PHP, while generally stateless by default, occasionally provides forms of “persistence” for connections, e.g. PDO::ATTR_PERSISTENT for persistent PDO connections.
Persistence allows PHP scripts to eliminate the overhead of establishing a connection on subsequent requests, which can improve performance and reliability.
curl, a popular URL transfer library made available as a core extension in PHP, provides the ability to share data between curl handles via a “share” interface. The PHP extension supports this functionality in curl_share_init and related functions.
The PHP extension does not, however, support persistent curl share handles. Connections (and DNS lookups, SSL session IDs, etc.) are only shared between handles within a single SAPI request.
This RFC proposes to enable users to create persistent curl share handles, by modifying the signature of curl_share_init to accept a persistent ID: curl_share_init(?array $share_options, ?string $persistent_id).
When called with a persistent ID, the function will first check the global memory within the SAPI worker for an existing curl share handle. If found, the function will return immediately.
If a curl share handle does not already exist, the function will construct a new one, apply the given share options, store it in global memory, and return it.
Since curl share handles are stateful, developers must consider whether a given CURL_LOCK_DATA_* constant is safe to use in a persistent context.
CURL_LOCK_DATA_CONNECT and CURL_LOCK_DATA_SSL_SESSION is safe to use; curl will not reuse connections between CurlHandle objects unless the connection settings (e.g. TLS client certificates) match.CURL_LOCK_DATA_COOKIE is not safe to use when making downstream requests on behalf of users; developers must take care to ensure that authentication cookies, etc. are not shared between separate users.CURL_LOCK_DATA_DNS is safe to use.CURL_LOCK_DATA_PSL is safe to use.None expected.
Next PHP minor release.
SAPIs will consume more memory proportional to the number of persistent curl share handles.
curl_share_init in ext/curl will have a new signature.
None.
None.
None.
Voting started on 2024-10-24 and will end on 2024-11-08 00:00 UTC.
This vote requires a ⅔ majority: