libcurl Manual curl_formadd(3)
NAME
curl_formadd - add a section to a multipart/formdata HTTP
POSTSYNOPSIS
#include
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 asRFC2388-style posts). Append one section at a time until
you've added all the sections you want included and then youpass the firstitem pointer as parameter to CURLOPT_HTTPPOST.
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 point-
ing to NULL in the first call to this function. All list-
data will be allocated by the function itself. You must callcurl_formfree(3) 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 withCURLOPT_HTTPHEADER as usual.
First, there are some basics you need to understand about multipart/formdata posts. Each part consists of at least aNAME 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 pro-
perties in the parts you want to add to your post. The options listed first are for making normal parts. Theoptions from CURLFORM_FILE through CURLFORM_BUFFERLENGTH are
for file upload parts. OPTIONSCURLFORM_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 functioncall. If the name isn't NUL-terminated, or if you'd
like it to contain zero bytes, you must set its lengthwith CURLFORM_NAMELENGTH. The copied data will be freed
by curl_formfree(3).
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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 nameisn't NUL-terminated, or if you'd like it to contain
zero bytes, you must set its length withCURLFORM_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 withCURLFORM_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. Ifthe data isn't NUL-terminated, or if you'd like it to
contain zero bytes, you must set its length withCURLFORM_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 fileand passes them as data and sets the content-type if
the given file match one of the internally known fileextensions. For CURLFORM_FILE the user may send one or
more files in one part by providing multipleCURLFORM_FILE arguments each followed by the filename
(and each CURLFORM_FILE is allowed to have a
CURLFORM_CONTENTTYPE).
CURLFORM_CONTENTTYPE
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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 ofCURLFORM_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 param-
eter is a pointer to the buffer to be uploaded. This buffer must not be freed until aftercurl_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 param-
eter 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 fileupload 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 aCURLFORM_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 beCURLFORM_END.
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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 tocurl_easy_setopt(3) (using the CURLOPT_HTTPPOST
option), you must not free the list until after you'vecalled curl_easy_cleanup(3) for the curl handle.
See example below. RETURN VALUE0 means everything was ok, non-zero means an error occurred
corresponding to a CURL_FORMADD_* constant defined in
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[] = "test buffer"; 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, "",
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,
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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)
ATTRIBUTES
See attributes(5) for descriptions of the following libcurl 7.9.8 Last change: 24 June 2002 5libcurl Manual curl_formadd(3)
attributes:_______________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE|
|____________________|__________________|_
| Availability | web/curl ||____________________|__________________|_
| Interface Stability| Uncommitted ||____________________|_________________|
NOTESSource for C-URL is available on http://opensolaris.org.
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