Printing out the Request?
Tags: node, javascript
Published: 2022-01-28 03:35:16

First of all, I love node. To say I love node, I haven't had enough exposure to other languages. So, I am a bad lover. I am not economical. But, that gives me a chance to dig in to Node further. So, today I am going to print out request when we make a request to a server. By the way, I am not just console logging which is way too easy to view and not really helping to save the content to a text file, which is I am about to show you how. 

## First of all, it wasn't very successful.

Why? Because I thought maybe I can just stringify the object

```javascript
const http = require('http');
const fs = require('fs')

const server = http.createServer((req, res) => {
    res.write('hello darling')
    const text = JSON.stringify(req)
    fs.writeFile("./request.txt", text, err => {
        if (err) {
            console.log(err)
            return
        }

    })
    res.end()
})

server.listen(5000)
```

When you run this, you will get the following error

```
const text = JSON.stringify(req, null, 2)
                      ^

TypeError: Converting circular structure to JSON
    --> starting at object with constructor 'Socket'
    |     property 'parser' -> object with constructor 'HTTPParser'
    --- property 'socket' closes the circle
    at JSON.stringify (<anonymous>)
    at Server.<anonymous> (/Users/matheism/Desktop/aws-practice/httpserver.js:7:23)
    at Server.emit (node:events:390:28)
    at parserOnIncoming (node:_http_server:951:12)
    at HTTPParser.parserOnHeadersComplete (node:_http_common:128:17)
```

What the hell? Why does it not make a string object as requested? What is circular structure? And, what makes it not able to be a string? Come on! After frustration, I google 'how to print circular structure to JSON'

You can find a very neat solution here:

https://www.geeksforgeeks.org/how-to-print-a-circular-structure-in-a-json-like-format-using-javascript/

But I did not use it cuz that was not the solution I initially found. 

https://stackoverflow.com/questions/11616630/how-can-i-print-a-circular-structure-in-a-json-like-format

In short, util.inspect will give me the result that I wish in my head. 

```javascript
const http = require('http');
const fs = require('fs')
//you need to import util first
const util = require('util')

const server = http.createServer((req, res) => {
    res.write('hello darling')
    const text = util.inspect(req)
    fs.writeFile("./request.txt", text, err => {
        if (err) {
            console.log(err)
            return
        }

    })
    res.end()
})

server.listen(5000)
```

Then, here is the end result. Request.txt is filled with text demonstrating the request parameters. 

