Context::find

(PHP 8.6+, True Async 1.0)

public Context::find(string|object $key): mixed

Searches for a value by key in the current context. If the key is not found, the search continues up the hierarchy of parent contexts. Returns null if the value is not found at any level.

This is a safe search method: it never throws an exception when a key is missing.

Parameters

key: The key to search for. Can be a string or an object. When using an object as a key, the search is performed by object reference.

Return Value

The value associated with the key, or null if the key is not found in the current or any parent context.

Examples

Example #1 Searching for a value by string key

<?php

use function Async\current_context;
use function Async\spawn;

current_context()->set('request_id', 'abc-123');

spawn(function() {
    // Child coroutine finds value from parent context
    $id = current_context()->find('request_id');
    echo $id . "\n"; // "abc-123"

    // Searching for a non-existent key returns null
    $missing = current_context()->find('nonexistent');
    var_dump($missing); // NULL
});

Example #2 Searching for a value by object key

<?php

use function Async\current_context;
use function Async\spawn;

$loggerKey = new stdClass();

current_context()->set($loggerKey, new MyLogger());

spawn(function() use ($loggerKey) {
    // Search by object key reference
    $logger = current_context()->find($loggerKey);
    $logger->info('Message from child coroutine');
});

Example #3 Hierarchical search

<?php

use function Async\current_context;
use function Async\spawn;

// Root level
current_context()->set('app_name', 'MyApp');

spawn(function() {
    // Level 1: add own value
    current_context()->set('user_id', 42);

    spawn(function() {
        // Level 2: search for values from all levels
        echo current_context()->find('user_id') . "\n";   // 42
        echo current_context()->find('app_name') . "\n";  // "MyApp"
    });
});

Documentation