support "ToString" from numbers

influxdata · Apr 3, 2023 · 09b7387 · 09b7387
1 parent 018f4bf
commit 09b7387
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Showing 3 changed files with 21 additions and 1 deletion.
diff --git a/Client.Linq.Test/InfluxDBQueryVisitorTest.cs b/Client.Linq.Test/InfluxDBQueryVisitorTest.cs
@@ -50,6 +50,18 @@ where s.SensorId.ToLower().Contains("aaa")
             Assert.AreEqual(expected, visitor.BuildFluxQuery());
         }
 
+        [Test]
+        public void ToStringFunctionQuery() {
+            var query = from s in InfluxDBQueryable<Sensor>.Queryable("my-bucket", "my-org", _queryApi)
+                        where s.Value.ToString() == "3"
+                        select s;
+            var visitor = BuildQueryVisitor(query);
+
+            const string expected = "start_shifted = int(v: time(v: p2))\n\nfrom(bucket: p1) |> range(start: time(v: start_shifted)) |> filter(fn: (r) => (string(v: r[\"data\"]) == p3)) |> pivot(rowKey:[\"_time\"], columnKey: [\"_field\"], valueColumn: \"_value\") |> drop(columns: [\"_start\", \"_stop\", \"_measurement\"]) |> filter(fn: (r) => (string(v: r[\"data\"]) == p3))";
+            var qry = visitor.BuildFluxQuery();
+            Assert.AreEqual(expected, visitor.BuildFluxQuery());
+        }
+
         [Test]
         public void DefaultQuery()
         {

diff --git a/Client.Linq/Internal/Expressions/StringFunction.cs b/Client.Linq/Internal/Expressions/StringFunction.cs
@@ -14,7 +14,8 @@ internal StringFunction(string functionName, IEnumerable<IExpressionPart> expres
         }
 
         public void AppendFlux(StringBuilder builder) {
-            builder.Append("strings.");
+            if (functionName != "string")
+                builder.Append("strings.");
             builder.Append(functionName);
             builder.Append("(v: ");
             foreach (var expressionPart in expressionParts) {

diff --git a/Client.Linq/Internal/QueryExpressionTreeVisitor.cs b/Client.Linq/Internal/QueryExpressionTreeVisitor.cs
@@ -243,6 +243,13 @@ protected override Expression VisitMethodCall(MethodCallExpression expression)
                 }
             }
 
+            if (expression.Method.Name.Equals("ToString")) {
+                var partsCount = this._expressionParts.Count;
+                this.Visit(expression.Object);
+                var part = this.GetAndRemoveExpressionParts(partsCount, this._expressionParts.Count);
+                this._expressionParts.Add(new StringFunction("string", part, null));
+                return expression;
+            }
 
             return base.VisitMethodCall(expression);
         }