fix(request-content-type): use provided content type in case of null …

…body (#75)

APIMatic.Core.Test/Api/HttpPost/ApiCallPostTest.cs

@@ -1,5 +1,5 @@
 using System;
-using System.Collections.Generic;
+using System.Collections.Generic;
 using System.Net;
 using System.Net.Http;
 using System.Net.Http.Json;
@@ -494,5 +494,31 @@ public void ApiCall_PostNullHeaderValue_OKResponse()
             Assert.NotNull(actual.Data);
             Assert.AreEqual(actual.Data.Message, expected.Message);
         }
+
+        [Test]
+        public void ApiCall_PostNullBodyValue_OKResponse()
+        {
+            //Arrange
+            const string url = "/apicall/null-body-post/200";
+
+            handlerMock.When(GetCompleteUrl(url))
+                .With(req =>
+                {
+                    Assert.AreEqual("application/json", req.Content?.Headers.ContentType?.MediaType);
+                    return true;
+                })
+                .Respond(HttpStatusCode.OK);
+
+            var apiCall = CreateApiCall<ServerResponse>()
+                .RequestBuilder(requestBuilderAction => requestBuilderAction
+                    .Setup(HttpMethod.Post, url)
+                    .Parameters(p => p
+                        .Body(b => b.Setup(null))
+                        .Header(h => h.Setup("content-type", "application/json"))))
+                .ExecuteAsync();
+
+            // Act
+            CoreHelper.RunTask(apiCall);
+        }
     }
 }

APIMatic.Core/Http/HttpClientWrapper.cs

@@ -14,6 +14,7 @@
 using System.Threading.Tasks;
 using APIMatic.Core.Http.Configuration;
 using APIMatic.Core.Types.Sdk;
+using APIMatic.Core.Utilities;
 using Polly;
 using Polly.Retry;
 using Polly.Timeout;
@@ -104,38 +105,19 @@ private HttpRequestMessage CreateHttpRequestMessageFromRequest(CoreRequest reque
             HttpRequestMessage requestMessage = new HttpRequestMessage
             {
                 RequestUri = new Uri(request.QueryUrl),
-                Method = request.HttpMethod,
+                Method = request.HttpMethod
             };
 
-            if (request.Headers != null)
-            {
-                foreach (var headers in request.Headers)
-                {
-                    requestMessage.Headers.TryAddWithoutValidation(headers.Key, headers.Value);
-                }
-            }
+            AddHeadersToRequestMessage(requestMessage, request);
+            if (IsHeaderOnlyHttpMethod(request.HttpMethod)) return requestMessage;
 
-            if (IsHeaderOnlyHttpMethod(request.HttpMethod))
+            if (request.HasFormParameters)
             {
+                requestMessage.Content = GetFormContent(request);
                 return requestMessage;
             }
 
-            if (request.Body == null)
-            {
-                if (CheckFormParametersForMultiPart(request.FormParameters))
-                {
-                    requestMessage.Content = GetMultipartFormDataContentFromRequest(request);
-                    return requestMessage;
-                }
-
-                requestMessage.Content = new FormUrlEncodedContent(request.FormParameters.Select(param => new KeyValuePair<string, string>(param.Key, param.Value.ToString())).ToList());
-                return requestMessage;
-            }
-
-            string contentType = request.Headers?.Where(p => p.Key.Equals("content-type", StringComparison.InvariantCultureIgnoreCase))
-                                .Select(x => x.Value)
-                                .FirstOrDefault();
-
+            var contentType = request.GetContentType();
             if (request.Body is CoreFileStreamInfo file)
             {
                 file.FileStream.Position = 0;
@@ -146,21 +128,50 @@ private HttpRequestMessage CreateHttpRequestMessageFromRequest(CoreRequest reque
 
             if (string.IsNullOrEmpty(contentType))
             {
-                requestMessage.Content = new StringContent(request.Body.ToString(), Encoding.UTF8, "text/plain");
+                requestMessage.Content =
+                    new StringContent(request.GetBodyAsString(), Encoding.UTF8, "text/plain");
                 return requestMessage;
             }
 
-            if (contentType.Equals("application/json; charset=utf-8", StringComparison.OrdinalIgnoreCase))
+            if (IsContentTypeJsonUtf8(contentType))
             {
-                requestMessage.Content = new StringContent(request.Body.ToString(), Encoding.UTF8, "application/json");
+                requestMessage.Content =
+                    new StringContent(request.GetBodyAsString(), Encoding.UTF8, "application/json");
                 return requestMessage;
             }
 
