Get and Set a Single Cookie with Node js HTTP Server

Question

I want to be able to set a single cookie  and read that single cookie with each request made to the nodejs server instance  Can it be done in a few lines of code  without the need to pull in a third party lib   var http   require  http     http createServer function  request  response      response writeHead 200    Content-Type    text plain       response end  Hello World n       listen 8124    console log  Server running at http   127 0 0 1 8124       Just trying to take the above code directly from nodejs org  and work a cookie into it

User · Answer

Let me repeat this part of question that answers here are ignoring:

Can it be done in a few lines of code, without the need to pull in a third party lib?

Reading Cookies

Cookies are read from requests with the Cookie header. They only include a name and value. Because of the way paths work, multiple cookies of the same name can be sent. In NodeJS, all Cookies in as one string as they are sent in the Cookie header. You split them with ;. Once you have a cookie, everything to the left of the equals (if present) is the name, and everything after is the value. Some browsers will accept a cookie with no equal sign and presume the name blank. Whitespaces do not count as part of the cookie. Values can also be wrapped in double quotes ("). Values can also contain =. For example, formula=5+3=8 is a valid cookie.

/**
 * @param {string} [cookieString='']
 * @return {[string,string][]} String Tuple
 */
function getEntriesFromCookie(cookieString = '') {
  return cookieString.split(';').map((pair) => {
    const indexOfEquals = pair.indexOf('=');
    let name;
    let value;
    if (indexOfEquals === -1) {
      name = '';
      value = pair.trim();
    } else {
      name = pair.substr(0, indexOfEquals).trim();
      value = pair.substr(indexOfEquals + 1).trim();
    }
    const firstQuote = value.indexOf('"');
    const lastQuote = value.lastIndexOf('"');
    if (firstQuote !== -1 && lastQuote !== -1) {
      value = value.substring(firstQuote + 1, lastQuote);
    }
    return [name, value];
  });
}

const cookieEntries = getEntriesFromCookie(request.headers.Cookie); 
const object = Object.fromEntries(cookieEntries.slice().reverse());

If you're not expecting duplicated names, then you can convert to an object which makes things easier. Then you can access like object.myCookieName to get the value. If you are expecting duplicates, then you want to do iterate through cookieEntries. Browsers feed cookies in descending priority, so reversing ensures the highest priority cookie appears in the object. (The .slice() is to avoid mutation of the array.)

Settings Cookies

"Writing" cookies is done by using the Set-Cookie header in your response. The response.headers['Set-Cookie'] object is actually an array, so you'll be pushing to it. It accepts a string but has more values than just name and value. The hardest part is writing the string, but this can be done in one line.

/**
 * @param {Object} options
 * @param {string} [options.name='']
 * @param {string} [options.value='']
 * @param {Date} [options.expires]
 * @param {number} [options.maxAge]
 * @param {string} [options.domain]
 * @param {string} [options.path]
 * @param {boolean} [options.secure]
 * @param {boolean} [options.httpOnly]
 * @param {'Strict'|'Lax'|'None'} [options.sameSite]
 * @return {string}
 */
function createSetCookie(options) {
  return (`${options.name || ''}=${options.value || ''}`)
    + (options.expires != null ? `; Expires=${options.expires.toUTCString()}` : '')
    + (options.maxAge != null ? `; Max-Age=${options.maxAge}` : '')
    + (options.domain != null ? `; Domain=${options.domain}` : '')
    + (options.path != null ? `; Path=${options.path}` : '')
    + (options.secure ? '; Secure' : '')
    + (options.httpOnly ? '; HttpOnly' : '')
    + (options.sameSite != null ? `; SameSite=${options.sameSite}` : '');
}

const newCookie = createSetCookie({
  name: 'cookieName',
  value: 'cookieValue',
  path:'/',
});
response.headers['Set-Cookie'].push(newCookie);

Remember you can set multiple cookies, because you can actually set multiple Set-Cookie headers in your request. That's why it's an array.

