Use given culture or invariant culture when converting strings to lower or upper

Author: nesc58

src/RestSharp/Authenticators/OAuth/Extensions/OAuthExtensions.cs

@@ -22,7 +22,7 @@ internal static class OAuthExtensions
     {
         public static string ToRequestValue(this OAuthSignatureMethod signatureMethod)
         {
-            var value    = signatureMethod.ToString().ToUpper();
+            var value    = signatureMethod.ToString().ToUpperInvariant();
             var shaIndex = value.IndexOf("SHA", StringComparison.Ordinal);
 
             return shaIndex > -1 ? value.Insert(shaIndex, "-") : value;

src/RestSharp/Authenticators/OAuth/OAuthTools.cs

@@ -191,7 +191,7 @@ static string ConstructRequestUrl(Uri url)
         public static string ConcatenateRequestElements(string method, string url, WebPairCollection parameters)
         {
             // Separating &'s are not URL encoded
-            var requestMethod     = method.ToUpper().Then("&");
+            var requestMethod     = method.ToUpperInvariant().Then("&");
             var requestUrl        = UrlEncodeRelaxed(ConstructRequestUrl(url.AsUri())).Then("&");
             var requestParameters = UrlEncodeRelaxed(NormalizeRequestParameters(parameters));
 

src/RestSharp/Http.cs

@@ -36,7 +36,7 @@ public partial class Http : IHttp
     {
         const string LineBreak = "\r\n";
 
-        public string FormBoundary { get; } = "---------" + Guid.NewGuid().ToString().ToUpper();
+        public string FormBoundary { get; } = "---------" + Guid.NewGuid().ToString().ToUpperInvariant();
 
         // ReSharper disable once PrivateFieldCanBeConvertedToLocalVariable
         static readonly Regex AddRangeRegex = new Regex("(\\w+)=(\\d+)-(\\d+)$");
@@ -53,7 +53,7 @@ public Http()
 
             void AddSyncHeaderActions()
             {
-                _restrictedHeaderActions.Add("Connection", (r, v) => { r.KeepAlive = v.ToLower().Contains("keep-alive"); });
+                _restrictedHeaderActions.Add("Connection", (r, v) => { r.KeepAlive = v.ToLowerInvariant().Contains("keep-alive"); });
                 _restrictedHeaderActions.Add("Content-Length", (r, v) => r.ContentLength = Convert.ToInt64(v));
                 _restrictedHeaderActions.Add("Expect", (r, v) => r.Expect                = v);
 

src/RestSharp/RestClient.cs

@@ -268,7 +268,7 @@ void AddHandler(Func<IDeserializer> deserializerFactory, params string[] content
 
         void DoBuildUriValidations(IRestRequest request)
         {
-            if (BaseUrl == null && !request.Resource.ToLower().StartsWith("http"))
+            if (BaseUrl == null && !request.Resource.ToLowerInvariant().StartsWith("http"))
                 throw new ArgumentOutOfRangeException(
                     nameof(request),
                     "Request resource doesn't contain a valid scheme for an empty client base URL"
@@ -547,8 +547,8 @@ IRestResponse<T> Deserialize<T>(IRestRequest request, IRestResponse raw)
                 response = raw.ToAsyncResponse<T>();
 
                 // Only attempt to deserialize if the request has not errored due
-                // to a transport or framework exception.  HTTP errors should attempt to 
-                // be deserialized 
+                // to a transport or framework exception.  HTTP errors should attempt to
+                // be deserialized
                 if (response.ErrorException == null)
                 {
                     var func    = GetHandler(raw.ContentType);

src/RestSharp/Serializers/SerializeAsAttribute.cs

@@ -76,7 +76,7 @@ public string TransformName(string input)
             {
                 NameStyle.CamelCase  => name.ToCamelCase(Culture),
                 NameStyle.PascalCase => name.ToPascalCase(Culture),
-                NameStyle.LowerCase  => name.ToLower(),
+                NameStyle.LowerCase  => name.ToLower(Culture),
                 _                    => input
             };
         }

src/RestSharp/Serializers/Xml/XmlDeserializer.cs

@@ -182,7 +182,7 @@ protected virtual object Map(object x, XElement root)
                 if (asType == typeof(bool))
                 {
                     var toConvert = value.ToString()
-                        .ToLower();
+                        .ToLower(Culture);
 
                     prop.SetValue(x, XmlConvert.ToBoolean(toConvert), null);
                 }
@@ -366,7 +366,7 @@ object HandleListDerivative(XElement root, string propName, Type type)
 
             if (!elements.Any())
             {
-                var lowerName = name.ToLower().AsNamespaced(Namespace);
+                var lowerName = name.ToLower(Culture).AsNamespaced(Namespace);
 
                 elements = root.Descendants(lowerName).ToList();
             }
@@ -385,7 +385,7 @@ object HandleListDerivative(XElement root, string propName, Type type)
 
             if (!elements.Any())
             {
-                var lowerName = name.ToLower().AsNamespaced(Namespace);
+                var lowerName = name.ToLower(Culture).AsNamespaced(Namespace);
 
                 elements = root.Descendants()
                     .Where(e => e.Name.LocalName.RemoveUnderscoresAndDashes() == lowerName)
@@ -448,7 +448,7 @@ protected virtual object GetValueFromXml(XElement root, XName name, PropertyInfo
 
         protected virtual XElement GetElementByName(XElement root, XName name)
         {
-            var lowerName = name.LocalName.ToLower().AsNamespaced(name.NamespaceName);
+            var lowerName = name.LocalName.ToLower(Culture).AsNamespaced(name.NamespaceName);
             var camelName = name.LocalName.ToCamelCase(Culture).AsNamespaced(name.NamespaceName);
 
             if (root.Element(name) != null)
@@ -487,7 +487,7 @@ protected virtual XAttribute GetAttributeByName(XElement root, XName name, bool
                 : new List<XName>
                 {
                     name.LocalName,
-                    name.LocalName.ToLower()
+                    name.LocalName.ToLower(Culture)
                         .AsNamespaced(name.NamespaceName),
                     name.LocalName.ToCamelCase(Culture)
                         .AsNamespaced(name.NamespaceName)