Initial

system/HTTP/Header.php

@@ -0,0 +1,182 @@
+<?php
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\HTTP;
+
+/**
+ * Class Header
+ *
+ * Represents a single HTTP header.
+ */
+class Header
+{
+    /**
+     * The name of the header.
+     *
+     * @var string
+     */
+    protected $name;
+
+    /**
+     * The value of the header. May have more than one
+     * value. If so, will be an array of strings.
+     *
+     * @var array|string
+     */
+    protected $value;
+
+    /**
+     * Header constructor. name is mandatory, if a value is provided, it will be set.
+     *
+     * @param array|string|null $value
+     */
+    public function __construct(string $name, $value = null)
+    {
+        $this->name = $name;
+        $this->setValue($value);
+    }
+
+    /**
+     * Returns the name of the header, in the same case it was set.
+     */
+    public function getName(): string
+    {
+        return $this->name;
+    }
+
+    /**
+     * Gets the raw value of the header. This may return either a string
+     * of an array, depending on whether the header has multiple values or not.
+     *
+     * @return array|string
+     */
+    public function getValue()
+    {
+        return $this->value;
+    }
+
+    /**
+     * Sets the name of the header, overwriting any previous value.
+     *
+     * @return $this
+     */
+    public function setName(string $name)
+    {
+        $this->name = $name;
+
+        return $this;
+    }
+
+    /**
+     * Sets the value of the header, overwriting any previous value(s).
+     *
+     * @param array|string|null $value
+     *
+     * @return $this
+     */
+    public function setValue($value = null)
+    {
+        $this->value = $value ?? '';
+
+        return $this;
+    }
+
+    /**
+     * Appends a value to the list of values for this header. If the
+     * header is a single value string, it will be converted to an array.
+     *
+     * @param array|string|null $value
+     *
+     * @return $this
+     */
+    public function appendValue($value = null)
+    {
+        if ($value === null) {
+            return $this;
+        }
+
+        if (! is_array($this->value)) {
+            $this->value = [$this->value];
+        }
+
+        if (! in_array($value, $this->value, true)) {
+            $this->value[] = $value;
+        }
+
+        return $this;
+    }
+
+    /**
+     * Prepends a value to the list of values for this header. If the
+     * header is a single value string, it will be converted to an array.
+     *
+     * @param array|string|null $value
+     *
+     * @return $this
+     */
+    public function prependValue($value = null)
+    {
+        if ($value === null) {
+            return $this;
+        }
+
+        if (! is_array($this->value)) {
+            $this->value = [$this->value];
+        }
+
+        array_unshift($this->value, $value);
+
+        return $this;
+    }
+
+    /**
+     * Retrieves a comma-separated string of the values for a single header.
+     *
+     * NOTE: Not all header values may be appropriately represented using
+     * comma concatenation. For such headers, use getHeader() instead
+     * and supply your own delimiter when concatenating.
+     *
+     * @see https://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2
+     */
+    public function getValueLine(): string
+    {
+        if (is_string($this->value)) {
+            return $this->value;
+        }
+        if (! is_array($this->value)) {
+            return '';
+        }
+
+        $options = [];
+
+        foreach ($this->value as $key => $value) {
+            if (is_string($key) && ! is_array($value)) {
+                $options[] = $key . '=' . $value;
+            } elseif (is_array($value)) {
+                $key       = key($value);
+                $options[] = $key . '=' . $value[$key];
+            } elseif (is_numeric($key)) {
+                $options[] = $value;
+            }
+        }
+
+        return implode(', ', $options);
+    }
+
+    /**
+     * Returns a representation of the entire header string, including
+     * the header name and all values converted to the proper format.
+     */
+    public function __toString(): string
+    {
+        return $this->name . ': ' . $this->getValueLine();
+    }
+}