Builder.cpp

#include <iostream>
#include <string>
#include <map>

class HTTPRequest {
public:
    std::string url;
    std::string method;
    std::map<std::string, std::string> headers;
    std::string body;
    int timeoutSeconds{30};

    void print() const {
        std::cout << "--- HTTP Request ---\n";
        std::cout << "Method: " << method << "\n";
        std::cout << "URL:    " << url << "\n";
        std::cout << "Headers:\n";
        for (const auto& [key, value] : headers) {
            std::cout << "  " << key << ": " << value << "\n";
        }
        std::cout << "Body:    " << (body.empty() ? "[empty]" : body) << "\n";
        std::cout << "Timeout: " << timeoutSeconds << "s\n";
        std::cout << "--------------------\n\n";
    }
};

class HTTPRequestBuilder {
private:
    HTTPRequest request;

public:
    HTTPRequestBuilder() = default;

    HTTPRequestBuilder& setURL(const std::string& url) {
        request.url = url;
        return *this;
    }

    HTTPRequestBuilder& setMethod(const std::string& method) {
        request.method = method;
        return *this;
    }

    HTTPRequestBuilder& addHeader(const std::string& key, const std::string& value) {
        request.headers[key] = value;
        return *this;
    }

    HTTPRequestBuilder& setBody(const std::string& body) {
        request.body = body;
        return *this;
    }

    HTTPRequestBuilder& setTimeout(int seconds) {
        request.timeoutSeconds = seconds;
        return *this;
    }

    HTTPRequest build() {
        if (request.url.empty()) {
            throw std::runtime_error("URL cannot be empty!");
        }
        if (request.method.empty()) {
            request.method = "GET";
        }
        return request;
    }
};

int main() {
    // 1. Building a simple GET request using method chaining (Fluent Interface)
    HTTPRequest getRequest = HTTPRequestBuilder()
                                .setURL("https://api.example.com/data")
                                .setMethod("GET")
                                .addHeader("Accept", "application/json")
                                .setTimeout(10)
                                .build();

    getRequest.print();

    // 2. Building a complex POST request
    HTTPRequest postRequest = HTTPRequestBuilder()
                                 .setURL("https://api.example.com/users")
                                 .setMethod("POST")
                                 .addHeader("Content-Type", "application/json")
                                 .addHeader("Authorization", "Bearer token123")
                                 .setBody("{\"name\": \"Alice\", \"role\": \"admin\"}")
                                 .build();

    postRequest.print();

    return 0;
}