+            if (request.Body == null) return requestMessage;
+
             requestMessage.Content = GetByteArrayContentFromRequestBody(request.Body);
             GetByteArrayContentType(requestMessage.Content.Headers, contentType);
             return requestMessage;
         }
+
+        private static void AddHeadersToRequestMessage(HttpRequestMessage requestMessage, CoreRequest request)
+        {
+            foreach (var headers in request.Headers ?? Enumerable.Empty<KeyValuePair<string, string>>())
+            {
+                requestMessage.Headers.TryAddWithoutValidation(headers.Key, headers.Value);
+            }
+        }
 
+        private static HttpContent GetFormContent(CoreRequest request)
+        {
+            if (CheckFormParametersForMultiPart(request.FormParameters))
+            {
+                return GetMultipartFormDataContentFromRequest(request);
+            }
+
+            return new FormUrlEncodedContent(request.FormParameters
+                .Select(param => new KeyValuePair<string, string>(param.Key, param.Value.ToString())).ToList());
+        }
+
+        private static bool IsContentTypeJsonUtf8(string contentType)
+        {
+            return contentType.EqualsIgnoreCase("application/json") || 
+                   contentType.EqualsIgnoreCase("application/json; charset=utf-8");
+        }
+
         private static void GetByteArrayContentType(HttpContentHeaders contentHeader, string contentType)
         {
             try
@@ -239,9 +250,8 @@ private static bool IsHeaderOnlyHttpMethod(HttpMethod method)
 
         private static bool CheckFormParametersForMultiPart(IReadOnlyCollection<KeyValuePair<string, object>> formParameters)
         {
-            return formParameters != null &&
-                   (formParameters.Any(f => f.Value is MultipartContent) ||
-                    formParameters.Any(f => f.Value is CoreFileStreamInfo));
+            return formParameters.Any(f => f.Value is MultipartContent) ||
+                    formParameters.Any(f => f.Value is CoreFileStreamInfo);
         }
 
         private bool ShouldRetry(HttpResponseMessage response, RetryOption retryOption)

APIMatic.Core/Request/RequestBuilder.cs

@@ -209,7 +209,7 @@ private bool ContentHeaderKeyRequired(string key)
             {
                 return false;
             }
-            if (headers.Any(p => p.Key.Equals(key, StringComparison.InvariantCultureIgnoreCase)))
+            if (headers.Any(p => p.Key.EqualsIgnoreCase(key)))
             {
                 return false;
             }

APIMatic.Core/Types/Sdk/CoreRequest.cs

@@ -81,6 +81,13 @@ public CoreRequest(HttpMethod method, string queryUrl, Dictionary<string, string
         /// </summary>
         internal bool HasBinaryResponse { get; set; }
 
+        /// <summary>
+        /// Gets a value indicating whether the request is likely to have form content.
+        /// This is determined by checking if the <see cref="Body"/> is null 
+        /// and if the <see cref="FormParameters"/> collection is not null and contains any items.
+        /// </summary>
+        internal bool HasFormParameters => Body == null && FormParameters != null && FormParameters.Any();
+
         /// <summary>
         /// Concatenate values from a Dictionary to this object.
         /// </summary>
@@ -103,6 +110,25 @@ public void AddQueryParameters(Dictionary<string, object> queryParamaters)
                 ?? new Dictionary<string, object>(queryParamaters);
         }
 
+        /// <summary>
+        /// Retrieves the value of the "Content-Type" header from the request headers.
+        /// </summary>
+        /// <returns>
+        /// The value of the "Content-Type" header if present; otherwise, <c>null</c>.
+        /// </returns>
+        internal string GetContentType() => Headers?.Where(p => p.Key.EqualsIgnoreCase("content-type"))
+            .Select(x => x.Value)
+            .FirstOrDefault();
+
+        /// <summary>
+        /// Converts the body of the request to a string representation.
+        /// </summary>
+        /// <returns>
+        /// The string representation of the <see cref="Body"/> if it is not <c>null</c>;
+        /// otherwise, returns an empty string.
+        /// </returns>
+        internal string GetBodyAsString() => Body == null ? string.Empty : Body.ToString();
+
         /// <inheritdoc/>
         public override string ToString()
         {

APIMatic.Core/Utilities/StringExtensions.cs

@@ -0,0 +1,15 @@
+// <copyright file="StringExtensions.cs" company="APIMatic">
+// Copyright (c) APIMatic. All rights reserved.
+// </copyright>
+using System;
+
+namespace APIMatic.Core.Utilities
+{
+    internal static class StringExtensions
+    {
+        public static bool EqualsIgnoreCase(this string source, string target)
+        {
+            return source.Equals(target, StringComparison.InvariantCultureIgnoreCase);
+        }
+    }
+}