curlformadd(3) libcurl Manual curlformadd(3)
NAME
curlformadd - add a section to a multipart/formdata HTP POST
SYNOPSIS
##include <>
CURLFORcode curlformadd(struct curlhttppost **** firstitem, struct
curlhttppost **** lastitem, ...);;
DESCRIPTION
curlformadd() is used to append sections when building a multi-
part/formdata HTP POST (sometimes referred 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 firstitem pointer as parameter to
CURLOPTHTPOST. lastitem 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 lastitem pointer follow the real arguments.
The pointers *firstitem and *lastitem should both be pointing to NUL
in the first call to this function. All list-data will be allocated by
the function itself. You must call curlformfree after the form post
has been done to free the resources again.
Using POST with HTP 1.1 implies the use of a "Expect: 100-continue"
header. You can disable this header with CURLOPTHTPHEADER as usual.
First, there are some basics you need to understand about multi-
part/formdata posts. Each part consists of at least a NAME and a CON-
TENTS part. If the part is made for file upload, there are also a
stored CONTENT-TYPE and a FILENAME. Below here, we'll discuss on what
options you use to set these properties in the parts you want to add to
your post.
OPTIONS
CURLFORMCOPYNAME
followed by string is used to set the name of this part. libcurl
copies the given data, so your application doesn't need to keep
it around after this function call. If the name isn't zero ter-
minated properly, or if you'd like it to contain zero bytes, you
need to set the length of the name with CURLFORMNAMELENGTH.
CURLFORMPTRNAME
followed by a string is used for the name of this part. libcurl
will use the pointer and refer to the data in your application,
you must make sure it remains until curl no longer needs it. If
the name isn't zero terminated properly, or if you'd like it to
contain zero bytes, you need to set the length of the name with
CURLFORMNAMELENGTH.
CURLFORMCOPYCONTENTS
followed by a string is used for the contents of this part, the
actual data to send away. libcurl copies the given data, so your
application doesn't need to keep it around after this function
call. If the data isn't zero terminated properly, or if you'd
like it to contain zero bytes, you need to set the length of the
name with CURLFORMCONTENTSLENGTH.
CURLFORMPTRCONTENTS
followed by a string is used for the contents of this part, the
actual data to send away. libcurl will use the pointer and refer
to the data in your application, you must make sure it remains
until curl no longer needs it. If the data isn't zero terminated
properly, or if you'd like it to contain zero bytes, you need to
set the length of the name with CURLFORMCONTENTSLENGTH.
CURLFORMCONTENTSLENGTH
followed by a long setting the length of the contents.
CURLFORMFILECONTENT
followed by a file name, makes that file read and the contents
will be used in as data in this part.
CURLFORMFILE
followed by a file name, makes this part a file upload part. It
sets the file name field to the actual file name used here, it
gets the contents of the file and passes as data and sets the
content-type if the given file match one of the new internally
known file extension. For CURLFORMFILE the user may send one
or more files in one part by providing multiple CURLFORMFILE
arguments each followed by the filename (and each CURLFORMFILE
is allowed to have a CURLFORMCONTENTYPE).
CURLFORMCONTENTYPE
followed by a pointer to a string with a content-type will make
curl use this given content-type for this file upload part, pos-
sibly instead of an internally chosen one.
CURLFORMFILENAME
followed by a pointer to a string to a name, will make libcurl
use the given name in the file upload part, instead of the
actual file name given to CURLFORMFILE.
BCURLFORMBUFER
followed by a string, tells libcurl that a buffer is to be used
to upload data instead of using a file. The given string is used
as the value of the file name field in the content header.
CURLFORMBUFERPTR
followed by a pointer to a data area, tells libcurl the address
of the buffer containing data to upload (as indicated with CURL-
FORMBUFER). The buffer containing this data must not be freed
until after curleasycleanup(3) is called. You must also use
CURLFORMBUFERLENGTH to set the length of the given buffer
area.
CURLFORMBUFERLENGTH
followed by a long with the size of the CURLFORMBUFERPTR data
area, tells libcurl the length of the buffer to upload.
