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Handling Status Code Errors

4:17 with Andrew Chalkley

In this video we'll handle HTTP errors.

Documentation

STATUS_CODES

The STATUS_CODES array is not on the https object. STATUS_CODES can be found on the http object. To include the STATUS_CODES use the following code:

const http = require('http');

http.STATUS_CODES;
  • 0:00

    We've assumed so far that each of the API responses will be OK.

  • 0:05

    In other words, have the HTTP status code of 200.

  • 0:09

    There are other status codes that an API endpoint can have.

  • 0:13

    Maybe there's errors in the code actually running on the server where the endpoint

  • 0:17

    is happening.

  • 0:17

    That's when you'd get a 500 error or internal server error.

  • 0:22

    Or maybe the API endpoint has been updated and has moved somewhere else.

  • 0:26

    You'd get the status code of 301.

  • 0:29

    If the endpoint is incorrect or has removed completely,

  • 0:33

    you'd get the HTTP status code of 404, not found.

  • 0:39

    Let's handle all status codes that aren't 200.

  • 0:43

    If the response .statusCode is equal

  • 0:48

    to 200, we want to do the parsing.

  • 1:02

    If the status code isn't 200,

  • 1:06

    we want to printout an error message for the status code.

  • 1:12

    So let's create a new

  • 1:17

    statusCodeError by creating

  • 1:22

    a new Error object,

  • 1:26

    with the message of a template string saying,

  • 1:35

    There was an error getting

  • 1:41

    the profile for ${username}.

  • 1:52

    Then we can add the status code in brackets.

  • 1:59

    We can print the error using the printError method that

  • 2:04

    we created earlier, passing in statusCodeError.

  • 2:11

    Save the file and open up the console.

  • 2:15

    And let's try and run node app.js chalkers-not.

  • 2:24

    And there's something wrong in my code.

  • 2:32

    I didn't close my else statement.

  • 2:38

    Run it again, and

  • 2:43

    we get the message there was an error getting the profile for chalkers-not,

  • 2:47

    with the status code of 404, not found.

  • 2:51

    You may know what 404 is being a web developer, and

  • 2:55

    you've probably seen it on many a site.

  • 2:59

    But what if the error was something else?

  • 3:02

    Is there a way to translate these error codes into something a human can

  • 3:07

    easily understand?

  • 3:08

    The HTTP module has a statusCodes object that

  • 3:13

    returns an English string from a status code.

  • 3:24

    Remember that we need to include the module at the top.

  • 3:46

    Let's try again, Awesome, it says not found.

  • 3:55

    Let's walk chalkers-not back to chalkers to make sure we haven't broken anything.

  • 4:02

    We haven't, cool.

  • 4:05

    Now that we've handled all the errors,

  • 4:07

    why not improve the messages that are generated by the printError function?

  • 4:11

    When you're done, I'll see you in the next video, and

  • 4:14

    I'll show you some techniques for organizing your code.

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