如何通过PHP Datastore API获取实体的ID/Key？

Hey there! I totally get the frustration when you can pull all the entity properties but can't grab that ID/key—been there myself. Let's break down exactly how to fix this.

First off, the reason your attempts with $user['id'], $user['key'], or $user['__key__'] aren't working is because the entity's key isn't stored as a regular property. It's metadata attached to the entity object itself, not part of the attributes you access via array syntax.

Here's the step-by-step solution:

• First, confirm your $user is an Entity instance: When you fetch entities via lookup() or a query, you get back Google\Cloud\Datastore\Entity objects, not plain arrays.
• Retrieve the Key object: Use the key() method on your entity:

  $key = $user->key();
  

• Extract the ID or Name from the Key:
  • For auto-generated numeric IDs, use the id() method:

    $entityId = $key->id();
    

  • For custom string names (if you didn't use auto-ID), use the name() method:

    $entityName = $key->name();
    

  • If you want the full path details (including the kind), use path() which returns an array:

    $path = $key->path();
    // Example output: ['kind' => 'User', 'id' => 12345]
    

Putting it all together in a quick example:

// Assume you've already fetched your $user entity from Datastore
$key = $user->key();

// Check if it's an ID-based entity
if ($id = $key->id()) {
    echo "This entity's ID is: " . $id;
}

// Or if it uses a custom name
if ($name = $key->name()) {
    echo "This entity's name is: " . $name;
}

That should get you the ID/key you need without any hassle.

内容的提问来源于stack exchange，提问作者Diego Barreiro