simple-telnet-client

Simplest Telnet Client Ever Made in C/C++

Dependencies

1. libtelnet: Install it easily using the folllwing command:

   $ sudo apt install libtelnet-dev

Installation

1. Make sure to download the repository. Use git clone https://github.com/ravijo/simple-telnet-client.git or download zip as per your convenience.
2. Create build directory and go inside it using mkdir build && cd build
3. Invoke cmake as cmake ..
4. Build files using make

Debug

In order to see the request and response from the server, please set DEBUG_MODE as shown below:

simple-telnet-client/include/simple_telnet_client/telnet_client.hpp

Lines 17 to 18 in 84a0565

	// flag to print requests and responses in the console for debugging purposes
	#define DEBUG_MODE true

Run

1. Please set the IP address and port number of the telnet server as shown below:

   simple-telnet-client/src/main.cpp

   Line 14 in 84a0565

   clientPtr = std::make_unique<simple_telnet_client::TelnetClient>("192.168.10.20", "23");

2. Do not forget to compile after changes
3. Invoke the client using ./client as shown below:

   $ ./client
   response: [Welcome
   ]
   response: [
   ]
   request: [INIT
   ]
   response: [OK
   ]
   request: [READ PT3
   ]
   response: [OK
   ]
   request: [READ PT4
   ]
   response: [OK
   ]
   request: [REM PT3
   ]
   response: [OK
   ]

Using libtelnet Installed on Custom Location

1. If the libtelnet is installed on a custom locaton, we need to provide its path in CMakeLists.txt.
2. First, let's find out where is our libtelnet

   $ whereis libtelnet
   libtelnet: /usr/lib/x86_64-linux-gnu/libtelnet.so /usr/lib/x86_64-linux-gnu/libtelnet.a /usr/include/libtelnet.h

3. Now, using the above information, we need to modify CMakeLists.txt as shown below:

   set(TELNET_INCLUDE_DIR
     /usr/include
   )
   
   set(TELNET_LIBRARY
     /usr/lib/x86_64-linux-gnu/libtelnet.so
   )
   
   include_directories(include
     ${TELNET_INCLUDE_DIR}
   )
   
   add_executable(client
     src/telnet_client.cpp
     src/main.cpp
   )
   
   target_link_libraries(client
     ${TELNET_LIBRARY}
   )

Using Docker

The package can be installed using Docker for testing purposes. Please use the following commands to build and run the docker:

1. Build Docker

   ravi@dell:~/simple-telnet-client$ docker build -t client .
   Sending build context to Docker daemon  92.67kB
   Step 1/8 : FROM ubuntu:20.04
    ---> 3bc6e9f30f51
   Step 2/8 : ENV TZ=Asia/Tokyo
    ---> f8e22625db16
   .
   .
   .
   Step 8/8 : WORKDIR /simple-telnet-client/build
    ---> efb6c90e291e
   Successfully built efb6c90e291e
   Successfully tagged client:latest

2. Run Docker

   ravi@dell:~/simple-telnet-client$ docker run -it client
   root@0ebe27c82992:/simple-telnet-client/build# 

3. CMake Porject

   root@0ebe27c82992:/simple-telnet-client/build# cmake ..
   -- The C compiler identification is GNU 9.4.0
   .
   .
   .
   -- Configuring done
   -- Generating done
   -- Build files have been written to: /simple-telnet-client/build

4. Make Project

   root@0ebe27c82992:/simple-telnet-client/build# make
   Scanning dependencies of target client
   [ 33%] Building CXX object CMakeFiles/client.dir/src/telnet_client.cpp.o
   [ 66%] Building CXX object CMakeFiles/client.dir/src/main.cpp.o
   [100%] Linking CXX executable client
   [100%] Built target client

References

1. libtelnet