Add Header Link Pagination

application/Config/Pager.php

@@ -20,6 +20,7 @@ class Pager extends BaseConfig
 	public $templates = [
 		'default_full'   => 'CodeIgniter\Pager\Views\default_full',
 		'default_simple' => 'CodeIgniter\Pager\Views\default_simple',
+		'default_head'   => 'CodeIgniter\Pager\Views\default_head',
 	];
 
 	/*

system/HTTP/Response.php

@@ -40,6 +40,7 @@
 use Config\App;
 use Config\Format;
 use CodeIgniter\HTTP\Exceptions\HTTPException;
+use CodeIgniter\Pager\PagerInterface;
 
 /**
  * Redirect exception
@@ -383,6 +384,43 @@ public function setDate(\DateTime $date)
 
 	//--------------------------------------------------------------------
 
+	/**
+	 * Set the Link Header
+	 *
+	 * @param \CodeIgniter\Pager\PagerInterface $pager
+	 *
+	 * @see http://tools.ietf.org/html/rfc5988
+	 *
+	 * @return Response
+	 */
+	public function setLink(PagerInterface $pager)
+	{
+		$links = '';
+
+		if ($previous = $pager->getPreviousPageURI())
+		{
+			$links .= '<' . $pager->getPageURI($pager->getFirstPage()) . '>; rel="first",';
+			$links .= '<' . $previous . '>; rel="prev"';
+		}
+
+		if (($next = $pager->getNextPageURI()) && $previous)
+		{
+			$links .= ',';
+		}
+
+		if ($next)
+		{
+			$links .= '<' . $next . '>; rel="next",';
+			$links .= '<' . $pager->getPageURI($pager->getLastPage()) . '>; rel="last"';
+		}
+
+		$this->setHeader('Link', $links);
+
+		return $this;
+	}
+
+	//--------------------------------------------------------------------
+
 	/**
 	 * Sets the Content Type header for this response with the mime type
 	 * and, optionally, the charset.

system/Pager/Pager.php

@@ -325,36 +325,33 @@ public function getPageURI(int $page = null, string $group = 'default', $returnO
 	{
 		$this->ensureGroup($group);
 
+		/**
+		 * @var \CodeIgniter\HTTP\URI $uri
+		 */
 		$uri = $this->groups[$group]['uri'];
 
 		$segment = $this->segment[$group] ?? 0;
 
+		if ($segment)
+		{
+			$uri->setSegment($segment, $page);
+		}
+		else
+		{
+			$uri->addQuery('page', $page);
+		}
+
 		if ($this->only)
 		{
 			$query = array_intersect_key($_GET, array_flip($this->only));
 
-			if ($segment > 0)
-			{
-				$uri->setSegment($segment, $page);
-			}
-			else
+			if (! $segment)
 			{
 				$query['page'] = $page;
 			}
 
 			$uri->setQueryArray($query);
 		}
-		else
-		{
-			if ($segment > 0)
-			{
-				$uri->setSegment($segment, $page);
-			}
-			else
-			{
-				$uri->addQuery('page', $page);
-			}
-		}
 
 		return $returnObject === true ? $uri : (string) $uri;
 	}

system/Pager/PagerInterface.php

@@ -127,6 +127,19 @@ public function getCurrentPage(string $group = 'default'): int;
 
 	//--------------------------------------------------------------------
 
+	/**
+	 * Returns the URI for a specific page for the specified group.
+	 *
+	 * @param integer|null $page
+	 * @param string       $group
+	 * @param boolean      $returnObject
+	 *
+	 * @return string|\CodeIgniter\HTTP\URI
+	 */
+	public function getPageURI(int $page = null, string $group = 'default', $returnObject = false);
+
+	//--------------------------------------------------------------------
+
 	/**
 	 * Tells whether this group of results has any more pages of results.
 	 *
@@ -138,6 +151,17 @@ public function hasMore(string $group = 'default'): bool;
 
 	//--------------------------------------------------------------------
 
+	/**
+	 * Returns the first page.
+	 *
+	 * @param string $group
+	 *
+	 * @return integer
+	 */
+	public function getFirstPage(string $group = 'default');
+
+	//--------------------------------------------------------------------
+
 	/**
 	 * Returns the last page, if we have a total that we can calculate with.
 	 *

system/Pager/PagerRenderer.php

@@ -223,6 +223,29 @@ public function getLast(): string
 
 	//--------------------------------------------------------------------
 
+	/**
+	 * Returns the URI of the current page.
+	 *
+	 * @return string
+	 */
+	public function getCurrent(): string
+	{
+		$uri = clone $this->uri;
+
+		if ($this->segment === 0)
+		{
+			$uri->addQuery('page', $this->current);
+		}
+		else
+		{
+			$uri->setSegment($this->segment, $this->current);
+		}
+
+		return (string) $uri;
+	}
+
+	//--------------------------------------------------------------------
+
 	/**
 	 * Returns an array of links that should be displayed. Each link
 	 * is represented by another array containing of the URI the link

system/Pager/Views/default_full.php

@@ -1,4 +1,10 @@
-<?php $pager->setSurroundCount(2) ?>
+<?php
+/**
+ * @var \CodeIgniter\Pager\PagerRenderer $pager
+ */
+
+$pager->setSurroundCount(2);
+?>
 