CURLFORMARAY
Another possibility to send options to curlformadd() is the
CURLFORMARAY option, that passes a struct curlforms array
pointer as its value. Each curlforms structure element has a
CURLformoption and a char pointer. The final element in the
array must be a CURLFORMEND. All available options can be used
in an array, except the CURLFORMARAY option itself! The last
argument in such an array must always be CURLFORMEND.
CURLFORMCONTENTHEADER
specifies extra headers for the form POST section. This takes a
curlslist prepared in the usual way using curlslistappend and
appends the list of headers to those libcurl automatically gen-
erates. 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 curleasysetopt(3)
(using the CURLOPTHTPOST option), you must not free the list
until after you've called curleasycleanup(3) for the curl han-
dle.
See example below.
RETURN VALUE
0 means everything was ok, non-zero means an error occurred as
defines.
EXAMPLE
struct curlhttppost* post = NUL;
struct curlhttppost* last = NUL;
char namebuffer[] = "name buffer";
long namelength = strlen(namebuffer);
char buffer[] = "test buffer";
char htmlbuffer[] = "test buffer";
long htmlbufferlength = strlen(htmlbuffer);
struct curlforms 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 */
curlformadd(&post, &last, CURLFORMCOPYNAME, "name",
CURLFORMCOPYCONTENTS, "content", CURLFORMEND);
/* Add simple name/content/contenttype section */
curlformadd(&post, &last, CURLFORMCOPYNAME, "htmlcode",
CURLFORMCOPYCONTENTS, "",
CURLFORMCONTENTYPE, "text/html", CURLFORMEND);
/* Add name/ptrcontent section */
curlformadd(&post, &last, CURLFORMCOPYNAME, "nameforptrcontent",
CURLFORMPTRCONTENTS, buffer, CURLFORMEND);
/* Add ptrname/ptrcontent section */
curlformadd(&post, &last, CURLFORMPTRNAME, namebuffer,
CURLFORMPTRCONTENTS, buffer, CURLFORMNAMELENGTH,
namelength, CURLFORMEND);
/* Add name/ptrcontent/contenttype section */
curlformadd(&post, &last, CURLFORMCOPYNAME, "htmlcodewithhole",
CURLFORMPTRCONTENTS, htmlbuffer,
CURLFORMCONTENTSLENGTH, htmlbufferlength,
CURLFORMCONTENTYPE, "text/html", CURLFORMEND);
/* Add simple file section */
curlformadd(&post, &last, CURLFORMCOPYNAME, "picture",
CURLFORMFILE, "my-face.jpg", CURLFORMEND);
/* Add file/contenttype section */
curlformadd(&post, &last, CURLFORMCOPYNAME, "picture",
CURLFORMFILE, "my-face.jpg",
CURLFORMCONTENTYPE, "image/jpeg", CURLFORMEND);
/* Add two file section */
curlformadd(&post, &last, CURLFORMCOPYNAME, "pictures",
CURLFORMFILE, "my-face.jpg",
CURLFORMFILE, "your-face.jpg", CURLFORMEND);
/* Add two file section using CURLFORMARAY */
forms[0].option = CURLFORMFILE;
forms[0].value = file1;
forms[1].option = CURLFORMFILE;
forms[1].value = file2;
forms[2].option = CURLFORMEND;
/* Add a buffer to upload */
curlformadd(&post, &last,
CURLFORMCOPYNAME, "name",
CURLFORMBUFER, "data",
CURLFORMBUFERPTR, record,
CURLFORMBUFERLENGTH, recordlength,
CURLFORMEND);
/* no option needed for the end marker */
curlformadd(&post, &last, CURLFORMCOPYNAME, "pictures",
CURLFORMARAY, forms, CURLFORMEND);
/* Add the content of a file as a normal post text value */
curlformadd(&post, &last, CURLFORMCOPYNAME, "filecontent",
CURLFORMFILECONTENT, ".bashrc", CURLFORMEND);
/* Set the form info */
curleasysetopt(curl, CURLOPTHTPOST, post);
SEE ALSO
curleasysetopt(3), curlformfree(3)
libcurl 7.9.8 24 June 2002 curlformadd(3)
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