MainJSON.java

import http.MyRequest;
import http.MyResponse;

import java.nio.charset.StandardCharsets;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class MainJSON {
    public static void main(String[] args) {
        String requestBody = "{\"name\":\"허혜\",\"age\":20}";

        String rawHttpRequest =
                "POST /users HTTP/1.1\r\n" +
                        "Host: localhost:8080\r\n" +
                        "id: 허연혜\r\n" +
                        "Content-Type: application/json; charset=UTF-8\r\n" +
                        "Content-Length: " + requestBody.getBytes(StandardCharsets.UTF_8).length + "\r\n" +
                        "\r\n" +
                        requestBody;

        MyRequest request = MyRequest.fromRaw(rawHttpRequest);

        String id = request.header("id").orElse("알 수 없음");
        String name = extractJsonString(request.body(), "name");
        String age = extractJsonNumber(request.body(), "age");

        String content = "id " + id + "님의 name: " + name + ", age: " + age + "으로 등록되었습니다.";

        String responseJson = """
                {
                  "content": "%s"
                }
                """.formatted(escapeJson(content));

        MyResponse response = MyResponse.json(201, request, responseJson);

        System.out.println("===== HTTP 요청 원본 String =====");
        System.out.println(rawHttpRequest);

        System.out.println();
        System.out.println("===== MyRequest 객체에 담긴 값 =====");
        System.out.println("method = " + request.method());
        System.out.println("path = " + request.path());
        System.out.println("uri = " + request.uri());
        System.out.println("version = " + request.httpVersionText());
        System.out.println("headers = " + request.headers().map());
        System.out.println("id header = " + request.header("id").orElse(""));
        System.out.println("body = " + request.body());

        System.out.println();
        System.out.println("===== MyResponse 객체에 담긴 값 =====");
        System.out.println("statusCode = " + response.statusCode());
        System.out.println("headers = " + response.headers().map());
        System.out.println("body = " + response.body());

        System.out.println();
        System.out.println("===== MyResponse가 만든 HTTP 응답 원본 =====");
        System.out.println(response.toRawHttpResponse());
    }

    private static String extractJsonString(String json, String key) {
        Pattern pattern = Pattern.compile("\"" + key + "\"\\s*:\\s*\"([^\"]*)\"");
        Matcher matcher = pattern.matcher(json);

        if (matcher.find()) {
            return matcher.group(1);
        }

        return "";
    }

    private static String extractJsonNumber(String json, String key) {
        Pattern pattern = Pattern.compile("\"" + key + "\"\\s*:\\s*(\\d+)");
        Matcher matcher = pattern.matcher(json);

        if (matcher.find()) {
            return matcher.group(1);
        }

        return "";
    }

    private static String escapeJson(String value) {
        return value
                .replace("\\", "\\\\")
                .replace("\"", "\\\"")
                .replace("\n", "\\n")
                .replace("\r", "\\r");
    }
}