#include <iostream>
#include <map>
#include <sstream>
#include <string>
 
std::string get_boundary(const std::string& content_type_header) {
    std::map<std::string, std::string> params;
    std::istringstream iss(content_type_header);
    std::string key;
    std::getline(iss, key, ';'); // 提取"Content-Type"
 
    std::string line;
    while (std::getline(iss, line, ';')) {
        std::istringstream param_iss(line);
        std::string param_key;
        if (std::getline(param_iss, param_key, '=')) {
            std::string param_value;
            if (std::getline(param_iss, param_value, '"')) {
                params[param_key] = param_value;
            }
        }
    }
 
    auto it = params.find("boundary");
    if (it != params.end()) {
        return "--" + it->second;
    }
    return "";
}
 
int main() {
    std::string content_type = "multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW";
    std::string boundary = get_boundary(content_type);
    std::cout << "Boundary: " << boundary << std::endl;
    return 0;
}