- Types of Persistence 3:27
- Using Forms for Persistence 5:37
- Data Persistence 5 questions
- Reading, Writing and Destroying Sessions 5:27
- Checking for Sessions 2 objectives
- Writing Cookies 4:56
- Reading and Deleting Cookies 7:14
- Cookies 1 objective
- Wrapping It All Up 1:12
- Browser Persistence 10 questions
Preview
Video Player
00:00
00:00
Using Forms for Persistence
5:37The most often used type of browser based persistence is through Forms. Forms allow you to share information from one page to the next. When used to construct a URL, you are able to persisting data over multiple users.
The most often used type of browser
based persistence is through forms.
0:00
Forms allow you to share information
from one page to the next.
0:05
They also allow you to capture user input
0:09
that can then be utilized
by the application.
0:12
This works great if we're going to use
the data to change the content of the next
0:14
page, or to perform some action on
the server, such as sending an email.
0:18
As an added benefit,
when using the get method on a form,
0:23
the constructed URL allows you to
share those results with others,
0:27
persisting data over multiple users.
0:31
We'll be using forms in our
project to accept user input and
0:35
also to tell our game which
word should be requested.
0:38
I'll be using works spaces for
this project, but
0:42
you’re always welcome to down load
the files and work on your own machine.
0:45
Let's get started.
0:49
We'll be starting a simple site that uses
the front in framework both strap for
0:50
design.
0:55
To learn more, so
the note associated with this video.
0:56
This site has three pages, a welcome page,
a game page, and a story page.
0:59
Let's take a look at what
we have in a browser.
1:04
From our welcome page, if we click play,
we are taken to step one of five,
1:07
where we're asked to enter our first word.
1:12
Once we enter a word, And
1:16
click submit,
we can see that the query string is added.
1:21
But we're still on step one of five, and
we'll stay on step one of five forever,
1:24
no matter how many times
we submit the form.
1:29
Let's go back to work spaces and
update the code so
1:32
that we can progress
through all five steps.
1:35
Open play.php.
1:38
At the top of the file,
you see a variable named page.
1:42
This page variable is used to show our
step, and update the hidden form field.
1:46
Once our page reaches a value greater than
the total, we redirect to the story page.
1:51
The first thing we need to do is read the
data from the hidden field named p, and
1:56
update our page variable.
2:01
Always make sure that we
filter incoming data.
2:06
Filter input, INPUT_GET,
2:09
p, FILTER_SANITIZE NUMBER_INT,
2:15
if the page variable is empty,
2:23
Then we still want to
set the page equals one.
2:33
Let's check these changes in the browser.
2:40
This time, we can go through each step of
the forum until finally reaching the story
2:53
at the end.
2:57
Our placeholders are not being
filled in with the user data yet, so
2:58
we still have some work to do, but
let's take a closer look at the form.
3:01
We don't actually need to use
a form to submit a get request.
3:05
We can just enter the query
string directly into the browser.
3:09
We don't need to worry about
re-submitting a form and
3:16
we can easily jump around to different
steps by changing our query string.
3:19
If following a link can
add items to a cart,
3:26
you might end up with products in your
cart that you never intended to purchase.
3:29
In contrast, post can help prevent
users from doing things unintentionally
3:33
by warning them when refreshing a page.
3:39
Post is also more secure, especially
when combined with a secure certificate,
3:42
because the values are not stored
directly in your browser history.
3:47
You really don't want to be
putting passwords in a URL, right?
3:51
One more thing to be aware of with
forms is that some browsers enforce
3:56
a maximum path link of just
over 2,000 characters.
4:00
This may seem like a lot, but
if you use the git method,
4:04
it can be easier to reach that
limit than you may think.
4:08
Long paths to files, long field names,
many field names, or
4:11
even just accepting large
amounts of user input
4:15
could mean that some of your
data is ignored without warning.
4:18
The good news is that we can pass a URL
parameter along with a posted form.
4:22
I want to be able to jump between steps
without actually submitting a form so
4:28
that's the part that I want in the URL.
4:32
Because our script is calculating
that value and it's not user input,
4:36
we can actually add the query
string directly to our action.
4:40
Now we can change the form method to post.
4:44
The page value will be passed
in the query string, but
4:50
the user entered data
will be passed via post.
4:53
Great, we're ready to actually collect
the user input to write our story.
4:57
One of the limitations with
forms is that by themselves,
5:03
they only pass data over one request.
5:06
If you want that data to be
available on another page,
5:09
you would have to send that data through
another form or in the query string.
5:13
For this project, we could continue to
AdWords as hidden values to the form, but
5:17
then we would need to make sure that
we pose that data to the story page
5:23
instead of redirecting
after handling the form.
5:27
Instead, I'll show you how
sessions can be used to
5:31
persist data throughout
a user's entire visit.
5:34