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3rdparty/curl/share/man/man3/curl_formadd.3 12.6 KB
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  .\" **************************************************************************
  .\" *                                  _   _ ____  _
  .\" *  Project                     ___| | | |  _ \| |
  .\" *                             / __| | | | |_) | |
  .\" *                            | (__| |_| |  _ <| |___
  .\" *                             \___|\___/|_| \_\_____|
  .\" *
  .\" * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  .\" *
  .\" * This software is licensed as described in the file COPYING, which
  .\" * you should have received as part of this distribution. The terms
  .\" * are also available at https://curl.se/docs/copyright.html.
  .\" *
  .\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
  .\" * copies of the Software, and permit persons to whom the Software is
  .\" * furnished to do so, under the terms of the COPYING file.
  .\" *
  .\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  .\" * KIND, either express or implied.
  .\" *
  .\" **************************************************************************
  .TH curl_formadd 3 "November 04, 2020" "libcurl 7.77.0" "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 curl_httppost ** " firstitem,
  .BI "struct curl_httppost ** " lastitem, " ...);"
  .ad
  .SH DESCRIPTION
  This function is deprecated. Do not use! See \fIcurl_mime_init(3)\fP instead!
  
  curl_formadd() is used to append sections when building a multipart/formdata
  HTTP POST (sometimes referred to as RFC2388-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 \fICURLOPT_HTTPPOST(3)\fP.
  \fIlastitem\fP is set after each \fIcurl_formadd(3)\fP 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.
  
  The pointers \fIfirstitem\fP and \fIlastitem\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(3)\fP on the
  \fIfirstitem\fP 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 \fICURLOPT_HTTPHEADER(3)\fP as usual.
  
  First, there are some basics you need to understand about multipart/formdata
  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'll 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
  \fICURLFORM_FILE\fP through \fICURLFORM_BUFFERLENGTH\fP are for file upload
  parts.
  .SH OPTIONS
  .IP CURLFORM_COPYNAME
  followed by a string which provides the \fIname\fP of this part. libcurl
  copies the string so your application doesn't need to keep it around after
  this function call. If the name isn't NUL-terminated, you must set its length
  with \fBCURLFORM_NAMELENGTH\fP. The \fIname\fP is not allowed to contain
  zero-valued bytes. The copied data will be freed by \fIcurl_formfree(3)\fP.
  .IP CURLFORM_PTRNAME
  followed by a string which provides the \fIname\fP 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
  isn't NUL-terminated, you must set its length with \fBCURLFORM_NAMELENGTH\fP.
  The \fIname\fP is not allowed to contain zero-valued bytes.
  .IP 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 with \fBCURLFORM_CONTENTSLENGTH\fP. The copied
  data will be freed by \fIcurl_formfree(3)\fP.
  .IP 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 isn't NUL-terminated, or if you'd like it to contain zero bytes,
  you must set its length  with \fBCURLFORM_CONTENTSLENGTH\fP.
  .IP CURLFORM_CONTENTLEN
  followed by a curl_off_t value giving the length of the contents. Note that
  for \fICURLFORM_STREAM\fP 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)
  .IP CURLFORM_CONTENTSLENGTH
  (This option is deprecated. Use \fICURLFORM_CONTENTLEN\fP instead!)
  
  followed by a long giving the length of the contents. Note that for
  \fICURLFORM_STREAM\fP 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.
  .IP CURLFORM_FILECONTENT
  followed by a filename, causes that file to be read and its contents used
  as data in this part. This part does \fInot\fP 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.
  .IP CURLFORM_FILE
  followed by a filename, makes this part a file upload part. It sets the
  \fIfilename\fP 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
  \fBCURLFORM_FILE\fP the user may send one or more files in one part by
  providing multiple \fBCURLFORM_FILE\fP arguments each followed by the filename
  (and each \fICURLFORM_FILE\fP is allowed to have a
  \fICURLFORM_CONTENTTYPE\fP).
  
  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.
  .IP CURLFORM_CONTENTTYPE
  is used in combination with \fICURLFORM_FILE\fP. Followed by a pointer to a
  string which provides the content-type for this part, possibly instead of an
  internally chosen one.
  .IP CURLFORM_FILENAME
  is used in combination with \fICURLFORM_FILE\fP. Followed by a pointer to a
  string, it tells libcurl to use the given string as the \fIfilename\fP in the
  file upload part instead of the actual file name.
  .IP CURLFORM_BUFFER
  is used for custom file upload parts without use of \fICURLFORM_FILE\fP.  It
  tells libcurl that the file contents are already present in a buffer.  The
  parameter is a string which provides the \fIfilename\fP field in the content
  header.
  .IP CURLFORM_BUFFERPTR
  is used in combination with \fICURLFORM_BUFFER\fP. The parameter is a pointer
  to the buffer to be uploaded. This buffer must not be freed until after
  \fIcurl_easy_cleanup(3)\fP is called. You must also use
  \fICURLFORM_BUFFERLENGTH\fP to set the number of bytes in the buffer.
  .IP CURLFORM_BUFFERLENGTH
  is used in combination with \fICURLFORM_BUFFER\fP. The parameter is a
  long which gives the length of the buffer.
  .IP CURLFORM_STREAM
  Tells libcurl to use the \fICURLOPT_READFUNCTION(3)\fP callback to get
  data. The parameter you pass to \fICURLFORM_STREAM\fP 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 \fICURLFORM_FILENAME\fP parameter as well. Note that
  when using \fICURLFORM_STREAM\fP, \fICURLFORM_CONTENTSLENGTH\fP 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)
  .IP CURLFORM_ARRAY
  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!  The
  last argument in such an array must always be \fBCURLFORM_END\fP.
  .IP CURLFORM_CONTENTHEADER
  specifies extra headers for the form POST section.  This takes a curl_slist
  prepared in the usual way using \fBcurl_slist_append\fP 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 to \fIcurl_easy_setopt(3)\fP (using
  the \fICURLOPT_HTTPPOST(3)\fP option), you must not free the list until after
  you've called \fIcurl_easy_cleanup(3)\fP for the curl handle.
  
  See example below.
  .SH 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.
  .SH RETURN VALUE
  0 means everything was ok, non-zero means an error occurred corresponding
  to a CURL_FORMADD_* constant defined in
  .I <curl/curl.h>
  .SH EXAMPLE
  .nf
  
   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);
  
  .SH "SEE ALSO"
  .BR curl_easy_setopt "(3),"
  .BR curl_formfree "(3),"
  .BR curl_mime_init "(3)"