<ref *2> IncomingMessage {
  _readableState: ReadableState {
    objectMode: false,
    highWaterMark: 16384,
    buffer: BufferList { head: null, tail: null, length: 0 },
    length: 0,
    pipes: [],
    flowing: null,
    ended: false,
    endEmitted: false,
    reading: false,
    constructed: true,
    sync: true,
    needReadable: false,
    emittedReadable: false,
    readableListening: false,
    resumeScheduled: false,
    errorEmitted: false,
    emitClose: true,
    autoDestroy: true,
    destroyed: false,
    errored: null,
    closed: false,
    closeEmitted: false,
    defaultEncoding: 'utf8',
    awaitDrainWriters: null,
    multiAwaitDrain: false,
    readingMore: true,
    dataEmitted: false,
    decoder: null,
    encoding: null,
    [Symbol(kPaused)]: null
  },
  _events: [Object: null prototype] { end: [Function: clearRequestTimeout] },
  _eventsCount: 1,
  _maxListeners: undefined,
  socket: <ref *1> Socket {
    connecting: false,
    _hadError: false,
    _parent: null,
    _host: null,
    _readableState: ReadableState {
      objectMode: false,
      highWaterMark: 16384,
      buffer: BufferList { head: null, tail: null, length: 0 },
      length: 0,
      pipes: [],
      flowing: true,
      ended: false,
      endEmitted: false,
      reading: true,
      constructed: true,
      sync: false,
      needReadable: true,
      emittedReadable: false,
      readableListening: false,
      resumeScheduled: false,
      errorEmitted: false,
      emitClose: false,
      autoDestroy: true,
      destroyed: false,
      errored: null,
      closed: false,
      closeEmitted: false,
      defaultEncoding: 'utf8',
      awaitDrainWriters: null,
      multiAwaitDrain: false,
      readingMore: false,
      dataEmitted: false,
      decoder: null,
      encoding: null,
      [Symbol(kPaused)]: false
    },
    _events: [Object: null prototype] {
      end: [Array],
      timeout: [Function: socketOnTimeout],
      data: [Function: bound socketOnData],
      error: [Function: socketOnError],
      close: [Array],
      drain: [Function: bound socketOnDrain],
      resume: [Function: onSocketResume],
      pause: [Function: onSocketPause]
    },
    _eventsCount: 8,
    _maxListeners: undefined,
    _writableState: WritableState {
      objectMode: false,
      highWaterMark: 16384,
      finalCalled: false,
      needDrain: false,
      ending: false,
      ended: false,
      finished: false,
      destroyed: false,
      decodeStrings: false,
      defaultEncoding: 'utf8',
      length: 149,
      writing: false,
      corked: 1,
      sync: false,
      bufferProcessing: false,
      onwrite: [Function: bound onwrite],
      writecb: null,
      writelen: 0,
      afterWriteTickInfo: null,
      buffered: [Array],
      bufferedIndex: 0,
      allBuffers: false,
      allNoop: false,
      pendingcb: 4,
      constructed: true,
      prefinished: false,
      errorEmitted: false,
      emitClose: false,
      autoDestroy: true,
      errored: null,
      closed: false,
      closeEmitted: false,
      [Symbol(kOnFinished)]: []
    },
    allowHalfOpen: true,
    _sockname: null,
    _pendingData: null,
    _pendingEncoding: '',
    server: Server {
      maxHeaderSize: undefined,
      insecureHTTPParser: undefined,
      _events: [Object: null prototype],
      _eventsCount: 2,
      _maxListeners: undefined,
      _connections: 1,
      _handle: [TCP],
      _usingWorkers: false,
      _workers: [],
      _unref: false,
      allowHalfOpen: true,
      pauseOnConnect: false,
      httpAllowHalfOpen: false,
      timeout: 0,
      keepAliveTimeout: 5000,
      maxHeadersCount: null,
      maxRequestsPerSocket: 0,
      headersTimeout: 60000,
      requestTimeout: 0,
      _connectionKey: '6::::5000',
      [Symbol(IncomingMessage)]: [Function: IncomingMessage],
      [Symbol(ServerResponse)]: [Function: ServerResponse],
      [Symbol(kCapture)]: false,
      [Symbol(async_id_symbol)]: 2
    },
    _server: Server {
      maxHeaderSize: undefined,
      insecureHTTPParser: undefined,
      _events: [Object: null prototype],
