Fixed: Query serializer with nested Arrays

The ToQueryString() method was not writing nested arrays as expected
causing MultipleQueries with nested arrays to return wrong responses.

Expected format:
query=&facetFilters=[["facet1:true"],["facet2:true"]]
query=&facetFilters=[["facet1:true","facet2:true"],["facet3:true"]]
query=&facetFilters=[["facet1:true"]]

Author: Ant-hem

src/Algolia.Search.Test/Serializer/SerializerTest.cs

@@ -103,14 +103,29 @@ public void TestQueryWithMultipleObjects()
         [Parallelizable]
         public void TestQueryWithNestedList()
         {
-            Query query = new Query("") { FacetFilters = new List<List<string>> { new List<string> { "facet1" }, new List<string> { "facet2" } } };
-            Assert.AreEqual(query.ToQueryString(), "query=&facetFilters=facet1%2Cfacet2");
+            Query query = new Query("") { FacetFilters = new List<List<string>> { new List<string> { "facet1:true" }, new List<string> { "facet2:true" } } };
+            // Expected: query=&facetFilters=[["facet1:true"],["facet2:true"]]
+            Assert.AreEqual(query.ToQueryString(), "query=&facetFilters=%5B%5B%22facet1%3Atrue%22%5D%2C%5B%22facet2%3Atrue%22%5D%5D");
 
-            Query query2 = new Query("") { FacetFilters = new List<List<string>> { new List<string> { "facet1", "facet2" } } };
-            Assert.AreEqual(query2.ToQueryString(), "query=&facetFilters=facet1%2Cfacet2");
+            Query query2 = new Query("") { FacetFilters = new List<List<string>> { new List<string> { "facet1:true", "facet2:true" } } };
+            // Expected: query=&facetFilters=[["facet1:true","facet2:true"]]
+            Assert.AreEqual(query2.ToQueryString(), "query=&facetFilters=%5B%5B%22facet1%3Atrue%22%2C%22facet2%3Atrue%22%5D%5D");
 
-            Query query3 = new Query("") { InsideBoundingBox = new List<List<float>> { new List<float> { 10, 35f, 1000, 42f } } };
-            Assert.AreEqual(query3.ToQueryString(), "query=&insideBoundingBox=10.0%2C35.0%2C1000.0%2C42.0");
+            Query query3 = new Query("") { FacetFilters = new List<List<string>> { new List<string> { "facet1:true", "facet2:true" }, new List<string> { "facet3:true" } } };
+            // Expected: query=&facetFilters=[["facet1:true","facet2:true"],["facet3:true"]]
+            Assert.AreEqual(query3.ToQueryString(), "query=&facetFilters=%5B%5B%22facet1%3Atrue%22%2C%22facet2%3Atrue%22%5D%2C%5B%22facet3%3Atrue%22%5D%5D");
+
+            Query query4 = new Query("") { FacetFilters = new List<List<string>> { new List<string> { "facet1:true" } } };
+            // Expected: query=&facetFilters=[["facet1:true"]]
+            Assert.AreEqual(query4.ToQueryString(), "query=&facetFilters=%5B%5B%22facet1%3Atrue%22%5D%5D");
+
+            Query query5 = new Query("") { InsideBoundingBox = new List<List<float>> { new List<float> { 47.3165f, 4.9665f, 47.3424f, 5.0201f }, new List<float> { 40.9234f, 2.1185f, 38.643f, 1.9916f } } };
+            // Expected: query=&insideBoundingBox=[[47.3165,4.9665,47.3424,5.0201],[40.9234,2.1185,38.643,1.9916]]
+            Assert.AreEqual(query5.ToQueryString(), "query=&insideBoundingBox=%5B%5B47.3165%2C4.9665%2C47.3424%2C5.0201%5D%2C%5B40.9234%2C2.1185%2C38.643%2C1.9916%5D%5D");
+
+            Query query6 = new Query("") { InsideBoundingBox = new List<List<float>> { new List<float> { 47.3165f, 4.9665f, 47.3424f, 5.0201f } } };
+            // Expected: query=&insideBoundingBox=[[47.3165,4.9665,47.3424,5.0201]]
+            Assert.AreEqual(query6.ToQueryString(), "query=&insideBoundingBox=%5B%5B47.3165%2C4.9665%2C47.3424%2C5.0201%5D%5D");
         }
 
