istream for command line input for C++/Poco

Question

I am starting to work with the Poco C++ libraries, especially for HTTP client/server parsing. I saw that there are classes such as HTTPRequest, HTTPResponse etc. and these have a method named "read(std::istream)". This method takes input argument of type "std::istream". However, I want to use this with something that i enter from the command line. I am using cin to take the input but this gives an error since istream and cin are of different types. Heres an example :

int main() {
  HTTPRequest* req = new HTTPRequest();
  std::string input;
  std::cout << "Enter something.. " << std::endl;
  std::cin >> input;
  req->read(input);

}

My understanding is that the read method will interpret the data as HTTPRequest type. I am doing this just for testing. I know "string" type wont work, but i tried using istream constructor with getline etc and it still gives compile time error. So what is the ideal way to do this ?

Answer 1

According to the docs for POCO, the HTTPRequest ::read method takes an std::istream object.

void read(
    std::istream & istr
);

If you want to read the request from standard input, pass std::cin as a parameter.

int main() {
  HTTPRequest* req = new HTTPRequest();
  // std::string input;
  // std::cout << "Enter something.. " << std::endl;
  // std::cin >> input;
  req->read(std::cin);

  return 0;
}

When it tries to read from std::cin , it will prompt you for input, so you can enter whatever you were trying to enter into the string you had there. I would then recommend, you either use an std::ifstream object or use std::istringstream . These both subclass std::istream , so you can pass that as parameter.

Ex:

int main() {
  HTTPRequest* req = new HTTPRequest();
  std::string input;
  std::cout << "Enter something.. " << std::endl;
  std::cin >> input;
  std::istringstream iss(input);

  req->read(iss);

  return 0;
}