UrlFilter
This library converts API filter expressions in the form of item eq 7 or value gt 17 into a linq expression to query a datasource
Supported operators
The set of filter operators supported is defined in the Microsoft REST Api Guidelines, specifically:
| Operator | Description | Example |
|---|---|---|
| Comparison | ||
| eq | Equal | firstname eq 'Bruce' |
| ne | Not equal | country ne 'Atlantis' |
| gt | Greater than | weight gt 200 |
| ge | Greater than or equal | height ge 75 |
| lt | Less than | quantity lt 20 |
| le | Less than or equal | price le 9.99 |
| Logical | ||
| and | Logical and | price le 75 and cost gt 40 |
| or | Logical or | superpower eq 'speed' or superpower eq 'strength' |
| not | Logical negation | not secretidentity eq 'Oliver Queen' |
| Grouping | ||
| ( ) | Precedence grouping | (priority eq 1 or city eq 'Metropolis') and price gt 100 |
Usage
There's an interface, IFilterExpression for registering with your IOC container or you can new up WhereExpression. The one method FromString<T>(string queryString) that accepts a type that's used to resolve the property names and the $filter string.
var filterString = "firstname eq 'Arthur' and not lastname eq 'Curry'";
var expressionGenerator = new WhereExpression();
var expression = expressionGenerator.FromString<SuperHero>(filterString);
using (var context = new SuperHeroContext())
{
var heros = context.SuperHeros.Where(expression);
}A static method is also available
var expression = WhereExpression.Build.FromString<SuperHero>(filterString);