http.h

// Copyright (c) 2014-2026 Savoir-faire Linux Inc.
// SPDX-License-Identifier: MIT
#pragma once
 
#include "def.h"
#include "infohash.h"
#include "crypto.h"
 
// some libraries may try to redefine snprintf
// but restinio will use it in std namespace
#ifdef _MSC_VER
#undef snprintf
#define snprintf snprintf
#endif
 
#include <asio/ip/tcp.hpp>
#include <asio/streambuf.hpp>
#include <asio/ssl/context.hpp>
#include <restinio/message_builders.hpp>
 
#include <memory>
#include <queue>
#include <mutex>
#include <future>
 
namespace Json {
class Value;
}
 
namespace restinio {
namespace impl {
class tls_socket_t;
}
} // namespace restinio
 
namespace dht {
namespace log {
struct Logger;
}
 
namespace crypto {
struct Certificate;
}
 
namespace http {
 
using HandlerCb = std::function<void(const asio::error_code& ec)>;
using BytesHandlerCb = std::function<void(const asio::error_code& ec, size_t bytes)>;
using ConnectHandlerCb = std::function<void(const asio::error_code& ec, const asio::ip::tcp::endpoint& endpoint)>;
 
using ssl_socket_t = restinio::impl::tls_socket_t;
using socket_t = asio::ip::tcp::socket;
 
class OPENDHT_PUBLIC Url
{
public:
    Url() = default;
    Url(std::string_view url);
    std::string url;
    std::string protocol {"http"};
    std::string_view user;
    std::string_view password;
    std::string_view host;
    std::string_view service;
    std::string target;
    std::string_view query;
    std::string_view fragment;
 
    std::string toString() const;
};
 
class OPENDHT_PUBLIC Connection : public std::enable_shared_from_this<Connection>
{
public:
    Connection(asio::io_context& ctx, const bool ssl = true, std::shared_ptr<log::Logger> l = {});
    Connection(asio::io_context& ctx,
               std::shared_ptr<dht::crypto::Certificate> server_ca,
               const dht::crypto::Identity& identity,
               std::shared_ptr<log::Logger> l = {});
    ~Connection();
 
    inline unsigned int id() const { return id_; };
    bool is_open() const;
    bool is_ssl() const;
    void checkOcsp(bool check = true) { checkOcsp_ = check; }
 
    void set_ssl_verification(const std::string& hostname, const asio::ssl::verify_mode verify_mode);
 
    asio::streambuf& input();
    std::istream& data() { return istream_; }
 
    std::string read_bytes(size_t bytes = 0);
    std::string read_until(const char delim);
 
    void async_connect(std::vector<asio::ip::tcp::endpoint>&& endpoints, ConnectHandlerCb);
    void async_handshake(HandlerCb cb);
    void async_write(BytesHandlerCb cb);
    void async_read_until(const char* delim, BytesHandlerCb cb);
    void async_read_until(char delim, BytesHandlerCb cb);
    void async_read(size_t bytes, BytesHandlerCb cb);
    void async_read_some(size_t bytes, BytesHandlerCb cb);
 
    void set_keepalive(uint32_t seconds);
 
    const asio::ip::address& local_address() const;
 
    void timeout(const std::chrono::seconds& timeout, HandlerCb cb = {});
 
    void close();
 
private:
    template<typename T>
    T wrapCallback(T cb) const
    {
        return [t = shared_from_this(), cb = std::move(cb)](auto... params) {
            cb(params...);
        };
    }
 
    mutable std::mutex mutex_;
 
    unsigned int id_;
    static std::atomic_uint ids_;
 
    asio::io_context& ctx_;
    std::unique_ptr<socket_t> socket_;
    std::shared_ptr<asio::ssl::context> ssl_ctx_;
    std::unique_ptr<ssl_socket_t> ssl_socket_;
 
    asio::ip::tcp::endpoint endpoint_;
 
    asio::streambuf write_buf_;
    asio::streambuf read_buf_;
    std::istream istream_;
 
    asio::ip::address local_address_;
 
    std::unique_ptr<asio::steady_timer> timeout_timer_;
    std::shared_ptr<log::Logger> logger_;
    bool checkOcsp_ {false};
};
 
