Merge pull request #1 from brokenhandsio/distance-sort

Add support for sorting by distance
brokenhandsio · Sep 17, 2019 · 93f82df · 93f82df
2 parents ffcca3a + a4fa1d2
commit 93f82df
Showing 1 changed file with 29 additions and 0 deletions.
diff --git a/Sources/FluentPostGIS/Queries/QueryBuilder+Sort.swift b/Sources/FluentPostGIS/Queries/QueryBuilder+Sort.swift
@@ -0,0 +1,29 @@
+import FluentPostgreSQL
+
+extension QueryBuilder where
+    Database: QuerySupporting,
+    Database.QuerySort: SQLOrderBy,
+    Database.QueryFilter: SQLExpression,
+    Database.QueryFilterValue == Database.QueryFilter
+{
+    @discardableResult
+    public func sortByDistance<T,V>(between key: KeyPath<Result, T>, _ filter: V) -> Self
+    where T: GeometryConvertible, V: GeometryConvertible {
+        return self.sort(Database.distanceSort(between: Database.queryField(.keyPath(key)), Database.queryFilterValueGeographic(filter)))
+    }
+
+}
+
+extension QuerySupporting where
+    QuerySort: SQLOrderBy
+{
+    public static func distanceSort(between field: QueryField, _ filter: QueryFilterValue) -> QuerySort {
+        let args: [QuerySort.Expression.Function.Argument] = [
+            GenericSQLFunctionArgument<PostgreSQLExpression>.expression(PostgreSQLExpression.column(field as! PostgreSQLColumnIdentifier)),
+            GenericSQLFunctionArgument<PostgreSQLExpression>.expression(filter as! PostgreSQLExpression),
+            ] as! [QuerySort.Expression.Function.Argument]
+        return .orderBy(.function("ST_Distance", args), .ascending)
+    }
+}
+
+