NAME

       curl_formadd - add a section to a multipart/formdata HTTP POST

SYNOPSIS

       #include <curl/curl.h>

       CURLFORMcode curl_formadd(struct curl_httppost ** firstitem, struct curl_httppost ** lastitem, ...);

DESCRIPTION

       curl_formadd()  is  used  to  append  sections  when  building  a multipart/formdata HTTP POST (sometimes
       referred to as RFC2388-style posts). Append one section at a time until you've added all the sections you
       want included and then you pass the firstitem pointer as parameter to CURLOPT_HTTPPOST.  lastitem is  set
       after  each  curl_formadd(3)  call  and  on  repeated  invokes it should be left as set to allow repeated
       invokes to find the end of the list faster.

       After the lastitem pointer follow the real arguments.

       The pointers firstitem and lastitem should both be pointing to NULL in the first call to  this  function.
       All  list-data  will be allocated by the function itself. You must call curl_formfree(3) on the firstitem
       after the form post has been done to free the resources.

       Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header.  You can disable this header
       with CURLOPT_HTTPHEADER as usual.

       First, there are some basics you need to understand about multipart/formdata posts. Each part consists of
       at least a NAME and a CONTENTS part. If the part is made  for  file  upload,  there  are  also  a  stored
       CONTENT-TYPE  and  a  FILENAME.  Below, we'll discuss what options you use to set these properties in the
       parts you want to add to your post.

       The  options  listed  first  are  for  making  normal  parts.  The  options  from  CURLFORM_FILE  through
       CURLFORM_BUFFERLENGTH are for file upload parts.

OPTIONS

       CURLFORM_COPYNAME
              followed  by  a  string  which  provides  the name of this part. libcurl copies the string so your
              application doesn't need to keep it around after this  function  call.  If  the  name  isn't  NUL-
              terminated,  or  if  you'd  like  it  to  contain  zero  bytes,  you  must  set  its  length  with
              CURLFORM_NAMELENGTH. The copied data will be freed by curl_formfree(3).

       CURLFORM_PTRNAME
              followed by a string which provides the name of this part. libcurl will use the pointer and  refer
              to  the  data in your application, so you must make sure it remains until curl no longer needs it.
              If the name isn't NUL-terminated, or if you'd like it to contain zero  bytes,  you  must  set  its
              length with CURLFORM_NAMELENGTH.

       CURLFORM_COPYCONTENTS
              followed  by  a pointer to the contents of this part, the actual data to send away. libcurl copies
              the provided data, so your application doesn't need to keep it around after this function call. If
              the data isn't null terminated, or if you'd like it to contain zero bytes, you must set the length
              of the name with CURLFORM_CONTENTSLENGTH. The copied data will be freed by curl_formfree(3).

       CURLFORM_PTRCONTENTS
              followed by a pointer to the contents of this part, the actual data to send away. libcurl will use
              the pointer and refer to the data in your application, so you must make sure it remains until curl
              no longer needs it.  If the data isn't NUL-terminated, or if you'd like it to contain zero  bytes,
              you must set its length  with CURLFORM_CONTENTSLENGTH.

       CURLFORM_CONTENTSLENGTH
              followed by a long giving the length of the contents. Note that for CURLFORM_STREAM contents, this
              option is mandatory.

       CURLFORM_FILECONTENT
              followed  by  a  filename, causes that file to be read and its contents used as data in this part.
              This part does not automatically become a file upload part simply because its data was read from a
              file.

       CURLFORM_FILE
              followed by a filename, makes this part a file upload part. It sets  the  filename  field  to  the
              basename  of  the provided filename, it reads the contents of the file and passes them as data and
              sets the content-type if the given file match one of the internally known  file  extensions.   For
              CURLFORM_FILE  the user may send one or more files in one part by providing multiple CURLFORM_FILE
              arguments  each  followed  by  the  filename  (and  each  CURLFORM_FILE  is  allowed  to  have   a
              CURLFORM_CONTENTTYPE).

       CURLFORM_CONTENTTYPE
              is  used  in  combination with CURLFORM_FILE. Followed by a pointer to a string which provides the
              content-type for this part, possibly instead of an internally chosen one.

       CURLFORM_FILENAME
              is used in combination with CURLFORM_FILE. Followed by a pointer to a string, it tells libcurl  to
              use the given string as the filename in the file upload part instead of the actual file name.

       CURLFORM_BUFFER
              is used for custom file upload parts without use of CURLFORM_FILE.  It tells libcurl that the file
              contents  are  already present in a buffer.  The parameter is a string which provides the filename
              field in the content header.

       CURLFORM_BUFFERPTR
              is used in combination with CURLFORM_BUFFER. The parameter is  a  pointer  to  the  buffer  to  be
              uploaded.  This buffer must not be freed until after curl_easy_cleanup(3) is called. You must also
              use CURLFORM_BUFFERLENGTH to set the number of bytes in the buffer.

       CURLFORM_BUFFERLENGTH
              is used in combination with CURLFORM_BUFFER. The parameter is a long which gives the length of the
              buffer.

