Overview: Network

Allows overriding the default use of libcurl in libquvi.  For example, an application could use libsoup instead of libcurl.

An application must set the necessary properties in its corresponding callbacks.  Besides the Common properties, each callback is expected to set any additional properties listed below.

quvi_net_setprop(net_handle, QUVI_NET_PROPERTY_RESPONSECODE, resp_code);

Common properties that are expected to be set by all callbacks.

• QUVI_NET_PROPERTY_RESPONSECODE

quvi_setopt(session_handle, QUVIOPT_FETCHFUNCTION, &fetch_callback_func);

In addition to the Common properties, must set

• QUVI_NET_PROPERTY_CONTENT

Return

• Either QUVI_OK or QUVI_CALLBACK if an error occurred

quvi_setopt(session_handle, QUVIOPT_RESOLVEFUNCTION, &resolve_callback_func);

In addition to the Common properties -- if a redirection to another location was found, then must set

• QUVI_NET_PROPERTY_REDIRECTURL

Notes

This callback should return QUVI_CALLBACK only if an unrecoverable error occurred, e.g. a network error.  Return QUVI_OK in all other cases, including those in which a redirection URL was not found.

Return

• Either QUVI_OK or QUVI_CALLBACK if an (e.g. network) error occurred
• Return QUVI_OK even if a redirection URL was not found

quvi_setopt(session_handle, QUVIOPT_VERIFYFUNCTION, &verify_callback_func);

In addition to the Common properties, must set

• QUVI_NET_PROPERTY_CONTENTTYPE
• QUVI_NET_PROPERTY_CONTENTLENGTH

Return

• Either QUVI_OK or QUVI_CALLBACK if an error occurred

Basic example.  This example assumes that a fictional `do_fetch’ function fetches the data over the network.  The callback then relays the data and any errors back to libquvi.  Some error checks omitted for brewity.

static QUVIcode fetch_callback(quvi_net_t net_handle)
{
  char *url, *reason, *content;
  long resp_code;
  int fetch_ok;

  quvi_net_getprop(net_handle, QUVI_NET_PROPERTY_URL, &url);

  fetch_ok = do_fetch(url, &content, &resp_code, &reason);

  quvi_net_setprop(net_handle, QUVI_NET_PROPERTY_RESPONSECODE, resp_code);

  if (fetch_ok)
    {
      quvi_net_setprop(net_handle, QUVI_NET_PROPERTY_CONTENT, content);
      return (QUVI_OK);
    }

  quvi_net_seterr(net_handle, "%s (http/%d)", reason, resp_code);

  return (QUVI_CALLBACK); /* Tell the library an error occurred */
}

int main(int argc, char **argv)
{
  quvi_t q;
  quvi_init(&q);
  quvi_setopt(q, QUVIOPT_FETCHFUNCTION, &fetch_callback);
  quvi_parse(...);
  quvi_close(&q);
  return (0);
}