FromRequest Attribute

The [FromRequest] attribute lets you combine data from multiple parts of an HTTP request — body, route, and query string — into a single model object. See FromRequest Attribute for full details on how model binding works.

OpenAPI documentation

Without special handling, parameters decorated with [FromRequest] would appear as individual query/route parameters in the API documentation even though they are bound as a single body object at runtime. The FromRequestOperationTransformer and FromRequestSchemaTransformer correct this.

What the transformers do

1. FromRequestOperationTransformer — For each parameter marked [FromRequest]:

   • Removes the parameter from the parameters list of the operation.
   • Creates a requestBody entry using the parameter’s type schema.

2. FromRequestSchemaTransformer — Ensures the schema for the request body accurately reflects the model’s properties, excluding any properties that come from route or query binding.

Example

public record UpdateCustomerRequest(
    [property: FromRoute] CustomerId CustomerId,
    string Name,
    string Email);

[HttpPut("{customerId}")]
public Task UpdateCustomer([FromRequest] UpdateCustomerRequest request) { ... }

The generated OpenAPI operation will show:

• Path parameter: customerId (from the route)
• Request body: a JSON schema with name and email properties

Rather than listing all three as individual query/route parameters.