       CURLFORM_STREAM
              Tells libcurl to use the CURLOPT_READFUNCTION callback to get data.  The  parameter  you  pass  to
              CURLFORM_STREAM  is  the pointer passed on to the read callback's fourth argument. If you want the
              part to look like a file upload one, set the CURLFORM_FILENAME parameter as well. Note  that  when
              using  CURLFORM_STREAM, CURLFORM_CONTENTSLENGTH must also be set with the total expected length of
              the part. (Option added in libcurl 7.18.2)

       CURLFORM_ARRAY
              Another possibility to send options to curl_formadd() is the CURLFORM_ARRAY option, that passes  a
              struct   curl_forms  array  pointer  as  its  value.  Each  curl_forms  structure  element  has  a
              CURLformoption and a char pointer. The final element in the array  must  be  a  CURLFORM_END.  All
              available  options  can  be  used  in an array, except the CURLFORM_ARRAY option itself!  The last
              argument in such an array must always be CURLFORM_END.

       CURLFORM_CONTENTHEADER
              specifies extra headers for the form POST section.  This takes a curl_slist prepared in the  usual
              way  using  curl_slist_append  and  appends  the  list  of  headers to those libcurl automatically
              generates. The list must exist while the POST occurs, if you free it before the post completes you
              may experience problems.

              When you've passed  the  HttpPost  pointer  to  curl_easy_setopt(3)  (using  the  CURLOPT_HTTPPOST
              option),  you  must  not free the list until after you've called curl_easy_cleanup(3) for the curl
              handle.

              See example below.

RETURN VALUE

       0 means everything was ok, non-zero means an error occurred corresponding to  a  CURL_FORMADD_*  constant
       defined in <curl/curl.h>

EXAMPLE

        struct curl_httppost* post = NULL;
        struct curl_httppost* last = NULL;
        char namebuffer[] = "name buffer";
        long namelength = strlen(namebuffer);
        char buffer[] = "test buffer";
        char htmlbuffer[] = "<HTML>test buffer</HTML>";
        long htmlbufferlength = strlen(htmlbuffer);
        struct curl_forms forms[3];
        char file1[] = "my-face.jpg";
        char file2[] = "your-face.jpg";
        /* add null character into htmlbuffer, to demonstrate that
           transfers of buffers containing null characters actually work
        */
        htmlbuffer[8] = '\0';

        /* Add simple name/content section */
        curl_formadd(&post, &last, CURLFORM_COPYNAME, "name",
                     CURLFORM_COPYCONTENTS, "content", CURLFORM_END);

        /* Add simple name/content/contenttype section */
        curl_formadd(&post, &last, CURLFORM_COPYNAME, "htmlcode",
                     CURLFORM_COPYCONTENTS, "<HTML></HTML>",
                     CURLFORM_CONTENTTYPE, "text/html", CURLFORM_END);

        /* Add name/ptrcontent section */
        curl_formadd(&post, &last, CURLFORM_COPYNAME, "name_for_ptrcontent",
                     CURLFORM_PTRCONTENTS, buffer, CURLFORM_END);

        /* Add ptrname/ptrcontent section */
        curl_formadd(&post, &last, CURLFORM_PTRNAME, namebuffer,
                     CURLFORM_PTRCONTENTS, buffer, CURLFORM_NAMELENGTH,
                     namelength, CURLFORM_END);

        /* Add name/ptrcontent/contenttype section */
        curl_formadd(&post, &last, CURLFORM_COPYNAME, "html_code_with_hole",
                     CURLFORM_PTRCONTENTS, htmlbuffer,
                     CURLFORM_CONTENTSLENGTH, htmlbufferlength,
                     CURLFORM_CONTENTTYPE, "text/html", CURLFORM_END);

        /* Add simple file section */
        curl_formadd(&post, &last, CURLFORM_COPYNAME, "picture",
                     CURLFORM_FILE, "my-face.jpg", CURLFORM_END);

        /* Add file/contenttype section */
        curl_formadd(&post, &last, CURLFORM_COPYNAME, "picture",
                     CURLFORM_FILE, "my-face.jpg",
                     CURLFORM_CONTENTTYPE, "image/jpeg", CURLFORM_END);

        /* Add two file section */
        curl_formadd(&post, &last, CURLFORM_COPYNAME, "pictures",
                     CURLFORM_FILE, "my-face.jpg",
                     CURLFORM_FILE, "your-face.jpg", CURLFORM_END);

        /* Add two file section using CURLFORM_ARRAY */
        forms[0].option = CURLFORM_FILE;
        forms[0].value  = file1;
        forms[1].option = CURLFORM_FILE;
        forms[1].value  = file2;
        forms[2].option  = CURLFORM_END;

        /* Add a buffer to upload */
        curl_formadd(&post, &last,
                     CURLFORM_COPYNAME, "name",
                     CURLFORM_BUFFER, "data",
                     CURLFORM_BUFFERPTR, record,
                     CURLFORM_BUFFERLENGTH, record_length,
                     CURLFORM_END);

        /* no option needed for the end marker */
        curl_formadd(&post, &last, CURLFORM_COPYNAME, "pictures",
                     CURLFORM_ARRAY, forms, CURLFORM_END);
        /* Add the content of a file as a normal post text value */
        curl_formadd(&post, &last, CURLFORM_COPYNAME, "filecontent",
                     CURLFORM_FILECONTENT, ".bashrc", CURLFORM_END);
        /* Set the form info */
        curl_easy_setopt(curl, CURLOPT_HTTPPOST, post);

SEE ALSO

       curl_easy_setopt(3), curl_formfree(3)

libcurl 7.9.8                                     24 June 2002                                   curl_formadd(3)