FastAPI: Invalid Request Body of openapi.json (OAS 3.0.3)

Question

I am trying to work with an openapi.json, which has been automatically created by FastAPI (version 0.109.0). The openapi version is 3.0.3 and I need to upload it to an app, which does not support schemas that have been defined using anyOf, allOf or OneOf.

The openapi.json looks like this:

{
    "openapi": "3.0.3",
    "info": {
        "title": "SomeTitle",
        "description": "SomeDescription",
        "version": "1.2.0"
    },
    "servers": [
        {
            "url": "http://localhost:8080",
            "description": "Local Environment for testing"
        },
        {
            "url": "Productive URL",
            "description": "Productive Instance"
        }
    ],
    "paths": {
        "/api/v1/rag/prepare-index": {
            "post": {
                "tags": [
                    "Retrieval Augmented Generation"
                ],
                "summary": "Build Index",
                "operationId": "Build_Index",
                "security": [
                    {
                        "APIKeyHeader": []
                    }
                ],
                "parameters": [
                    {
                        "name": "project_id",
                        "in": "query",
                        "required": true,
                        "schema": {
                            "type": "string",
                            "title": "Project Id"
                        }
                    },
                    {
                        "name": "max_docs",
                        "in": "query",
                        "required": true,
                        "schema": {
                            "type": "integer",
                            "title": "Max Docs"
                        }
                    },
                    {
                        "name": "vector_store",
                        "in": "query",
                        "required": false,
                        "schema": {
                            "allOf": [
                                {
                                    "$ref": "#/components/schemas/VectorStores"
                                }
                            ],
                            "default": "in_memory",
                            "title": "Vector Store"
                        }
                    }
                ],
                "responses": {
                    "200": {
                        "description": "Successful Response",
                        "content": {
                            "application/json": {
                                "schema": {
                                    "type": "object",
                                    "title": "Response Build Index"
                                }
                            }
                        }
                    },
                    "404": {
                        "description": "Not found"
                    },
                    "422": {
                        "description": "Validation error"
                    }
                }
            }
        },
        ...
    },
    "components":
        "schemas": {
            ...
            "VectorStores": {
                "type": "string",
                "enum": [
                    "redis",
                    "in_memory"
                ],
                "title": "VectorStores"
            },
            ...
        }
    }
}

When uploading, the documentation is shown correctly, but upon trying to finish the import into the app, I am receiving the following error:

Import failed
Please adjust your OpenAPI specification and try again. Reason: Invalid Request Body
/specification/body/paths/~1api~1v1~1rag~1prepare-index/post/parameters/2/schema
must NOT have additional properties
/specification/body/paths/~1api~1v1~1rag~1prepare-index/post/parameters/2/schema/allOf
schema cannot contain anyOf,oneOf,allOf
/specification/body/paths/~1api~1v1~1rag~1prepare-index/post/parameters/2/schema/oneOf
schema cannot contain anyOf,oneOf,allOf
/specification/body/paths/~1api~1v1~1rag~1prepare-index/post/parameters/2/schema
must match exactly one schema in oneOf
/specification/body/paths/~1api~1v1~1rag~1prepare-index/post/parameters/2
must have required property '$ref'
/specification/body/paths/~1api~1v1~1rag~1prepare-index/post/parameters/2
must NOT have additional properties
/specification/body/paths/~1api~1v1~1rag~1prepare-index/post/parameters/2
must match exactly one schema in oneOf

So I tried deleting the allOf part in the schema of the path parameter vector_store. Now $ref is a direct child of schema property of that parameter. However, it still throws the same error. Also, when deleting the title and default properties or providing $ref on the same level as is_required did not help. Further, I tried working with the swagger-editor in order to make it a valid openapi.json, however unfortunately none of that worked out...

What am I missing here?

Answer 1

It looks like the error is coming from the third parameter definition and the use of allOf. The error states you cannot have anyOf, allOf, or oneOf.

I also wonder if FastAPI is looking for a requestBody property because it's a POST operation. You don't have one defined and it has an error related to that.

Try this...

{
    "openapi": "3.0.3",
    "info": {
        "title": "SomeTitle",
        "description": "SomeDescription",
        "version": "1.2.0"
    },
    "servers": [
        {
            "url": "http://localhost:8080",
            "description": "Local Environment for testing"
        },
        {
            "url": "Productive URL",
            "description": "Productive Instance"
        }
    ],
    "paths": {
        "/api/v1/rag/prepare-index": {
            "post": {
                "tags": [
                    "Retrieval Augmented Generation"
                ],
                "summary": "Build Index",
                "operationId": "Build_Index",
                "security": [
                    {
                        "APIKeyHeader": []
                    }
                ],
                "parameters": [
                    {
                        "name": "project_id",
                        "in": "query",
                        "required": true,
                        "schema": {
                            "type": "string",
                            "title": "Project Id"
                        }
                    },
                    {
                        "name": "max_docs",
                        "in": "query",
                        "required": true,
                        "schema": {
                            "type": "integer",
                            "title": "Max Docs"
                        }
                    },
                    {
                        "name": "vector_store",
                        "in": "query",
                        "required": false,
                        "schema": {
                            "$ref": "#/components/schemas/VectorStores"
                        }
                    }
                ],
                "requestBody": {
                    "description": "a request body",
                    "content": {
                        "application/json": {
                            "schema": {
                                "type": "object"
                            }
                        }
                    },
                    "required": true
                },
                "responses": {
                    "200": {
                        "description": "Successful Response",
                        "content": {
                            "application/json": {
                                "schema": {
                                    "type": "object",
                                    "title": "Response Build Index"
                                }
                            }
                        }
                    },
                    "404": {
                        "description": "Not found"
                    },
                    "422": {
                        "description": "Validation error"
                    }
                }
            }
        }
    },
    "components": {
        "schemas": {
            "VectorStores": {
                "type": "string",
                "enum": [
                    "redis",
                    "in_memory"
                ],
                "title": "VectorStores",
                "default": "in_memory"
            }
        }
    }
}

---

In your original example, you had title and default as sibling properties to the allOf rather than inside the allOf as a subschema.

How to compose an allOf to overwrite sibling properties of a $ref.

{
    "parameters": [
        {
            "name": "test",
            "in": "query",
            "schema": {
                "allOf": [
                    {
                        "$ref": "#/components/schemas/test"
                    },
                    {
                        "title": "this is the title I really want!",
                        "default": "default value over written"
                    }
                ]
            }
        }
    ],
...
"components": {
    "schemas": {
        "test": {
            "title": "it's a title",
            "description": "it's a description",
            "type": "string",
            "default": "default value"
        }
    }
}
}