 <nav aria-label="<?= lang('Pager.pageNavigation') ?>">
 	<ul class="pagination">

system/Pager/Views/default_head.php

@@ -0,0 +1,18 @@
+<?php
+/**
+ * @var \CodeIgniter\Pager\PagerRenderer $pager
+ */
+
+$pager->setSurroundCount(0);
+
+if ($pager->hasPrevious())
+{
+	echo '<link rel="prev" href="' . $pager->getPrevious() . '">' . PHP_EOL;
+}
+
+echo '<link rel="canonical" href="' . $pager->getCurrent() . '">' . PHP_EOL;
+
+if ($pager->hasNext())
+{
+	echo '<link rel="next" href="' . $pager->getNext() . '">' . PHP_EOL;
+}

system/Pager/Views/default_simple.php

@@ -1,4 +1,10 @@
-<?php $pager->setSurroundCount(0) ?>
+<?php
+/**
+ * @var \CodeIgniter\Pager\PagerRenderer $pager
+ */
+
+$pager->setSurroundCount(0);
+?>
 <nav>
 	<ul class="pager">
 		<li <?= $pager->hasPrevious() ? '' : 'class="disabled"' ?>>

tests/system/HTTP/ResponseTest.php

@@ -156,6 +156,38 @@ public function testSetDateRemembersDateInUTC()
 
 	//--------------------------------------------------------------------
 
+	public function testSetLink()
+	{
+		$response = new Response(new App());
+		$pager    = \Config\Services::pager();
+
+		$pager->store('default', 3, 10, 200);
+		$response->setLink($pager);
+
+		$this->assertEquals(
+			'<http://example.com?page=1>; rel="first",<http://example.com?page=2>; rel="prev",<http://example.com?page=4>; rel="next",<http://example.com?page=20>; rel="last"',
+			$response->getHeader('Link')->getValue()
+		);
+
+		$pager->store('default', 1, 10, 200);
+		$response->setLink($pager);
+
+		$this->assertEquals(
+			'<http://example.com?page=2>; rel="next",<http://example.com?page=20>; rel="last"',
+			$response->getHeader('Link')->getValue()
+		);
+
+		$pager->store('default', 20, 10, 200);
+		$response->setLink($pager);
+
+		$this->assertEquals(
+			'<http://example.com?page=1>; rel="first",<http://example.com?page=19>; rel="prev"',
+			$response->getHeader('Link')->getValue()
+		);
+	}
+
+	//--------------------------------------------------------------------
+
 	public function testSetContentType()
 	{
 		$response = new Response(new App());

tests/system/Pager/PagerRendererTest.php

@@ -4,7 +4,9 @@
 
 class PagerRendererTest extends \CIUnitTestCase
 {
-
+	/**
+	 * @var URI
+	 */
 	protected $uri;
 
 	//--------------------------------------------------------------------
@@ -194,6 +196,45 @@ public function testGetFirstAndGetLast()
 
 	//--------------------------------------------------------------------
 
+	public function testGetCurrent()
+	{
+		$uri = $this->uri;
+		$uri->addQuery('foo', 'bar');
+
+		$details = [
+			'uri'         => $uri,
+			'pageCount'   => 50,
+			'currentPage' => 10,
+			'total'       => 100,
+		];
+
+		$pager = new PagerRenderer($details);
+
+		$this->assertEquals('http://example.com/foo?foo=bar&page=10', $pager->getCurrent());
+	}
+
+	//--------------------------------------------------------------------
+
+	public function testGetCurrentWithSegment()
+	{
+		$uri = $this->uri;
+		$uri->addQuery('foo', 'bar');
+
+		$details = [
+			'uri'         => $uri,
+			'pageCount'   => 50,
+			'currentPage' => 10,
+			'total'       => 100,
+			'segment'     => 2,
+		];
+
+		$pager = new PagerRenderer($details);
+
+		$this->assertEquals('http://example.com/foo/10?foo=bar', $pager->getCurrent());
+	}
+
+	//--------------------------------------------------------------------
+
 	public function testSurroundCount()
 	{
 		$uri = $this->uri;