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[MUSIC]

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We can add new wiki pages show pages
we've added and then update them.

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The only thing missing now is
the ability to delete pages.

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Let's add that now.

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Our wiki.rb file has a page_content method
that loads the contents of a text file and

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a save_content method that saves a file.

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I've added another method called
delete_content which deletes a file from

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the pages directory.

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It simply calls the File.delete method
which takes the name of a file to delete.

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If you launch a work space
from this video's page,

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you'll get a wiki.rb file with this
method already set up for you.

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This time I'll leave
testing the method up to.

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If you want to experiment with delete
content, you can copy it to a separate

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file and add a call to it with the name of
a file in your pages directory to delete.

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You may need to refresh the sidebar
before you can see the changes.

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Now we just need a way for users to call
this method with a particular page title.

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Let's set up a button on each wiki
page that lets users send a request

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to delete that page.

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There's one more commonly used request
type that Sinatra recognizes and

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that's delete request.

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But as with put requests,

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there's no way to send a delete requests
from plain HTML links or forms.

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As with put the best way is
to create an HTML form and

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use a hidden underscore method
parameter with a value of delete.

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We won't add any text fields to this form,

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it's just going to consist
of a single delete button.

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In the show.erb template,
let's add a form element.

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We're going to place it
within the div element so

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that it's easier to style it later.

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As before, the only requests type
supported by HTML are get and post, so

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we'll set the form's
method attribute to post.

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Then within the form, will add an input
element with the type of hidden.

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It'll have a name of _method And
a value of delete.

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That will cause Sinatra to delete
the form submission as delete request.

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As with all the other requests types,
delete request need a path to act on.

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We'll set that by adding an action
attribute to the form tag.

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We'll give it the path of the wiki
page we're trying to delete.

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That is a slash followed by the page
title which will embed using an erb tag.

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As before, we can reuse the title instance
variable which is already used elsewhere

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in the template.

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Lastly, we'll need the button that users
will click to submit the requests.

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Will add an input element
with a type of submit.

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The value attribute determines
what the button will be labeled.

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So we'll give it a value
of delete this page.

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Let's start up our server and
run a preview.

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And now let's view a wiki page.

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We'll see a new Delete This Page
button at the bottom.

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If we click that button,

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we'll see Sinatra doesn't know this ditty
again because there's no matching route.

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At the bottom of the page,

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we'll see a recommendation to create
a route using a method named delete.

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That means our form submission is
being treated as a delete request.

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Now we just need to edit our wiki.rb
file and add a delete route.

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Again, order doesn't matter.

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There's no way a delete request
will accidentally be matched by

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our route's forget, post or put requests.

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Just as a method to set up a route for get
requests is called GET and the method for

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post routes is called POST the method for
delete routes is called Delete.

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So we'll add a call to that method now.

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And you probably know what comes
next by now, the path to match.

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We set up our form to submit to a path
of a slash followed by the current

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page title.

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So that's what will match here a slash
followed by a URL parameter for the title.

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And of course we need a block to
invoke when the routers match.

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In that block, what we'll have to do
is call our delete_content method

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with the page title and it will delete
the appropriate text file for us.

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So, we'll call delete_content and
give it the title from the URL parameter.

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We'll also need to redirect
the browser to another page, so

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we'll call the redirect method.

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We'll just redirect them to the root path.

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There's no need to call URI dot
escape on the redirect path this time

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since there's no chance of it
containing an invalid character.

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Save that.

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Let's restart our server.

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And go back to the home page.

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We'll create a new page to test
our delete functionality out on.

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We'll use the title of John Doe and
text of just some guy.

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Submit it.

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And if we go back to our workspace and
refresh the file sidebar,

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We'll see John Doe.text here
in the page's directory.

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If we go back to the new page and

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click delete,
we'll be redirected back to the root path.

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And if we refresh our workspace
sidebar again, we'll see if

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the John Doe.text file has been deleted.