PHP RFC: Object-oriented curl API v2
- Version: 1.4
- Date: 2025-06-24
- Author: Eric Norris, [email protected]
- Status: Under Discussion
- Implementation: TBA
Introduction
As part of the Resource to object conversion project, PHP internals developers converted curl
resource types to objects. These objects do not have any methods, and do not currently provide an object-oriented API for developers to use.
There have been at least two prior attempts at suggesting an object-oriented API for curl, but they never made it to a voting phase:
Creating an object-oriented API for curl
still seems worth doing, however. We can leverage PHP features (e.g. namespace, enumerations, and asymmetric visibility) to provide a clean and safe interface for developers.
Proposal
New 'Curl' Namespace
We'll move all existing Curl*
classes to the Curl
namespace, e.g. CurlHandle
will become Curl\Handle
. We'll maintain non-namespaced aliases for backwards compatibility.
New enumerations
Multiple developers suggested using enumerations in response to the prior object-oriented curl
RFC:
What about making the CURL options an enumeration?
- kalle
I was also going to suggest to use enums for the options, and have them be grouped by what value type they need.
- girgias
The suggestion to use an Enum (or several) here is a good one and would help a lot with that, so I'm +1 there.
- crell
Using enumerations for curl
options will improve usability and discoverability, as today the curl_setopt
and curl_multi_setopt
only specify an int
type for the option; this solely relies on documentation and convention to inform users that they should use CURLOPT_*
and CURLMOPT_*
constants.
This RFC proposes enumerations for any constants that are in fact enumerations, e.g. the aforementioned CURLOPT_*
and CURLMOPT_*
constants, as well as the CURLINFO_*
and CURLPAUSE_*
constants, etc. For brevity, I will not list all of the implementations.
Curl\HandleOption
namespace Curl; enum HandleOption: int { case AbstractUnixSocket = CURLOPT_ABSTRACT_UNIX_SOCKET; case AcceptEncoding = CURLOPT_ACCEPT_ENCODING; case AcceptTimeoutMs = CURLOPT_ACCEPTTIMEOUT_MS; // ...other options elided... }
Note: some options will not be a part of the enumeration list when applicable. For example, CURLOPT_RETURNTRANSFER
, CURLOPT_FILE
, and CURLOPT_WRITEFUNCTION
are no longer valid options, as the Curl\Handle
class has the more straightforward fetch(): string
and execute(resource|callable $out): void
methods.
Curl\MultiHandleOption
namespace Curl; enum MultiHandleOption: int { case ChunkLengthPenaltySize = CURLMOPT_CHUNK_LENGTH_PENALTY_SIZE; case ContentLengthPenaltySize = CURLMOPT_CONTENT_LENGTH_PENALTY_SIZE; case MaxConnects = CURLMOPT_MAXCONNECTS; // ...other options elided... }
Curl\Info
namespace Curl; enum Info: int { case AppConnectTime = CURLINFO_APPCONNECT_TIME; // ...other values elided... }
Curl\Pause
namespace Curl; enum Pause: int { case All = CURLPAUSE_ALL; // ...other values elided... }
New Curl exception hierarchy
Like the previous RFC, this RFC proposes that we add a new exception class to represent curl
errors. Unlike the previous RFC, this will follow the newly ratified PHP RFC: Throwable Hierarchy Policy for Extensions:
namespace Curl; // "At the lowest level of the hierarchy there MUST be a base ``Exception`` and // base ``Error`` defined within the top-level of the extension's namespace." class CurlException extends \Exception {} class CurlError extends \Error {} // The HandleException class represents an exception generated by a Handle or MultiHandle. class HandleException extends CurlException { /** Equivalent to curl_error() or the non-existent curl_multi_error(). */ protected string $message; /** Equivalent to curl_errno() or curl_multi_errno(). */ protected int $code; }
Curl\Handle class implementation
The Curl\Handle
class is a relatively straightforward translation of the non-object-oriented APIs, albeit with a few differences:
- Instead of returning
false
, errors are treated as exceptions. curl_exec
has two equivalents:fetch
, for cases whereCURLOPT_RETURNTRANSFER
was previously used, andexecute
, forCURLOPT_FILE
.
namespace Curl; class Handle { /** Equivalent to curl_errno(). */ public private(set) int $errorNumber; /** Equivalent to curl_error(). */ public private(set) string $errorMessage; /** * Equivalent to curl_init(). */ public function __construct(?string $uri = null); /** * Equivalent to curl_exec(), except it (a) throws exceptions on failure, and (b) * always returns the content as a string. * * @throws \Curl\HandleException */ public function fetch(): string; /** * Equivalent to curl_exec(), except it (a) throws exceptions on failure, and (b) * will always write to the specified stream resource or write callback. * * A callable must have the following signature: * * callback(resource $curlHandle, string $data): int * * curlHandle * The cURL handle. * * data * The data to be written. * * The data must be saved by the callback and the callback must return the exact * number of bytes written or the transfer will be aborted with an error. * * @throws \Curl\HandleException */ public function execute(resource|callable $out): void /** * Equivalent to curl_getinfo(). */ public function getInfo(?\Curl\Info $option): mixed; /** * Equivalent to curl_pause(). */ public function pause(\Curl\Pause $flag): mixed; /** * Equivalent to curl_reset(). */ public function reset(): void; /** * Equivalent to curl_setopt(). * * @throws \Curl\HandleException */ public function setOption(\Curl\HandleOption $opt, mixed $value): \Curl\Handle; /** * Equivalent to curl_escape(). * * @throws \Curl\HandleException */ public function escapeUrl(string $string): string; /** * Equivalent to curl_unescape(). * * @throws \Curl\HandleException */ public function unescapeUrl(string $string): string; /** * Equivalent to curl_upkeep(). * * @throws \Curl\HandleException */ public function upkeep(): void; }
Curl\MultiHandle class implementation
The Curl\MultiHandle
class is again a relatively straightforward translation of the non-object-oriented APIs with the same differences as the Cur\Handle
translation.
