至此我们一共只写了48行代码就完成了一个高性能的异步C++服务器。
Echo Client
echo客户端的实现与我们的服务端非常类似:
// the handler for receiving messages back from the server
class EchoHandler : public HandlerAdapter {
public:
virtual void read(Context* ctx, std::string msg) override {
std::cout << "received back: " << msg;
}
virtual void readException(Context* ctx, exception_wrapper e) override {
std::cout << exceptionStr(e) << std::endl;
close(ctx);
}
virtual void readEOF(Context* ctx) override {
std::cout << "EOF received :(" << std::endl;
close(ctx);
}
};
注意我们重载了readException和readEOF两个方法，还有其他一些方法可以被重载。如果你需要控制某个特别的事件，只需要重载对应的虚函数即可。
这是客户端的pipeline factory的实现，与我们的服务端结构基本一致，只有EventBaseHandler这个handler在服务端代码中不曾出现，它可以确保我们可以从任意一个线程写入数据。
// the handler for receiving messages back from the server
class EchoHandler : public HandlerAdapter {
public:
virtual void read(Context* ctx, std::string msg) override {
std::cout << "received back: " << msg;
}
virtual void readException(Context* ctx, exception_wrapper e) override {
std::cout << exceptionStr(e) << std::endl;
close(ctx);
}
virtual void readEOF(Context* ctx) override {
std::cout << "EOF received :(" << std::endl;
close(ctx);
}
};
客户端所有的代码如下图所示
#include <gflags/gflags.h>
#include
#include <wangle/bootstrap/ClientBootstrap.h>
#include <wangle/channel/AsyncSocketHandler.h>
#include <wangle/channel/EventBaseHandler.h>
#include <wangle/codec/LineBasedFrameDecoder.h>
#include <wangle/codec/StringCodec.h>
using namespace folly;
using namespace wangle;
DEFINE_int32(port, 8080, "echo server port");
DEFINE_string(host, "::1", "echo server address");
typedef Pipeline<folly::IOBufQueue&, std::string> EchoPipeline;
// the handler for receiving messages back from the server
class EchoHandler : public HandlerAdapter {
public:
virtual void read(Context* ctx, std::string msg) override {
std::cout << "received back: " << msg;
}
virtual void readException(Context* ctx, exception_wrapper e) override {
std::cout << exceptionStr(e) << std::endl;
close(ctx);
}
virtual void readEOF(Context* ctx) override {
std::cout << "EOF received :(" << std::endl;
close(ctx);
}
};
// chains the handlers together to define the response pipeline
class EchoPipelineFactory : public PipelineFactory {
public:
EchoPipeline::Ptr newPipeline(std::shared_ptr sock) {
auto pipeline = EchoPipeline::create();
pipeline->addBack(AsyncSocketHandler(sock));
pipeline->addBack(
EventBaseHandler()); // ensure we can write from any thread
pipeline->addBack(LineBasedFrameDecoder(8192, false));
pipeline->addBack(StringCodec());
pipeline->addBack(EchoHandler());
pipeline->finalize();
return pipeline;
}
};
int main(int argc, char** argv) {
google::ParseCommandLineFlags(&argc, &argv, true);
ClientBootstrap client;
client.group(std::make_shared(1));
client.pipelineFactory(std::make_shared());
auto pipeline = client.connect(SocketAddress(FLAGS_host, FLAGS_port)).get();
try {
while (true) {
std::string line;
std::getline(std::cin, line);
if (line == "") {
break;
}
pipeline->write(line + "rn").get();
if (line == "bye") {
pipeline->close();
break;
}
}
} catch (const std::exception& e) {
std::cout << exceptionStr(e) << std::endl;
}
return 0;
}