      _eventsCount: 2,
      _maxListeners: undefined,
      _connections: 1,
      _handle: [TCP],
      _usingWorkers: false,
      _workers: [],
      _unref: false,
      allowHalfOpen: true,
      pauseOnConnect: false,
      httpAllowHalfOpen: false,
      timeout: 0,
      keepAliveTimeout: 5000,
      maxHeadersCount: null,
      maxRequestsPerSocket: 0,
      headersTimeout: 60000,
      requestTimeout: 0,
      _connectionKey: '6::::5000',
      [Symbol(IncomingMessage)]: [Function: IncomingMessage],
      [Symbol(ServerResponse)]: [Function: ServerResponse],
      [Symbol(kCapture)]: false,
      [Symbol(async_id_symbol)]: 2
    },
    parser: HTTPParser {
      '0': [Function: bound setRequestTimeout],
      '1': [Function: parserOnHeaders],
      '2': [Function: parserOnHeadersComplete],
      '3': [Function: parserOnBody],
      '4': [Function: parserOnMessageComplete],
      '5': [Function: bound onParserExecute],
      '6': [Function: bound onParserTimeout],
      _headers: [],
      _url: '',
      socket: [Circular *1],
      incoming: [Circular *2],
      outgoing: null,
      maxHeaderPairs: 2000,
      _consumed: true,
      onIncoming: [Function: bound parserOnIncoming],
      [Symbol(owner_symbol)]: [HTTPServerAsyncResource]
    },
    on: [Function: socketListenerWrap],
    addListener: [Function: socketListenerWrap],
    prependListener: [Function: socketListenerWrap],
    setEncoding: [Function: socketSetEncoding],
    _paused: false,
    _httpMessage: ServerResponse {
      _events: [Object: null prototype],
      _eventsCount: 1,
      _maxListeners: undefined,
      outputData: [],
      outputSize: 0,
      writable: true,
      destroyed: false,
      _last: false,
      chunkedEncoding: true,
      shouldKeepAlive: true,
      maxRequestsOnConnectionReached: false,
      _defaultKeepAlive: true,
      useChunkedEncodingByDefault: true,
      sendDate: true,
      _removedConnection: false,
      _removedContLen: false,
      _removedTE: false,
      _contentLength: null,
      _hasBody: true,
      _trailer: '',
      finished: false,
      _headerSent: true,
      _closed: false,
      socket: [Circular *1],
      _header: 'HTTP/1.1 200 OK\r\n' +
        'Date: Wed, 26 Jan 2022 20:34:40 GMT\r\n' +
        'Connection: keep-alive\r\n' +
        'Keep-Alive: timeout=5\r\n' +
        'Transfer-Encoding: chunked\r\n' +
        '\r\n',
      _keepAliveTimeout: 5000,
      _onPendingData: [Function: bound updateOutgoingData],
      req: [Circular *2],
      _sent100: false,
      _expect_continue: false,
      statusMessage: 'OK',
      statusCode: 200,
      [Symbol(kCapture)]: false,
      [Symbol(kNeedDrain)]: false,
      [Symbol(corked)]: 0,
      [Symbol(kOutHeaders)]: null
    },
    timeout: 0,
    [Symbol(async_id_symbol)]: 4,
    [Symbol(kHandle)]: TCP {
      reading: true,
      onconnection: null,
      _consumed: true,
      [Symbol(owner_symbol)]: [Circular *1]
    },
    [Symbol(kSetNoDelay)]: false,
    [Symbol(lastWriteQueueSize)]: 0,
    [Symbol(timeout)]: Timeout {
      _idleTimeout: -1,
      _idlePrev: null,
      _idleNext: null,
      _idleStart: 6331,
      _onTimeout: null,
      _timerArgs: undefined,
      _repeat: null,
      _destroyed: true,
      [Symbol(refed)]: false,
      [Symbol(kHasPrimitive)]: false,
      [Symbol(asyncId)]: 14,
      [Symbol(triggerId)]: 10
    },
    [Symbol(kBuffer)]: null,
    [Symbol(kBufferCb)]: null,
    [Symbol(kBufferGen)]: null,
    [Symbol(kCapture)]: false,
    [Symbol(kBytesRead)]: 0,
    [Symbol(kBytesWritten)]: 0,
    [Symbol(RequestTimeout)]: undefined
  },
  httpVersionMajor: 1,
  httpVersionMinor: 1,
  httpVersion: '1.1',
  complete: false,
  rawHeaders: [
    'Host',
    'localhost:5000',
    'Connection',
    'keep-alive',
    'sec-ch-ua',
    '" Not;A Brand";v="99", "Google Chrome";v="97", "Chromium";v="97"',
    'sec-ch-ua-mobile',
    '?0',
    'User-Agent',
    'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.99 Safari/537.36',
    'sec-ch-ua-platform',
    '"macOS"',
    'Accept',
