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Post Model
4:05To let users make posts, we have to have a model to store the posts in. We'll also want to add some methods to our `User` model to make fetching posts easier.
Our post model is going to be really
simple.
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And actually very similar to our entry
model from the databases course.
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But then we'll set up some handy methods
on our user model to make it
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easier to get messages that a given user
has posted.
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'Kay.
So we need to create our post model.
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This is gonna be the thing that users can
submit.
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So these are like your Status Updates on
Facebook or your Tweets on Twitter.
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So, let's go down here and make a new
class.
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And we're gonna call this Post.
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And it's going to be a model.
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Now, we don't need to use the user mix in
on this because this isn't a user, so
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we're just gonna do straight model.
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So, we're gonna have a timestamp for when
the post was created,
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DateTimeField default equals
datetime.datetime.now.
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So just like when our user was created.
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The user, which is a foreign key.
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I have a hard time typing foreign key at
times.
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And we have to add a couple of attributes
here.
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Let's talk about these attributes.
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So we add one here that's called
rel_model.
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And that's the model that this foreign key
points to, so it points to the user model.
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Notice we have the capital U down there on
user.
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And then we have related_name, and we're
gonna call this posts.
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So related_name is what the related_model
would call this model.
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So, if you're a user, what do you call the
post model instances that you've created?
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You call those your posts, right?
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So, related_name is posts.
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And then we need to create a text area to
hold all the stuff.
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And that's going to be a text field.
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All right, class meta database equals
DATABASE,
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all caps, order_by is going to be negative
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timestamp because we want to have the
newest items first.
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Now I wanna point out, we did this up here
on users.
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And I did it again down here on post.
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Those have to be tuples and to be tuples
they have to have a comma in them.
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Now order_by could be a list if you wanna
do it as a list instead of a tuple.
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But if you're gonna make it a tuple, which
I really think you should.
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Because they're not going to be changed,
they're not going to be modified.
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Then you want to be sure and put in that
comma.
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The reason that we're doing the tuple with
the comma instead of just a string for
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an individual field is you can have it
order by multiple fields, and
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if there's a conflict, two of them came in
at the exact same timestamp,
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you could then have it sorted by something
else.
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Okay.
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Let's change our user just a little bit.
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We're gonna add a new method here called
get_posts.
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And we're gonna return
Post.select().where(Post.user == self).
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Now we could use the reverse foreign key
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that we have where we can do like
user.posts.
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And that's probably a better idea, really.
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But writing this get_post let's us see how
we're doing this join thing.
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Well not join but this, this query.
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And then let's add another one here called
get_stream.
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Eventually this is going to be our posts
plus the posts of people that we follow.
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But for now it's just going to basically
be exactly the same as get_posts.
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But we're gonna structure it just a little
bit different.
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And you'll see what here.
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We're going to do it here.
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So post.user == self.
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And notice that inside those parentheses
so.
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These are almost identical to each other.
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But this is going to get changed later.
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So, these two let us select the posts that
we want.
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So, these are all the posts that belong to
a certain user.
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Once we get our social graph set up, we'll
be able to change that
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get_stream method to gets posts from
users you followed too.
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I can't wait.
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Before we get there though, let's set up
the form and
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the view that we'll use to create a new
post.
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