cpp-libp2p/example/01-echo

Example Libp2p Echo

General description

This example shows you how to create a simple Echo client and server in cpp-libp2p. There are three ways to launch this example: C++ to C++, C++ Client to Go Server and C++ Server to Go Client. The last two examples can be used to test a compatibility between the implementations and should be moved to some separate repository to produce automatic tests.

C++ Server and Client

Currently, libp2p_echo_server can operate in two modes - via Plaintext or SECIO security protocols. By default, it is launched in SECIO secured mode. To run it with Plaintext exclusive mode just add -insecure command-line argument.

libp2p_echo_server -insecure

The client application does not have such an option and supports both types of connection at any time. Which security type is going to be used is defined by the server's working mode and its preferences.

Golang Implementation Compatibility Note

The libp2p_client.go which is an echo server source from go-libp2p-examples can be built only when go.mod file is present. The current version of the go.mod is outdated, and only Plaintext security could be cross-tested. To update the go.mod file there are changes required in c++ implementation of libp2p. Those changes are the subject of ongoin work.

C++ to C++

1. Build C++ targets libp2p_echo_server and libp2p_echo_client
2. Start a C++ server. If you build using CMake and now are in this directory, executable can be launched as ../../cmake-build-debug/example/01-echo/libp2p_echo_server.
3. Start a C++ client. If you build using CMake and now are in directory, executable can be launched as ../../cmake-build-debug/example/01-echo/libp2p_echo_client /ip4/127.0.0.1/tcp/40010/ipfs/12D3KooWLs7RC93EGXZzn9YdKyZYYx3f9UjTLYNX1reThpCkFb83.
4. Watch how the message is exchanged between server and client

C++ Client to Go Server

1. Build C++ target libp2p_echo_client
2. Build a Go example via go build libp2p_client.go
3. Execute ./libp2p_client -insecure -l 40010. It will start a Go server
4. Go server outputs its address in form I am /ip4/.../tcp/.../ipfs/.... Please, take a note of this address
5. Start C++ client. If you build using CMake and now are in directory, executable can be launched as ../../cmake-build-debug/example/01-echo/libp2p_echo_client $ADDRESS_OF_GO_SERVER$.
6. Watch how message is exchanged

C++ Server and Go Client

1. Build C++ target libp2p_echo_server
2. Build a Go example via go build libp2p_client.go
3. Execute ../../cmake-build-debug/example/01-echo/libp2p_echo_server -insecure. It will start a C++ server.
4. Execute ./libp2p_client -insecure -l 40011 -d /ip4/127.0.0.1/tcp/40010/ipfs/12D3KooWLs7RC93EGXZzn9YdKyZYYx3f9UjTLYNX1reThpCkFb83
5. Watch how message is exchanged