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

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