WEBVTT

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In this video we're going to learn how to handle errors using BHB.

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So first of all let's write a simple BHP statement that we know is going to trigger an error.

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So for example let's echo the file size of a file that we know doesn't exist.

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OK.

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So for example a file called an existing file.

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Those texts.

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OK so we know the file doesn't exist.

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So we know that if we refresh our page we're going to get an error.

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OK.

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So this is not a syntax error but this is what we call a runtime error which has been generated by the

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BHB engine.

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So in this first example we are going to see how to customize the way we showed this error to our user

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.

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So we want to show the error in a more user friendly way.

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OK.

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So we're going to do we going to create something we call an error handler.

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It's going to be a function OK which is going to process some promises and he's going to show the error

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in the way we like.

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OK.

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So this creates this function.

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So this function is we need to create it before we run the statements which is going to give us an error

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.

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OK.

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So let's call this function for example error handler.

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One they've been going to create another one in the second example.

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So this function function is going to take a few parameters and then it's going to run some code.

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So the barometers we're going to give to this function are going to be hours following.

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So the first Parminter which is a required Parmitano we're going to call it error number.

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OK you can call it anything you want but the first bar is a, is going to be referring to the error number

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and the error number in BHB refers to the error level without many error levels.

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OK.

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As an example error level 1 means that we are dealing with a fatal error and our great script is going

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to stop immediately.

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OK.

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At this stage we get the error.

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Ok there are other error numbers.

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Level 2 for example is a runtime warning.

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OK so is this type of error is not fatal and basically the the execution of our scripts is not going

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to be stopped.

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OK.

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And this is an example of an era of level 2 or warning.

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OK.

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So that's going to be the first parameter error them.

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The second Prometa is going to be the Arab Spring.

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We're going to call it.

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Error.

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OK.

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We can call it you can call it anything you want but it's going to be the second barometer.

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And the Arab Spring is just the error message that we get.

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So in our case this is our Arab Spring.

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OK.

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OK so these are the the required permits for any error handler.

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There are other other barometers we can use.

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OK.

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They are not required.

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Nobody's going to add them for now.

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So we are going to have

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the Arab file which is just the place we found as we are that is running our scripts.

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OK.

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So in our case it's our file that came with the complete part of the file and we can see it here.

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OK.

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And then the next parameter is going to be the airline.

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So the airline is the line where the error happened.

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And in our case it's happened in 9:34.

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OK.

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And finally we've got a variable or parameter error context.

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OK so Eric contex is just an array which will tell us all the variables that we had at the time our

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error happened.

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OK.

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We'll see in the bits where you can find them.

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Basically in the context you can find anything including the post variable the Gets variable the cookie

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variable and so on.

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OK OK so now what we want to do.

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We would like to echo our error in a nice readable way.

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So we're just going to echo a paragraph Okay.

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And inside our paragraph

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let's rights era and then after that let's write the error number between brackets.

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OK.

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So it is going to be this terrible error number and then let's have the Arab spring rise out of us which

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is this problem.

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OK.

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Then.

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So that's how we want to show our error on the screen.

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OK so now AAVSO we have defined our error handler.

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Now we need to use another function OK to set our error handler.

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This function is going to be set error handler.

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OK so this function is just going to set the error handler for us

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.

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OK so it's going to take as a parameter a string.

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Well we're going to place the name of our error handler.

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So our error handler is going to handle all the errors which are triggered after the setting of the

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error handler.

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OK.

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So if we save and refresh now we can see how our error is displayed this time.

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OK so we can see our paragraph echoed code.

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So you've got the error number.

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And of course our errors drink.

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OK let's just make a quick change inside our program.

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So let's make the area look bold by putting it inside the strong stacks.

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OK now

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that looks better.

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OK.

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So that's how we can handle errors using BHB