cpp-httplib
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!
NOTE: This is a multi-threaded 'blocking' HTTP library. If you are looking for a 'non-blocking' library, this is not the one that you want.
Simple examples
Server
#define CPPHTTPLIB_OPENSSL_SUPPORT
#include "path/to/httplib.h"
// HTTP
httplib::Server svr;
// HTTPS
httplib::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);
Client
#define CPPHTTPLIB_OPENSSL_SUPPORT
#include "path/to/httplib.h"
// HTTP
httplib::Client cli("http://cpp-httplib-server.yhirose.repl.co");
// HTTPS
httplib::Client cli("https://cpp-httplib-server.yhirose.repl.co");
auto res = cli.Get("/hi");
res->status;
res->body;
Try out the examples on Repl.it!
- Run server at https://repl.it/@yhirose/cpp-httplib-server
- Run client at https://repl.it/@yhirose/cpp-httplib-client
Server
#include <httplib.h>
int main(void)
{
using namespace httplib;
Server svr;
svr.Get("/hi", [](const Request& req, Response& res) {
res.set_content("Hello World!", "text/plain");
});
svr.Get(R"(/numbers/(\d+))", [&](const Request& req, Response& res) {
auto numbers = req.matches[1];
res.set_content(numbers, "text/plain");
});
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.
Bind a socket to multiple interfaces and any available port
int port = svr.bind_to_any_port("0.0.0.0");
svr.listen_after_bind();
Static File Server
// Mount / to ./www directory
auto ret = svr.set_mount_point("/", "./www");
if (!ret) {
// The specified base directory doesn't exist...
}
// Mount /public to ./www directory
ret = svr.set_mount_point("/public", "./www");
// Mount /public to ./www1 and ./www2 directories
ret = svr.set_mount_point("/public", "./www1"); // 1st order to search
ret = svr.set_mount_point("/public", "./www2"); // 2nd order to search
// Remove mount /
ret = svr.remove_mount_point("/");
// Remove mount /public
ret = svr.remove_mount_point("/public");
// User defined file extension and MIME type mappings
svr.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 |
NOTE: These static file server methods are not thread-safe.
Logging
svr.set_logger([](const auto& req, const auto& res) {
your_logger(req, res);
});
Error handler
svr.set_error_handler([](const auto& req, auto& res) {
auto fmt = "<p>Error Status: <span style='color:red;'>%d</span></p>";
char buf[BUFSIZ];
snprintf(buf, sizeof(buf), fmt, res.status);
res.set_content(buf, "text/html");
});
Exception handler
The exception handler gets called if a user routing handler throws an error.
svr.set_exception_handler([](const auto& req, auto& res, std::exception &e) {
res.status = 500;
auto fmt = "<h1>Error 500</h1><p>%s</p>";
char buf[BUFSIZ];
snprintf(buf, sizeof(buf), fmt, e.what());
res.set_content(buf, "text/html");
});
Pre routing handler
svr.set_pre_routing_handler([](const auto& req, auto& res) -> bool {
if (req.path == "/hello") {
res.set_content("world", "text/html");
return Server::HandlerResponse::Handled;
}
return Server::HandlerResponse::Unhandled;
});
Post routing handler
svr.set_post_routing_handler([](const auto& req, auto& res) {
res.set_header("ADDITIONAL_HEADER", "value");
});
'multipart/form-data' POST data
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;
});
Receive content with a content receiver
svr.Post("/content_receiver",
[&](const Request &req, Response &res, const ContentReader &content_reader) {
if (req.is_multipart_form_data()) {
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;
});
res.set_content(body, "text/plain");
}
});
Send content with the content provider
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] { delete data; });
});
Without content length:
svr.Get("/stream", [&](const Request &req, Response &res) {
res.set_content_provider(
"text/plain", // Content type
[&](size_t offset, size_t length, DataSink &sink) {
if (/* there is still data */) {
std::vector<char> 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.
});
});
Chunked transfer encoding
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.
}
);
});
'Expect: 100-continue' handler
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 417;
});
// Send a final status without reading the message body.
svr.set_expect_100_continue_handler([](const Request &req, Response &res) {
return res.status = 401;
});
Keep-Alive connection
svr.set_keep_alive_max_count(2); // Default is 5
svr.set_keep_alive_timeout(10); // Default is 5
Timeout
svr.set_read_timeout(5, 0); // 5 seconds
svr.set_write_timeout(5, 0); // 5 seconds
svr.set_idle_interval(0, 100000); // 100 milliseconds
Set maximum payload length for reading a request body
svr.set_payload_max_length(1024 * 1024 * 512); // 512MB
Server-Sent Events
Please see Server example and Client example.
Default thread pool support
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); };
Override the default thread pool with yours
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 void enqueue(std::function<void()> fn) override {
pool_.enqueue(fn);
}
virtual void shutdown() override {
pool_.shutdown_gracefully();
}
private:
YourThreadPool pool_;
};
svr.new_task_queue = [] {
return new YourThreadPoolTaskQueue(12);
};
Client
#include <httplib.h>
#include <iostream>
int main(void)
{
httplib::Client cli("localhost", 1234);
if (auto res = cli.Get("/hi")) {
if (res->status == 200) {
std::cout << res->body << std::endl;
}
} else {
auto err = res.error();
...
