C13. Set an Overall Timeout

The three timeouts from C12. Set timeouts all apply to a single send or recv call. To cap the total time a request can take, use set_max_timeout().

Basic usage

httplib::Client cli("http://localhost:8080");

cli.set_max_timeout(5000); // 5 seconds (in milliseconds)

auto res = cli.Get("/slow-endpoint");

httplib::Client cli("http://localhost:8080");

cli.set_max_timeout(5000); // 5 seconds (in milliseconds)

auto res = cli.Get("/slow-endpoint");

The value is in milliseconds. Once that much time has passed since the request started, waiting for the response is cut off. The limit does not shorten the connection and write waits themselves, so bound those with set_connection_timeout and set_write_timeout.

Use std::chrono

There's also an overload that takes a std::chrono duration.

using namespace std::chrono_literals;
cli.set_max_timeout(5s);

using namespace std::chrono_literals;
cli.set_max_timeout(5s);

When to use which

set_read_timeout fires when no data arrives for a while. If data keeps trickling in bit by bit, it will never fire. An endpoint that sends one byte per second can make set_read_timeout useless no matter how short you set it.

set_max_timeout caps elapsed time, so it handles those cases cleanly. It's great for calls to external APIs or anywhere you don't want users waiting forever.

cli.set_connection_timeout(3s);
cli.set_read_timeout(10s);
cli.set_max_timeout(30s); // abort if the whole request takes over 30s

cli.set_connection_timeout(3s);
cli.set_read_timeout(10s);
cli.set_max_timeout(30s); // abort if the whole request takes over 30s

Note: set_max_timeout() works alongside the regular timeouts. Short stalls get caught by set_read_timeout; long-running requests get capped by set_max_timeout. Use both for a safety net.