/* @class Resolver
 * @brief The purpose is to only resolve once to avoid mutliple dns requests per operation.
 */
class OPENDHT_PUBLIC Resolver
{
public:
    using ResolverCb
        = std::function<void(const asio::error_code& ec, const std::vector<asio::ip::tcp::endpoint>& endpoints)>;
 
    Resolver(asio::io_context& ctx, const std::string& url, std::shared_ptr<log::Logger> logger = {});
    Resolver(asio::io_context& ctx,
             std::string_view host,
             std::string_view service,
             const bool ssl = false,
             std::shared_ptr<log::Logger> logger = {});
 
    // use already resolved endpoints with classes using this resolver
    Resolver(asio::io_context& ctx,
             std::vector<asio::ip::tcp::endpoint> endpoints,
             const bool ssl = false,
             std::shared_ptr<log::Logger> logger = {});
    Resolver(asio::io_context& ctx,
             const std::string& url,
             std::vector<asio::ip::tcp::endpoint> endpoints,
             std::shared_ptr<log::Logger> logger = {});
 
    ~Resolver();
 
    inline const Url& get_url() const { return url_; }
 
    void add_callback(ResolverCb cb, sa_family_t family = AF_UNSPEC);
 
    std::shared_ptr<log::Logger> getLogger() const { return logger_; }
 
    void cancel();
 
private:
    void resolve(std::string_view host, std::string_view service);
 
    mutable std::mutex mutex_;
 
    Url url_;
    asio::error_code ec_;
    asio::ip::tcp::resolver resolver_;
    std::shared_ptr<bool> destroyed_;
    std::vector<asio::ip::tcp::endpoint> endpoints_;
 
    bool completed_ {false};
    std::queue<ResolverCb> cbs_;
 
    std::shared_ptr<log::Logger> logger_;
};
 
class Request;
 
struct Response
{
    unsigned status_code {0};
    std::map<std::string, std::string> headers;
    std::string body;
    bool aborted {false};
    std::weak_ptr<Request> request;
};
 
class OPENDHT_PUBLIC Request : public std::enable_shared_from_this<Request>
{
public:
    enum class State { CREATED, SENDING, HEADER_RECEIVED, RECEIVING, DONE };
    using OnStatusCb = std::function<void(unsigned status_code)>;
    using OnDataCb = std::function<void(const char* at, size_t length)>;
    using OnStateChangeCb = std::function<void(State state, const Response& response)>;
    using OnJsonCb = std::function<void(Json::Value value, const Response& response)>;
    using OnDoneCb = std::function<void(const Response& response)>;
 
    // resolves implicitly
    Request(asio::io_context& ctx,
            const std::string& url,
            const Json::Value& json,
            OnJsonCb jsoncb,
            std::shared_ptr<log::Logger> logger = {});
    Request(asio::io_context& ctx, const std::string& url, OnJsonCb jsoncb, std::shared_ptr<log::Logger> logger = {});
 
    Request(asio::io_context& ctx, const std::string& url, std::shared_ptr<log::Logger> logger = {});
    Request(asio::io_context& ctx,
            std::string_view host,
            std::string_view service,
            const bool ssl = false,
            std::shared_ptr<log::Logger> logger = {});
    Request(asio::io_context& ctx, const std::string& url, OnDoneCb onDone, std::shared_ptr<log::Logger> logger = {});
 
    // user defined resolver
    Request(asio::io_context& ctx, std::shared_ptr<Resolver> resolver, sa_family_t family = AF_UNSPEC);
    Request(asio::io_context& ctx,
            std::shared_ptr<Resolver> resolver,
            const std::string& target,
            sa_family_t family = AF_UNSPEC);
 
