Multi-Value headers support for PHP Generation

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added support for external documentation links on request execution methods (PHP Generation). [2038](https://github.com/microsoft/kiota/issues/2138)
 - Adds support for nullable reference types in dotnet for projects running Netstandard 2.1/Net 6.0 and above []()
 - Added support for multi-value headers to CLI generation. (Shell)
+- Add support for multi-value headers for PHP Generation. [#2052](https://github.com/microsoft/kiota/issues/2052)
 
 ### Changed
 

src/Kiota.Builder/Refiners/PhpRefiner.cs

@@ -135,11 +135,13 @@ public override Task Refine(CodeNamespace generatedCode, CancellationToken cance
         new (x => x is CodeProperty prop && prop.IsOfKind(CodePropertyKind.RequestAdapter),
             "Microsoft\\Kiota\\Abstractions", "RequestAdapter"),
         new (x => x is CodeMethod method && method.IsOfKind(CodeMethodKind.RequestGenerator),
-            "Microsoft\\Kiota\\Abstractions", "HttpMethod", "RequestInformation", "RequestOption"),
+            "Microsoft\\Kiota\\Abstractions", "HttpMethod", "RequestInformation"),
         new (x => x is CodeMethod method && method.IsOfKind(CodeMethodKind.RequestExecutor),
             "Microsoft\\Kiota\\Abstractions", "ResponseHandler"),
         new (static x => x is CodeClass @class && @class.IsOfKind(CodeClassKind.Model) && @class.Properties.Any(static y => y.IsOfKind(CodePropertyKind.AdditionalData)),
             "Microsoft\\Kiota\\Abstractions\\Serialization", "AdditionalDataHolder"),
+        new (static x => x is CodeProperty property && property.IsOfKind(CodePropertyKind.Headers),
+        "Microsoft\\Kiota\\Abstractions","RequestHeaders"),
         new (x => x is CodeMethod method && method.IsOfKind(CodeMethodKind.Serializer),
             "Microsoft\\Kiota\\Abstractions\\Serialization", "SerializationWriter"),
         new (x => x is CodeMethod method && method.IsOfKind(CodeMethodKind.Deserializer),
@@ -188,10 +190,13 @@ private static void CorrectPropertyType(CodeProperty currentProperty) {
         } else if (currentProperty.Type?.Name?.Equals("DateTimeOffset", StringComparison.OrdinalIgnoreCase) ?? false)
         {
             currentProperty.Type.Name = "DateTime";
-        } else if (currentProperty.IsOfKind(CodePropertyKind.Options, CodePropertyKind.Headers))
+        } else if (currentProperty.IsOfKind(CodePropertyKind.Options))
         {
             currentProperty.Type.CollectionKind = CodeTypeBase.CodeTypeCollectionKind.Complex;
             currentProperty.Type.Name = "array";
+        } else if (currentProperty.IsOfKind(CodePropertyKind.Headers))
+        {
+            currentProperty.DefaultValue = $"new {currentProperty.Type?.Name}()";
         }
         CorrectCoreTypes(currentProperty.Parent as CodeClass, DateTypesReplacements, currentProperty.Type);
     }