         [Test]

src/Algolia.Search/Utils/QueryStringHelper.cs

@@ -28,7 +28,6 @@
 using System.Collections.Generic;
 using System.Globalization;
 using System.Linq;
-using System.Net;
 using System.Reflection;
 
 namespace Algolia.Search.Utils
@@ -92,32 +91,32 @@ public static string ToQueryString<T>(T value, params string[] ignoreList)
                     p.GetCustomAttribute<JsonPropertyAttribute>() == null)
                 .Select(p =>
                 {
-                    string encodedValue = null;
+                    string values = null;
                     var genericTypeArgument = p.PropertyType.GenericTypeArguments[0];
 
                     // In case of nested lists
                     if (typeof(IEnumerable).GetTypeInfo().IsAssignableFrom(genericTypeArgument.GetTypeInfo()) && genericTypeArgument != typeof(string))
                     {
                         if (typeof(IEnumerable<float>).GetTypeInfo().IsAssignableFrom(genericTypeArgument.GetTypeInfo()))
                         {
-                            IEnumerable<float> flatList = ((IEnumerable)p.GetValue(value, null)).Cast<IEnumerable<float>>().SelectMany(i => i).ToList();
+                            IEnumerable<IEnumerable<float>> nestedParametersLists = ((IEnumerable)p.GetValue(value, null)).Cast<IEnumerable<float>>();
                             // Culture set to en-US to have floating points separators with "."
-                            encodedValue = Uri.EscapeDataString(string.Join(",", flatList.Select(f => f.ToString("0.0", CultureInfo.InvariantCulture))));
+                            values = WrapValues(string.Join(",", nestedParametersLists.Select(f => WrapValues(string.Join(",", f.Select(x => x.ToString(CultureInfo.InvariantCulture)))))));
                         }
                         else
                         {
-                            IEnumerable<Object> flatList = ((IEnumerable)p.GetValue(value, null)).Cast<IEnumerable<Object>>().SelectMany(i => i).ToList();
-                            encodedValue = Uri.EscapeDataString(string.Join(",", flatList));
+                            IEnumerable<IEnumerable<object>> nestedParametersLists = ((IEnumerable)p.GetValue(value, null)).Cast<IEnumerable<object>>();
+                            values = WrapValues(string.Join(",", nestedParametersLists.Select(x => WrapValues(string.Join(",", x.Select(y => "\"" + y + "\""))))));
                         }
                     }
                     else
                     {
                         // One level list
-                        IEnumerable<Object> flatList = ((IEnumerable)p.GetValue(value, null)).Cast<Object>();
-                        encodedValue = Uri.EscapeDataString(string.Join(",", flatList));
+                        IEnumerable<object> parameterList = ((IEnumerable)p.GetValue(value, null)).Cast<object>();
+                        values = string.Join(",", parameterList);
                     }
 
-                    return p.Name.ToCamelCase() + "=" + encodedValue;
+                    return p.Name.ToCamelCase() + "=" + Uri.EscapeDataString(values);
                 });
 
             // Handle properties with JsonPropertyAttribute
@@ -147,5 +146,10 @@ public static string ToQueryString(this Dictionary<string, string> dic)
                 dic.Select(kvp =>
                     string.Format($"{kvp.Key}={Uri.EscapeDataString(kvp.Value)}")));
         }
+
+        private static string WrapValues(string values)
+        {
+            return "[" + values + "]";
+        }
     }
 }