cpp httplib
Bug fixes
A C++11 single-file header-only cross platform HTTP/HTTPS library.
It's extremely easy to setup. Just include the httplib.h file in your code!
Important
This library uses 'blocking' socket I/O. If you are looking for a library with 'non-blocking' socket I/O, this is not the one that you want.
#define CPPHTTPLIB_OPENSSL_SUPPORT#include "path/to/httplib.h"// HTTPhttplib::Server svr;// HTTPShttplib::SSLServer svr;
svr.Get("/hi", [](const httplib::Request &, httplib::Response &res) {
res.set_content("Hello World!", "text/plain");
});
svr.listen("0.0.0.0", 8080);#define CPPHTTPLIB_OPENSSL_SUPPORT#include "path/to/httplib.h"// HTTPhttplib::Client cli("http://cpp-httplib-server.yhirose.repl.co");// HTTPShttplib::Client cli("https://cpp-httplib-server.yhirose.repl.co");auto res = cli.Get("/hi");
res->status;
res->body;SSL support is available with CPPHTTPLIB_OPENSSL_SUPPORT. libssl and libcrypto should be linked.
Note
cpp-httplib currently supports only version 3.0 or later. Please see this page to get more information.
Tip
For macOS: cpp-httplib now can use system certs with CPPHTTPLIB_USE_CERTS_FROM_MACOSX_KEYCHAIN. CoreFoundation and Security should be linked with -framework.
#define CPPHTTPLIB_OPENSSL_SUPPORT#include "path/to/httplib.h"// Serverhttplib::SSLServer svr("./cert.pem", "./key.pem");// Clienthttplib::Client cli("https://localhost:1234"); // scheme + hosthttplib::SSLClient cli("localhost:1234"); // hosthttplib::SSLClient cli("localhost", 1234); // host, port// Use your CA bundlecli.set_ca_cert_path("./ca-bundle.crt");// Disable cert verificationcli.enable_server_certificate_verification(false);// Disable host verificationcli.enable_server_host_verification(false);Note
When using SSL, it seems impossible to avoid SIGPIPE in all cases, since on some operating systems, SIGPIPE can only be suppressed on a per-message basis, but there is no way to make the OpenSSL library do so for its internal communications. If your program needs to avoid being terminated on SIGPIPE, the only fully general way might be to set up a signal handler for SIGPIPE to handle or ignore it yourself.
#includeint main(void) { using namespace httplib; Server svr; svr.Get("/hi", [](const Request& req, Response& res) { res.set_content("Hello World!", "text/plain"); }); // Match the request path against a regular expression // and extract its captures svr.Get(R"(/numbers/(d+))", [&](const Request& req, Response& res) { auto numbers = req.matches[1]; res.set_content(numbers, "text/plain"); }); // Capture the second segment of the request path as "id" path param svr.Get("/users/:id", [&](const Request& req, Response& res) { auto user_id = req.path_params.at("id"); res.set_content(user_id, "text/plain"); }); // Extract values from HTTP headers and URL query params svr.Get("/body-header-param", [](const Request& req, Response& res) { if (req.has_header("Content-Length")) { auto val = req.get_header_value("Content-Length"); } if (req.has_param("key")) { auto val = req.get_param_value("key"); } res.set_content(req.body, "text/plain"); }); svr.Get("/stop", [&](const Request& req, Response& res) { svr.stop(); }); svr.listen("localhost", 1234); }
Post, Put, Delete and Options methods are also supported.