Note on external libraries:

If you decide to use the express, cookie-parser, or cookie, note they have defaults that are non-standard. Cookies parsed are always URI Decoded (percent-decoded). That means if you use a name or value that has any of the following characters: !#$%&'()*+/:<=>?@[]^`{|} they will be handled differently with those libraries. If you're setting cookies, they are encoded with %{HEX}. And if you're reading a cookie you have to decode them.

For example, while [email protected] is a valid cookie, these libraries will encode it as email=name%40domain.com. Decoding can exhibit issues if you are using the % in your cookie. It'll get mangled. For example, your cookie that was: secretagentlevel=50%007and50%006 becomes secretagentlevel=507and506. That's an edge case, but something to note if switching libraries.

Also, on these libraries, cookies are set with a default path=/ which means they are sent on every url request to the host.

If you want to encode or decode these values yourself, you can use encodeURIComponent or decodeURIComponent, respectively.

References:

Additional information:

User · Answer

To get a cookie splitter to work with cookies that have     in the cookie values   var get cookies   function request      var cookies         request headers  amp  amp  request headers cookie split      forEach function cookie        var parts   cookie match                    cookies  parts 1  trim        parts 2         trim            return cookies       then to get an individual cookie   get cookies request   my cookie

User · Answer

There is no quick function access to getting setting cookies  so I came up with the following hack   var http   require  http     function parseCookies  request        var list               rc   request headers cookie       rc  amp  amp  rc split      forEach function  cookie             var parts   cookie split               list parts shift   trim      decodeURI parts join                     return list      http createServer function  request  response          To Read a Cookie   var cookies   parseCookies request         To Write a Cookie   response writeHead 200         Set-Cookie    mycookie test        Content-Type    text plain          response end  Hello World n       listen 8124    console log  Server running at http   127 0 0 1 8124       This will store all cookies into the cookies object  and you need to set cookies when you write the head

User · Answer

As an enhancement to  Corey Hart s answer  I ve rewritten the parseCookies   using   RegExp prototype exec - use regex to parse  quot name value quot  strings  Here s the working example  let http   require  http     function parseCookies str      let rx          s            g    let obj          for   let m   m   rx exec str          obj  m 1      decodeURIComponent  m 2       return obj     function stringifyCookies cookies      return Object entries  cookies        map    k v     gt  k         encodeURIComponent v         join            http createServer function   request  response       let cookies   parseCookies  request headers cookie      console log   Input cookies     cookies      cookies search    google     if   cookies counter       cookies counter      else     cookies counter   1    console log   Output cookies     cookies      response writeHead  200         Set-Cookie   stringifyCookies cookies        Content-Type    text plain           response end  Hello World n        listen 1234    I also note that the OP uses the http module  If the OP was using restify  he can make use of restify-cookies  var CookieParser   require  restify-cookies    var Restify   require  restify    var server   Restify createServer    server use CookieParser parse   server get      function req  res  next     var cookies   req cookies     Gets read-only cookies from the request   res setCookie  my-new-cookie    Hi There       Adds a new cookie to the response   res send JSON stringify cookies        server listen 8080

User · Answer

I wrote this simple function just pass req headers cookie and cookie name  const getCookieByName   cookies name   gt       const arrOfCookies   cookies split          let yourCookie   null      arrOfCookies forEach element   gt            if element includes name                yourCookie   element replace name                               return yourCookie

User · Answer

First one needs to create cookie  I have wrapped token inside cookie as an example  and then set it in response To use the cookie in following way install cookieParser  app use cookieParser       The browser will have it saved in its  Resource  tab and will be used for every request thereafter taking the initial URL as base  var token   student generateToken  authentication            res cookie  token   token                expires  new Date Date now     9999999               httpOnly  false            status 200  send      To get cookie from a request on the server side is easy too You have to extract the cookie from request by calling  cookie  property of the request object   var token   req cookies token     Retrieving Token stored in cookies

User · Answer

Cookies are transfered through HTTP-Headers You ll only have to parse the request-headers and put response-headers

User · Answer

If you re using the express library  as many node js developers do  there is an easier way  Check the Express js documentation page for more information   The parsing example above works but express gives you a nice function to take care of that   app use express cookieParser       To set a cookie   res cookie  cookiename    cookievalue     maxAge  900000  httpOnly  true       To clear the cookie   res clearCookie  cookiename

