cpp-httplib/docs-src/pages/en/cookbook/c15-compression.md

title, order, status

title	order	status
C15. Enable Compression	15	draft

cpp-httplib supports compression when sending and decompression when receiving. You just need to build it with zlib or Brotli enabled.

Build-time setup

To use compression, define these macros before including httplib.h:

#define CPPHTTPLIB_ZLIB_SUPPORT    // gzip / deflate
#define CPPHTTPLIB_BROTLI_SUPPORT  // brotli
#include <httplib.h>

You'll also need to link against zlib or brotli.

Compress the request body

httplib::Client cli("https://api.example.com");
cli.set_compress(true);

std::string big_payload = build_payload();
auto res = cli.Post("/api/data", big_payload, "application/json");

With set_compress(true), the body of POST or PUT requests gets gzipped before sending. The server needs to handle compressed bodies too.

Decompress the response

httplib::Client cli("https://api.example.com");
cli.set_decompress(true); // on by default

auto res = cli.Get("/api/data");
std::cout << res->body << std::endl;

With set_decompress(true), the client automatically decompresses responses that arrive with Content-Encoding: gzip or similar. res->body contains the decompressed data.

It's on by default, so normally you don't need to do anything. Set it to false only if you want the raw compressed bytes.

Warning: If you build without CPPHTTPLIB_ZLIB_SUPPORT, calling set_compress() or set_decompress() does nothing. If compression isn't working, check the macro definition first.