initial checkin

[m6w6/seekat] / lib / API / Links.php

diff --git a/lib/API/Links.php b/lib/API/Links.php
new file mode 100644 (file)
index 0000000..5546e65
--- /dev/null
+++ b/lib/API/Links.php
@@ -0,0 +1,135 @@
+<?php
+
+namespace seekat\API;
+
+use http\Header;
+use http\Params;
+use http\QueryString;
+use http\Url;
+
+class Links implements \Serializable
+{
+       /**
+        * Parsed "Link" relations
+        * @var \http\Params
+        */
+       private $params;
+       
+       /**
+        * Parsed "Link" relations
+        * @var array
+        */
+       private $relations = [];
+
+       /**
+        * Parse the hypermedia link header
+        *
+        * @var string $header_value The value of the "Link" header
+        */
+       function __construct(Header $links) {
+               if (strcasecmp($links->name, "Link")) {
+                       throw new \UnexpectedValueException("Expected 'Link' header, got: '{$links->name}'");
+               }
+               $this->unserialize($links->value);
+       }
+
+       function __toString() : string {
+               return $this->serialize();
+       }
+
+       function serialize() {
+               return (string) $this->params;
+       }
+
+       function unserialize($links) {
+               $this->params = new Params($links, ",", ";", "=",
+                       Params::PARSE_RFC5988 | Params::PARSE_ESCAPED);
+               if ($this->params->params) {
+                       foreach ($this->params->params as $link => $param) {
+                               $this->relations[$param["arguments"]["rel"]] = new Url($link);
+                       }
+               }
+       }
+
+       /**
+        * Receive the link header's parsed relations
+        *
+        * @return array
+        */
+       function getRelations() : array {
+               return $this->relations;
+       }
+
+       /**
+        * Get the URL of the link's "next" relation
+        *
+        * Returns the link's "last" relation if it exists and "next" is not set.
+        *
+        * @return \http\Url
+        */
+       function getNext() {
+               if (isset($this->relations["next"])) {
+                       return $this->relations["next"];
+               }
+               if (isset($this->relations["last"])) {
+                       return $this->relations["last"];
+               }
+               return null;
+       }
+
+       /**
+        * Get the URL of the link's "prev" relation
+        *
+        * Returns the link's "first" relation if it exists and "prev" is not set.
+        *
+        * @return \http\Url
+        */
+       function getPrev() {
+               if (isset($this->relations["prev"])) {
+                       return $this->relations["prev"];
+               }
+               if (isset($this->relations["first"])) {
+                       return $this->relations["first"];
+               }
+               return null;
+       }
+
+       /**
+        * Get the URL of the link's "last" relation
+        *
+        * @return \http\Url
+        */
+       function getLast() {
+               if (isset($this->relations["last"])) {
+                       return $this->relations["last"];
+               }
+               return null;
+       }
+
+       /**
+        * Get the URL of the link's "first" relation
+        *
+        * @return \http\Url
+        */
+       function getFirst() {
+               if (isset($this->relations["first"])) {
+                       return $this->relations["first"];
+               }
+               return null;
+       }
+
+       /**
+        * Get the page sequence of the current link's relation
+        *
+        * @param string $which The relation of which to extract the page
+        * @return int The current page sequence
+        */
+       function getPage($which) {
+               if (($link = $this->{"get$which"}())) {
+                       $url = new Url($link, null, 0);
+                       $qry = new QueryString($url->query);
+                       return $qry->getInt("page", 1);
+               }
+               return 1;
+       }
+}