How to get an option previously set with curl_setopt?

After setting cURL options using the curl_setopt() function, if you want to retrieve or inspect these set options, a common practice is to maintain an array or class property in your code to record the options and values set during each invocation of curl_setopt(). Unfortunately, the cURL library itself does not provide a direct function to retrieve the set option values. This is because the cURL design does not include a mechanism for reverse querying settings.

Practical Example

Assume you are using PHP to set up a cURL request; you can create a wrapper class to track all options set via curl_setopt(). Below is a simple example:

php
class CurlWrapper {
    private $curl;
    private $options = array();

    public function __construct() {
        $this->curl = curl_init();
    }

    public function setOption($option, $value) {
        $this->options[$option] = $value;
        curl_setopt($this->curl, $option, $value);
    }

    public function getOption($option) {
        return isset($this->options[$option]) ? $this->options[$option] : null;
    }

    public function execute() {
        return curl_exec($this->curl);
    }

    public function close() {
        curl_close($this->curl);
    }
}

// Usage example
$curl = new CurlWrapper();
$curl->setOption(CURLOPT_URL, "http://example.com");
$curl->setOption(CURLOPT_RETURNTRANSFER, true);

// Retrieve set options
$url = $curl->getOption(CURLOPT_URL);
$returnTransfer = $curl->getOption(CURLOPT_RETURNTRANSFER);

// Execute cURL request
$result = $curl->execute();
$curl->close();

In the above code, we define a CurlWrapper class that has methods setOption and getOption to set and retrieve cURL options. This way, even though cURL itself does not provide a way to retrieve set options, you can track these options through your own wrapper.

The benefit of this approach is that it increases code maintainability and testability, and also provides a more straightforward way to review and inspect the cURL configuration.