Module Curl.Multi

Curl multi stack. Functions may raise Failure on critical errors

type mt

type of Curl multi stack

type curlPipelining =
  1. | PIPE_NOTHING
  2. | PIPE_HTTP1
  3. | PIPE_MULTIPLEX
type curlMultiOption =
  1. | CURLMOPT_PIPELINING of curlPipelining list
  2. | CURLMOPT_MAXCONNECTS of int
  3. | CURLMOPT_MAX_PIPELINE_LENGTH of int
  4. | CURLMOPT_MAX_HOST_CONNECTIONS of int
  5. | CURLMOPT_MAX_TOTAL_CONNECTIONS of int
exception Error of string

exception raised on internal errors

type cerror
val int_of_cerror : cerror -> int
exception CError of string * cerror * string

exception raised on libcurl errors : origin * code * message

val create : unit -> mt

create new multi stack

val add : mt -> t -> unit

add handle to multi stack

val remove : mt -> t -> unit

remove handle from multi stack (effectively halting the transfer)

val perform : mt -> int

perform pending data transfers (if any) on all handles currently in multi stack

  • returns

    the number of handles that still transfer data

type waitfd_event =
  1. | CURL_WAIT_POLLIN
  2. | CURL_WAIT_POLLPRI
  3. | CURL_WAIT_POLLOUT
type waitfd
val waitfd : Unix.file_descr -> waitfd_event list -> waitfd
val waitfd_fd : waitfd -> Unix.file_descr
val waitfd_isset : waitfd -> waitfd_event -> bool
val wait : ?timeout_ms:int -> ?extra_fds:waitfd list -> mt -> bool

wait till there are some active data transfers on multi stack

  • returns

    whether perform should be called

val poll : ?timeout_ms:int -> ?extra_fds:waitfd list -> mt -> bool

poll till there are some active data transfers on multi stack. Contrary to wait, this function does not return immediately when there are no pending transfer but waits for timeout_ms The module falls back to wait if this function is unavailable.

  • returns

    whether perform should be called

val remove_finished : mt -> (t * curlCode) option

remove finished handle from the multi stack if any. The returned handle may be reused

val cleanup : mt -> unit

destroy multi handle (all transfers are stopped, but individual Curl.t handles can be reused)

type poll =
  1. | POLL_NONE
    (*

    none

    *)
  2. | POLL_IN
    (*

    available for reading

    *)
  3. | POLL_OUT
    (*

    available for writing

    *)
  4. | POLL_INOUT
    (*

    both

    *)
  5. | POLL_REMOVE
    (*

    socket not needed anymore

    *)

events that should be reported for the socket

type fd_status =
  1. | EV_AUTO
    (*

    determine socket status automatically (with extra system call)

    *)
  2. | EV_IN
    (*

    socket has incoming data

    *)
  3. | EV_OUT
    (*

    socket is available for writing

    *)
  4. | EV_INOUT
    (*

    both

    *)

socket status

val set_socket_function : mt -> (Unix.file_descr -> poll -> unit) -> unit

set the function to receive notifications on what socket events are currently interesting for libcurl on the specified socket handle

val set_timer_function : mt -> (int -> unit) -> unit

set the function to receive notification when libcurl internal timeout changes, timeout value is in milliseconds

NB action_timeout should be called when timeout occurs

val set_closesocket_function : mt -> (Unix.file_descr -> unit) -> unit

set a function to be called to close a socket.

The underlying callback is a property of the easy handle, but cannot be stored there in these bindings because libcurl's use of this callback may occur outside the lifetime of the easy handle. This means that all easy handles added to a multi handle must use the same closesocket function.

val action_all : mt -> int

perform pending data transfers (if any) on all handles currently in multi stack (not recommended, action should be used instead)

  • returns

    the number of handles that still transfer data

val action_timeout : mt -> unit

inform libcurl that timeout occured

val action : mt -> Unix.file_descr -> fd_status -> int

action mt fd status informs libcurl about event on the specified socket. status specifies socket status. Perform pending data transfers.

  • returns

    the number of handles still active

val timeout : mt -> int

timeout mt polls multi handle for timeout (not recommended, use set_timer_function instead).

  • returns

    maximum allowed number of milliseconds to wait before calling libcurl to perform actions

val setopt : mt -> curlMultiOption -> unit