man pages section 3: Library Interfaces and Headers

CURLOPT_CHUNK_BGN_FUNCTION (3)

Name

CURLOPT_CHUNK_BGN_FUNCTION - cardmatch

Synopsis

#include <curl/curl.h>

struct curl_fileinfo {
char *filename;
curlfiletype filetype;
time_t time;   /* always zero! */
unsigned int perm;
int uid;
int gid;
curl_off_t size;
long int hardlinks;

struct {
/* If some of these fields is not NULL, it is a pointer to b_data. */
char *time;
char *perm;
char *user;
char *group;
char *target; /* pointer to the target filename of a symlink */
} strings;

unsigned int flags;

/* used internally */
char *b_data;
size_t b_size;
size_t b_used;
};

long chunk_bgn_callback(const void *transfer_info, void *ptr,
int remains);

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CHUNK_BGN_FUNCTION,
chunk_bgn_callback);

Description

curl_easy_setopt options                         CURLOPT_CHUNK_BGN_FUNCTION(3)



NAME
       CURLOPT_CHUNK_BGN_FUNCTION  - callback before a transfer with FTP wild-
       cardmatch

SYNOPSIS
       #include <curl/curl.h>

       struct curl_fileinfo {
         char *filename;
         curlfiletype filetype;
         time_t time;   /* always zero! */
         unsigned int perm;
         int uid;
         int gid;
         curl_off_t size;
         long int hardlinks;

         struct {
           /* If some of these fields is not NULL, it is a pointer to b_data. */
           char *time;
           char *perm;
           char *user;
           char *group;
           char *target; /* pointer to the target filename of a symlink */
         } strings;

         unsigned int flags;

         /* used internally */
         char *b_data;
         size_t b_size;
         size_t b_used;
       };

       long chunk_bgn_callback(const void *transfer_info, void *ptr,
                               int remains);

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CHUNK_BGN_FUNCTION,
                                 chunk_bgn_callback);

DESCRIPTION
       Pass a pointer to your callback function, which should match the proto-
       type shown above.

       This  callback  function  gets  called  by libcurl before a part of the
       stream is going to be transferred (if the transfer supports chunks).

       The transfer_info pointer will point to  a  struct  curl_fileinfo  with
       details about the file that is about to get transferred.

       This  callback makes sense only when using the CURLOPT_WILDCARDMATCH(3)
       option for now.

       The target of transfer_info parameter is a  "feature  depended"  struc-
       ture. For the FTP wildcard download, the target is curl_fileinfo struc-
       ture (see curl/curl.h).  The parameter ptr is a pointer given  by  CUR-
       LOPT_CHUNK_DATA(3).  The  parameter  remains  contains number of chunks
       remaining per the transfer. If the feature is not available, the param-
       eter has zero value.

       Return     CURL_CHUNK_BGN_FUNC_OK     if     everything     is    fine,
       CURL_CHUNK_BGN_FUNC_SKIP if you want to  skip  the  concrete  chunk  or
       CURL_CHUNK_BGN_FUNC_FAIL   to  tell  libcurl  to  stop  if  some  error
       occurred.

DEFAULT
       NULL

PROTOCOLS
       FTP

EXAMPLE
       static long file_is_coming(struct curl_fileinfo *finfo,
                                  struct callback_data *data,
                                  int remains)
       {
         printf("%3d %40s %10luB ", remains, finfo->filename,
                (unsigned long)finfo->size);

         switch(finfo->filetype) {
         case CURLFILETYPE_DIRECTORY:
           printf(" DIR\n");
           break;
         case CURLFILETYPE_FILE:
           printf("FILE ");
           break;
         default:
           printf("OTHER\n");
           break;
         }

         if(finfo->filetype == CURLFILETYPE_FILE) {
           /* do not transfer files >= 50B */
           if(finfo->size > 50) {
             printf("SKIPPED\n");
             return CURL_CHUNK_BGN_FUNC_SKIP;
           }

           data->output = fopen(finfo->filename, "wb");
           if(!data->output) {
             return CURL_CHUNK_BGN_FUNC_FAIL;
           }
         }

         return CURL_CHUNK_BGN_FUNC_OK;
       }

       int main()
       {
         /* data for callback */
         struct callback_data callback_info;

         /* callback is called before download of concrete file started */
         curl_easy_setopt(curl, CURLOPT_CHUNK_BGN_FUNCTION, file_is_coming);
         curl_easy_setopt(curl, CURLOPT_CHUNK_DATA, &callback_info);
       }

AVAILABILITY
       This was added in 7.21.0

RETURN VALUE
       Returns CURLE_OK if the option is supported,  and  CURLE_UNKNOWN_OPTION
       if not.


ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:


       +---------------+------------------+
       |ATTRIBUTE TYPE | ATTRIBUTE VALUE  |
       +---------------+------------------+
       |Availability   | web/curl         |
       +---------------+------------------+
       |Stability      | Uncommitted      |
       +---------------+------------------+

SEE ALSO
       CURLOPT_CHUNK_END_FUNCTION(3), CURLOPT_WILDCARDMATCH(3),



NOTES
       Source  code  for open source software components in Oracle Solaris can
       be found at https://www.oracle.com/downloads/opensource/solaris-source-
       code-downloads.html.

       This     software     was    built    from    source    available    at
       https://github.com/oracle/solaris-userland.   The  original   community
       source       was       downloaded      from       https://curl.se/down-
       load/curl-7.83.1.tar.bz2.

       Further information about this software can be found on the open source
       community website at http://curl.haxx.se/.



libcurl 7.83.1                 November 04, 2020
                                                 CURLOPT_CHUNK_BGN_FUNCTION(3)