int port = svr.bind_to_any_port("0.0.0.0");
svr.listen_after_bind();// Mount / to ./www directoryauto ret = svr.set_mount_point("/", "./www");if (!ret) { // The specified base directory doesn't exist...}// Mount /public to ./www directoryret = svr.set_mount_point("/public", "./www");// Mount /public to ./www1 and ./www2 directoriesret = svr.set_mount_point("/public", "./www1"); // 1st order to searchret = svr.set_mount_point("/public", "./www2"); // 2nd order to search// Remove mount /ret = svr.remove_mount_point("/");// Remove mount /publicret = svr.remove_mount_point("/public");// User defined file extension and MIME type mappingssvr.set_file_extension_and_mimetype_mapping("cc", "text/x-c");
svr.set_file_extension_and_mimetype_mapping("cpp", "text/x-c");
svr.set_file_extension_and_mimetype_mapping("hh", "text/x-h");The followings are built-in mappings:
| Extension | MIME Type | Extension | MIME Type |
|---|---|---|---|
| css | text/css | mpga | audio/mpeg |
| csv | text/csv | weba | audio/webm |
| txt | text/plain | wav | audio/wave |
| vtt | text/vtt | otf | font/otf |
| html, htm | text/html | ttf | font/ttf |
| apng | image/apng | woff | font/woff |
| avif | image/avif | woff2 | font/woff2 |
| bmp | image/bmp | 7z | application/x-7z-compressed |
| gif | image/gif | atom | application/atom+xml |
| png | image/png | application/pdf | |
| svg | image/svg+xml | mjs, js | application/javascript |
| webp | image/webp | json | application/json |
| ico | image/x-icon | rss | application/rss+xml |
| tif | image/tiff | tar | application/x-tar |
| tiff | image/tiff | xhtml, xht | application/xhtml+xml |
| jpeg, jpg | image/jpeg | xslt | application/xslt+xml |
| mp4 | video/mp4 | xml | application/xml |
| mpeg | video/mpeg | gz | application/gzip |
| webm | video/webm | zip | application/zip |
| mp3 | audio/mp3 | wasm | application/wasm |
Warning
These static file server methods are not thread-safe.
// The handler is called right before the response is sent to a clientsvr.set_file_request_handler([](const Request &req, Response &res) {
...
});svr.set_logger([](const auto& req, const auto& res) { your_logger(req, res);
});svr.set_error_handler([](const auto& req, auto& res) { auto fmt = "Error Status: %d
"; char buf[BUFSIZ]; snprintf(buf, sizeof(buf), fmt, res.status);
res.set_content(buf, "text/html");
});The exception handler gets called if a user routing handler throws an error.
svr.set_exception_handler([](const auto& req, auto& res, std::exception_ptr ep) { auto fmt = "Error 500
%s
"; char buf[BUFSIZ]; try { std::rethrow_exception(ep);
} catch (std::exception &e) { snprintf(buf, sizeof(buf), fmt, e.what());
} catch (...) { // See the following NOTE snprintf(buf, sizeof(buf), fmt, "Unknown Exception");
}
res.set_content(buf, "text/html");
res.status = StatusCode::InternalServerError_500;
});Caution
if you don't provide the catch (...) block for a rethrown exception pointer, an uncaught exception will end up causing the server crash. Be careful!
svr.set_pre_routing_handler([](const auto& req, auto& res) { if (req.path == "/hello") {
res.set_content("world", "text/html"); return Server::HandlerResponse::Handled;
} return Server::HandlerResponse::Unhandled;
});svr.set_post_routing_handler([](const auto& req, auto& res) {
res.set_header("ADDITIONAL_HEADER", "value");
});svr.Post("/multipart", [&](const auto& req, auto& res) { auto size = req.files.size(); auto ret = req.has_file("name1"); const auto& file = req.get_file_value("name1"); // file.filename; // file.content_type; // file.content;});svr.Post("/content_receiver",
[&](const Request &req, Response &res, const ContentReader &content_reader) { if (req.is_multipart_form_data()) { // NOTE: `content_reader` is blocking until every form data field is read
MultipartFormDataItems files; content_reader(
[&](const MultipartFormData &file) {
files.push_back(file); return true;
},
[&](const char *data, size_t data_length) {
files.back().content.append(data, data_length); return true;
});
} else {
std::string body; content_reader([&](const char *data, size_t data_length) {
body.append(data, data_length); return true;
});
}
});const size_t DATA_CHUNK_SIZE = 4;
svr.Get("/stream", [&](const Request &req, Response &res) { auto data = new std::string("abcdefg");
res.set_content_provider(
data->size(), // Content length "text/plain", // Content type
[&, data](size_t offset, size_t length, DataSink &sink) { const auto &d = *data;
sink.write(&d[offset], std::min(length, DATA_CHUNK_SIZE)); return true; // return 'false' if you want to cancel the process.
},
[data](bool success) { delete data; });
});Without content length:
svr.Get("/stream", [&](const Request &req, Response &res) {
res.set_content_provider( "text/plain", // Content type
[&](size_t offset, DataSink &sink) { if (/* there is still data */) {
std::vector data; // prepare data...
sink.write(data.data(), data.size());
} else {
sink.done(); // No more data
} return true; // return 'false' if you want to cancel the process.
