CURLOPT_ACCEPT_ENCODING - automatic decompression of HTTP downloads
#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_ACCEPT_ENCODING, char *enc);
curl_easy_setopt options CURLOPT_ACCEPT_ENCODING(3)
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 * 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 encod-
ings you want in the response. Four 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-sep-
arated 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 will be 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.
DEFAULT
NULL
PROTOCOLS
HTTP
EXAMPLE
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
This option was called CURLOPT_ENCODING before 7.21.6
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.
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.
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+---------------+------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+------------------+
|Availability | web/curl |
+---------------+------------------+
|Stability | Uncommitted |
+---------------+------------------+
SEE ALSO
CURLOPT_TRANSFER_ENCODING(3), CURLOPT_HTTPHEADER(3), CURLOPT_HTTP_CON-
TENT_DECODING(3),
NOTES
Source code for open source software components in Oracle Solaris can
be found at https://www.oracle.com/downloads/opensource/solaris-source-
code-downloads.html.
This software was built from source available at
https://github.com/oracle/solaris-userland. The original community
source was downloaded from https://curl.se/down-
load/curl-7.83.1.tar.bz2.
Further information about this software can be found on the open source
community website at http://curl.haxx.se/.
libcurl 7.83.1 November 26, 2021
CURLOPT_ACCEPT_ENCODING(3)