CODEWITHSUNDEEP
c++json
Graindor
Graindor

Reputation: 59

Receiving a string and using it to call a method C++

Now I'm doing like this: Client Side: (python)

data = json.dumps({"A":"PRINT","B":"ARTIFACTS","C":10})
s.send(data)

Server Side: (C++)

recv(newSd, (char*)&msg, sizeof(msg), 0);
string str(msg);
string text = msg;
bool parsingSuccessful = reader.parse( text, root );
if  ((root["A"] == "PRINT") &&
            (root["B"]== "ARTIFACTS")&&
            (root["C"]==10)){
                PRINT(ARTIFICATS,10);
            }

I know this is not the correct way to do and help me out.

Thanks.

Upvotes: 0

Views: 110

Answers (1)

Paul Belanger
Paul Belanger

Reputation: 2434

You can implement a map from the command string to the implementation of the function that handles that command using an unordered_map.

An example implementation could work as follows: 

// A function handler takes its arguments as strings and returns some sort of result
// that can be returned to the user. 
using CommandHandler = std::function<Result(std::vector<std::string> const&)>

// various handers for command requests
Result handle_print(std::vector<std::string> const& args);
Result handle_delete(std::vector<std::string> const& args);
Result handle_add(std::vector<std::string> const& args);
Result handle_version(std::vector<std::string> const& args);

// the table that holds our commands
std::unordered_map<string, CommandHandler> command_table = {
    {"print", handle_print},
    {"delete", handle_delete},
    {"add", handle_add},
    {"version", handle_version},
};

// take your json doucment, extract the first value as the command, and put the rest into an arg array: 

void handle_request(Connection& connection, json const& request)
{
    std::string cmd = root["A"];
    std::vector<std:string> args;
    // parse the rest of your arguments into an array here. 

    if(command_table.count(cmd))
    {
        // command is valid
        auto& handler = command_table[cmd];
        auto result = handler(args);
        send_result(connection, result);
    }
    else
    {
        // send bad command error or something

        send_bad_command(connection);
    }
}

Upvotes: 6

Related Questions