Configure a Proxy in Yii2’s CurlTransport

Select CurlTransport before passing numeric CURLOPT options. Yii2's HTTP client defaults to StreamTransport, which does not become cURL because those constants are present:

$client = new \yii\httpclient\Client([
    'transport' => \yii\httpclient\CurlTransport::class,
]);

$response = $client->createRequest()
    ->setMethod('GET')
    ->setUrl('https://api.example/items')
    ->setOptions([
        CURLOPT_PROXY => 'http://proxy.example:8080',
        CURLOPT_PROXYAUTH => CURLAUTH_BASIC,
        CURLOPT_PROXYUSERNAME => $proxyUser,
        CURLOPT_PROXYPASSWORD => $proxyPassword,
        CURLOPT_CONNECTTIMEOUT => 5,
        CURLOPT_TIMEOUT => 15,
    ])
    ->send();

Use a PHP runtime with its cURL extension. This example expects an HTTP proxy accepting Basic; match the proxy and transport's supported method.

CURLOPT_PROXYAUTH chooses intermediary authentication. CURLOPT_HTTPAUTH and API Authorization serve the destination instead.

Yii2's shared request options, including case-sensitive proxy and timeout, are another interface. They do not make arbitrary cURL constants portable across backends.

If Client.requestConfig provides defaults that must survive, use addOptions for per-request additions. The shown setOptions replaces that collection and can remove inherited choices.