fix header parameter parsing

Author: cordellfreeman

modules/openapi-generator/src/main/resources/go-server/controller-api.mustache

@@ -528,13 +528,24 @@ func (c *{{classname}}Controller) {{nickname}}(w http.ResponseWriter, r *http.Re
 	{{/isFile}}
 	{{/isFormParam}}
 	{{#isHeaderParam}}
-	{{paramName}}Param := getPointerOrNilIfEmpty(r.Header.Get("{{baseName}}"))
+	{{paramName}}ParamValues := r.Header.Values("{{baseName}}")
 	{{#required}}
-	if {{paramName}}Param == nil {
+	if len({{paramName}}ParamValues) == 0 {
 		c.errorHandler(w, r, &RequiredError{"{{baseName}}"}, nil)
 		return
 	}
 	{{/required}}
+	{{#isArray}}
+	{{paramName}}Param := {{paramName}}ParamValues
+	{{/isArray}}
+	{{^isArray}}
+	{{#required}}
+	{{paramName}}Param := getPointer({{paramName}}ParamValues[0])
+	{{/required}}
+	{{^required}}
+	{{paramName}}Param := getPointerOrNilIfEmpty(r.Header.Get("{{baseName}}"))
+	{{/required}}
+	{{/isArray}}
 	{{/isHeaderParam}}
 	{{#isBodyParam}}
 	{{paramName}}Param := {{^isArray}}&{{/isArray}}{{dataType}}{}

samples/openapi3/server/petstore/go/go-petstore/go/api_pet.go

@@ -130,6 +130,7 @@ func (c *PetAPIController) DeletePet(w http.ResponseWriter, r *http.Request) {
 		c.errorHandler(w, r, &ParsingError{Err: err}, nil)
 		return
 	}
+	apiKeyParamValues := r.Header.Values("api_key")
 	apiKeyParam := getPointerOrNilIfEmpty(r.Header.Get("api_key"))
 	result, err := c.service.DeletePet(r.Context(), *petIdParam, apiKeyParam)
 	// If an error occurred, encode the error with the status code

samples/server/petstore/go-api-server/go/api_pet.go

@@ -156,6 +156,7 @@ func (c *PetAPIController) DeletePet(w http.ResponseWriter, r *http.Request) {
 		c.errorHandler(w, r, &ParsingError{Err: err}, nil)
 		return
 	}
+	apiKeyParamValues := r.Header.Values("api_key")
 	apiKeyParam := getPointerOrNilIfEmpty(r.Header.Get("api_key"))
 	result, err := c.service.DeletePet(r.Context(), *petIdParam, apiKeyParam)
 	// If an error occurred, encode the error with the status code

samples/server/petstore/go-chi-server/go/api_pet.go

@@ -155,6 +155,7 @@ func (c *PetAPIController) DeletePet(w http.ResponseWriter, r *http.Request) {
 		c.errorHandler(w, r, &ParsingError{Err: err}, nil)
 		return
 	}
+	apiKeyParamValues := r.Header.Values("api_key")
 	apiKeyParam := getPointerOrNilIfEmpty(r.Header.Get("api_key"))
 	result, err := c.service.DeletePet(r.Context(), *petIdParam, apiKeyParam)
 	// If an error occurred, encode the error with the status code