});
}); svr.Get("/chunked", [&](const Request& req, Response& res) {
res.set_chunked_content_provider( "text/plain",
[](size_t offset, DataSink &sink) {
sink.write("123", 3);
sink.write("345", 3);
sink.write("789", 3);
sink.done(); // No more data return true; // return 'false' if you want to cancel the process.
}
);
});With trailer:
svr.Get("/chunked", [&](const Request& req, Response& res) {
res.set_header("Trailer", "Dummy1, Dummy2");
res.set_chunked_content_provider( "text/plain",
[](size_t offset, DataSink &sink) {
sink.write("123", 3);
sink.write("345", 3);
sink.write("789", 3);
sink.done_with_trailer({
{"Dummy1", "DummyVal1"},
{"Dummy2", "DummyVal2"}
}); return true;
}
);
});svr.Get("/content", [&](const Request &req, Response &res) {
res.set_file_content("./path/to/conent.html");
});
svr.Get("/content", [&](const Request &req, Response &res) {
res.set_file_content("./path/to/conent", "text/html");
});By default, the server sends a 100 Continue response for an Expect: 100-continue header.
// Send a '417 Expectation Failed' response.svr.set_expect_100_continue_handler([](const Request &req, Response &res) { return StatusCode::ExpectationFailed_417;
});// Send a final status without reading the message body.svr.set_expect_100_continue_handler([](const Request &req, Response &res) { return res.status = StatusCode::Unauthorized_401;
});svr.set_keep_alive_max_count(2); // Default is 5svr.set_keep_alive_timeout(10); // Default is 5
svr.set_read_timeout(5, 0); // 5 secondssvr.set_write_timeout(5, 0); // 5 secondssvr.set_idle_interval(0, 100000); // 100 milliseconds
svr.set_payload_max_length(1024 * 1024 * 512); // 512MB
Note
When the request body content type is 'www-form-urlencoded', the actual payload length shouldn't exceed CPPHTTPLIB_FORM_URL_ENCODED_PAYLOAD_MAX_LENGTH.
Please see Server example and Client example.
ThreadPool is used as a default task queue, and the default thread count is 8, or std::thread::hardware_concurrency(). You can change it with CPPHTTPLIB_THREAD_POOL_COUNT.
If you want to set the thread count at runtime, there is no convenient way... But here is how.
svr.new_task_queue = [] { return new ThreadPool(12); };You can also provide an optional parameter to limit the maximum number
of pending requests, i.e. requests accept()ed by the listener but
still waiting to be serviced by worker threads.
svr.new_task_queue = [] { return new ThreadPool(/*num_threads=*/12, /*max_queued_requests=*/18); };Default limit is 0 (unlimited). Once the limit is reached, the listener will shutdown the client connection.
You can supply your own thread pool implementation according to your need.
class YourThreadPoolTaskQueue : public TaskQueue {public: YourThreadPoolTaskQueue(size_t n) {
pool_.start_with_thread_count(n);
} virtual bool enqueue(std::function fn) override { /* Return true if the task was actually enqueued, or false * if the caller must drop the corresponding connection. */ return pool_.enqueue(fn);
} virtual void shutdown() override {
pool_.shutdown_gracefully();
}private:
YourThreadPool pool_;
};
svr.new_task_queue = [] { return new YourThreadPoolTaskQueue(12);
}; #include#include int main(void) { httplib::Client cli("localhost", 1234); if (auto res = cli.Get("/hi")) { if (res->status == StatusCode::OK_200) { std::cout << res->body << std::endl; } } else { auto err = res.error(); std::cout << "HTTP error: " << httplib::to_string(err) << std::endl; } }
Tip
Constructor with scheme-host-port string is now supported!
httplib::Client cli("localhost");
httplib::Client cli("localhost:8080");
httplib::Client cli("http://localhost");
httplib::Client cli("http://localhost:8080");
httplib::Client cli("https://localhost");
httplib::SSLClient cli("localhost");Here is the list of errors from Result::error().
