multi interface, debug callback

docs/examples/multi-debugcallback.c

+/*****************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * $Id$
+ *
+ * This is a very simple example using the multi interface and the debug
+ * callback.
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+/* somewhat unix-specific */
+#include <sys/time.h>
+#include <unistd.h>
+
+/* curl stuff */
+#include <curl/curl.h>
+
+typedef char bool;
+#define TRUE 1
+
+static
+void dump(const char *text,
+          FILE *stream, unsigned char *ptr, size_t size,
+          bool nohex)
+{
+  size_t i;
+  size_t c;
+
+  unsigned int width=0x10;
+
+  if(nohex)
+    /* without the hex output, we can fit more on screen */
+    width = 0x40;
+
+  fprintf(stream, "%s, %zd bytes (0x%zx)\n", text, size, size);
+
+  for(i=0; i<size; i+= width) {
+
+    fprintf(stream, "%04zx: ", i);
+
+    if(!nohex) {
+      /* hex not disabled, show it */
+      for(c = 0; c < width; c++)
+        if(i+c < size)
+          fprintf(stream, "%02x ", ptr[i+c]);
+        else
+          fputs("   ", stream);
+    }
+
+    for(c = 0; (c < width) && (i+c < size); c++) {
+      /* check for 0D0A; if found, skip past and start a new line of output */
+      if (nohex && (i+c+1 < size) && ptr[i+c]==0x0D && ptr[i+c+1]==0x0A) {
+        i+=(c+2-width);
+        break;
+      }
+      fprintf(stream, "%c",
+              (ptr[i+c]>=0x20) && (ptr[i+c]<0x80)?ptr[i+c]:'.');
+      /* check again for 0D0A, to avoid an extra \n if it's at width */
+      if (nohex && (i+c+2 < size) && ptr[i+c+1]==0x0D && ptr[i+c+2]==0x0A) {
+        i+=(c+3-width);
+        break;
+      }
+    }
+    fputc('\n', stream); /* newline */
+  }
+  fflush(stream);
+}
+
+static
+int my_trace(CURL *handle, curl_infotype type,
+             unsigned char *data, size_t size,
+             void *userp)
+{
+  const char *text;
+
+  (void)handle; /* prevent compiler warning */
+
+  switch (type) {
+  case CURLINFO_TEXT:
+    fprintf(stderr, "== Info: %s", data);
+  default: /* in case a new one is introduced to shock us */
+    return 0;
+
+  case CURLINFO_HEADER_OUT:
+    text = "=> Send header";
+    break;
+  case CURLINFO_DATA_OUT:
+    text = "=> Send data";
+    break;
+  case CURLINFO_HEADER_IN:
+    text = "<= Recv header";
+    break;
+  case CURLINFO_DATA_IN:
+    text = "<= Recv data";
+    break;
+  }
+
+  dump(text, stderr, data, size, TRUE);
+  return 0;
+}
+
+/*
+ * Simply download a HTTP file.
+ */
+int main(int argc, char **argv)
+{
+  CURL *http_handle;
+  CURLM *multi_handle;
+
+  int still_running; /* keep number of running handles */
+
+  http_handle = curl_easy_init();
+
+  /* set the options (I left out a few, you'll get the point anyway) */
+  curl_easy_setopt(http_handle, CURLOPT_URL, "http://www.haxx.se/");
+
+  curl_easy_setopt(http_handle, CURLOPT_DEBUGFUNCTION, my_trace);
+  curl_easy_setopt(http_handle, CURLOPT_VERBOSE, TRUE);
+
+  /* init a multi stack */
+  multi_handle = curl_multi_init();
+
+  /* add the individual transfers */
+  curl_multi_add_handle(multi_handle, http_handle);
+
+  /* we start some action by calling perform right away */
+  while(CURLM_CALL_MULTI_PERFORM ==
+        curl_multi_perform(multi_handle, &still_running));
+
+  while(still_running) {
+    struct timeval timeout;
+    int rc; /* select() return code */
+
+    fd_set fdread;
+    fd_set fdwrite;
+    fd_set fdexcep;
+    int maxfd;
+
+    FD_ZERO(&fdread);
+    FD_ZERO(&fdwrite);
+    FD_ZERO(&fdexcep);
+
+    /* set a suitable timeout to play around with */
+    timeout.tv_sec = 1;
+    timeout.tv_usec = 0;
+
+    /* get file descriptors from the transfers */
+    curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd);
+
+    rc = select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout);
+
+    switch(rc) {
+    case -1:
+      /* select error */
+      still_running = 0;
+      printf("select() returns error, this is badness\n");
+      break;
+    case 0:
+    default:
+      /* timeout or readable/writable sockets */
+      while(CURLM_CALL_MULTI_PERFORM ==
+            curl_multi_perform(multi_handle, &still_running));
+      break;
+    }
+  }
+
+  curl_multi_cleanup(multi_handle);
+
+  curl_easy_cleanup(http_handle);
+
+  return 0;
+}