    'image/avif,image/webp,image/apng,image/svg+xml,image/*,*/*;q=0.8',
    'Sec-Fetch-Site',
    'same-origin',
    'Sec-Fetch-Mode',
    'no-cors',
    'Sec-Fetch-Dest',
    'image',
    'Referer',
    'http://localhost:5000/',
    'Accept-Encoding',
    'gzip, deflate, br',
    'Accept-Language',
    'en-US,en;q=0.9,ko;q=0.8'
  ],
  rawTrailers: [],
  aborted: false,
  upgrade: false,
  url: '/favicon.ico',
  method: 'GET',
  statusCode: null,
  statusMessage: null,
  client: <ref *1> Socket {
    connecting: false,
    _hadError: false,
    _parent: null,
    _host: null,
    _readableState: ReadableState {
      objectMode: false,
      highWaterMark: 16384,
      buffer: BufferList { head: null, tail: null, length: 0 },
      length: 0,
      pipes: [],
      flowing: true,
      ended: false,
      endEmitted: false,
      reading: true,
      constructed: true,
      sync: false,
      needReadable: true,
      emittedReadable: false,
      readableListening: false,
      resumeScheduled: false,
      errorEmitted: false,
      emitClose: false,
      autoDestroy: true,
      destroyed: false,
      errored: null,
      closed: false,
      closeEmitted: false,
      defaultEncoding: 'utf8',
      awaitDrainWriters: null,
      multiAwaitDrain: false,
      readingMore: false,
      dataEmitted: false,
      decoder: null,
      encoding: null,
      [Symbol(kPaused)]: false
    },
    _events: [Object: null prototype] {
      end: [Array],
      timeout: [Function: socketOnTimeout],
      data: [Function: bound socketOnData],
      error: [Function: socketOnError],
      close: [Array],
      drain: [Function: bound socketOnDrain],
      resume: [Function: onSocketResume],
      pause: [Function: onSocketPause]
    },
    _eventsCount: 8,
    _maxListeners: undefined,
    _writableState: WritableState {
      objectMode: false,
      highWaterMark: 16384,
      finalCalled: false,
      needDrain: false,
      ending: false,
      ended: false,
      finished: false,
      destroyed: false,
      decodeStrings: false,
      defaultEncoding: 'utf8',
      length: 149,
      writing: false,
      corked: 1,
      sync: false,
      bufferProcessing: false,
      onwrite: [Function: bound onwrite],
      writecb: null,
      writelen: 0,
      afterWriteTickInfo: null,
      buffered: [Array],
      bufferedIndex: 0,
      allBuffers: false,
      allNoop: false,
      pendingcb: 4,
      constructed: true,
      prefinished: false,
      errorEmitted: false,
      emitClose: false,
      autoDestroy: true,
      errored: null,
      closed: false,
      closeEmitted: false,
      [Symbol(kOnFinished)]: []
    },
    allowHalfOpen: true,
    _sockname: null,
    _pendingData: null,
    _pendingEncoding: '',
    server: Server {
      maxHeaderSize: undefined,
      insecureHTTPParser: undefined,
      _events: [Object: null prototype],
      _eventsCount: 2,
      _maxListeners: undefined,
      _connections: 1,
      _handle: [TCP],
      _usingWorkers: false,
      _workers: [],
      _unref: false,
      allowHalfOpen: true,
      pauseOnConnect: false,
      httpAllowHalfOpen: false,
      timeout: 0,
      keepAliveTimeout: 5000,
      maxHeadersCount: null,
      maxRequestsPerSocket: 0,
      headersTimeout: 60000,
      requestTimeout: 0,
      _connectionKey: '6::::5000',
      [Symbol(IncomingMessage)]: [Function: IncomingMessage],
      [Symbol(ServerResponse)]: [Function: ServerResponse],
      [Symbol(kCapture)]: false,
      [Symbol(async_id_symbol)]: 2
    },
    _server: Server {
      maxHeaderSize: undefined,
      insecureHTTPParser: undefined,
      _events: [Object: null prototype],
      _eventsCount: 2,
      _maxListeners: undefined,
      _connections: 1,
      _handle: [TCP],
      _usingWorkers: false,
      _workers: [],
      _unref: false,
      allowHalfOpen: true,
      pauseOnConnect: false,
      httpAllowHalfOpen: false,
      timeout: 0,
      keepAliveTimeout: 5000,
      maxHeadersCount: null,
      maxRequestsPerSocket: 0,
      headersTimeout: 60000,
      requestTimeout: 0,
      _connectionKey: '6::::5000',