enum Error {
Success = 0,
Unknown,
Connection,
BindIPAddress,
Read,
Write,
ExceedRedirectCount,
Canceled,
SSLConnection,
SSLLoadingCerts,
SSLServerVerification,
UnsupportedMultipartBoundaryChars,
Compression,
ConnectionTimeout,
};httplib::Headers headers = {
{ "Accept-Encoding", "gzip, deflate" }
};auto res = cli.Get("/hi", headers);or
auto res = cli.Get("/hi", {{"Accept-Encoding", "gzip, deflate"}});or
cli.set_default_headers({
{ "Accept-Encoding", "gzip, deflate" }
});auto res = cli.Get("/hi");res = cli.Post("/post", "text", "text/plain");
res = cli.Post("/person", "name=john1¬e=coder", "application/x-www-form-urlencoded");httplib::Params params;
params.emplace("name", "john");
params.emplace("note", "coder");auto res = cli.Post("/post", params);or
httplib::Params params{
{ "name", "john" },
{ "note", "coder" }
};auto res = cli.Post("/post", params);httplib::MultipartFormDataItems items = {
{ "text1", "text default", "", "" },
{ "text2", "aωb", "", "" },
{ "file1", "hnennlnlnon", "hello.txt", "text/plain" },
{ "file2", "{n "world", truen}n", "world.json", "application/json" },
{ "file3", "", "", "application/octet-stream" },
};auto res = cli.Post("/multipart", items);res = cli.Put("/resource/foo", "text", "text/plain");res = cli.Delete("/resource/foo");res = cli.Options("*");
res = cli.Options("/resource/foo");cli.set_connection_timeout(0, 300000); // 300 millisecondscli.set_read_timeout(5, 0); // 5 secondscli.set_write_timeout(5, 0); // 5 seconds
std::string body;auto res = cli.Get("/large-data",
[&](const char *data, size_t data_length) {
body.append(data, data_length); return true;
});std::string body;auto res = cli.Get( "/stream", Headers(),
[&](const Response &response) { EXPECT_EQ(StatusCode::OK_200, response.status); return true; // return 'false' if you want to cancel the request.
},
[&](const char *data, size_t data_length) {
body.append(data, data_length); return true; // return 'false' if you want to cancel the request.
});std::string body = ...;auto res = cli.Post( "/stream", body.size(),
[](size_t offset, size_t length, DataSink &sink) {
sink.write(body.data() + offset, length); return true; // return 'false' if you want to cancel the request.
}, "text/plain");auto res = cli.Post( "/stream",
[](size_t offset, DataSink &sink) {
sink.os << "chunked data 1";
sink.os << "chunked data 2";
sink.os << "chunked data 3";
sink.done(); return true; // return 'false' if you want to cancel the request.
}, "text/plain");httplib::Client cli(url, port);// prints: 0 / 000 bytes => 50% completeauto res = cli.Get("/", [](uint64_t len, uint64_t total) { printf("%lld / %lld bytes => %d%% completen",
len, total,
(int)(len*100/total)); return true; // return 'false' if you want to cancel the request.}
);
// Basic Authenticationcli.set_basic_auth("user", "pass");// Digest Authenticationcli.set_digest_auth("user", "pass");// Bearer Token Authenticationcli.set_bearer_token_auth("token");Note
OpenSSL is required for Digest Authentication.
cli.set_proxy("host", port);// Basic Authenticationcli.set_proxy_basic_auth("user", "pass");// Digest Authenticationcli.set_proxy_digest_auth("user", "pass");// Bearer Token Authenticationcli.set_proxy_bearer_token_auth("pass");Note
OpenSSL is required for Digest Authentication.
httplib::Client cli("httpbin.org");auto res = cli.Get("/range/32", { httplib::make_range_header({{1, 10}}) // 'Range: bytes=1-10'});// res->status should be 206.// res->body should be "bcdefghijk".httplib::make_range_header({{1, 10}, {20, -1}}) // 'Range: bytes=1-10, 20-'httplib::make_range_header({{100, 199}, {500, 599}}) // 'Range: bytes=100-199, 500-599'httplib::make_range_header({{0, 0}, {-1, 1}}) // 'Range: bytes=0-0, -1'httplib::Client cli("localhost", 1234);
cli.Get("/hello"); // with "Connection: close"cli.set_keep_alive(true);
cli.Get("/world");
cli.set_keep_alive(false);
cli.Get("/last-request"); // with "Connection: close"httplib::Client cli("yahoo.com");auto res = cli.Get("/");
res->status; // 301cli.set_follow_location(true);
res = cli.Get("/");
res->status; // 200Note
This feature is not available on Windows, yet.
cli.set_interface("eth0"); // Interface name, IP address or host nameThe server can apply compression to the following MIME type contents:
all text types except text/event-stream
image/svg+xml
application/javascript
application/json
application/xml
application/xhtml+xml
'gzip' compression is available with CPPHTTPLIB_ZLIB_SUPPORT. libz should be linked.
