When executing requests on multiple threads with 1 restclient, there is sometimes an exception

[Nick Van Eeckhout]

I already posted following issue on github:

https://github.com/restsharp/RestSharp/issues/368

before noticing the https://github.com/restsharp/RestSharp/blob/master/CONTRIBUTING.markdown

This is a possible fix:

---

 RestSharp/RestClient.Async.cs     |  4 ----

 RestSharp/RestClient.Sync.cs      |  4 ----

 RestSharp/RestClient.cs           |  7 ++++++-

 RestSharp/RestClientExtensions.cs | 18 ++++++++++++++++++

 4 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/RestSharp/RestClient.Async.cs b/RestSharp/RestClient.Async.cs

index 94a56fd..95acde0 100644

--- a/RestSharp/RestClient.Async.cs

+++ b/RestSharp/RestClient.Async.cs

@@ -73,10 +73,6 @@ namespace RestSharp

  var http = HttpFactory.Create();

  AuthenticateIfNeeded(this, request);

 

- // add Accept header based on registered deserializers

- var accepts = string.Join(", ", AcceptTypes.ToArray());

- this.AddDefaultParameter("Accept", accepts, ParameterType.HttpHeader);

-

  ConfigureHttp(request, http);

 

  var asyncHandle = new RestRequestAsyncHandle();

diff --git a/RestSharp/RestClient.Sync.cs b/RestSharp/RestClient.Sync.cs

index c8db267..66df054 100644

--- a/RestSharp/RestClient.Sync.cs

+++ b/RestSharp/RestClient.Sync.cs

@@ -62,10 +62,6 @@ namespace RestSharp

  {

  AuthenticateIfNeeded(this, request);

 

- // add Accept header based on registered deserializers

- var accepts = string.Join(", ", AcceptTypes.ToArray());

- this.AddDefaultParameter("Accept", accepts, ParameterType.HttpHeader);

-

  IRestResponse response = new RestResponse();

  try

  {

diff --git a/RestSharp/RestClient.cs b/RestSharp/RestClient.cs

index 5501e63..8b0bc0d 100644

--- a/RestSharp/RestClient.cs

+++ b/RestSharp/RestClient.cs

@@ -90,6 +90,9 @@ namespace RestSharp

  if (contentType != "*")

  {

  AcceptTypes.Add(contentType);

+                // add Accept header based on registered deserializers

+                var accepts = string.Join(", ", AcceptTypes.ToArray());

+                this.AddDefaultParameter("Accept", accepts, ParameterType.HttpHeader);

  }

  }

 

@@ -101,6 +104,7 @@ namespace RestSharp

  {

  ContentHandlers.Remove(contentType);

  AcceptTypes.Remove(contentType);

+    this.RemoveDefaultParameter("Accept");

  }

 

  /// <summary>

@@ -109,7 +113,8 @@ namespace RestSharp

  public void ClearHandlers()

  {

  ContentHandlers.Clear();

- AcceptTypes.Clear();

+            AcceptTypes.Clear();

+            this.RemoveDefaultParameter("Accept");

  }

 

  /// <summary>

diff --git a/RestSharp/RestClientExtensions.cs b/RestSharp/RestClientExtensions.cs

index 40ba914..4f1c3fc 100644

--- a/RestSharp/RestClientExtensions.cs

+++ b/RestSharp/RestClientExtensions.cs

@@ -1,4 +1,5 @@

 using System;

+using System.Linq;

 

 namespace RestSharp

 {

@@ -209,10 +210,27 @@ namespace RestSharp

  throw new NotSupportedException(

  "Cannot set request body from default headers. Use Request.AddBody() instead.");

  }

+            // If parameter already exists, remove it first.

+            restClient.RemoveDefaultParameter(p.Name);

 

  restClient.DefaultParameters.Add(p);

  }

 

+        /// <summary>

+        /// Removes a parameter from the default parameters that are used on every request made with this client instance

+        /// </summary>

+        /// <param name="restClient">The IRestClient instance</param>

+        /// <param name="name">The name of the parameter that needs to be removed</param>

+        /// <returns></returns>

+        public static void RemoveDefaultParameter(this IRestClient restClient, string name)

+        {

+            var parameter = restClient.DefaultParameters.SingleOrDefault(p => p.Name.Equals(name, StringComparison.OrdinalIgnoreCase));

+            if (parameter != null)

+            {

+                restClient.DefaultParameters.Remove(parameter);

+            }

+        }

+

  /// <summary>

  /// Adds a HTTP parameter (QueryString for GET, DELETE, OPTIONS and HEAD; Encoded form for POST and PUT)

  /// Used on every request made by this client instance

--