jsonschema：抽象数据类型和正确的错误信息

Question

我正在使用这样的jsonschema Python 库：

import jsonschema

schema = {
    "type": "object",
    "oneOf": [
        {
            "type": "object",
            "additionalProperties": False,
            "required": ["key"],
            "properties": {"key": {"enum": ["foo"], "type": "string"}},
        },
        {
            "type": "object",
            "additionalProperties": False,
            "required": ["key", "baritem"],
            "properties": {
                "key": {"enum": ["bar"], "type": "string"},
                "baritem": {"type": "string"},
            },
        },
    ],
}

我可以验证正确的数据：

jsonschema.validate({"key": "bar", "baritem": "ok"}, schema)

但是如果缺少一个属性，如果失败（如预期的那样），但有一个奇怪的错误消息：

jsonschema.validate({"key": "bar"}, schema)

Traceback (most recent call last):
  File "valid.py", line 29, in <module>
    jsonschema.validate({"key": "bar"}, schema)
  File "/home/david/.pyenv/versions/3.7.11/lib/python3.7/site-packages/jsonschema/validators.py", line 934, in validate
    raise error
jsonschema.exceptions.ValidationError: 'bar' is not one of ['foo']

Failed validating 'enum' in schema[0]['properties']['key']:
    {'enum': ['foo'], 'type': 'string'}

On instance['key']:
    'bar'

我的第一个问题是：定义JSON模式是否正确，尤其是使用enum定义key的部分？

我的第二个问题是：有没有办法用jsonschema正确定义这样的抽象数据类型，即告诉jsonschema根据key属性选择object中列出的oneOf ，并基于此 rest？

Answer 1

现在，我的解决方案是选择自己使用的特定模式：

import jsonschema
from jsonschema.exceptions import ValidationError

schema_foo = {
    "type": "object",
    "additionalProperties": False,
    "required": ["key"],
    "properties": {"key": {"enum": ["foo"], "type": "string"}},
}

schema_bar = {
    "type": "object",
    "additionalProperties": False,
    "required": ["key", "baritem"],
    "properties": {
        "key": {"enum": ["bar"], "type": "string"},
        "baritem": {"type": "string"},
    },
}

schema = {
    "type": "object",
    "oneOf": [
        schema_foo,
        schema_bar,
    ],
}

schema_by_key = {"foo": schema_foo, "bar": schema_bar}

data = {"key": "bar"}

try:
    key = data["key"]
except KeyError:
    raise ValidationError("key is missing")

try:
    specific_schema = schema_by_key[key]
except KeyError:
    raise ValidationError("key is invalid")

jsonschema.validate(data, specific_schema)

所以错误被正确报告：

Traceback (most recent call last):
  File "valid.py", line 43, in <module>
    jsonschema.validate(data, specific_schema)
  File "/home/david/.pyenv/versions/3.7.11/lib/python3.7/site-packages/jsonschema/validators.py", line 934, in validate
    raise error
jsonschema.exceptions.ValidationError: 'baritem' is a required property

Failed validating 'required' in schema:
    {'additionalProperties': False,
     'properties': {'baritem': {'type': 'string'},
                    'key': {'enum': ['bar'], 'type': 'string'}},
     'required': ['key', 'baritem'],
     'type': 'object'}

On instance:
    {'key': 'bar'}

Answer 2

您可以根据if / then / else以及dependentSchemas的其他属性的值选择要应用的子模式： https://json-schema.org/understanding-json-schema/reference/conditionals.html