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 $links = null) {
  35                 if ($links) {
  36                         if (strcasecmp($links->name, "Link")) {
  37                                 throw new UnexpectedValueException("Expected 'Link' header, got: '{$links->name}'");
  38                         }
  39                         $this->unserialize($links->value);
  40                 }
  41         }
  42
  43         /**
  44          * @return string
  45          */
  46         function __toString() : string {
  47                 return $this->serialize();
  48         }
  49
  50         /**
  51          * @return string
  52          */
  53         function serialize() {
  54                 return (string) $this->params;
  55         }
  56
  57         /**
  58          * @param string $links
  59          */
  60         function unserialize($links) {
  61                 $this->params = new Params($links, ",", ";", "=",
  62                         Params::PARSE_RFC5988 | Params::PARSE_ESCAPED);
  63                 if ($this->params->params) {
  64                         foreach ($this->params->params as $link => $param) {
  65                                 $this->relations[$param["arguments"]["rel"]] = new Url($link);
  66                         }
  67                 }
  68         }
  69
  70         /**
  71          * Receive the link header's parsed relations
  72          *
  73          * @return array
  74          */
  75         function getRelations() : array {
  76                 return $this->relations;
  77         }
  78
  79         /**
  80          * Get the URL of the link's "next" relation
  81          *
  82          * Returns the link's "last" relation if it exists and "next" is not set.
  83          *
  84          * @return Url
  85          */
  86         function getNext() {
  87                 if (isset($this->relations["next"])) {
  88                         return $this->relations["next"];
  89                 }
  90                 if (isset($this->relations["last"])) {
  91                         return $this->relations["last"];
  92                 }
  93                 return null;
  94         }
  95
  96         /**
  97          * Get the URL of the link's "prev" relation
  98          *
  99          * Returns the link's "first" relation if it exists and "prev" is not set.
 100          *
 101          * @return Url
 102          */
 103         function getPrev() {
 104                 if (isset($this->relations["prev"])) {
 105                         return $this->relations["prev"];
 106                 }
 107                 if (isset($this->relations["first"])) {
 108                         return $this->relations["first"];
 109                 }
 110                 return null;
 111         }
 112
 113         /**
 114          * Get the URL of the link's "last" relation
 115          *
 116          * @return Url
 117          */
 118         function getLast() {
 119                 if (isset($this->relations["last"])) {
 120                         return $this->relations["last"];
 121                 }
 122                 return null;
 123         }
 124
 125         /**
 126          * Get the URL of the link's "first" relation
 127          *
 128          * @return Url
 129          */
 130         function getFirst() {
 131                 if (isset($this->relations["first"])) {
 132                         return $this->relations["first"];
 133                 }
 134                 return null;
 135         }
 136
 137         /**
 138          * Get the page sequence of the current link's relation
 139          *
 140          * @param string $which The relation of which to extract the page
 141          * @return int The current page sequence
 142          */
 143         function getPage($which) {
 144                 if (($link = $this->{"get$which"}())) {
 145                         $url = new Url($link, null, 0);
 146                         $qry = new QueryString($url->query);
 147                         return $qry->getInt("page", 1);
 148                 }
 149                 return 1;
 150         }
 151 }