Added custom props attribute

docs/usage.md

@@ -215,6 +215,21 @@ request.AddParameter("ids", "123,456");
 
 Remember that `AddObject` only works if your properties have primitive types. It also works with collections of primitive types as shown above.
 
+If you need to override the property name or format, you can do it using the `RequestProperty` attribute. For example:
+
+```csharp
+public class RequestModel {
+    // override the name and the format
+    [RequestAttribute(Name = "from_date", Format = "d")]
+    public DateTime FromDate { get; set; }
+}
+
+// add it to the request
+request.AddObject(new RequestModel { FromDate = DateTime.Now });
+```
+
+In this case, the request will get a GET or POST parameter named `from_date` and its value would be the current date in short date format.
+
 ### Url Segment
 
 Unlike `GetOrPost`, this `ParameterType` replaces placeholder values in the `RequestUrl`:

src/RestSharp/Extensions/MiscExtensions.cs → src/RestSharp/Extensions/StreamExtensions.cs

@@ -17,7 +17,7 @@ namespace RestSharp.Extensions;
 /// <summary>
 /// Extension method overload!
 /// </summary>
-static class MiscExtensions {
+static class StreamExtensions {
     /// <summary>
     /// Read a stream into a byte array
     /// </summary>
@@ -39,40 +39,4 @@ public static async Task<byte[]> ReadAsBytes(this Stream input, CancellationToke
 
         return ms.ToArray();
     }
-
-    internal static IEnumerable<(string Name, string? Value)> GetProperties(this object obj, params string[] includedProperties) {
-        // automatically create parameters from object props
-        var type  = obj.GetType();
-        var props = type.GetProperties();
-
-        foreach (var prop in props) {
-            if (!IsAllowedProperty(prop.Name))
-                continue;
-
-            var val = prop.GetValue(obj, null);
-
-            if (val == null)
-                continue;
-
-            var propType = prop.PropertyType;
-
-            if (propType.IsArray) {
-                var elementType = propType.GetElementType();
-                var array       = (Array)val;
-
-                if (array.Length > 0 && elementType != null) {
-                    // convert the array to an array of strings
-                    var values = array.Cast<object>().Select(item => item.ToString());
-                    yield return (prop.Name, string.Join(",", values));
-
-                    continue;
-                }
-            }
-
-            yield return (prop.Name, val.ToString());
-        }
-
-        bool IsAllowedProperty(string propertyName)
-            => includedProperties.Length == 0 || includedProperties.Length > 0 && includedProperties.Contains(propertyName);
-    }
 }

src/RestSharp/Parameters/ObjectParser.cs

@@ -0,0 +1,73 @@
+//  Copyright © 2009-2020 John Sheehan, Andrew Young, Alexey Zimarev and RestSharp community
+// 
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// 
+// http://www.apache.org/licenses/LICENSE-2.0
+// 
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// 
+
+using System.Reflection;
+
+namespace RestSharp;
+
+static class ObjectParser {
+    public static IEnumerable<(string Name, string? Value)> GetProperties(this object obj, params string[] includedProperties) {
+        // automatically create parameters from object props
+        var type  = obj.GetType();
+        var props = type.GetProperties();
+
+        foreach (var prop in props.Where(x => IsAllowedProperty(x.Name))) {
+            var val = prop.GetValue(obj, null);
+
+            if (val == null) continue;
+
+            yield return prop.PropertyType.IsArray
+                ? GetArray(prop, val)
+                : GetValue(prop, val);
+        }
+
+        string? ParseValue(string? format, object? value) => format == null ? value?.ToString() : string.Format($"{{0:{format}}}", value);
+
+        (string, string?) GetArray(PropertyInfo propertyInfo, object? value) {
+            var elementType = propertyInfo.PropertyType.GetElementType();
+            var array       = (Array)value!;
+
+            var attribute = propertyInfo.GetCustomAttribute<RequestPropertyAttribute>();
+            var name      = attribute?.Name ?? propertyInfo.Name;
+
+            if (array.Length > 0 && elementType != null) {
+                // convert the array to an array of strings
+                var values = array
+                    .Cast<object>()
+                    .Select(item => ParseValue(attribute?.Format, item));
+                return (name, string.Join(",", values));
+            }
+
+            return (name, null);
+        }
+
+        (string, string?) GetValue(PropertyInfo propertyInfo, object? value) {
+            var attribute = propertyInfo.GetCustomAttribute<RequestPropertyAttribute>();
+            var name      = attribute?.Name ?? propertyInfo.Name;
+            var val       = ParseValue(attribute?.Format, value);
+            return (name, val);
+        }
+
+        bool IsAllowedProperty(string propertyName)
+            => includedProperties.Length == 0 || includedProperties.Length > 0 && includedProperties.Contains(propertyName);
+    }
+}
+
+[AttributeUsage(AttributeTargets.Property)]
+public class RequestPropertyAttribute : Attribute {
+    public string? Name { get; set; }
+
+    public string? Format { get; set; }
+}

test/RestSharp.Tests/ObjectParserTests.cs

@@ -0,0 +1,40 @@
+using System.Globalization;
+
+namespace RestSharp.Tests;
+
+public class ObjectParserTests {
+    [Fact]
+    public void ShouldUseRequestProperty() {
+        var now   = DateTime.Now;
+        var dates = new[] { now, now.AddDays(1), now.AddDays(2) };
+        var request = new TestObject {
+            SomeData   = "test",
+            SomeDate   = now,
+            Plain      = 123,
+            PlainArray = dates,
+            DatesArray = dates
+        };
+
+        var parsed = request.GetProperties().ToDictionary(x => x.Name, x => x.Value);
+        parsed["some_data"].Should().Be(request.SomeData);
+        parsed["SomeDate"].Should().Be(request.SomeDate.ToString("d"));
+        parsed["Plain"].Should().Be(request.Plain.ToString());
+        // ReSharper disable once SpecifyACultureInStringConversionExplicitly
+        parsed["PlainArray"].Should().Be(string.Join(",", dates.Select(x => x.ToString())));
+        parsed["dates"].Should().Be(string.Join(",", dates.Select(x => x.ToString("d"))));
+    }
+
+    class TestObject {
+        [RequestProperty(Name = "some_data")]
+        public string SomeData { get; set; }
+
+        [RequestProperty(Format = "d")]
+        public DateTime SomeDate { get; set; }
+
+        [RequestProperty(Name = "dates", Format = "d")]
+        public DateTime[] DatesArray { get; set; }
+
+        public int      Plain      { get; set; }
+        public DateTime[] PlainArray { get; set; }
+    }
+}