Brotli compression is available with CPPHTTPLIB_BROTLI_SUPPORT. Necessary libraries should be linked.
Please see https://github.com/google/brotli for more detail.
cli.set_compress(true);
res = cli.Post("/resource/foo", "...", "text/plain");cli.set_decompress(false);
res = cli.Get("/resource/foo", {{"Accept-Encoding", "gzip, deflate, br"}});
res->body; // Compressed datapoll instead of selectselect system call is used as default since it's more widely supported. If you want to let cpp-httplib use poll instead, you can do so with CPPHTTPLIB_USE_POLL.
Unix Domain Socket support is available on Linux and macOS.
// Serverhttplib::Server svr("./my-socket.sock");
svr.set_address_family(AF_UNIX).listen("./my-socket.sock", 80);// Clienthttplib::Client cli("./my-socket.sock");
cli.set_address_family(AF_UNIX);"my-socket.sock" can be a relative path or an absolute path. You application must have the appropriate permissions for the path. You can also use an abstract socket address on Linux. To use an abstract socket address, prepend a null byte ('x00') to the path.
$ ./split.py -husage: split.py [-h] [-e EXTENSION] [-o OUT]This script splits httplib.h into .h and .cc parts.optional arguments: -h, --help show this help message and exit -e EXTENSION, --extension EXTENSION extension of the implementation file (default: cc) -o OUT, --out OUT where to write the files (default: out)$ ./split.pyWrote out/httplib.h and out/httplib.cc
Dockerfile for static HTTP server is available. Port number of this HTTP server is 80, and it serves static files from /html directory in the container.
> docker build -t cpp-httplib-server ....> docker run --rm -it -p 8080:80 -v ./docker/html:/html cpp-httplib-server Serving HTTP on 0.0.0.0 port 80 ... 192.168.65.1 - - [31/Aug/2024:21:33:56 +0000] "GET / HTTP/1.1" 200 599 "-" "curl/8.7.1"192.168.65.1 - - [31/Aug/2024:21:34:26 +0000] "GET / HTTP/1.1" 200 599 "-" "Mozilla/5.0 ..."192.168.65.1 - - [31/Aug/2024:21:34:26 +0000] "GET /favicon.ico HTTP/1.1" 404 152 "-" "Mozilla/5.0 ..."
From Docker Hub
> docker run --rm -it -p 8080:80 -v ./docker/html:/html yhirose4dockerhub/cpp-httplib-server ...> docker run --init --rm -it -p 8080:80 -v ./docker/html:/html cpp-httplib-server Serving HTTP on 0.0.0.0 port 80 ... 192.168.65.1 - - [31/Aug/2024:21:33:56 +0000] "GET / HTTP/1.1" 200 599 "-" "curl/8.7.1"192.168.65.1 - - [31/Aug/2024:21:34:26 +0000] "GET / HTTP/1.1" 200 599 "-" "Mozilla/5.0 ..."192.168.65.1 - - [31/Aug/2024:21:34:26 +0000] "GET /favicon.ico HTTP/1.1" 404 152 "-" "Mozilla/5.0 ..."
g++ 4.8 and below cannot build this library since
Include httplib.h before Windows.h or include Windows.h by defining WIN32_LEAN_AND_MEAN beforehand.
#include#include
#define WIN32_LEAN_AND_MEAN#include#include
Note
cpp-httplib officially supports only the latest Visual Studio. It might work with former versions of Visual Studio, but I can no longer verify it. Pull requests are always welcome for the older versions of Visual Studio unless they break the C++11 conformance.
Note
Windows 8 or lower, Visual Studio 2013 or lower, and Cygwin and MSYS2 including MinGW are neither supported nor tested.
MIT license (© 2024 Yuji Hirose)
These folks made great contributions to polish this library to totally another level from a simple toy!
