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curl_formadd(3)                  libcurl Manual                  curl_formadd(3)




NAME

       curl_formadd - add a section to a multipart form POST


SYNOPSIS

       #include <curl/curl.h>

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


DESCRIPTION

       This function is deprecated. Use curl_mime_init(3) instead.

       curl_formadd() is used to append sections when building a multipart form
       post. Append one section at a time until you have added all the sections
       you want included and then you pass the firstitem pointer as parameter to
       CURLOPT_HTTPPOST(3).  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(3) as usual.

       First, there are some basics you need to understand about multipart form
       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 will 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 does not need to keep it
              around after this function call. If the name is not null-
              terminated, you must set its length with CURLFORM_NAMELENGTH. The
              name is not allowed to contain zero-valued bytes. 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 is not null-terminated, you must set its length with
              CURLFORM_NAMELENGTH.  The name is not allowed to contain zero-
              valued bytes.

       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 does not need to keep it around after this function
              call. If the data is not null terminated, or if you would 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 is not null-terminated, or
              if you would like it to contain zero bytes, you must set its
              length with CURLFORM_CONTENTSLENGTH.

       CURLFORM_CONTENTLEN
              followed by a curl_off_t value giving the length of the contents.
              Note that for CURLFORM_STREAM contents, this option is mandatory.

              If you pass a 0 (zero) for this option, libcurl will instead do a
              strlen() on the contents to figure out the size. If you really
              want to send a zero byte content then you must make sure strlen()
              on the data pointer returns zero.

              (Option added in 7.46.0)

       CURLFORM_CONTENTSLENGTH
              (This option is deprecated. Use CURLFORM_CONTENTLEN instead!)

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

              If you pass a 0 (zero) for this option, libcurl will instead do a
              strlen() on the contents to figure out the size. If you really
              want to send a zero byte content then you must make sure strlen()
              on the data pointer returns zero.

       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.

              The specified file needs to kept around until the associated
              transfer is done.

       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).

              The given upload file has to exist in its full in the file system
              already when the upload starts, as libcurl needs to read the
              correct file size beforehand.

              The specified file needs to kept around until the associated
              transfer is done.

       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(3) 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 unless the formpost is sent chunked encoded.
              (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 have passed the struct curl_httppost pointer to
              curl_easy_setopt(3) (using the CURLOPT_HTTPPOST(3) option), you
              must not free the list until after you have called
              curl_easy_cleanup(3) for the curl handle.

              See example below.


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);


AVAILABILITY

       Deprecated in 7.56.0. Before this release, field names were allowed to
       contain zero-valued bytes. The pseudo-filename "-" to read stdin is
       discouraged although still supported, but data is not read before being
       actually sent: the effective data size can then not be automatically
       determined, resulting in a chunked encoding transfer. Backslashes and
       double quotes in field and file names are now escaped before
       transmission.


RETURN VALUE

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


SEE ALSO

       curl_easy_setopt(3), curl_formfree(3), curl_mime_init(3)



libcurl 7.86.0                   October 3, 2022                 curl_formadd(3)

curl 7.86.0 - Generated Sat Nov 5 11:14:21 CDT 2022
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