A few additional notable differences:
curl_multi_exec
will not returnCURLM_CALL_MULTI_PERFORM
, and will instead emulate newercurl
libraries by internally callingcurl
until it no longer returnsCURLM_CALL_MULTI_PERFORM
.- Since
CURLOPT_RETURNTRANSFER
etc. are no longer valid options,addHandle
takes a parameter to indicate where PHP should direct the output of theCurl\Handle
. Anull
parameter value retains theCURLOPT_RETURNTRANSFER
behavior, where a user must then callgetContent
. curl_multi_select
is calledpoll
.curl_multi_info_read
is calledgetMessages
.
namespace Curl; class MultiHandle { /** Equivalent to curl_multi_errno(). */ public private(set) int $errorNumber; /** Equivalent to curl_multi_error(), if it existed. */ public private(set) string $errorMessage; /** * Equivalent to curl_multi_init(). */ public function __construct(); /** * Equivalent to curl_multi_add_handle(). * * $out, if specified, will write the output of the Curl\Handle to the stream or callback * when the Curl\MultiHandle is executed. If not specified, you can retrieve the content of * the handle via the getContent() method. * * @throws \Curl\HandleException */ public function addHandle(\Curl\Handle $handle, resource|callable|null $out = null): void; /** * Equivalent to curl_multi_remove_handle(). * * @throws \Curl\HandleException */ public function removeHandle(\Curl\Handle $handle): void; /** * Equivalent to curl_multi_exec(). Note that it will never return CURLM_CALL_MULTI_PERFORM, and will * internally emulate newer curl libraries. Returns true if there are still active connections. * * @throws \Curl\HandleException */ public function execute(): bool; /** * Equivalent to curl_multi_getcontent(). */ public function getContent(\Curl\Handle $handle): ?string; /** * Equivalent to curl_multi_info_read(). */ public function getMessages(int &$queued_messages = null): array|false; /** * Equivalent to curl_multi_select(). */ public function poll(float $timeout = 1.0): int /** * Equivalent to curl_multi_setopt(). * * @throws \Curl\HandleException */ public function setOption(\Curl\MultiHandleOption $opt, mixed $value): \Curl\MultiHandle; }
Examples
Curl\Handle
:
<?php $ch = new Curl\Handle("https://example.com") ->setOption(Curl\HandleOption::ConnectTimeout, 30) ->setOption(Curl\HandleOption::FollowLocation, true); try { echo $ch->fetch() . "\n"; } catch (\Curl\HandleException $ex) { echo "curl error ($ex->code): $ex->message\n"; }
Curl\MultiHandle
:
<?php $ch = new Curl\Handle("https://example.com") ->setOption(Curl\HandleOption::ConnectTimeout, 30) ->setOption(Curl\HandleOption::FollowLocation, true); $mh = new Curl\MultiHandle(); $mh->addHandle($ch); while ($mh->execute()) { echo "multi handle is still active...\n"; $mh->poll(1.0); } echo $mh->getContent($ch) . "\n";
Backward Incompatible Changes
The Curl
namespace will no longer be safe to use, and the aforementioned class names will be reserved, for example:
Curl\Handle
Curl\MultiHandle
Curl\CurlException
Curl\HandleOption
- ...
CurlHandle
and other existing classes will still work, as this RFC proposes to alias them to their new namespaced counterparts.
Proposed PHP Version(s)
Next PHP 8.x (currently 8.5, potentially 8.6).
RFC Impact
To the Ecosystem
None expected.
To Existing Extensions
curl
will gain new classes, and existing curl
classes will gain new methods.
To SAPIs
None expected.
Open Issues
Should we organize theResponses from the mailing list were skeptical of the value of typed-based enumerations.curl
option enumerations by value type? Or have a single enumeration for allcurl_setopt
options and allcurl_multi_setopt
options?Should we provide methods to improve the experience of usingWhile responses were positive, I would like to leave this for future scope.curl
for HTTP-based transfers?
Future Scope
There is a strong appetite from the community to simplify basic HTTP operations (GET, POST w/ a form body, POST w/ a JSON body). A future RFC could propose this, with or without a standard Request / Response interface in PHP's core.
Voting Choices
Patches and Tests
TBA, pending initial discussion.
References
- Previous RFC (PHP RFC: Add OOP methods to Curl objects) and discussion
- Previous discussion Discussion about new Curl URL API and ext/curl improvements
Rejected Features
Changelog
- 2025-07-01
- Updated exception hierarchy to conform with PHP RFC: Throwable Hierarchy Policy for Extensions.
- Proposed monolithic option enumerations in lieu of smaller typed enumerations.
- Translated
curl_exec
tofetch
andexecute
.
- 2025-07-07
- Removed open question around proposing a simple HTTP client, and moved it to the Future Scope section.
- Updated the
addHandle
method in theCurl\MultiHandle
class to account for the lack ofCURLOPT_RETURNTRANSFER
, etc. options.