How to efficiently use try…catch blocks in PHP

Question

I have been using try..catch blocks in my PHP code, but I\'m not sure if I\'ve been using them correctly.

For example, some of my code looks like:

 t         


        

Answer 1

Important note

The following discussion assumes that we are talking about code structured as in the example above: no matter which alternative is chosen, an exception will cause the method to logically stop doing whatever it was in the middle of.

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As long as you intend to do the same thing no matter which statement in the try block throws an exception, then it's certainly better to use a single try/catch. For example:

function createCar()
{
    try {
      install_engine();
      install_brakes();
    } catch (Exception $e) {
        die("I could not create a car");
    }
}

Multiple try/catch blocks are useful if you can and intend to handle the failure in a manner specific to what exactly caused it.

function makeCocktail()
{
    try {
        pour_ingredients();
        stir();
    } catch (Exception $e) {
        die("I could not make you a cocktail");
    }

    try {
        put_decorative_umbrella();
    } catch (Exception $e) {
        echo "We 're out of umbrellas, but the drink itself is fine"
    }
}

Answer 2

try
{
    $tableAresults = $dbHandler->doSomethingWithTableA();
    if(!tableAresults)
    {
        throw new Exception('Problem with tableAresults');
    }
    $tableBresults = $dbHandler->doSomethingElseWithTableB();
    if(!tableBresults) 
    {
        throw new Exception('Problem with tableBresults');
    }
} catch (Exception $e)
{
    echo $e->getMessage();
}