- POST Requests 6:26
- The Request Object 4:29
- Review: The Request Object 5 questions
- The Response Object 5:29
- Review: The Response Object 5 questions
- Review Adding Multiple Routes 2 objectives
- Statelessness, Setting and Reading Cookies 9:41
- Review: Statelessness 5 questions
- Redirects 5:44
- Challenges: Redirects 2:37
- Solution: Clearing Cookies and Redirecting 1:55
- Review: Redirects 5 questions
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The Response Object
5:29A closer look at Express's Response object.
In the last video we took a closer
look at the request object,
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now let's check out the response object.
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While the request object allows the
application to look at the request that
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the client has made,
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the response object offers ways to
shape the response back to the client.
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In this video, we'll use the name
received from the form and
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send it back in a message
that greets the user.
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Before we dive in,
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let's take a look at the response
object from the express documentation.
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Here's the documentation for
the request object.
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Over on the right you can see there's
quite a few different methods that control
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how the app responds to a client.
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For example, we've seen the send method,
it sends a response string.
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We've also been using
the render method too.
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It merges the data with
the templates to serve dynamic pages.
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There's also another method
that's commonly used to send back
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data to the client, JSON.
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Sometimes clients don't want all
the presentation of HTML and
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CSS, they just want the data.
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That's what JSON is good for.
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Serving data is the primary use for
Express for many developers.
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We won't cover that in
detail in this course,
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but check the teacher's notes for
more resources if you're interested.
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For now, let's just have a quick
look at the JSON method.
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Open the app.js file, let's replace
the render method with JSON and
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serve the request's body.
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Also remove the logging line
if you haven't done already.
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If I go to the browser now and
enter my name and hit submit.
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I don't get an HTML page at all.
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I just get the JSON string for now.
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I just wanted to show you a little of
the response object's flexibility.
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We'll look at some more of
the Response object's methods soon.
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For now,
I'll revert back to the hello template.
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We'll serve the same template
when the user posts the form,
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remember pug lets you add some basic
programming logic to your templates.
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So you can use the same template
to show different HTML content.
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For example, we can show only
the form when the browser
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issues a get request to this route.
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But we'll add the user's name to the
welcome message above the forum when we
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rendered the same template
from the post request.
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First, I'll pass in the name
to the render method.
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Then, I'll open up the hello pug.
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I want to welcome the student
when they enter their name.
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So, I'll nest the H2 element
under the if statement,
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checking whether if name is defined.
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Now, the welcome message will only
show up if the name is defined.
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The only way that the name can be defined
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is when the out root
receives a form submission.
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In other words, when we make
a get request to the application,
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the name won't be defined and
will render the get route.
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But when a post request comes in, or
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when the form is submitted,
the name will be defined.
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And the welcome message will appear.
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Let's switch back to the template and
replace the student with a name variable.
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Because we want to surround the name with
a static text, we will use interpolation.
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While we're at it, let's hide
the form if the name is defined.
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We do that by using the else keyword and
then indenting the form under it.
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Save the hello.pug file and
switch back to the browser.
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You might notice that if you just refresh
the browser after submitting the form,
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you'll see the welcome message.
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That's because the name has
been already entered earlier.
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This happens because the browser refreshes
the last post request from the forum.
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Including the data for the request.
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To make sure that you're getting
a get request, hit enter on the URL.
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Now you can see that
the welcome message is gone.
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And if I enter a name and hit Submit,
the welcome message is back.
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Cool, it's working.
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Again, if I send another get request,
we'd get the same behavior.
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The name would get lost.
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We've completed the request response cycle
using the data we collected from the user.
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That's really cool.
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The basics you've learned are like
a scaffold you can build out from here.
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Next, we'll take a closer look at the
problem of the name not being saved and
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see how we can fix that.
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