}
}
NOTE: 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");
Error code
Here is the list of errors from Result::error().
enum Error {
Success = 0,
Unknown,
Connection,
BindIPAddress,
Read,
Write,
ExceedRedirectCount,
Canceled,
SSLConnection,
SSLLoadingCerts,
SSLServerVerification,
UnsupportedMultipartBoundaryChars
};
GET with HTTP headers
httplib::Headers headers = {
{ "Accept-Encoding", "gzip, deflate" }
};
auto res = cli.Get("/hi", headers);
or
cli.set_default_headers({
{ "Accept-Encoding", "gzip, deflate" }
});
auto res = cli.Get("/hi");
POST
res = cli.Post("/post", "text", "text/plain");
res = cli.Post("/person", "name=john1¬e=coder", "application/x-www-form-urlencoded");
POST with parameters
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);
POST with Multipart Form Data
httplib::MultipartFormDataItems items = {
{ "text1", "text default", "", "" },
{ "text2", "aωb", "", "" },
{ "file1", "h\ne\n\nl\nl\no\n", "hello.txt", "text/plain" },
{ "file2", "{\n \"world\", true\n}\n", "world.json", "application/json" },
{ "file3", "", "", "application/octet-stream" },
};
auto res = cli.Post("/multipart", items);
PUT
res = cli.Put("/resource/foo", "text", "text/plain");
DELETE
res = cli.Delete("/resource/foo");
OPTIONS
res = cli.Options("*");
res = cli.Options("/resource/foo");
Timeout
cli.set_connection_timeout(0, 300000); // 300 milliseconds
cli.set_read_timeout(5, 0); // 5 seconds
cli.set_write_timeout(5, 0); // 5 seconds
Receive content with a content receiver
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(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.
});
Send content with a content provider
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");
Chunked transfer encoding
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");
With Progress Callback
httplib::Client client(url, port);
// prints: 0 / 000 bytes => 50% complete
auto res = cli.Get("/", [](uint64_t len, uint64_t total) {
printf("%lld / %lld bytes => %d%% complete\n",
len, total,
(int)(len*100/total));
return true; // return 'false' if you want to cancel the request.
}
);
Authentication
// Basic Authentication
cli.set_basic_auth("user", "pass");
// Digest Authentication
cli.set_digest_auth("user", "pass");
// Bearer Token Authentication
cli.set_bearer_token_auth("token");
NOTE: OpenSSL is required for Digest Authentication.
Proxy server support
cli.set_proxy("host", port);
// Basic Authentication
cli.set_proxy_basic_auth("user", "pass");
// Digest Authentication
cli.set_proxy_digest_auth("user", "pass");
// Bearer Token Authentication
cli.set_proxy_bearer_token_auth("pass");
NOTE: OpenSSL is required for Digest Authentication.
Range
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'
Keep-Alive connection
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"
Redirect
httplib::Client cli("yahoo.com");
auto res = cli.Get("/");
res->status; // 301
cli.set_follow_location(true);
res = cli.Get("/");
res->status; // 200
Use a specific network interface
NOTE: This feature is not available on Windows, yet.
cli.set_interface("eth0"); // Interface name, IP address or host name
Compression
The 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
Zlib Support
'gzip' compression is available with CPPHTTPLIB_ZLIB_SUPPORT. libz should be linked.
Brotli Support
Brotli compression is available with CPPHTTPLIB_BROTLI_SUPPORT. Necessary libraries should be linked. Please see https://github.com/google/brotli for more detail.
Compress request body on client
cli.set_compress(true);
res = cli.Post("/resource/foo", "...", "text/plain");
Compress response body on client
cli.set_decompress(false);
res = cli.Get("/resource/foo", {{"Accept-Encoding", "gzip, deflate, br"}});
res->body; // Compressed data
SSL Support
SSL support is available with CPPHTTPLIB_OPENSSL_SUPPORT. libssl and libcrypto should be linked.
NOTE: cpp-httplib currently supports only version 1.1.1.
#define CPPHTTPLIB_OPENSSL_SUPPORT
#include "path/to/httplib.h"
// Server
httplib::SSLServer svr("./cert.pem", "./key.pem");
// Client
httplib::Client cli("https://localhost:1234");
// Use your CA bundle
cli.set_ca_cert_path("./ca-bundle.crt");
// Disable cert verification
cli.enable_server_certificate_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.
Split httplib.h into .h and .cc
> python3 split.py
> ls out
httplib.h httplib.cc
NOTE
g++
g++ 4.8 and below cannot build this library since <regex> in the versions are broken.
Windows
Include httplib.h before Windows.h or include Windows.h by defining WIN32_LEAN_AND_MEAN beforehand.
#include <httplib.h>
#include <Windows.h>
#define WIN32_LEAN_AND_MEAN
#include <Windows.h>
#include <httplib.h>
Note: Windows 8 or lower and Cygwin on Windows are not supported.
License
MIT license (© 2020 Yuji Hirose)
Special Thanks To
These folks made great contributions to polish this library to totally another level from a simple toy!
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