Add content negotiation (fixes #11)

1 files changed, 108 insertions, 0 deletions

diff --git a/src/Controller/ContentNegotiation.php b/src/Controller/ContentNegotiation.php
new file mode 100644
index 0000000..75aa4f1
--- /dev/null
+++ b/src/Controller/ContentNegotiation.php
@@ -0,0 +1,108 @@
+<?php
+
+namespace Jasny\Controller;
+
+/**
+ * Controller methods to negotiate content
+ */
+trait ContentNegotiation
+{
+    /**
+     * Get request, set for controller
+     *
+     * @return ServerRequestInterface
+     */
+    abstract public function getRequest();
+
+    /**
+     * Pick best content type
+     *
+     * @param array $priorities
+     * @return string
+     */
+    public function negotiateContentType(array $priorities)
+    {
+        return $this->negotiate($priorities);
+    }
+
+    /**
+     * Pick best language
+     *
+     * @param array $priorities
+     * @return string
+     */
+    public function negotiateLanguage(array $priorities)
+    {
+        return $this->negotiate($priorities, 'language');
+    }
+
+    /**
+     * Pick best encoding
+     *
+     * @param array $priorities
+     * @return string
+     */
+    public function negotiateEncoding(array $priorities)
+    {
+        return $this->negotiate($priorities, 'encoding');
+    }
+
+    /**
+     * Pick best charset
+     *
+     * @param array $priorities
+     * @return string
+     */
+    public function negotiateCharset(array $priorities)
+    {
+        return $this->negotiate($priorities, 'charset');
+    }
+
+    /**
+     * Generalize negotiation
+     *
+     * @param array $priorities
+     * @param string $type       Negotiator type
+     * @return string
+     */
+    protected function negotiate(array $priorities, $type = '')
+    {
+        $header = 'Accept';
+
+        if ($type) {
+            $header .= '-' . ucfirst($type);
+        }
+
+        $header = $this->getRequest()->getHeader($header);
+        $header = join(', ', $header);
+
+        $negotiator = $this->getNegotiator($type);
+        $chosen = $negotiator->getBest($header, $priorities);
+
+        return $chosen ? $chosen->getType() : '';
+    }
+
+    /**
+     * Get negotiation library instance
+     *
+     * @param string $type  Negotiator type
+     * @return Negotiation\AbstractNegotiator
+     */
+    protected function getNegotiator($type = '')
+    {
+        $class = $this->getNegotiatorName($type);
+
+        return new $class();
+    }
+
+    /**
+     * Get negotiator name
+     *
+     * @param string $type
+     * @return string
+     */
+    protected function getNegotiatorName($type = '')
+    {
+        return 'Negotiation\\' . ucfirst($type) . 'Negotiator';
+    }
+}