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
   8 final class Links {
   9         /**
  10          * Parsed "Link" relations
  11          * @var array<string, Url>
  12          */
  13         private $relations = [];
  14
  15         /**
  16          * Parse the hypermedia link header
  17          *
  18          * @param ?Header $links The Link header
  19          * @throws UnexpectedValueException
  20          */
  21         function __construct(Header $links = null) {
  22                 if ($links) {
  23                         if (strcasecmp($links->name, "Link")) {
  24                                 throw new UnexpectedValueException("Expected 'Link' header, got: '{$links->name}'");
  25                         }
  26                         $params = new Params($links->value, ",", ";", "=",
  27                                 Params::PARSE_RFC5988 | Params::PARSE_ESCAPED);
  28                         if ($params->params) {
  29                                 foreach ($params->params as $link => $param) {
  30                                         $this->relations[$param["arguments"]["rel"]] = new Url($link);
  31                                 }
  32                         }
  33                 }
  34         }
  35
  36         /**
  37          * Receive the link header's parsed relations
  38          *
  39          * @return array<string, Url>
  40          */
  41         function getRelations() : array {
  42                 return $this->relations;
  43         }
  44
  45         /**
  46          * Get the URL of the link's "next" relation
  47          *
  48          * Returns the link's "last" relation if it exists and "next" is not set.
  49          */
  50         function getNext() : ?Url {
  51                 if (isset($this->relations["next"])) {
  52                         return $this->relations["next"];
  53                 }
  54                 if (isset($this->relations["last"])) {
  55                         return $this->relations["last"];
  56                 }
  57                 return null;
  58         }
  59
  60         /**
  61          * Get the URL of the link's "prev" relation
  62          *
  63          * Returns the link's "first" relation if it exists and "prev" is not set.
  64          */
  65         function getPrev() : ?Url {
  66                 if (isset($this->relations["prev"])) {
  67                         return $this->relations["prev"];
  68                 }
  69                 if (isset($this->relations["first"])) {
  70                         return $this->relations["first"];
  71                 }
  72                 return null;
  73         }
  74
  75         /**
  76          * Get the URL of the link's "last" relation
  77          */
  78         function getLast() : ?Url {
  79                 if (isset($this->relations["last"])) {
  80                         return $this->relations["last"];
  81                 }
  82                 return null;
  83         }
  84
  85         /**
  86          * Get the URL of the link's "first" relation
  87          */
  88         function getFirst() : ?Url {
  89                 if (isset($this->relations["first"])) {
  90                         return $this->relations["first"];
  91                 }
  92                 return null;
  93         }
  94
  95         /**
  96          * Get the page sequence of the current link's relation
  97          *
  98          * @param string $which The relation of which to extract the page
  99          * @return int The current page sequence
 100          */
 101         function getPage($which) : int {
 102                 if (($link = $this->{"get$which"}())) {
 103                         $url = new Url($link, null, 0);
 104                         $qry = new QueryString($url->query);
 105                         return $qry->getInt("page", 1);
 106                 }
 107                 return 1;
 108         }
 109 }