S01. Register GET / POST / PUT / DELETE Handlers

With httplib::Server, you register a handler per HTTP method. Just pass a pattern and a lambda to Get(), Post(), Put(), or Delete().

Basic usage

#include <httplib.h>

int main() {
  httplib::Server svr;

  svr.Get("/hello", [](const httplib::Request &req, httplib::Response &res) {
    res.set_content("Hello, World!", "text/plain");
  });

  svr.Post("/api/items", [](const httplib::Request &req, httplib::Response &res) {
    // req.body holds the request body
    res.status = 201;
    res.set_content("Created", "text/plain");
  });

  svr.Put("/api/items/1", [](const httplib::Request &req, httplib::Response &res) {
    res.set_content("Updated", "text/plain");
  });

  svr.Delete("/api/items/1", [](const httplib::Request &req, httplib::Response &res) {
    res.status = 204;
  });

  svr.listen("0.0.0.0", 8080);
}

#include <httplib.h>

int main() {
  httplib::Server svr;

  svr.Get("/hello", [](const httplib::Request &req, httplib::Response &res) {
    res.set_content("Hello, World!", "text/plain");
  });

  svr.Post("/api/items", [](const httplib::Request &req, httplib::Response &res) {
    // req.body holds the request body
    res.status = 201;
    res.set_content("Created", "text/plain");
  });

  svr.Put("/api/items/1", [](const httplib::Request &req, httplib::Response &res) {
    res.set_content("Updated", "text/plain");
  });

  svr.Delete("/api/items/1", [](const httplib::Request &req, httplib::Response &res) {
    res.status = 204;
  });

  svr.listen("0.0.0.0", 8080);
}

Handlers take (const Request&, Response&). Use res.set_content() to set the body and Content-Type, and res.status for the status code. listen() starts the server and blocks.

Read query parameters

svr.Get("/search", [](const httplib::Request &req, httplib::Response &res) {
  auto q = req.get_param_value("q");
  auto limit = req.get_param_value("limit");
  res.set_content("q=" + q + ", limit=" + limit, "text/plain");
});

svr.Get("/search", [](const httplib::Request &req, httplib::Response &res) {
  auto q = req.get_param_value("q");
  auto limit = req.get_param_value("limit");
  res.set_content("q=" + q + ", limit=" + limit, "text/plain");
});

req.get_param_value() pulls a value from the query string. Use req.has_param("q") if you want to check existence first.

Read request headers

svr.Get("/me", [](const httplib::Request &req, httplib::Response &res) {
  auto ua = req.get_header_value("User-Agent");
  res.set_content("UA: " + ua, "text/plain");
});

svr.Get("/me", [](const httplib::Request &req, httplib::Response &res) {
  auto ua = req.get_header_value("User-Agent");
  res.set_content("UA: " + ua, "text/plain");
});

To add a response header, use res.set_header("Name", "Value").

Note: listen() is a blocking call. To run it on a different thread, wrap it in std::thread. If you need non-blocking startup, see S18. Control startup order with listen_after_bind.

To use path parameters like /users/:id, see S03. Use path parameters.