Sessions

Quick reference

• 00:04 In this video, I wanna talk about session variables and
• 00:07 session variables are one of the super global we looked at a couple of years ago.
• 00:11 So what exactly are they?
• 00:12 Well, they're sort of like cookies in
• 00:14 that they let us save information across different pages of our app.
• 00:19 But unlike cookies,
• 00:19 we're not actually saving that information on a user's computer.
• 00:22 So here, I've created our index page and I 've
• 00:25 just created this regular variable, favorite pizza named it pepperoni and
• 00:29 then I'm echoing out onto the screen.
• 00:31 So if I come back here and hit reload, we'll see pepperoni.
• 00:33 So then I've created a second web page, index2.php and
• 00:37 I've just echoed out that same variable.
• 00:39 So if we save this, come back here and just go to index2.php.
• 00:45 You can see it's not there, because this variable only exists on this page.
• 00:50 It doesn't exist on this page.
• 00:52 We haven't set this variable yet.
• 00:53 Well, with session variables, we can set it on one page and
• 00:56 use it on all the pages in our app.
• 00:57 So super, super useful.
• 00:59 To do that, what we do is we create a session.
• 01:02 So here at the top of the screen, I'm just gonna do a php tag and start session and
• 01:08 I'm gonna copy this and I'm gonna put this also on our second page, save that.
• 01:14 So that's what you have to do to start a session.
• 01:16 Now like I said earlier to create a session variable,
• 01:19 we use the session super global.
• 01:21 And that's just if you remember back, it's just that.
• 01:24 We can set it and let's call this fav_pizza, all right?
• 01:29 And I'm gonna get rid of that, get rid of that and
• 01:32 I'm gonna do the same thing on the second page.
• 01:35 So we can start from scratch here.
• 01:36 So session equals or session fav_pizza, we just set that equal to whatever we want.
• 01:43 I'm gonna say, lets change it.
• 01:45 Cheese and save that.
• 01:47 Now to echo that out, we just echo $_SESSION and then fav_pizza.
• 01:54 So if we save this, come back here to our first page and click reload,
• 01:58 we see cheese.
• 01:59 Now if we go forward to our second page and
• 02:01 hit reload, still nothing has happened, because we haven't echoed this out.
• 02:05 So let's copy this, come back over here and echo this out.
• 02:09 So echo $_SESSION fav_pizza.
• 02:12 Save this, come back here and hit reload.
• 02:14 And boom, we've cheese.
• 02:15 So you can see on this index2 page, we haven't created this variable
• 02:20 anywhere we haven't assigned anything to this variable anywhere.
• 02:24 We did all that on our first page, our index.php page.
• 02:28 But now any page we create in our app, we can use this session variable and
• 02:33 it will know that it's cheese, because we said it on this index page.
• 02:37 Now like I said, these are like cookies.
• 02:39 These are set for specific people.
• 02:42 So if one person comes to your website, it will set for them and
• 02:45 this session variable will be available to that person as long as they keep their
• 02:50 web browser open.
• 02:51 As soon as they close their web browser, the session ends and
• 02:54 the session variable disappears.
• 02:56 So that's a very sort of important distinction.
• 02:58 Now, there's lots of ways to pass variables around from page to page.
• 03:02 You can use a form and the GET method.
• 03:05 We talked about web forms earlier, but that's sort of clunky and it's hard to do
• 03:09 or you can just use the session variable to pass things from page to page and
• 03:13 it's very very useful.
• 03:14 So that's sessions.
• 03:16 We're done talking about superglobals now.
• 03:18 In the next video, we're gonna start building our math flash card app.
• 03:21 It's gonna be a lot of fun and that's all for this video.

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