Important
The reference documentation for this library is available at https://open-policy-agent.github.io/ucast-linq
dotnet add package OpenPolicyAgent.Ucast.LinqLet's assume that we have a collection of random integers, and wish to filter them with a LINQ query using multiple criteria:
using System;
using System.Linq;
public record SimpleRecord(int Value);
var numbers = new int[] { -1523, 1894, -456, 789, -1002, 345, -1789, 567, 1234, -890, 123, -1456, 1678, -234, 567, -1890, 901, -345, 1567, -789 };
var collection = numbers.Select(n => new SimpleRecord(n)).ToList();
var results = collection.Where(x => x.Value >= 1500 || (x.Value < 400 && (x.Value > 0 || x.Value < -1500)))
.OrderBy(x => x.Value)
.ToList();
Console.WriteLine(string.Join("\n", results));Output
SimpleRecord { Value = -1890 }
SimpleRecord { Value = -1789 }
SimpleRecord { Value = -1523 }
SimpleRecord { Value = 123 }
SimpleRecord { Value = 345 }
SimpleRecord { Value = 1567 }
SimpleRecord { Value = 1678 }
SimpleRecord { Value = 1894 }Using this library, the same filters can be constructed dynamically using UCAST expressions (which can be deserialized from JSON):
using System;
using System.Linq;
using OpenPolicyAgent.Ucast.Linq;
public record SimpleRecord(int Value);
var conditions = new UCASTNode { Type = "compound", Op = "or", Value = new List<UCASTNode>{
new UCASTNode { Type = "field", Op = "ge", Field = "r.value", Value = 1500 },
new UCASTNode { Type = "compound", Op = "and", Value = new List<UCASTNode>{
new UCASTNode { Type = "field", Op = "lt", Field = "r.value", Value = 400 },
new UCASTNode { Type = "compound", Op = "or", Value = new List<UCASTNode>{
new UCASTNode { Type = "field", Op = "gt", Field = "r.value", Value = 0 },
new UCASTNode { Type = "field", Op = "lt", Field = "r.value", Value = -1500 },
} },
} },
} };
var numbers = new int[] { -1523, 1894, -456, 789, -1002, 345, -1789, 567, 1234, -890, 123, -1456, 1678, -234, 567, -1890, 901, -345, 1567, -789 };
var collection = numbers.Select(n => new SimpleRecord(n)).ToList();
var results = collection.AsQueryable()
.ApplyUCASTFilter(conditions, QueryableExtensions.BuildDefaultMapperDictionary<SimpleRecord>("r"))
.OrderBy(x => x.Value)
.ToList();
Console.WriteLine(string.Join("\n", results));Output
SimpleRecord { Value = -1890 }
SimpleRecord { Value = -1789 }
SimpleRecord { Value = -1523 }
SimpleRecord { Value = 123 }
SimpleRecord { Value = 345 }
SimpleRecord { Value = 1567 }
SimpleRecord { Value = 1678 }
SimpleRecord { Value = 1894 }For questions, discussions, and announcements, please join the OPA community on Slack!