add libcurl example

examples/poll-libcurl.lua

@@ -0,0 +1,191 @@
+-- FFI example for libcurl integration into the libuv event loop
+local ffi = require('ffi')
+local bit = require('bit')
+local uv = require('uv')
+
+local timer = require('timer')
+local Object = require('core').Object
+local utils = require('utils')
+
+local libcurl = ffi.load('libcurl')
+ffi.cdef[[
+  enum CURLMSG {
+    CURLMSG_NONE, /* first, not used */
+    CURLMSG_DONE, /* This easy handle has completed. 'result' contains the CURLcode of the transfer */
+    CURLMSG_LAST /* last, not used */
+  };
+
+  struct CURLMsg {
+    enum CURLMSG msg;       /* what this message means */
+    void *easy_handle; /* the handle it concerns */
+    union {
+      void *whatever;    /* message-specific data */
+      int result;   /* return code for transfer */
+    } data;
+  };
+
+  enum curl_global_option
+  {
+    CURL_GLOBAL_ALL = 2,
+  };
+
+  enum curl_multi_option
+  {
+    CURLMOPT_SOCKETFUNCTION = 20000 + 1,
+    CURLMOPT_TIMERFUNCTION = 20000 + 4
+  };
+
+  enum curl_socket_option
+  {
+    CURL_SOCKET_TIMEOUT = -1
+  };
+
+  enum curl_poll_option
+  {
+    CURL_POLL_IN = 1,
+    CURL_POLL_OUT = 2,
+    CURL_POLL_REMOVE = 4
+  };
+
+  enum curl_option
+  {
+    CURLOPT_CAINFO    = 10065,
+    CURLOPT_CONNECTTIMEOUT  = 78,
+    CURLOPT_COOKIE    = 10022,
+    CURLOPT_FOLLOWLOCATION  = 52,
+    CURLOPT_HEADER    = 42,
+    CURLOPT_HTTPHEADER  = 10023,
+    CURLOPT_INTERFACE   = 10062,
+    CURLOPT_POST    = 47,
+    CURLOPT_POSTFIELDS  = 10015,
+    CURLOPT_REFERER   = 10016,
+    CURLOPT_SSL_VERIFYPEER  = 64,
+    CURLOPT_URL   = 10002,
+    CURLOPT_USERAGENT   = 10018,
+    CURLOPT_WRITEFUNCTION = 20011
+  };
+
+  enum curl_cselect_option
+  {
+    CURL_CSELECT_IN = 0x01,
+    CURL_CSELECT_OUT = 0x02
+  };
+
+  /*
+  #define CURLOPTTYPE_LONG          0
+  #define CURLOPTTYPE_OBJECTPOINT   10000
+  #define CURLOPTTYPE_FUNCTIONPOINT 20000
+  #define CURLOPTTYPE_OFF_T         30000
+  */
+
+  void *curl_easy_init();
+  int   curl_easy_setopt(void *curl, enum curl_option option, ...);
+  int   curl_easy_perform(void *curl);
+  void  curl_easy_cleanup(void *curl);
+  char *curl_easy_strerror(int code);
+
+  int   curl_global_init(enum curl_global_option option);
+
+  void *curl_multi_init();
+  int   curl_multi_setopt(void *curlm, enum curl_multi_option option, ...);
+  int   curl_multi_add_handle(void *curlm, void *curl_handle);
+  int   curl_multi_socket_action(void *curlm, int s, int ev_bitmask, int *running_handles);
+  int   curl_multi_assign(void *curlm, int sockfd, void *sockp);
+  int   curl_multi_remove_handle(void *curlm, void *curl_handle);
+  struct CURLMsg *curl_multi_info_read(void *culm, int *msgs_in_queue);
+
+  typedef int (*curlm_socketfunction_ptr_t)(void *curlm, int sockfd, int ev_bitmask, int *running_handles);
+  typedef int (*curlm_timeoutfunction_ptr_t)(void *curlm, long timeout_ms, int *userp);
