NAME

       CURLOPT_ACCEPT_ENCODING - automatic decompression of HTTP downloads

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_ACCEPT_ENCODING, char *enc);

DESCRIPTION

       Pass a char pointer argument specifying what encoding you would like.

       Sets  the  contents  of  the  Accept-Encoding: header sent in an HTTP request, and enables
       decoding of a response when a Content-Encoding: header is received.

       libcurl potentially supports several different  compressed  encodings  depending  on  what
       support that has been built-in.

       To  aid  applications  not having to bother about what specific algorithms this particular
       libcurl build supports, libcurl allows a zero-length string to be set ("") to ask  for  an
       Accept-Encoding: header to be used that contains all built-in supported encodings.

       Alternatively,  you  can specify exactly the encoding or list of encodings you want in the
       response. The following encodings are supported: identity, meaning non-compressed, deflate
       which  requests  the  server to compress its response using the zlib algorithm, gzip which
       requests the gzip algorithm, (since curl 7.57.0)  br  which  is  brotli  and  (since  curl
       7.72.0)  zstd  which  is  zstd.  Provide  them  in the string as a comma-separated list of
       accepted encodings, like: "br, gzip, deflate".

       Set CURLOPT_ACCEPT_ENCODING(3) to NULL to explicitly disable it, which makes  libcurl  not
       send an Accept-Encoding: header and not decompress received contents automatically.

       You  can  also  opt  to  just  include  the  Accept-Encoding:  header in your request with
       CURLOPT_HTTPHEADER(3) but then there is no automatic decompressing when receiving data.

       This is a request, not an order; the server may or may not do it. This option must be  set
       (to any non-NULL value) or else any unsolicited encoding done by the server is ignored.

       Servers might respond with Content-Encoding even without getting a Accept-Encoding: in the
       request. Servers might respond with a different Content-Encoding than what was  asked  for
       in the request.

       The  Content-Length:  servers  send  for a compressed response is supposed to indicate the
       length of the compressed content so when auto decoding is enabled it may not match the sum
       of   bytes  reported  by  the  write  callbacks  (although,  sending  the  length  of  the
       non-compressed content is a common server mistake).

       The application does not have to keep the string around after setting this option.

HISTORY

       This option was called CURLOPT_ENCODING before 7.21.6

NOTES

       The specific libcurl you are using must have been built with zlib to be able to decompress
       gzip  and  deflate  responses,  with the brotli library to decompress brotli responses and
       with the zstd library to decompress zstd responses.

DEFAULT

       NULL

PROTOCOLS

       This functionality affects http only

EXAMPLE

       int main(void)
       {
         CURL *curl = curl_easy_init();
         if(curl) {
           curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

           /* enable all supported built-in compressions */
           curl_easy_setopt(curl, CURLOPT_ACCEPT_ENCODING, "");

           /* Perform the request */
           curl_easy_perform(curl);
         }
       }

AVAILABILITY

       Added in curl 7.21.6

RETURN VALUE

       Returns  CURLE_OK  if  the  option  is  supported,   CURLE_UNKNOWN_OPTION   if   not,   or
       CURLE_OUT_OF_MEMORY if there was insufficient heap space.

SEE ALSO

       CURLOPT_HTTPHEADER(3), CURLOPT_HTTP_CONTENT_DECODING(3), CURLOPT_TRANSFER_ENCODING(3)