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Apr 13 2014 02:30pm

I have a few powershell assignments i need to do was wondering if you guys could look over them for me see if im doing it right

Create a script that uses a function to request a stock quote from webservicex.net. Include a trap for system exceptions to show a graceful error message if one arises. Use read-host to ask the user of the script for a stock symbol to look up and verify you were given one before trying to look it up.

Code

function get-stockQuote([Parameter(Mandatory=$true)][string]$symbol)
{
$URI = "http://www.webservicex.net/stockquote.asmx?WSDL"
$stockProxy = New-WebServiceProxy -uri $URI
$quote = [xml]$stockProxy.getquote($symbol)
$stock = $quote.StockQuotes.stock
$stock|ft -AutoSize
} #end Get-stockQuote

trap [System.SystemException]
{
$_.exception
continue
} # end of exception trap

while ($true) {
$symbol= read-host -Prompt "Please enter a stock symbol: "
if (-not $symbol) {
exit
}
get-stockQuote($symbol)
}

Qord

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Apr 14 2014 08:59pm

Looks fine to me. And it functions too!! Only thing you're missing is a "graceful" error message. You can test it by disconnecting from the network and then running the script to see what your error message will look like.

Personally, I would have done it a bit different, using a try/catch instead of trap, but I'm not sure if that counts as using a "trap" to catch the error.

Minkomonster

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Apr 14 2014 09:14pm

Quote (Qord @ Apr 14 2014 09:59pm)

traps are globally scoped, whereas try/catch/finally have local scope to the statements you have wrapped. You can look at a trap as being just a massive "catch" that wraps the entire script.

Qord

Member

Posts: 8,112

Joined: Sep 23 2006

Gold: 3,558.23

Apr 14 2014 09:20pm

I haven't used a trap in anything I've written so far. Most of it's pretty small though, so it might not be necessary for those. I'm not even a fan of try/catch, but my boss says to use it so I am. I'm still newb enough to not worry too much about error handling, but I'm seeing the value of it as my tools get larger and more complex.

Minkomonster

Member

Posts: 1,995

Joined: Jun 28 2006

Gold: 7.41

Apr 14 2014 09:24pm

Quote (Qord @ Apr 14 2014 10:20pm)

They both have their places.

For statements which may go wrong in localized areas of your script, you will want to wrap them in try/catch and do your error handling as needed. However, bigger scripts may have specific errors which can occur througout different parts of the scripts. Instead of having multiple try/catchs doing the exact same thing, you can define a trap, which for ALL exceptions that are trapped, no matter where in the script it occurs, will be piped through that one trap block.

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