Provided by: libcurl4-doc_7.35.0-1ubuntu2_all bug

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)