What is a session? How does Rails know to show the right data to the right person? And how do you decide where you keep your session data? A session is just a place to store data during one request that you can read during later requests. It might not seem that interesting. And it all starts with cookies.
Your browser will store those cookies. And until the cookie expires, every time you make a request, your browser will send the cookies back to the server:. Many cookies just look like gibberish. Your Rails app is in charge of figuring out what a cookie means. Your app set it, so your app can read it. So, you have a cookie. You put data in during one request, and you get that same data in the next.
Rails does some work with the cookie to make it more secure. Your Rails app puts some data into the cookie, the same data comes out of the cookie. Storing the wrong kind of data inside a cookie can be insecure. If you were keeping track of your sessions with ActiveRecord :. Rails will create a new record in your sessions table with a random session ID say, dbf6ffefb5cc Your app grabs the session ID out of your cookie, and finds its record in the sessions table.
Your cookie only contains a session ID, and your Rails app looks up the data in your session store using that ID. When it works, storing your sessions in cookies is by far the easiest way to go. You might already be using something like Memcache to cache your partials or data. Most applications need to keep track of certain state of a particular user.
This could be the contents of a shopping basket or the user id of the currently logged in user Rails will create a new session automatically if a new user accesses the application. It will load an existing session if the user has already used the application.
A session usually consists of a hash of values and a session id, usually a character string, to identify the hash. Every cookie sent to the client's browser includes the session id. And the other way round: the browser will send it to the server on every request from the client.
In other words, each unique user has their own session hash. As 7stud stated, all sessions are created on a user by user basis. Since HTTP is a "stateless" protocol, you would potentially need someone to enter their login information everytime they wanted to look at a new page or even refresh the existing one.
This is where sessions comes in. In Rails, each session is assigned a unique session id a 32 character string of random hex numbers when it's created and a cookie containing this id is then sent to the client's browser. From that point on, every request from the browser sends the session id back to the server thus maintaining continuity.
Normal guidelines to follow are you should only keep track of the bare minimum in a session such as info to determine the current user like a primary key etc. Stack Overflow for Teams — Collaborate and share knowledge with a private group.
Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. How session works in Rails Ask Question. Asked 5 years, 1 month ago. Active 5 years, 1 month ago.
Viewed 3k times. Aetherus After returning the new hash, Is it maintains any data about logged in user in server side? I just gave an answer. Add a comment. Active Oldest Votes. Let's take a look at 2 typical session stores. Encrypted cookie store This is the default session store of Rails applications.
Redis session store This session store is not shipped with Rails. It's a separate gem. Stack Overflow for Teams — Collaborate and share knowledge with a private group.
Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. How do sessions work in Ruby on Rails? Ask Question. Asked 6 years, 5 months ago. Active 6 years, 5 months ago. Viewed 2k times. I want to know how sessions work in Ruby on Rails. Thus, does Rails save the session to cookie store, cache store, or database store? Improve this question. Glorfindel Archie Reyes Archie Reyes 51 5 5 bronze badges.
Session is stored in cookies by default. But you can change it to cache or database if you need.
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