git.m6w6.name Git - m6w6/seekat/blob - lib/API/Links.php

   1 <?php
   2
   3 namespace seekat\API;
   4
   5 use seekat\Exception\UnexpectedValueException;
   6 use http\ {
   7         Header,
   8         Params,
   9         QueryString,
  10         Url
  11 };
  12 use Serializable;
  13
  14 final class Links implements Serializable
  15 {
  16         /**
  17          * Parsed "Link" relations
  18          * @var Params
  19          */
  20         private $params;
  21
  22         /**
  23          * Parsed "Link" relations
  24          * @var array
  25          */
  26         private $relations = [];
  27
  28         /**
  29          * Parse the hypermedia link header
  30          *
  31          * @param Header $links The Link header
  32          * @throws UnexpectedValueException
  33          */
  34         function __construct(Header $links) {
  35                 if (strcasecmp($links->name, "Link")) {
  36                         throw new UnexpectedValueException("Expected 'Link' header, got: '{$links->name}'");
  37                 }
  38                 $this->unserialize($links->value);
  39         }
  40
  41         /**
  42          * @return string
  43          */
  44         function __toString() : string {
  45                 return $this->serialize();
  46         }
  47
  48         /**
  49          * @return string
  50          */
  51         function serialize() {
  52                 return (string) $this->params;
  53         }
  54
  55         /**
  56          * @param string $links
  57          */
  58         function unserialize($links) {
  59                 $this->params = new Params($links, ",", ";", "=",
  60                         Params::PARSE_RFC5988 | Params::PARSE_ESCAPED);
  61                 if ($this->params->params) {
  62                         foreach ($this->params->params as $link => $param) {
  63                                 $this->relations[$param["arguments"]["rel"]] = new Url($link);
  64                         }
  65                 }
  66         }
  67
  68         /**
  69          * Receive the link header's parsed relations
  70          *
  71          * @return array
  72          */
  73         function getRelations() : array {
  74                 return $this->relations;
  75         }
  76
  77         /**
  78          * Get the URL of the link's "next" relation
  79          *
  80          * Returns the link's "last" relation if it exists and "next" is not set.
  81          *
  82          * @return Url
  83          */
  84         function getNext() {
  85                 if (isset($this->relations["next"])) {
  86                         return $this->relations["next"];
  87                 }
  88                 if (isset($this->relations["last"])) {
  89                         return $this->relations["last"];
  90                 }
  91                 return null;
  92         }
  93
  94         /**
  95          * Get the URL of the link's "prev" relation
  96          *
  97          * Returns the link's "first" relation if it exists and "prev" is not set.
  98          *
  99          * @return Url
 100          */
 101         function getPrev() {
 102                 if (isset($this->relations["prev"])) {
 103                         return $this->relations["prev"];
 104                 }
 105                 if (isset($this->relations["first"])) {
 106                         return $this->relations["first"];
 107                 }
 108                 return null;
 109         }
 110
 111         /**
 112          * Get the URL of the link's "last" relation
 113          *
 114          * @return Url
 115          */
 116         function getLast() {
 117                 if (isset($this->relations["last"])) {
 118                         return $this->relations["last"];
 119                 }
 120                 return null;
 121         }
 122
 123         /**
 124          * Get the URL of the link's "first" relation
 125          *
 126          * @return Url
 127          */
 128         function getFirst() {
 129                 if (isset($this->relations["first"])) {
 130                         return $this->relations["first"];
 131                 }
 132                 return null;
 133         }
 134
 135         /**
 136          * Get the page sequence of the current link's relation
 137          *
 138          * @param string $which The relation of which to extract the page
 139          * @return int The current page sequence
 140          */
 141         function getPage($which) {
 142                 if (($link = $this->{"get$which"}())) {
 143                         $url = new Url($link, null, 0);
 144                         $qry = new QueryString($url->query);
 145                         return $qry->getInt("page", 1);
 146                 }
 147                 return 1;
 148         }
 149 }