Convert Curl to PHP

The command

curl -X POST https://httpbin.org/post \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"name":"Ada","role":"admin"}'

Curl flag to PHP option

The same request in PHP

Build a handle, set options, execute. Use single-quoted PHP strings for anything containing a dollar sign, since double-quoted strings interpolate variables and would mangle a literal $ in a body or token. Encode JSON with json_encode rather than writing it by hand.

<?php
$ch = curl_init('https://httpbin.org/post');
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_POST           => true,
    CURLOPT_HTTPHEADER     => [
        'Authorization: Bearer ' . getenv('TOKEN'),
        'Content-Type: application/json',
    ],
    CURLOPT_POSTFIELDS     => json_encode(['name' => 'Ada', 'role' => 'admin']),
    CURLOPT_TIMEOUT        => 20,
]);

$body = curl_exec($ch);
if ($body === false) {
    throw new RuntimeException('curl error: ' . curl_error($ch));
}
$status = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
$data = json_decode($body, true);

Two defaults that bite

CURLOPT_RETURNTRANSFER. Without it, curl_exec prints the response straight into your page output and returns true. Set it and you get the body back as a string. Forgetting it is the single most common PHP cURL mistake.

CURLOPT_POSTFIELDS changes meaning with its type. A string is sent as given, with a form-encoded content type, like -d. An array is sent as multipart/form-data, like -F. Passing an array to an endpoint that expects URL-encoded fields fails in ways that look like missing parameters; wrap the array in http_build_query() to get the -d behaviour.

curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query(['a' => 1, 'b' => 2]));  // like -d
curl_setopt($ch, CURLOPT_POSTFIELDS, ['a' => 1, 'file' => new CURLFile('x.png')]); // like -F

Errors come in two layers

curl_exec returns false only for transport failures: DNS, connection, TLS, timeout. An HTTP 404 or 500 is a successful transfer as far as cURL is concerned, the same as the command line without -f. Check curl_error for the first kind and the response code for the second.

Common mistakes

• Do not disable CURLOPT_SSL_VERIFYPEER to silence a certificate error. Point CURLOPT_CAINFO at a current CA bundle instead.
• Redirects are not followed by default, matching the command line, and unlike most other HTTP libraries.
• curl_close() has done nothing since PHP 8.0; the handle is freed when it goes out of scope.

Related curl examples

More under Converting curl

• Convert Curl to a Raw HTTP Request

References

• PHP manual: cURL — The curl_setopt options that correspond to command-line flags.
• curl man page — What each flag being translated actually does.

These links leave api-tester.com, which is independent of the projects they point to.

FAQ