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We can add new wiki pages, show pages we've added, and then update them. The only thing missing now is the ability to delete pages. Let's add that now.
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[MUSIC]
0:00
We can add new wiki pages show pages
we've added and then update them.
0:04
The only thing missing now is
the ability to delete pages.
0:08
Let's add that now.
0:12
Our wiki.rb file has a page_content method
that loads the contents of a text file and
0:13
a save_content method that saves a file.
0:18
I've added another method called
delete_content which deletes a file from
0:22
the pages directory.
0:26
It simply calls the File.delete method
which takes the name of a file to delete.
0:27
If you launch a work space
from this video's page,
0:33
you'll get a wiki.rb file with this
method already set up for you.
0:34
This time I'll leave
testing the method up to.
0:39
If you want to experiment with delete
content, you can copy it to a separate
0:41
file and add a call to it with the name of
a file in your pages directory to delete.
0:44
You may need to refresh the sidebar
before you can see the changes.
0:48
Now we just need a way for users to call
this method with a particular page title.
0:52
Let's set up a button on each wiki
page that lets users send a request
0:56
to delete that page.
1:00
There's one more commonly used request
type that Sinatra recognizes and
1:01
that's delete request.
1:05
But as with put requests,
1:07
there's no way to send a delete requests
from plain HTML links or forms.
1:08
As with put the best way is
to create an HTML form and
1:12
use a hidden underscore method
parameter with a value of delete.
1:15
We won't add any text fields to this form,
1:19
it's just going to consist
of a single delete button.
1:21
In the show.erb template,
let's add a form element.
1:23
We're going to place it
within the div element so
1:29
that it's easier to style it later.
1:31
As before, the only requests type
supported by HTML are get and post, so
1:35
we'll set the form's
method attribute to post.
1:40
Then within the form, will add an input
element with the type of hidden.
1:44
It'll have a name of _method And
a value of delete.
1:53
That will cause Sinatra to delete
the form submission as delete request.
2:02
As with all the other requests types,
delete request need a path to act on.
2:06
We'll set that by adding an action
attribute to the form tag.
2:09
We'll give it the path of the wiki
page we're trying to delete.
2:14
That is a slash followed by the page
title which will embed using an erb tag.
2:17
As before, we can reuse the title instance
variable which is already used elsewhere
2:22
in the template.
2:26
Lastly, we'll need the button that users
will click to submit the requests.
2:27
Will add an input element
with a type of submit.
2:31
The value attribute determines
what the button will be labeled.
2:37
So we'll give it a value
of delete this page.
2:42
Let's start up our server and
run a preview.
2:46
And now let's view a wiki page.
2:51
We'll see a new Delete This Page
button at the bottom.
2:55
If we click that button,
3:00
we'll see Sinatra doesn't know this ditty
again because there's no matching route.
3:01
At the bottom of the page,
3:05
we'll see a recommendation to create
a route using a method named delete.
3:06
That means our form submission is
being treated as a delete request.
3:10
Now we just need to edit our wiki.rb
file and add a delete route.
3:15
Again, order doesn't matter.
3:19
There's no way a delete request
will accidentally be matched by
3:20
our route's forget, post or put requests.
3:23
Just as a method to set up a route for get
requests is called GET and the method for
3:27
post routes is called POST the method for
delete routes is called Delete.
3:31
So we'll add a call to that method now.
3:36
And you probably know what comes
next by now, the path to match.
3:37
We set up our form to submit to a path
of a slash followed by the current
3:42
page title.
3:45
So that's what will match here a slash
followed by a URL parameter for the title.
3:46
And of course we need a block to
invoke when the routers match.
3:52
In that block, what we'll have to do
is call our delete_content method
3:58
with the page title and it will delete
the appropriate text file for us.
4:01
So, we'll call delete_content and
give it the title from the URL parameter.
4:05
We'll also need to redirect
the browser to another page, so
4:12
we'll call the redirect method.
4:15
We'll just redirect them to the root path.
4:19
There's no need to call URI dot
escape on the redirect path this time
4:22
since there's no chance of it
containing an invalid character.
4:25
Save that.
4:29
Let's restart our server.
4:30
And go back to the home page.
4:36
We'll create a new page to test
our delete functionality out on.
4:37
We'll use the title of John Doe and
text of just some guy.
4:42
Submit it.
4:50
And if we go back to our workspace and
refresh the file sidebar,
4:51
We'll see John Doe.text here
in the page's directory.
4:57
If we go back to the new page and
5:00
click delete,
we'll be redirected back to the root path.
5:02
And if we refresh our workspace
sidebar again, we'll see if
5:08
the John Doe.text file has been deleted.
5:13
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