diff --git a/modules/swagger-codegen/src/main/resources/php/api.mustache b/modules/swagger-codegen/src/main/resources/php/api.mustache
index 22ae27fc77..cce59f4d94 100644
--- a/modules/swagger-codegen/src/main/resources/php/api.mustache
+++ b/modules/swagger-codegen/src/main/resources/php/api.mustache
@@ -184,14 +184,14 @@ use \{{invokerPackage}}\ObjectSerializer;
         {{#authMethods}}{{#isApiKey}}
         // this endpoint requires API key authentication
         $apiKey = $this->apiClient->getApiKeyWithPrefix('{{keyParamName}}');
-        if ($apiKey !== null) {
+        if (strlen($apiKey) !== 0) {
             {{#isKeyInHeader}}$headerParams['{{keyParamName}}'] = $apiKey;{{/isKeyInHeader}}{{#isKeyInQuery}}$queryParams['{{keyParamName}}'] = $apiKey;{{/isKeyInQuery}}
         }{{/isApiKey}}
         {{#isBasic}}// this endpoint requires HTTP basic authentication
-        if ($this->apiClient->getConfig()->getUsername() !== null or $this->apiClient->getConfig()->getPassword() !== null) {
+        if (strlen($this->apiClient->getConfig()->getUsername()) !== 0 or strlen($this->apiClient->getConfig()->getPassword()) !== 0) {
             $headerParams['Authorization'] = 'Basic ' . base64_encode($this->apiClient->getConfig()->getUsername() . ":" . $this->apiClient->getConfig()->getPassword());
         }{{/isBasic}}{{#isOAuth}}// this endpoint requires OAuth (access token)
-        if ($this->apiClient->getConfig()->getAccessToken() !== null) {
+        if (strlen($this->apiClient->getConfig()->getAccessToken()) !== 0) {
             $headerParams['Authorization'] = 'Bearer ' . $this->apiClient->getConfig()->getAccessToken();
         }{{/isOAuth}}
         {{/authMethods}}
diff --git a/samples/client/petstore/php/SwaggerClient-php/lib/Api/PetApi.php b/samples/client/petstore/php/SwaggerClient-php/lib/Api/PetApi.php
index 18aeba6407..bd82444f4f 100644
--- a/samples/client/petstore/php/SwaggerClient-php/lib/Api/PetApi.php
+++ b/samples/client/petstore/php/SwaggerClient-php/lib/Api/PetApi.php
@@ -152,7 +152,7 @@ class PetApi
         }
         
         // this endpoint requires OAuth (access token)
-        if ($this->apiClient->getConfig()->getAccessToken() !== null) {
+        if (strlen($this->apiClient->getConfig()->getAccessToken()) !== 0) {
             $headerParams['Authorization'] = 'Bearer ' . $this->apiClient->getConfig()->getAccessToken();
         }
         
@@ -235,7 +235,7 @@ class PetApi
         }
         
         // this endpoint requires OAuth (access token)
-        if ($this->apiClient->getConfig()->getAccessToken() !== null) {
+        if (strlen($this->apiClient->getConfig()->getAccessToken()) !== 0) {
             $headerParams['Authorization'] = 'Bearer ' . $this->apiClient->getConfig()->getAccessToken();
         }
         
@@ -317,7 +317,7 @@ class PetApi
         }
         
         // this endpoint requires OAuth (access token)
-        if ($this->apiClient->getConfig()->getAccessToken() !== null) {
+        if (strlen($this->apiClient->getConfig()->getAccessToken()) !== 0) {
             $headerParams['Authorization'] = 'Bearer ' . $this->apiClient->getConfig()->getAccessToken();
         }
         
@@ -407,7 +407,7 @@ class PetApi
         }
         
         // this endpoint requires OAuth (access token)
-        if ($this->apiClient->getConfig()->getAccessToken() !== null) {
+        if (strlen($this->apiClient->getConfig()->getAccessToken()) !== 0) {
             $headerParams['Authorization'] = 'Bearer ' . $this->apiClient->getConfig()->getAccessToken();
         }
         
@@ -506,7 +506,7 @@ class PetApi
         
         // this endpoint requires API key authentication
         $apiKey = $this->apiClient->getApiKeyWithPrefix('api_key');
-        if ($apiKey !== null) {
+        if (strlen($apiKey) !== 0) {
             $headerParams['api_key'] = $apiKey;
         }
         
@@ -621,7 +621,7 @@ class PetApi
         }
         
         // this endpoint requires OAuth (access token)
-        if ($this->apiClient->getConfig()->getAccessToken() !== null) {
+        if (strlen($this->apiClient->getConfig()->getAccessToken()) !== 0) {
             $headerParams['Authorization'] = 'Bearer ' . $this->apiClient->getConfig()->getAccessToken();
         }
         
@@ -716,7 +716,7 @@ class PetApi
         }
         
         // this endpoint requires OAuth (access token)
-        if ($this->apiClient->getConfig()->getAccessToken() !== null) {
+        if (strlen($this->apiClient->getConfig()->getAccessToken()) !== 0) {
             $headerParams['Authorization'] = 'Bearer ' . $this->apiClient->getConfig()->getAccessToken();
         }
         
@@ -828,7 +828,7 @@ class PetApi
         }
         
         // this endpoint requires OAuth (access token)
-        if ($this->apiClient->getConfig()->getAccessToken() !== null) {
+        if (strlen($this->apiClient->getConfig()->getAccessToken()) !== 0) {
             $headerParams['Authorization'] = 'Bearer ' . $this->apiClient->getConfig()->getAccessToken();
         }
         
diff --git a/samples/client/petstore/php/SwaggerClient-php/lib/Api/StoreApi.php b/samples/client/petstore/php/SwaggerClient-php/lib/Api/StoreApi.php
index 4539aeeeab..4faed9a36b 100644
--- a/samples/client/petstore/php/SwaggerClient-php/lib/Api/StoreApi.php
+++ b/samples/client/petstore/php/SwaggerClient-php/lib/Api/StoreApi.php
@@ -147,7 +147,7 @@ class StoreApi
         
         // this endpoint requires API key authentication
         $apiKey = $this->apiClient->getApiKeyWithPrefix('api_key');
-        if ($apiKey !== null) {
+        if (strlen($apiKey) !== 0) {
             $headerParams['api_key'] = $apiKey;
         }