client.js

const net = require("net");
const parser = require("./parser.js");

class Request {
  /**
   * method url=host+port+path
   * body:k/v
   * headers
   */
  constructor(options) {
    this.method = options.method || "GET";
    this.host = options.host;
    this.port = options.port || 80;
    this.path = options.path || "/";
    this.body = options.body || {};
    this.headers = options.headers || {};
    if (!this.headers["Content-Type"]) {
      this.headers["Content-Type"] = "application/x-www-form-urlencoded";
    }
    if (this.headers["Content-Type"] === "application/json")
      this.bodyText = JSON.stringify(this.body);
    else if (
      this.headers["Content-Type"] === "application/x-www-form-urlencoded"
    )
      this.bodyText = Object.keys(this.body)
        .map((key) => `${key}=${encodeURIComponent(this.body[key])}`)
        .join("&");

    this.headers["Content-Length"] = this.bodyText.length;
  }
  toString() {

    return `${this.method} ${this.path} HTTP/1.1\r
${Object.keys(this.headers)
  .map((key) => `${key}: ${this.headers[key]}`)
  .join("\r\n")}\r
\r
${this.bodyText}
\r`;
  }
  //   使用send方法
  send(connection) {
    return new Promise((resolve, reject) => {
      const parser = new ResponseParser();
      if (connection) {
        connection.write(this.toString());
      } else {
        connection = net.createConnection(
          {
            host: this.host,
            port: this.port,
          },
          () => {
            connection.write(this.toString());
          }
        );
      }

      connection.on("data", (data) => {
        console.log(data.toString());
        parser.receive(data.toString());
        if (parser.isFinished) {
          resolve(parser.response);
          connection.end();
        }
      });
      connection.on("error", (err) => {
        reject(err);
        connection.end();
      });
    });
  }
}

class Response {}
/**
 * ResponseParser 产生Response
 * 利用状态机处理response
 *
 */
class ResponseParser {
  constructor() {
    this.WATTING_STATUS_LINE = 0;
    this.WATTING_STATUS_LINE_END = 1;
    this.WATTING_HEADER_NAME = 2;
    this.WATTING_HEADER_SPACE = 3;
    this.WATTING_HEADER_VALUE = 4;
    this.WATTING_HEADER_LINE_END = 5;
    this.WATTING_HEADER_BLOCK_END = 6;
    this.WATTING_BODY = 7;

    this.current = this.WATTING_STATUS_LINE;
    this.statusLine = "";
    this.headers = {};
    this.headName = "";
    this.headValue = "";
    this.bodyParser = null;
  }
  get isFinished() {
    return this.bodyParser && this.bodyParser.isFinished;
  }
  get response() {
    this.statusLine.match(/HTTP\/1.1 ([0-9]+) ([\s\S]+)/);
    return {
      StatusCode: RegExp.$1,
      StatusText: RegExp.$2,
      headers: this.headers,
      body: this.bodyParser.content.join(""),
    };
  }

  receive(string) {
    for (let i = 0; i < string.length; i++) {
      this.receiveChar(string.charAt(i));
    }
  }
  receiveChar(char) {
    if (this.current === this.WATTING_STATUS_LINE) {
      if (char === "\r") this.current = this.WATTING_STATUS_LINE_END;
      else this.statusLine += char;
    } else if (this.current === this.WATTING_STATUS_LINE_END) {
      if (char === "\n") {
        this.current = this.WATTING_HEADER_NAME;
      }
    } else if (this.current === this.WATTING_HEADER_NAME) {
      if (char === ":") {
        this.current = this.WATTING_HEADER_SPACE;
      } else if (char === "\r") {
        this.current = this.WATTING_HEADER_BLOCK_END;
        if (this.headers["Transfer-Encoding"] === "chunked") {
          this.bodyParser = new TrunkedBodyParser();
        }
      } else {
        this.headName += char;
      }
    } else if (this.current === this.WATTING_HEADER_SPACE) {
      if (char === " ") {
        this.current = this.WATTING_HEADER_VALUE;
      }
      //  else {
      //   this.statusLine += char;
      // }
    } else if (this.current === this.WATTING_HEADER_VALUE) {
      if (char === "\r") {
        this.current = this.WATTING_HEADER_LINE_END;
        this.headers[this.headName] = this.headValue;
        this.headName = "";
        this.headValue = "";
      } else {
        this.headValue += char;
      }
    } else if (this.current === this.WATTING_HEADER_LINE_END) {
      if (char === "\n") {
        this.current = this.WATTING_HEADER_NAME;
      }
    } else if (this.current === this.WATTING_HEADER_BLOCK_END) {
      if (char === "\n") {
        this.current = this.WATTING_BODY;
      }
    } else if (this.current === this.WATTING_BODY) {
      this.bodyParser.receiveChar(char);
    }
  }
}

class TrunkedBodyParser {
  constructor() {
    this.WATTING_LENGTH = 0;
    this.WATTING_LENGTH_LINE_END = 1;
    this.REANING_TRUNK = 2;
    this.WATTING_NEW_LINE = 3;
    this.WATTING_NEW_LINE_END = 4;

    this.length = 0;
    this.content = []; //字符串加号运算性能相对较差，所以用数组
    this.isFinished = false;
    this.current = this.WATTING_LENGTH;
  }
  receiveChar(char) {
    if (this.current === this.WATTING_LENGTH) {
      if (char === "\r") {
        if (this.length === 0) {
          this.isFinished = true;
        }
        this.current = this.WATTING_LENGTH_LINE_END;
      } else {
        this.length *= 16; //chunked的length是十六进制
        this.length += parseInt(char, 16);
      }
    } else if (this.current === this.WATTING_LENGTH_LINE_END) {
      if (char === "\n") {
        this.current = this.REANING_TRUNK;
      }
    } else if (this.current === this.REANING_TRUNK) {
      if (this.length != 0) {
        //去掉最后边的\r\n
        this.content.push(char);
        this.length--;
      }

      if (this.length === 0) {
        this.current = this.WATTING_NEW_LINE;
      }
    } else if (this.current === this.WATTING_NEW_LINE) {
      if (char === "\r") {
        this.current = this.WATTING_NEW_LINE_END;
      }
    } else if (this.current === this.WATTING_NEW_LINE_END) {
      if (char === "\n") {
        this.current = this.WATTING_LENGTH;
      }
    }
  }
}

// 第二步
void async function () {
  let request = new Request({
    method: "POST",
    host: "127.0.0.1",
    port: "8089",
    path: "/",
    headers: {
      ["x-foo2"]: "customed",
    },
    body: {
      name: "winter",
    },
  });
  let response = await request.send();

  let dom = parser.parseHTML(response.body);
  console.log(dom, "res");
}();