src/Kiota.Builder/Writers/Php/CodeMethodWriter.cs

@@ -372,7 +372,7 @@ private void WriteRequestConfiguration(RequestParams requestParams, LanguageWrit
                     var headersName = $"{requestConfigParamName}->{headers.Name.ToFirstCharacterLowerCase()}";
                     writer.WriteLine($"if ({headersName} !== null) {{");
                     writer.IncreaseIndent();
-                    writer.WriteLine($"{RequestInfoVarName}->headers = array_merge({RequestInfoVarName}->headers, {headersName});");
+                    writer.WriteLine($"{RequestInfoVarName}->headers->putAll({RequestInfoVarName}->headers);");
                     writer.CloseBlock();
                 }
                 if (queryString != null)
@@ -398,7 +398,7 @@ private void WriteRequestConfiguration(RequestParams requestParams, LanguageWrit
         private void WriteAcceptHeaderDef(CodeMethod codeMethod, LanguageWriter writer)
         {
             if(codeMethod.AcceptedResponseTypes.Any())
-                writer.WriteLine($"{RequestInfoVarName}->headers = array_merge({RequestInfoVarName}->headers, [\"Accept\" => \"{string.Join(", ", codeMethod.AcceptedResponseTypes)}\"]);");
+                writer.WriteLine($"{RequestInfoVarName}->headers->add('Accept', \"{string.Join(", ", codeMethod.AcceptedResponseTypes)}\");");
         }
         private void WriteDeserializerBody(CodeClass parentClass, LanguageWriter writer, CodeMethod method) {
             var inherits = parentClass.StartBlock?.Inherits != null;

tests/Kiota.Builder.Tests/Writers/Php/CodeMethodWriterTests.cs

@@ -388,7 +388,7 @@ public void WriteRequestGeneratorForParsable()
                 result);
             Assert.Contains("if ($requestConfiguration !== null", result);
             Assert.Contains("if ($requestConfiguration->h !== null)", result);
-            Assert.Contains("$requestInfo->headers = array_merge($requestInfo->headers, $requestConfiguration->h);", result);
+            Assert.Contains("$requestInfo->headers->putAll($requestInfo->headers);", result);
             Assert.Contains("$requestInfo->setQueryParameters($requestConfiguration->q);", result);
             Assert.Contains("$requestInfo->addRequestOptions(...$requestConfiguration->o);", result);
             Assert.Contains("$requestInfo->setContentFromParsable($this->requestAdapter, \"\", $body);", result);
@@ -415,7 +415,7 @@ public void WritesRequestGeneratorBodyForParsableCollection()
                 result);
             Assert.Contains("if ($requestConfiguration !== null", result);
             Assert.Contains("if ($requestConfiguration->h !== null)", result);
-            Assert.Contains("$requestInfo->headers = array_merge($requestInfo->headers, $requestConfiguration->h);", result);
+            Assert.Contains("$requestInfo->headers->putAll($requestInfo->headers);", result);
             Assert.Contains("$requestInfo->setQueryParameters($requestConfiguration->q);", result);
             Assert.Contains("$requestInfo->addRequestOptions(...$requestConfiguration->o);", result);
             Assert.Contains("$requestInfo->setContentFromParsableCollection($this->requestAdapter, \"\", $body);", result);
@@ -441,7 +441,7 @@ public void WriteRequestGeneratorForScalarType()
                 result);
             Assert.Contains("if ($requestConfiguration !== null", result);
             Assert.Contains("if ($requestConfiguration->h !== null)", result);
-            Assert.Contains("$requestInfo->headers = array_merge($requestInfo->headers, $requestConfiguration->h);", result);
+            Assert.Contains("$requestInfo->headers->putAll($requestInfo->headers);", result);
             Assert.Contains("$requestInfo->setQueryParameters($requestConfiguration->q);", result);
             Assert.Contains("$requestInfo->addRequestOptions(...$requestConfiguration->o);", result);
             Assert.Contains("$requestInfo->setContentFromScalar($this->requestAdapter, \"\", $body);", result);
@@ -472,7 +472,7 @@ public void WritesRequestGeneratorBodyForScalarCollection()
                 result);
             Assert.Contains("if ($requestConfiguration !== null", result);
             Assert.Contains("if ($requestConfiguration->h !== null)", result);
-            Assert.Contains("$requestInfo->headers = array_merge($requestInfo->headers, $requestConfiguration->h);", result);
+            Assert.Contains("$requestInfo->headers->putAll($requestInfo->headers);", result);
             Assert.Contains("$requestInfo->setQueryParameters($requestConfiguration->q);", result);
             Assert.Contains("$requestInfo->addRequestOptions(...$requestConfiguration->o);", result);
             Assert.Contains("$requestInfo->setContentFromScalarCollection($this->requestAdapter, \"\", $body);", result);