plucky (3) CURLOPT_POSTFIELDS.3.gz

Provided by: libcurl4-doc_8.12.1-2ubuntu1_all bug

NAME

       CURLOPT_POSTFIELDS - data to POST to server

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_POSTFIELDS, char *postdata);

DESCRIPTION

       Pass a char pointer as parameter, pointing to the data buffer to use in an HTTP POST operation or an MQTT
       subscribe. The data must be formatted and encoded the way you want the server to receive it. libcurl does
       not convert or encode it in any way. For example, a web server may assume that this data is URL encoded.

       The  data  pointed to is NOT copied by the library: as a consequence, it must be preserved by the calling
       application until the associated transfer finishes.  This behavior can be changed (so libcurl  does  copy
       the data) by instead using the CURLOPT_COPYPOSTFIELDS(3) option.

       This  POST  is  a  normal  application/x-www-form-urlencoded  kind (and libcurl sets that Content-Type by
       default when this option is used), which is  commonly  used  by  HTML  forms.  Change  Content-Type  with
       CURLOPT_HTTPHEADER(3).

       You can use curl_easy_escape(3) to URL encode your data, if necessary. It returns a pointer to an encoded
       string that can be passed as postdata.

       Using CURLOPT_POSTFIELDS(3) implies setting CURLOPT_POST(3) to 1.

       If CURLOPT_POSTFIELDS(3) is explicitly set to NULL  then  libcurl  gets  the  POST  data  from  the  read
       callback.  To  send  a  zero-length  (empty)  POST,  set CURLOPT_POSTFIELDS(3) to an empty string, or set
       CURLOPT_POST(3) to 1 and CURLOPT_POSTFIELDSIZE(3) to 0.

       libcurl  assumes   this   option   points   to   a   null-terminated   string   unless   you   also   set
       CURLOPT_POSTFIELDSIZE(3)  to  specify the length of the provided data, which then is strictly required if
       you want to send off null bytes included in the data.

       Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header, and libcurl adds that header
       automatically  if  the POST is either known to be larger than 1MB or if the expected size is unknown. You
       can disable this header with CURLOPT_HTTPHEADER(3) as usual.

       To  make  multipart/formdata  posts,   check   out   the   CURLOPT_MIMEPOST(3)   option   combined   with
       curl_mime_init(3).

       Using this option multiple times makes the last set pointer override the previous ones. Set it to NULL to
       disable its use again.

DEFAULT

       NULL

PROTOCOLS

       This functionality affects http and mqtt

EXAMPLE

       /* send an application/x-www-form-urlencoded POST */
       int main(void)
       {
         CURL *curl = curl_easy_init();
         if(curl) {
           const char *data = "data to send";

           curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

           /* size of the POST data if strlen() is not good enough */
           curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, 12L);

           /* pass in a pointer to the data - libcurl does not copy */
           curl_easy_setopt(curl, CURLOPT_POSTFIELDS, data);

           curl_easy_perform(curl);
         }

         /* send an application/json POST */
         curl = curl_easy_init();
         if(curl) {
           const char *json = "{\"name\": \"daniel\"}";
           struct curl_slist *slist1 = NULL;
           slist1 = curl_slist_append(slist1, "Content-Type: application/json");
           slist1 = curl_slist_append(slist1, "Accept: application/json");

           /* set custom headers */
           curl_easy_setopt(curl, CURLOPT_HTTPHEADER, slist1);

           curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

           /* pass in a pointer to the data - libcurl does not copy */
           curl_easy_setopt(curl, CURLOPT_POSTFIELDS, json);

           curl_easy_perform(curl);
         }
       }

AVAILABILITY

       Added in curl 7.1

RETURN VALUE

       curl_easy_setopt(3) returns a CURLcode indicating success or error.

       CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors(3).

SEE ALSO

       CURLOPT_COPYPOSTFIELDS(3),   CURLOPT_MIMEPOST(3),   CURLOPT_POSTFIELDSIZE(3),    CURLOPT_READFUNCTION(3),
       CURLOPT_UPLOAD(3)