Add support for lower case headers in pagination

README.md

@@ -194,6 +194,16 @@ Woocommerce::hasNotPreviousPage(); // false
 Woocommerce::hasNotNextPage(); // false
 ```
 
+In some cases the web server returns headers only in lower case. This may cause errors when
+using the pagination functions. If that is your case, call the following method before calling 
+any pagination methods.
+
+```php
+use Woocommerce;
+
+Woocommerce::useLowerCaseHeaders();
+```
+
 ### HTTP Request & Response (Headers)
 
 ```php
@@ -212,7 +222,6 @@ Woocommerce::getResponse();
 Woocommerce::getResponse()->getHeaders()['X-WP-Total']
 ```
 
-
 ### More Examples
 Refer to [WooCommerce REST API Documentation](https://woocommerce.github.io/woocommerce-rest-api-docs) for more examples and documention.
 

src/WoocommerceClient.php

@@ -12,6 +12,11 @@ class WoocommerceClient
      */
     protected $client;
 
+    /**
+     * @var bool
+     */
+    protected $usingLowerCaseHeaders = false;
+
     /**
      */
     public function __construct(Client $client)
@@ -128,7 +133,7 @@ public function currentPage()
      */
     public function totalResults()
     {
-        return (int)$this->getResponse()->getHeaders()['X-WP-Total'];
+        return (int)$this->getResponse()->getHeaders()[$this->getHeaderWithCase('X-WP-Total')];
     }
 
     /**
@@ -138,7 +143,7 @@ public function totalResults()
      */
     public function totalPages()
     {
-        return (int)$this->getResponse()->getHeaders()['X-WP-TotalPages'];
+        return (int)$this->getResponse()->getHeaders()[$this->getHeaderWithCase('X-WP-TotalPages')];
     }
 
     /**
@@ -212,4 +217,32 @@ public function hasNotPreviousPage()
     {
         return (bool)!$this->previousPage();
     }
+
+    /**
+     * Set if headers should be indexed using lower case
+     */
+    public function useLowerCaseHeaders()
+    {
+        $this->usingLowerCaseHeaders = true;
+    }
+
+    /**
+     * Set if headers should be case sensitive
+     */
+    public function useCaseSensitiveHeaders()
+    {
+        $this->usingLowerCaseHeaders = false;
+    }
+
+    /**
+     * Convert header to correct case
+     *
+     * @param $header
+     *
+     * @return string
+     */
+    public function getHeaderWithCase($header)
+    {
+        return $this->usingLowerCaseHeaders ? strtolower($header) : $header;
+    }
 }

tests/WoocommerceClient.php

@@ -274,11 +274,27 @@ public function pagination_next_page_returns_valid_page_number()
         $this->assertFalse($this->woocommerce->hasNotNextPage());
     }
 
+    /**
+     * @test
+     */
+    public function headers_are_converted_to_lower_case_when_requested()
+    {
+        $header = "X-Test-Header";
+
+        $this->woocommerce->useCaseSensitiveHeaders();
+
+        $this->assertEquals($header, $this->woocommerce->getHeaderWithCase($header));
+
+        $this->woocommerce->useLowerCaseHeaders();
+
+        $this->assertEquals(strtolower($header), $this->woocommerce->getHeaderWithCase($header));
+    }
+
     /**
      * tear down
      */
     public function tearDown()
     {
         Mockery::close();
     }
-}
+}