User · Answer

Using Some ES5 6 Sorcery   RegEx Magic  Here is an option to read the cookies and turn them into an object of Key  Value pairs for client side  could also use it server side   Note  If there is a   in the value  no worries  If there is an   in the key  trouble in paradise   More Notes  Some may argue readability so break it down as you like   I Like Notes  Adding an error handler  try catch  wouldn t hurt   const iLikeCookies        gt        return Object fromEntries document cookie split       map v   gt  v split                 const main        gt           Add Test Cookies     document cookie    name Cookie Monster expires false domain localhost      document cookie    likesCookies yes withARandomEquals expires false domain localhost           Show the Objects     console log document cookie      console log  The Object    iLikeCookies            Get a value from key     console log  Username    iLikeCookies   name        console log  Enjoys Cookies    iLikeCookies   likesCookies          What is going on   iLikeCookies   will split the cookies by    space after        name Cookie Monster    likesCookies yes withARandomEquals     Then we map that array and split by first occurrence of   using regex capturing parens      name    Cookie Monster      likesCookies    yes withARandomEquals     Then use our friend  Object fromEntries to make this an object of key  val pairs   Nooice

User · Answer

RevNoah had the best answer with the suggestion of using Express s cookie parser  But  that answer is now 3 years old and is out of date    Using Express  you can read a cookie as follows   var express   require  express    var cookieParser   require  cookie-parser    var app   express    app use cookieParser     app get   myapi   function req  resp       console log req cookies  Your-Cookie-Name-Here          And update your package json with the following  substituting the appropriate relatively latest versions    dependencies          express    4 12 3        cookie-parser    1 4 0         More operations like setting and parsing cookies are described here and here

User · Answer

Here s a neat copy-n-paste patch for managing cookies in node  I ll do this in CoffeeScript  for the beauty   http   require  http   http IncomingMessage  getCookie    name  - gt    cookies        this headers cookie  amp  amp  this headers cookie split      forEach  cookie  - gt      parts   cookie split         cookies parts 0  trim       parts 1         trim       return    return cookies name     null  http IncomingMessage  getCookies   - gt    cookies        this headers cookie  amp  amp  this headers cookie split      forEach  cookie  - gt      parts   cookie split         cookies parts 0  trim       parts 1         trim       return    return cookies  http OutgoingMessage  setCookie    name  value  exdays  domain  path  - gt    cookies   this getHeader  Set-Cookie    if typeof cookies isnt  object      cookies         exdate   new Date     exdate setDate exdate getDate     exdays     cookieText   name     value   expires   exdate toUTCString         if domain     cookieText     domain   domain       if path     cookieText     path   path        cookies push cookieText   this setHeader  Set-Cookie   cookies   return   Now you ll be able to handle cookies just as you d expect   server   http createServer  request  response  - gt     get individually   cookieValue   request getCookie  testCookie    console log  testCookie  s value is   cookieValue     get altogether   allCookies   request getCookies     console log allCookies     set   response setCookie  newCookie    cookieValue   30    response end  I luvs da cookies     return  server listen 8080

User · Answer

var cookie    your cookie   var cookie value  var i   request headers indexOf cookie       if  i    -1      var eq   i cookie length 1    var end   request headers indexOf      eq     cookie value   request headers substring eq  end    -1   undefined   end

User · Answer

You can use the  cookies  npm module  which has a comprehensive set of features   Documentation and examples at  https   github com jed cookies

User · Answer

If you don t care what s in the cookie and you just want to use it  try this clean approach using request  a popular node module                            var request   require  request    var j   request jar    var request   request defaults  jar j    request  http   www google com   function        request  http   images google com   function  error  response  body           this request will will have the cookie which first request received         do stuff

[javascript] Get and Set a Single Cookie with Node.js HTTP Server

Reading Cookies

Settings Cookies

Note on external libraries:

Examples related to javascript

Examples related to node.js

Examples related to cookies

Examples related to httpserver