Description
SUMMARY
I'm trying to allow custom filter strings like this:
http://localhost/ressource?filter=lessThan(createdAt,'-00:10:00')
which would mean to return all ressources where the createdAt datetime value is less than 10 minutes in the past.
In JADNC before 5.2.0 this worked when using a QueryRewriter like my TimespanExpressionRewriter below. Since version 5.2.0, JADNC throws an exception: "Failed to convert '-00:10:00' of type 'String' to type 'DateTime'."
I suppose the TimespanExpressionRewriter is not the right way to go. Hence my question: How do we implement a custom filter like that?
I've already dug around in the JADNC sources without success.
DETAILS
My TimespanExpressionRewriter class overrides VisitComparison() and replaces an expression when the right value looks like -00:00:00. It returns the rewritten expression like this:
- Input:
lessThan(updatedAt,'-1.06:00') - Output:
and(greaterThan(updatedAt,'2000-06-30T10:00:00+02:00'),lessOrEqual(updatedAt,'2000-07-01T16:00:00+02:00'))
In JADNC <5.2.0 this worked, when adding the expression rewriting in a ResourceDefinition like this:
public override FilterExpression? OnApplyFilter(FilterExpression? existingFilter)
{
if (existingFilter != null)
{
// Timespan expression
// Example:
// http://localhost/ressources?filter=lessThan(createdAt%2C'-0.00%3A50%3A00')
existingFilter = new TimespanExpressionRewriter().Visit(existingFilter, null) as FilterExpression;
}
return existingFilter;
}TimespanExpressionRewriter:
public class TimespanExpressionRewriter : QueryExpressionRewriter<object?>
{
public override QueryExpression? VisitComparison(ComparisonExpression expression, object? argument)
{
// TryCreate() replaces "expression" if it contains a relative timespan
if (TimespanExpressionFactory.TryCreate(expression, () => DateTime.UtcNow, out var expr))
{
return expr;
}
return base.VisitComparison(expression, argument);
}
public override QueryExpression? Visit(QueryExpression expression, object argument)
{
return base.Visit(expression, argument);
}
}STEPS TO REPRODUCE
VERSIONS USED
- JsonApiDotNetCore version: 5.2.0
- ASP.NET Core version: 7
- Entity Framework Core version: 7.0.5
- Database provider: MSSQL