Why Does curl_exec() Sometimes Return False?

Troubleshooting curl_exec() Return Value of False

In this issue, the user experiences unexpected false return values from curl_exec() in a simple code snippet aimed at retrieving website content.

To address this problem, it's crucial to incorporate error checking and handling into your code. curl_exec() might return false due to initialization errors or execution failures.

To debug this effectively, utilize the curl_error() and curl_errno() functions. These utilities provide detailed error messages and corresponding error codes in the event of failures.

Here's an example of how to implement error handling and checking:

<code class="php">try {
    $ch = curl_init();

    // Check if initialization had gone wrong
    if ($ch === false) {
        throw new Exception('failed to initialize');
    }

    // Set options and execute
    curl_setopt(/* ... */);
    $content = curl_exec($ch);

    // Check the return value of curl_exec(), too
    if ($content === false) {
        throw new Exception(curl_error($ch), curl_errno($ch));
    }

} catch(Exception $e) {

    trigger_error(sprintf(
        'Curl failed with error #%d: %s',
        $e->getCode(), $e->getMessage()),
        E_USER_ERROR);

} finally {
    // Close curl handle unless it failed to initialize
    if (is_resource($ch)) {
        curl_close($ch);
    }
}</code>

Additional Insights on curl_init()

The curl_init() manual explicitly states that it returns FALSE on errors. It's worth noting that the function might return FALSE when using the $url parameter if the domain cannot be resolved. However, if the parameter is left unused, the function is less likely to return FALSE.

Nonetheless, it's always recommended to check the return value of curl_init() to avoid any potential issues. Error checking and handling are essential practices in programming, especially when working with external APIs or third-party libraries.

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