curl/docs/libcurl/curl_formadd.3

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.TH curl_formadd 3 "24 June 2002" "libcurl 7.9.8" "libcurl Manual"
.SH NAME
curl_formadd - add a section to a multipart/formdata HTTP POST
.SH SYNOPSIS
.B #include <curl/curl.h>
.sp
.BI "CURLFORMcode curl_formadd(struct HttpPost ** " firstitem,
.BI "struct HttpPost ** " lastitem, " ...);"
.ad
.SH DESCRIPTION
curl_formadd() is used to append sections when building a multipart/formdata
HTTP POST (sometimes refered to as rfc1867-style posts). Append one section at
a time until you've added all the sections you want included and then you pass
the \fIfirstitem\fP pointer as parameter to \fBCURLOPT_HTTPPOST\fP.
\fIlastitem\fP is set after each 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 \fIlastitem\fP pointer follow the real arguments. (If the following
description confuses you, jump directly to the examples):

\fBCURLFORM_COPYNAME\fP or \fBCURLFORM_PTRNAME\fP followed by a string is used
for the name of the section. Optionally one may use \fBCURLFORM_NAMELENGTH\fP
to specify the length of the name (allowing null characters within the
name). All options that use the word COPY in their names copy the given
contents, while the ones with PTR in their names simply points to the (static)
data you must make sure remain until curl no longer needs it.

The options for providing values are: \fBCURLFORM_COPYCONTENTS\fP,
\fBCURLFORM_PTRCONTENTS\fP, \fBCURLFORM_FILE\fP, \fBCURLFORM_BUFFER\fP,
or \fBCURLFORM_FILECONTENT\fP followed by a char or void pointer
(allowed for PTRCONTENTS).

\fBCURLFORM_FILECONTENT\fP does a normal post like \fBCURLFORM_COPYCONTENTS\fP
but the actual value is read from the filename given as a string.

Other arguments may be \fBCURLFORM_CONTENTTYPE\fP if the user wishes to
specify one (for FILE if no type is given the library tries to provide the
correct one; for CONTENTS no Content-Type is sent in this case).

For \fBCURLFORM_PTRCONTENTS\fP or \fBCURLFORM_COPYNAME\fP the user may also
add \fBCURLFORM_CONTENTSLENGTH\fP followed by the length as a long (if not
given the library will use strlen to determine the length).

For \fBCURLFORM_FILE\fP the user may send multiple files in one section by
providing multiple \fBCURLFORM_FILE\fP arguments each followed by the filename
(and each FILE is allowed to have a CONTENTTYPE).

\fBCURLFORM_BUFFER\fP 
tells libcurl that a buffer is to be used to upload data instead of using a
file. The value of the next parameter is used as the value of the "filename"
parameter in the content header.

\fBCURLFORM_BUFFERPTR\fP
tells libcurl that the address of the next parameter is a pointer to the buffer
containing data to upload. The buffer containing this data must not be freed
until after curl_easy_cleanup is called.

\fBCURLFORM_BUFFERLENGTH\fP
tells libcurl that the length of the buffer to upload is the value of the
next parameter.

Another possibility to send options to curl_formadd() is the
\fBCURLFORM_ARRAY\fP 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!

Should you need to specify extra headers for the form POST section, use
\fBCURLFORM_CONTENTHEADER\fP. This takes a curl_slist prepared in the usual way
using \fBcurl_slist_append\fP and appends the list of headers to those Curl
automatically generates for \fBCURLFORM_CONTENTTYPE\fP and the content 
disposition. The list must exist while the POST occurs, if you free it before
the post completes you may experience problems.

The last argument in such an array must always be \fBCURLFORM_END\fP.

The pointers \fI*firstitem\fP and \fI*lastitem\fP 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 \fIcurl_formfree\fP after the form post has
been done to free the resources again.

This function will copy all input data except the data pointed to by the
arguments after \fBCURLFORM_PTRNAME\fP and \fBCURLFORM_PTRCONTENTS\fP and keep
its own version of it allocated until you call \fIcurl_formfree\fP. When
you've passed the pointer to \fIcurl_easy_setopt\fP, you must not free the
list until after you've called \fIcurl_easy_cleanup\fP for the curl handle. If
you provide a pointer as an arguments after \fBCURLFORM_PTRNAME\fP or
\fBCURLFORM_PTRCONTENTS\fP you must ensure that the pointer stays valid until
you call \fIcurl_form_free\fP and \fIcurl_easy_cleanup\fP.

See example below.
.SH RETURN VALUE
0 means everything was ok, non-zero means an error occurred as
.I <curl/curl.h>
defines.
.SH EXAMPLE
.nf

 struct HttpPost* post = NULL;
 struct 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);

.SH "SEE ALSO"
.BR curl_easy_setopt "(3), "
.BR curl_formparse "(3) [deprecated], "
.BR curl_formfree "(3)"
.SH BUGS
Surely there are some, you tell me!