curl/docs/curl_formadd.3

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.TH curl_formadd 3 "29 October 2001" "libcurl 7.9.1" "libcurl Manual"
.SH NAME
curl_formadd - add a section to a multipart/formdata HTTP POST
.SH SYNOPSIS
.B #include <curl/curl.h>
.sp
.BI "int 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 four options for providing values are: \fBCURLFORM_COPYCONTENTS\fP,
\fBCURLFORM_PTRCONTENTS\fP, \fBCURLFORM_FILE\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).

Another possibility to send single or multiple files in one section is to use
\fBCURLFORM_ARRAY\fP that gets a struct curl_forms array pointer as its
value. Each structure element has a CURLformoption and a char pointer. For the
options only \fBCURLFORM_FILE\fP, \fBCURLFORM_CONTENTTYPE\fP, and
\fBCURLFORM_END\fP (that is used to determine the end of the array and thus
must be the option of the last and no other element of the curl_forms array)
are allowed. The effect of this parameter is the same as giving multiple
\fBCURLFORM_FILE\fP options possibly with \fBCURLFORM_CONTENTTYPE\fP after or
before each \fBCURLFORM_FILE\fP option.

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
Returns non-zero if an error occurs.
.SH EXAMPLE
.nf

 HttpPost* post = NULL;
 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;

 /* 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!