curly.hpp
Simple cURL C++17 wrapper
Features
- Custom headers
- Asynchronous requests
- Different types of timeouts
- URL encoded query parameters
- Completion and progress callbacks
- Custom uploading and downloading streams
- PUT, GET, HEAD, POST, PATCH, DELETE, OPTIONS methods
Requirements
Installation
Just add the root repository directory to your cmake project:
add_subdirectory(external/curly.hpp)
target_link_libraries(your_project_target curly.hpp)CMake options
USE_STATIC_CRTUse static C runtime library. Default: OFFUSE_SYSTEM_CURLBuild with cURL from system paths. Default: OFFUSE_EMBEDDED_CURLBuild with embedded cURL library. Default: ON
Examples
#include <curly.hpp/curly.hpp>
namespace net = curly_hpp;
// creates and hold a separate thread for automatically update async requests
net::performer performer;
// also, you can update requests manually from your favorite thread
net::perform();GET Requests
// makes a GET request and async send it
auto request = net::request_builder()
.method(net::http_method::GET)
.url("http://www.httpbin.org/get")
.send();
// synchronous waits and take a response
auto response = request.take();
// prints results
std::cout << "Status code: " << response.http_code() << std::endl;
std::cout << "Content type: " << response.headers["content-type"] << std::endl;
std::cout << "Body content: " << response.content.as_string_view() << std::endl;
// Status code: 200
// Content type: application/json
// Body content: {
// "args": {},
// "headers": {
// "Accept": "*/*",
// "Host": "www.httpbin.org",
// "User-Agent": "cURL/7.54.0"
// },
// "origin": "37.195.66.134, 37.195.66.134",
// "url": "https://www.httpbin.org/get"
// }POST Requests
auto request = net::request_builder()
.method(net::http_method::POST)
.url("http://www.httpbin.org/post")
.header("Content-Type", "application/json")
.content(R"({"hello" : "world"})")
.send();
auto response = request.take();
std::cout << "Body content: " << response.content.as_string_view() << std::endl;
std::cout << "Content Length: " << response.headers["content-length"] << std::endl;
// Body content: {
// "args": {},
// "data": "{\"hello\" : \"world\"}",
// "files": {},
// "form": {},
// "headers": {
// "Accept": "*/*",
// "Content-Length": "19",
// "Content-Type": "application/json",
// "Host": "www.httpbin.org",
// "User-Agent": "cURL/7.54.0"
// },
// "json": {
// "hello": "world"
// },
// "origin": "37.195.66.134, 37.195.66.134",
// "url": "https://www.httpbin.org/post"
// }
// Content Length: 389Query Parameters
auto request = net::request_builder()
.url("http://httpbin.org/anything")
.qparam("hello", "world")
.send();
auto response = request.take();
std::cout << "Last URL: " << response.last_url() << std::endl;
// Last URL: http://httpbin.org/anything?hello=worldError Handling
auto request = net::request_builder()
.url("http://unavailable.site.com")
.send();
request.wait();
if ( request.is_done() ) {
auto response = request.take();
std::cout << "Status code: " << response.http_code() << std::endl;
} else {
// throws net::exception because a response is unavailable
// auto response = request.take();
std::cout << "Error message: " << request.get_error() << std::endl;
}
// Error message: Could not resolve host: unavailable.site.comRequest Callbacks
auto request = net::request_builder("http://www.httpbin.org/get")
.callback([](net::request request){
if ( request.is_done() ) {
auto response = request.take();
std::cout << "Status code: " << response.http_code() << std::endl;
} else {
std::cout << "Error message: " << request.get_error() << std::endl;
}
}).send();
request.wait_callback();
// Status code: 200Streamed Requests
Downloading
class file_dowloader : public net::download_handler {
public:
file_dowloader(const char* filename)
: stream_(filename, std::ofstream::binary) {}
std::size_t write(const char* src, std::size_t size) override {
stream_.write(src, static_cast<std::streamsize>(size));
return size;
}
private:
std::ofstream stream_;
};
net::request_builder()
.url("https://httpbin.org/image/jpeg")
.downloader<file_dowloader>("image.jpeg")
.send().wait();Uploading
class file_uploader : public net::upload_handler {
public:
file_uploader(const char* filename)
: stream_(filename, std::ifstream::binary) {
stream_.seekg(0, std::ios::end);
size_ = static_cast<std::size_t>(stream_.tellg());
stream_.seekg(0, std::ios::beg);
}
std::size_t size() const override {
return size_;
}
std::size_t upload(char* dst, std::size_t size) override {
stream_.read(dst, static_cast<std::streamsize>(size));
return size;
}
private:
std::size_t size_{0u};
std::ifstream stream_;
};
net::request_builder()
.method(net::http_method::POST)
.url("https://httpbin.org/anything")
.uploader<file_uploader>("image.jpeg")
.send().wait();Promised Requests
Also, you can easily integrate promises like a promise.hpp.
#include <curly.hpp/curly.hpp>
namespace net = curly_hpp;
#include <promise.hpp/promise.hpp>
namespace netex = promise_hpp;
netex::promise<net::content_t> download(std::string url) {
return netex::make_promise<net::content_t>([
url = std::move(url)
](auto resolve, auto reject){
net::request_builder(std::move(url))
.callback([resolve,reject](net::request request) mutable {
if ( !request.is_done() ) {
reject(net::exception("network error"));
return;
}
net::response response = request.take();
if ( response.is_http_error() ) {
reject(net::exception("server error"));
return;
}
resolve(std::move(response.content));
}).send();
});
}
auto promise = download("https://httpbin.org/image/png")
.then([](const net::content_t& content){
std::cout << content.size() << " bytes downloaded" << std::endl;
}).except([](std::exception_ptr e){
try {
std::rethrow_exception(e);
} catch (const std::exception& ee) {
std::cerr << "Failed to download: " << ee.what() << std::endl;
}
});
promise.wait();
// 8090 bytes downloaded