# asio_http2_client.h

    /*
     * nghttp2 - HTTP/2 C Library
     *
     * Copyright (c) 2015 Tatsuhiro Tsujikawa
     *
     * Permission is hereby granted, free of charge, to any person obtaining
     * a copy of this software and associated documentation files (the
     * "Software"), to deal in the Software without restriction, including
     * without limitation the rights to use, copy, modify, merge, publish,
     * distribute, sublicense, and/or sell copies of the Software, and to
     * permit persons to whom the Software is furnished to do so, subject to
     * the following conditions:
     *
     * The above copyright notice and this permission notice shall be
     * included in all copies or substantial portions of the Software.
     *
     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
     * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
     * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
     * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     */
    #ifndef ASIO_HTTP2_CLIENT_H
    #define ASIO_HTTP2_CLIENT_H

    #include <nghttp2/asio_http2.h>

    namespace nghttp2 {

    namespace asio_http2 {

    namespace client {

    class response_impl;

    class response {
    public:
      // Application must not call this directly.
      response();
      ~response();

      // Sets callback which is invoked when chunk of response body is
      // received.
      void on_data(data_cb cb) const;

      // Returns status code.
      int status_code() const;

      // Returns content-length.  -1 if it is unknown.
      int64_t content_length() const;

      // Returns the response header fields.  The pusedo header fields,
      // which start with colon (:), are exluced from this list.
      const header_map &header() const;

      // Application must not call this directly.
      response_impl &impl() const;

    private:
      std::unique_ptr<response_impl> impl_;
    };

    class request;

    using response_cb = std::function<void(const response &)>;
    using request_cb = std::function<void(const request &)>;
    using connect_cb =
        std::function<void(boost::asio::ip::tcp::resolver::iterator)>;

    class request_impl;

    class request {
    public:
      // Application must not call this directly.
      request();
      ~request();

      // Sets callback which is invoked when response header is received.
      void on_response(response_cb cb) const;

      // Sets callback which is invoked when push request header is
      // received.
      void on_push(request_cb cb) const;

      // Sets callback which is invoked when this request and response are
      // finished.  After the invocation of this callback, the application
      // must not access request and response object.
      void on_close(close_cb cb) const;

      // Write trailer part.  This must be called after setting both
      // NGHTTP2_DATA_FLAG_EOF and NGHTTP2_DATA_FLAG_NO_END_STREAM set in
      // *data_flag parameter in generator_cb passed to session::submit()
      // function.
      void write_trailer(header_map h) const;

      // Cancels this request and response with given error code.
      void cancel(uint32_t error_code = NGHTTP2_INTERNAL_ERROR) const;

      // Resumes deferred uploading.
      void resume() const;

      // Returns method (e.g., GET).
      const std::string &method() const;

      // Returns request URI, split into components.
      const uri_ref &uri() const;

      // Returns request header fields.  The pusedo header fields, which
      // start with colon (:), are exluced from this list.
      const header_map &header() const;

      // Application must not call this directly.
      request_impl &impl() const;

    private:
      std::unique_ptr<request_impl> impl_;
    };

    // Wrapper around an nghttp2_priority_spec.
    class priority_spec {
    public:
      // The default ctor is used only by sentinel values.
      priority_spec() = default;

      // Create a priority spec with the given priority settings.
      explicit priority_spec(const int32_t stream_id, const int32_t weight,
                             const bool exclusive = false);

      // Return a pointer to a valid nghttp2 priority spec, or null.
      const nghttp2_priority_spec *get() const;

      // Indicates whether or not this spec is valid (i.e. was constructed with
      // values).
      bool valid() const;

    private:
      nghttp2_priority_spec spec_;
      bool valid_ = false;
    };

    class session_impl;

    class session {
    public:
      // Starts HTTP/2 session by connecting to |host| and |service|
      // (e.g., "80") using clear text TCP connection with connect timeout
      // 60 seconds.
      session(boost::asio::io_service &io_service, const std::string &host,
              const std::string &service);

      // Same as previous but with pegged local endpoint
      session(boost::asio::io_service &io_service,
              const boost::asio::ip::tcp::endpoint &local_endpoint,
              const std::string &host, const std::string &service);

      // Starts HTTP/2 session by connecting to |host| and |service|
      // (e.g., "80") using clear text TCP connection with given connect
      // timeout.
      session(boost::asio::io_service &io_service, const std::string &host,
              const std::string &service,
              const boost::posix_time::time_duration &connect_timeout);

      // Same as previous but with pegged local endpoint
      session(boost::asio::io_service &io_service,
              const boost::asio::ip::tcp::endpoint &local_endpoint,
              const std::string &host, const std::string &service,
              const boost::posix_time::time_duration &connect_timeout);

      // Starts HTTP/2 session by connecting to |host| and |service|
      // (e.g., "443") using encrypted SSL/TLS connection with connect
      // timeout 60 seconds.
      session(boost::asio::io_service &io_service,
              boost::asio::ssl::context &tls_context, const std::string &host,
              const std::string &service);

      // Starts HTTP/2 session by connecting to |host| and |service|
      // (e.g., "443") using encrypted SSL/TLS connection with given
      // connect timeout.
      session(boost::asio::io_service &io_service,
              boost::asio::ssl::context &tls_context, const std::string &host,
              const std::string &service,
              const boost::posix_time::time_duration &connect_timeout);

      ~session();

      session(session &&other) noexcept;
      session &operator=(session &&other) noexcept;

      // Sets callback which is invoked after connection is established.
      void on_connect(connect_cb cb) const;

      // Sets callback which is invoked there is connection level error
      // and session is terminated.
      void on_error(error_cb cb) const;

      // Sets read timeout, which defaults to 60 seconds.
      void read_timeout(const boost::posix_time::time_duration &t);

      // Shutdowns connection.
      void shutdown() const;

      // Returns underlying io_service object.
      boost::asio::io_service &io_service() const;

      // Submits request to server using |method| (e.g., "GET"), |uri|
      // (e.g., "http://localhost/") and optionally additional header
      // fields.  This function returns pointer to request object if it
      // succeeds, or nullptr and |ec| contains error message.
      const request *submit(boost::system::error_code &ec,
                            const std::string &method, const std::string &uri,
                            header_map h = header_map{},
                            priority_spec prio = priority_spec()) const;

      // Submits request to server using |method| (e.g., "GET"), |uri|
      // (e.g., "http://localhost/") and optionally additional header
      // fields.  The |data| is request body.  This function returns
      // pointer to request object if it succeeds, or nullptr and |ec|
      // contains error message.
      const request *submit(boost::system::error_code &ec,
                            const std::string &method, const std::string &uri,
                            std::string data, header_map h = header_map{},
                            priority_spec prio = priority_spec()) const;

      // Submits request to server using |method| (e.g., "GET"), |uri|
      // (e.g., "http://localhost/") and optionally additional header
      // fields.  The |cb| is used to generate request body.  This
      // function returns pointer to request object if it succeeds, or
      // nullptr and |ec| contains error message.
      const request *submit(boost::system::error_code &ec,
                            const std::string &method, const std::string &uri,
                            generator_cb cb, header_map h = header_map{},
                            priority_spec prio = priority_spec()) const;

    private:
      std::shared_ptr<session_impl> impl_;
    };

    // configure |tls_ctx| for client use.  Currently, we just set NPN
    // callback for HTTP/2.
    boost::system::error_code
    configure_tls_context(boost::system::error_code &ec,
                          boost::asio::ssl::context &tls_ctx);

    } // namespace client

    } // namespace asio_http2

    } // namespace nghttp2

    #endif // ASIO_HTTP2_CLIENT_H