+  typedef size_t (*curl_datafunction_ptr_t)(char *ptr, size_t size, size_t nmemb, void *userdata);
+]]
+
+local Multi = Object:extend()
+function Multi:initialize()
+  self.polls = {}
+  self.socketWrapper = ffi.cast('curlm_socketfunction_ptr_t', utils.bind(Multi._onSocket, self))
+  self.timeoutWrapper = ffi.cast('curlm_timeoutfunction_ptr_t', utils.bind(Multi._onTimeout, self))
+  self.multi = libcurl.curl_multi_init()
+  libcurl.curl_multi_setopt(self.multi, ffi.C.CURLMOPT_SOCKETFUNCTION, self.socketWrapper)
+  libcurl.curl_multi_setopt(self.multi, ffi.C.CURLMOPT_TIMERFUNCTION, self.timeoutWrapper)
+end
+
+function Multi:add(url)
+  local handle = libcurl.curl_easy_init()
+  local dataCallback = ffi.cast('curl_datafunction_ptr_t', utils.bind(Multi._onData, self))
+  libcurl.curl_easy_setopt(handle,
+                           ffi.C.CURLOPT_URL,
+                           url)
+  libcurl.curl_easy_setopt(handle,
+                           ffi.C.CURLOPT_WRITEFUNCTION,
+                           dataCallback)
+  libcurl.curl_multi_add_handle(self.multi, handle);
+end
+
+function Multi:_onData(ptr, size, nmemb, userdata)
+  print(ffi.string(ptr))
+  return size
+end
+
+function Multi:_onSocket(easy, sockfd, action)
+  timer.clearTimer(self.timer)
+  local function perform(err, events)
+    local flags = bit.tobit(0)
+    if events == 'r' then
+      flags = bit.bor(flags, ffi.C.CURL_CSELECT_IN)
+    elseif events == 'w' then
+      flags = bit.bor(flags, ffi.C.CURL_CSELECT_OUT)
+    end
+
+    local running_handles = ffi.new('int[1]')
+    libcurl.curl_multi_socket_action(self.multi, sockfd, flags, running_handles)
+
+    while true do
+      local pending = ffi.new('int[1]')
+      local msg = libcurl.curl_multi_info_read(self.multi, pending)
+      if msg == nil then break end
+      if msg.msg == ffi.C.CURLMSG_DONE then
+        libcurl.curl_multi_remove_handle(self.multi, easy)
+        libcurl.curl_easy_cleanup(easy)
+        break
+      end
+    end
+  end
+
+  local poll = self.polls[sockfd]
+  if not poll then
+    poll = uv.new_poll(sockfd)
+    self.polls[sockfd] = poll
+  end
+
+  if action == ffi.C.CURL_POLL_IN then
+    uv.poll_start(poll, 'r', perform)
+  elseif action == ffi.C.CURL_POLL_OUT then
+    uv.poll_start(poll, 'w', perform)
+  elseif action == ffi.C.CURL_POLL_REMOVE then
+    uv.poll_stop(poll)
+    uv.close(poll)
+    self.polls[sockfd] = nil
+  end
+
+  return 0
+end
+
+function Multi:_onTimeout(curlm, timeout_ms)
+  timeout_ms = tonumber(timeout_ms)
+  if timeout_ms < 0 then
+    timeout_ms = 1
+  end
+  if self.timer then timer.clearTimer(self.timer) end
+  local function action()
+    local running_handles = ffi.new('int[1]')
+    libcurl.curl_multi_socket_action(curlm, ffi.C.CURL_SOCKET_TIMEOUT, 0, running_handles)
+  end
+  self.timer = timer.setTimeout(timeout_ms, action)
+  return 0
+end
+
+libcurl.curl_global_init(ffi.C.CURL_GLOBAL_ALL)
+local m = Multi:new()
+for i=1, 2 do
+  m:add('https://luvit.io/')
+end