      [Symbol(IncomingMessage)]: [Function: IncomingMessage],
      [Symbol(ServerResponse)]: [Function: ServerResponse],
      [Symbol(kCapture)]: false,
      [Symbol(async_id_symbol)]: 2
    },
    parser: HTTPParser {
      '0': [Function: bound setRequestTimeout],
      '1': [Function: parserOnHeaders],
      '2': [Function: parserOnHeadersComplete],
      '3': [Function: parserOnBody],
      '4': [Function: parserOnMessageComplete],
      '5': [Function: bound onParserExecute],
      '6': [Function: bound onParserTimeout],
      _headers: [],
      _url: '',
      socket: [Circular *1],
      incoming: [Circular *2],
      outgoing: null,
      maxHeaderPairs: 2000,
      _consumed: true,
      onIncoming: [Function: bound parserOnIncoming],
      [Symbol(owner_symbol)]: [HTTPServerAsyncResource]
    },
    on: [Function: socketListenerWrap],
    addListener: [Function: socketListenerWrap],
    prependListener: [Function: socketListenerWrap],
    setEncoding: [Function: socketSetEncoding],
    _paused: false,
    _httpMessage: ServerResponse {
      _events: [Object: null prototype],
      _eventsCount: 1,
      _maxListeners: undefined,
      outputData: [],
      outputSize: 0,
      writable: true,
      destroyed: false,
      _last: false,
      chunkedEncoding: true,
      shouldKeepAlive: true,
      maxRequestsOnConnectionReached: false,
      _defaultKeepAlive: true,
      useChunkedEncodingByDefault: true,
      sendDate: true,
      _removedConnection: false,
      _removedContLen: false,
      _removedTE: false,
      _contentLength: null,
      _hasBody: true,
      _trailer: '',
      finished: false,
      _headerSent: true,
      _closed: false,
      socket: [Circular *1],
      _header: 'HTTP/1.1 200 OK\r\n' +
        'Date: Wed, 26 Jan 2022 20:34:40 GMT\r\n' +
        'Connection: keep-alive\r\n' +
        'Keep-Alive: timeout=5\r\n' +
        'Transfer-Encoding: chunked\r\n' +
        '\r\n',
      _keepAliveTimeout: 5000,
      _onPendingData: [Function: bound updateOutgoingData],
      req: [Circular *2],
      _sent100: false,
      _expect_continue: false,
      statusMessage: 'OK',
      statusCode: 200,
      [Symbol(kCapture)]: false,
      [Symbol(kNeedDrain)]: false,
      [Symbol(corked)]: 0,
      [Symbol(kOutHeaders)]: null
    },
    timeout: 0,
    [Symbol(async_id_symbol)]: 4,
    [Symbol(kHandle)]: TCP {
      reading: true,
      onconnection: null,
      _consumed: true,
      [Symbol(owner_symbol)]: [Circular *1]
    },
    [Symbol(kSetNoDelay)]: false,
    [Symbol(lastWriteQueueSize)]: 0,
    [Symbol(timeout)]: Timeout {
      _idleTimeout: -1,
      _idlePrev: null,
      _idleNext: null,
      _idleStart: 6331,
      _onTimeout: null,
      _timerArgs: undefined,
      _repeat: null,
      _destroyed: true,
      [Symbol(refed)]: false,
      [Symbol(kHasPrimitive)]: false,
      [Symbol(asyncId)]: 14,
      [Symbol(triggerId)]: 10
    },
    [Symbol(kBuffer)]: null,
    [Symbol(kBufferCb)]: null,
    [Symbol(kBufferGen)]: null,
    [Symbol(kCapture)]: false,
    [Symbol(kBytesRead)]: 0,
    [Symbol(kBytesWritten)]: 0,
    [Symbol(RequestTimeout)]: undefined
  },
  _consuming: false,
  _dumped: false,
  [Symbol(kCapture)]: false,
  [Symbol(kHeaders)]: {
    host: 'localhost:5000',
    connection: 'keep-alive',
    'sec-ch-ua': '" Not;A Brand";v="99", "Google Chrome";v="97", "Chromium";v="97"',
    'sec-ch-ua-mobile': '?0',
    'user-agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.99 Safari/537.36',
    'sec-ch-ua-platform': '"macOS"',
    accept: 'image/avif,image/webp,image/apng,image/svg+xml,image/*,*/*;q=0.8',
    'sec-fetch-site': 'same-origin',
    'sec-fetch-mode': 'no-cors',
    'sec-fetch-dest': 'image',
    referer: 'http://localhost:5000/',
    'accept-encoding': 'gzip, deflate, br',
    'accept-language': 'en-US,en;q=0.9,ko;q=0.8'
  },
  [Symbol(kHeadersCount)]: 26,
  [Symbol(kTrailers)]: null,
  [Symbol(kTrailersCount)]: 0,
  [Symbol(RequestTimeout)]: undefined
}

Tada! i didn't do triple backtick to make a code block for the last one! what's going on?