Query string parameters

The parsing of built-in query string parameters is done by types that implement IQueryStringParameterReader, which accepts the incoming parameter value. Those types also implement IQueryConstraintProvider, which they use to expose the parse result.

The parse result consists of an expression in a scope. For example:

?filter[articles]=lessThan(price,'1.23')

has expression lessThan(price,'1.23') in scope articles.

For more information on the various built-in query string parameters, see the documentation for them.

Custom query string parameters

When using Entity Framework Core, resource definitions provide a concise syntax to bind a LINQ expression to a query string parameter. See here for details.

Custom query string parsing

In order to add parsing of custom query string parameters, you can implement the IQueryStringParameterReader interface and register your reader.

public class CustomQueryStringParameterReader : IQueryStringParameterReader
{
    // ...
}

// Program.cs
builder.Services.AddScoped<CustomQueryStringParameterReader>();
builder.Services.AddScoped<IQueryStringParameterReader>(serviceProvider =>
    serviceProvider.GetRequiredService<CustomQueryStringParameterReader>());

Now you can inject your custom reader in resource services, repositories, resource definitions etc.