or transforms, can be applied to entire requests (see RequestTransform) or on a per-document basis (see DocumentTransform). Classes that implement either type of transforms can be used to perform modifications to queries and their response data.

For example, the TypeTransform class is used to tranform the response data of BigInt and BigDecimal fields (which are represented as strings in the response JSON data) to python int and float respectively (see the actual transforms in DEFAULT_SUBGRAPH_TRANSFORMS).

Transforms are also used to apply SyntheticField to queries and the response data (see LocalSyntheticField transform class). Each SyntheticField defined on a subgraph creates a new transformation layer by instantiating a new LocalSyntheticField object.

subgrounds.transform.select_data(select, data)

class subgrounds.transform.RequestTransform

Bases: abc.ABC

Abstract class representing a transformation layer to be applied to entire DataRequest objects.

abstract transform_request(req)

Method that will be applied to all DataRequest objects that pass through the transformation layer.

Parameters: req (DataRequest) -- The initial request object
Returns: The transformed request object
Return type: DataRequest

abstract transform_response(req, data)

Method to be applied to all response data data of requests that pass through the transformation layer.

req is the initial DataRequest object that yielded the resulting JSON data data.

Parameters

req (DataRequest) -- Initial data request object
data (list[dict[str, Any]]) -- JSON data blob resulting from the execution of the transformed data request.

Returns

The transformed response data

Return type

list[dict[str, Any]]

class subgrounds.transform.DocumentTransform

Bases: abc.ABC

Abstract class representing a transformation layer to be applied to Document objects.

abstract transform_document(doc)

Method that will be applied to all Document objects that pass through the transformation layer.

Parameters: doc (Document) -- The initial document
Returns: The transformed document
Return type: Document

abstract transform_response(req, data)

Method to be applied to all response data data of requests that pass through the transformation layer.

doc is the initial Document object that yielded the resulting JSON data data.

Parameters

doc (Document) -- Initial document
data (dict[str, Any]) -- JSON data blob resulting from the execution of the transformed document.

Returns

The transformed response data

Return type

dict[str, Any]

class subgrounds.transform.TypeTransform(type_, f)

Bases: subgrounds.transform.DocumentTransform

Transform to be applied to scalar fields on a per-type basis.

type_

Type indicating which scalar values (i.e.: values of that type) should be transformed using the function f

Type: TypeRef.T

f

Function to be applied to scalar values of type type_ in the response data.

Type: Callable[[Any], Any]

type_: subgrounds.schema.TypeRef.T

f: Callable[[Any], Any]

transform_document(doc)

Method that will be applied to all Document objects that pass through the transformation layer.

Parameters: doc (Document) -- The initial document
Returns: The transformed document
Return type: Document

transform_response(doc, data)

Method to be applied to all response data data of requests that pass through the transformation layer.

doc is the initial Document object that yielded the resulting JSON data data.

Parameters

doc (Document) -- Initial document
data (dict[str, Any]) -- JSON data blob resulting from the execution of the transformed document.

Returns

The transformed response data

Return type

dict[str, Any]

class subgrounds.transform.LocalSyntheticField(subgraph, fmeta, type_, f, default, args)

Bases: subgrounds.transform.DocumentTransform

Transform used to implement synthetic fields on GraphQL objects that only depend on values accessible from that object.

transform_document() replaces the field fmeta by the argument fields selections args if the synthetic field fmeta is present in the document.

transform_response() applied f to the fields corresponding to the argument selections args and places the result in the response.

subgraph

The subgraph to which the synthetic field's object belongs.

Type: Subgraph

fmeta

The synthetic field

Type: TypeMeta.FieldMeta

type_

The object for which the synthetic field is defined

Type: TypeMeta.ObjectMeta | TypeMeta.InterfaceMeta

f

The function to be applied to the argument fields

Type: Callable

default

The default value of the synthetic field used in case of exceptions (e.g.: division by zero)

Type: Any

args

The selections of the fields used as arguments to compute the synthetic field

Type: list[Selection]

subgraph: Subgraph

fmeta: TypeMeta.FieldMeta

type_: TypeMeta.ObjectMeta | TypeMeta.InterfaceMeta

f: Callable

default: Any

args: list[Selection]

transform_document(doc)

Method that will be applied to all Document objects that pass through the transformation layer.

Parameters: doc (Document) -- The initial document
Returns: The transformed document
Return type: Document

transform_response(doc, data)

Method to be applied to all response data data of requests that pass through the transformation layer.

doc is the initial Document object that yielded the resulting JSON data data.

Parameters

doc (Document) -- Initial document
data (dict[str, Any]) -- JSON data blob resulting from the execution of the transformed document.

Returns

The transformed response data

Return type

dict[str, Any]

class subgrounds.transform.SplitTransform(query)

Bases: subgrounds.transform.RequestTransform

transform_request(req)

Method that will be applied to all DataRequest objects that pass through the transformation layer.

Parameters: req (DataRequest) -- The initial request object
Returns: The transformed request object
Return type: DataRequest

transform_response(req, data)

Method to be applied to all response data data of requests that pass through the transformation layer.

req is the initial DataRequest object that yielded the resulting JSON data data.

Parameters

req (DataRequest) -- Initial data request object
data (list[dict[str, Any]]) -- JSON data blob resulting from the execution of the transformed data request.

Returns

The transformed response data

Return type

list[dict[str, Any]]