python-json-api-drupal-filters

This package is intended as a generic parser for tree-based filters using the Filter Syntax defined by Drupal for use with APIs following the JSON:API specification.

Usage

Input data is expected in a dict with the following format:

{
    ...
    "groupName1": {
        "group": {
            "conjunction": "AND"
        }
    },
    "conditionName1": {
        "condition": {
            "path": "field1",
            "operator": "%3D",
            "value": 42,
            "memberOf": "groupName1"
        }
    },
    "conditionName2": {
        "condition": {
            "path": "field2",
            "operator": "%3D",
            "value": 23,
            "memberOf": "groupName1"
        }
    },
    ...
}

Projects using this package should provide their own implementations of the Condition and Group classes as defined in json_api_drupal_filters/filter_tree.py.

The parse_filter_data method of a FilterParser object calls evaluate on the parser's root group. A group's evaluate method should call evaluate on all the group's members (which can be conditions or other groups). In this way, all groups are evaluated recursively, as every group without an explicit memberOf value is a member of the root group, as specified. Loops are avoided because every group can only be member of one other group, and the root. is a member of no other group.

Very basic examples of a Condition and Group class that evaluate to a string representation of the underlying filter logic are provided here:

from json_api_drupal_filters.filter_tree import Condition, Group

class TestCondition(Condition):
    def evaluate(self):
        return f"{self.path} {self.operator} {self.value}" 


class TestGroup(Group):
    def evaluate(self):
        return "(" + f" {self.conjunction} ".join([member.evaluate() for member in self.members]) + ")"