#100DaysOfCode in Python Transcripts
Chapter: Days 97-99: Building JSON APIs
Lecture: Implementing the find-user method
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Now let's turn our attention to finding a user.
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This is pretty straightforward,
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but it does introduce an entirely new concept.
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I could ask for a user that doesn't exist, right?
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Over here, we can go to our get_user,
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and Mark, I don't think Mark exists in the database,
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it just says, hey, we would find him.
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I'm sure that Mark doesn't exist.
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Eh, it still thinks it would find him.
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And the status code is 200 OK.
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So what we need to do is say,
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yes, this user was found and here's their details,
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or no, the user was not found, and here's what happened.
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So it's really easy to do this with the code
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we've already written and encapsulated in our service.
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Alright, so, there's our user.
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And if it wasn't null, we could return it.
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Be super easy.
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Let's go ahead and write that code really quick.
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Now, to all these database entities
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that need to be returned, if I just try to return Player,
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let's try to make this work here.
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We know Computer exists, let's try to get them.
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What happens? Boom.
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Player is not JSON serializable.
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Failure.
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What we have to put here is not
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a random object out of the database, but a dictionary.
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I've added this to_json method for every one of these.
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The one that's most interesting is this,
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this move here, so you can see this to_json,
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that is going to create this dictionary to be sent back,
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right, and it's kind of encapsulated here with this class,
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which I think is pretty cool.
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So what we got to go over here and say to_json now,
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we do that, boom, there's our computer, ID is 1.
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What about Michael, does he exist?
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None type has no attribute to JSON.
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No, there is no Michael, so what we need to do
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instead of let it crash, is we need to say,
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sorry, that user wasn't found.
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So we'll say if not player,
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and we can just say this, abort, sorry flask.abort(404), Not Found
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Alright, now let's try it for one that doesn't exist.
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Okay, the page was not found, 404, that's fine.
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Maybe we could give a better message about the user,
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but notice this is a little bit off.
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What we need to do is actually return a response
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and set the status to be 404
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in our little not found handler.
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Alright, there we go, 404 not found.
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That's what our client can use
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to say no no no, that didn't work.
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We could put a little JSON message in here if we want,
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but it doesn't really matter for what we're doing.
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Okay, go back to working one.
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Here we go.
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Okay, so our get user is implemented,
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and the interesting thing that we learned here
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is this response message, a flask.abort(404)
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which really redirects over to this not found handler,
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and does whatever it's going to do.
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So this is really important when people are trying
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to interact with things that don't exist.
