GraphEdge.md

GraphEdge for the Facebook SDK for PHP

When a list of nodes is returned from a Graph request, it can be cast as a GraphEdge which provides convenient ways of interacting with the data which includes pagination.

Facebook\GraphNodes\GraphEdge

You can grab a GraphEdge from a response from Graph.

$graphEdge = $request->getGraphEdge();

Usage:

// Iterate over all the GraphNode's returned from the edge
foreach ($graphEdge as $graphNode) {
  // . . .
}

Pagination

With the help of the Facebook\Facebook super service class, the GraphEdge collection can grab the next and previous sets of data.

$albumsEdge = $response->getGraphEdge();

// Get the next page of results
$nextPageOfAlbums = $fb->next($albumsEdge);
// Or the previous page of results
$previousPageOfAlbums = $fb->previous($previousOfAlbums);

When the next or previous page returns no results, $fb->next() will return null.

Deep Pagination

Sometimes Graph will return a list of nodes within a node. Paginating on these sub lists can be non-trivial. Fortunately, the GraphEdge collection takes the guesswork out and allows you to paginate deeply within a GraphEdge.

The following example paginates over the first 5 pages of a list of Facebook pages. For each page it paginates over all the likes for that page.

$pagesEdge = $response->getGraphEdge();
// Only grab 5 pages
$maxPages = 5;
$pageCount = 0;

do {
  echo '<h1>Page #' . $pageCount . ':</h1>' . "\n\n";

  foreach ($pagesEdge as $page) {
    var_dump($page->asArray());

    $likes = $page['likes'];
    do {
      echo '<p>Likes:</p>' . "\n\n";
      var_dump($likes->asArray());
    } while ($likes = $fb->next($likes));
  }
  $pageCount++;
} while ($pageCount < $maxPages && $pagesEdge = $fb->next($pagesEdge));

Method Reference

getMetaData()

public array getMetaData()

Sometimes Graph will return additional data associated with an edge. You can access this raw data as an array with getMetaData().

$metaData = $graphEdge->getMetaData();

getNextCursor()

public string|null getNextCursor()

Returns the $.paging.cursors.after value if it exists or null if it does not exist. Since cursors are sort of like bookmarks for paginating over an edge, it is sometimes handy to store the last cursor used so that you can revisit the exact position at a later time.

$nextCursor = $graphEdge->getNextCursor();
// Returns: MMAyDDM5NjA0OTEyMDc0OTM=

getPreviousCursor()

public string|null getPreviousCursor()

Returns the $.paging.cursors.before value if it exists or null if it does not exist.

$previousCursor = $graphEdge->getPreviousCursor();
// Returns: ODOxMTUzMjQzNTg5zzU5

getTotalCount()

public int|null getTotalCount()

Some endpoints and edges of Graph support a summary of data. If the summary=true modifier was sent with a request on a supported endpoint or edge, Graph will return the total count of results in the meta data under $.summary.total_count. getTotalCount() will return that value or null if it does not exist.

$response = $fb->get('/{post-id}/likes?summary=true');
$likesEdge = $response->getGraphEdge();
$totalCount = $likesEdge->getTotalCount();
// Returns: 10