Reputation: 5673
I wanted to know the interactions of a browser (i.e. Firefox ) and a website.
When I submit my user name and password to the login form, what happens? I think that website sends me some cookies and authorizes me by checking those cookies.
Is there a standard structure for cookies?
Also, how I can see the cookies of specific URL sent to my browser if I want to use that cookie?
Upvotes: 43
Views: 42746
Reputation: 930
I found some information at this site that was really helpful to me and figure it might be of use: Webfundamentals - Cookies. It goes through what a cookie is, how they work, and the headers that are used to send them.
It says in summary that, cookies are pieces of information that are sent in HTTP requests inside the 'Set-Cookie' header from the server to the client/browser, or in the 'cookie' header in the client/browser to the server.
HTTP is stateless, meaning that one request to another has no knowledge of the state of the page you are browsing. Cookies were made to help address this issue, allowing users be 'known' by the site for as long as the cookie is set to be stored. By default cookies are stored until the client is closed, unless specified otherwise.
Upvotes: -1
Reputation: 35725
Freddie works at the Government Taxation Office (IRS/HMRC/ATO/CBDT etc). He deals with millions of people who come to see him everyday. And he has a very poor memory.
One day a customer walks in to Freddie's customer care desk:
Customer 1: "Good morning Freddie, so did you change my address like I asked you to?"
Freddie: "I'm sorry. I don't remember who you are? Who are you?"
Customer 1: "Dude, I spoke to you last Monday regarding this issue! How could you forget!"
Unfortunately, the HTTP protocol is stateless. There is no way Freddie (the server) can identify different customers (clients) apart from each other. He doesn't remember. He has a very short memory. There is a solution though:
The customer walks in to see Freddie (his name is Brian), but this time, the customer gives Freddie his taxation office ID card:
Brian May: "Good morning Freddie, My name is Brian May...so did you change my address like I asked you to?"
Freddie: "ah yes...hmmm......Brian May, Queen, Lead Guitarist, We Will Rock you......very interesting, I have your records here on my back end system.........let me bring up the records pertaining to your address........YES: I did in fact change your address. BTW since you gave me your ID that's all I need, you don't need to tell me your name is Brian May. Just give me your ID and I will be able to see that on my system".
You can think of a cookie as kinda like an ID card: if you identify yourself to the server, the server will remember who you are and will treat you accordingly:
e.g. it will remember what you've already ordered in your cart so far.
it will remember that you like reading your website in Tamil / Cantonese / Swahili etc.
it can (basically) identify who you are.
In this particular case, it is the Government Taxation Office who issues out the ID cards.
Granted the analogy is a little strained and very simplified but hopefully, it will help you understand and remember the underlying concept.
Upvotes: 22
Reputation: 931
Cookies are small data packets that the Web Pages load on to the browser for various purposes.
Every time you re-visit a URL, the browser sends back a tiny package of this information back to the server which detects that you've returned to the page.
Upvotes: 0
Reputation: 35264
Understanding Cookies
Cookies are given to a browser by the server. The browser reveals the cookies as applicable only to the domain that provided the cookie in the first place.
The data in the cookie allows the server to continue a conversation, so to speak. Without the cookie, the server considers the browser a first-time visitor.
Have a look at these to know about browser cookies
http://internet-security.suite101.com/article.cfm/understanding_computer_browser_cookies
http://www.willmaster.com/library/cookies/understanding-cookies.php
https://web.archive.org/web/1/http://articles.techrepublic%2ecom%2ecom/5100-22_11-6063884.html
Upvotes: 34
Reputation: 719
After logging , the request to server is sent. At server side, it checks the visitor's identification against an ID that identifies whether it is a new user or the older one. If it determines it a new visitor,it then creates a cookie for it and sends it back in its response to browser. Cookie that is generated in response to Server has a name and unique identification is sent back to a user end. AT the user end ,after every visit to the same URL, browser rechecks cookie list and if it has the cookie for the same url , it is sent to server which identifies cookie ID and server shows the related history for this user then .
Upvotes: 0
Reputation: 11232
It depends, because there are many scenarios and abilities of usage of cookies.
One of scenarios is:
For more details read Wikipedia article about cookies.
Upvotes: 2
Reputation: 91983
Usually the cookie contains a session id number. The id number is then connected to session data that is stored on the server. The usual process is then:
Usually the password is not sent more than once (at login in step 1).
Upvotes: 11