    // user defined resolved endpoints
    Request(asio::io_context& ctx,
            std::vector<asio::ip::tcp::endpoint>&& endpoints,
            const bool ssl = false,
            std::shared_ptr<log::Logger> logger = {});
 
    ~Request();
 
    inline unsigned int id() const { return id_; };
    void set_connection(std::shared_ptr<Connection> connection);
    std::shared_ptr<Connection> get_connection() const;
    inline const Url& get_url() const { return resolver_->get_url(); };
 
    void timeout(const std::chrono::seconds& timeout, HandlerCb cb = {})
    {
        timeout_ = timeout;
        timeoutCb_ = cb;
    }

    std::shared_ptr<Request> getPrevious() const { return prev_.lock(); }
 
    inline std::string& to_string() { return request_; }
 
    void set_certificate_authority(std::shared_ptr<dht::crypto::Certificate> certificate);
    void set_identity(const dht::crypto::Identity& identity);
    void set_logger(std::shared_ptr<log::Logger> logger);

    void set_header(restinio::http_request_header_t header);
    void set_method(restinio::http_method_id_t method);
    void set_target(std::string target);
    void set_header_field(restinio::http_field_t field, std::string value);
    void set_connection_type(restinio::http_connection_header_t connection);
    void set_body(std::string body);
    void set_body(const uint8_t* data, size_t length);
    void set_auth(const std::string& username, const std::string& password);
 
    void add_on_status_callback(OnStatusCb cb);
    void add_on_body_callback(OnDataCb cb);
    void add_on_state_change_callback(OnStateChangeCb cb);
    void add_on_done_callback(OnDoneCb cb);
 
    void send();

    const Response& await();

    void cancel();
    void terminate(const asio::error_code& ec);
 
private:
    using OnCompleteCb = std::function<void()>;
 
    struct Callbacks
    {
        OnStatusCb on_status;
        OnDataCb on_header_field;
        OnDataCb on_header_value;
        OnDataCb on_body;
        OnStateChangeCb on_state_change;
    };
 
    static std::string getRelativePath(const Url& origin, const std::string& path);
 
    void notify_state_change(State state);
 
    void build();
 
    static std::string url_encode(std::string_view value);
 
    void init_default_headers();
    void init_parser();
 
    void connect(std::vector<asio::ip::tcp::endpoint>&& endpoints, HandlerCb cb = {});
 
    void post();
 
    void handle_request(const asio::error_code& ec);
    void handle_response(const asio::error_code& ec, size_t bytes);
 
    void onHeadersComplete();
    void onBody(const char* at, size_t length);
    void onComplete();
 
    mutable std::mutex mutex_;
 
    std::shared_ptr<log::Logger> logger_;
 
    restinio::http_request_header_t header_;
    std::map<restinio::http_field_t, std::string> headers_;
    restinio::http_connection_header_t connection_type_ {restinio::http_connection_header_t::close};
    std::string body_;
 
    Callbacks cbs_;
    State state_;
 
    dht::crypto::Identity client_identity_;
    std::shared_ptr<dht::crypto::Certificate> server_ca_;
    std::string service_;
    std::string host_;
 
    unsigned int id_;
    static std::atomic_uint ids_;
    asio::io_context& ctx_;
    sa_family_t family_ = AF_UNSPEC;
    std::shared_ptr<Connection> conn_;
    std::shared_ptr<Resolver> resolver_;
 
    Response response_ {};
    std::string request_;
    std::atomic<bool> finishing_ {false};
    std::unique_ptr<llhttp_t> parser_;
    std::unique_ptr<llhttp_settings_t> parser_s_;
 
    // Next request in case of redirect following
    std::shared_ptr<Request> next_;
    std::weak_ptr<Request> prev_;
    unsigned num_redirect {0};
    bool follow_redirect {true};
 
    HandlerCb timeoutCb_ {};
    std::chrono::seconds timeout_ {0};
};
 
} // namespace http
} // namespace dht