PHP switch - default if the variable is not set

Question

is there any way to simplify this code to avoid the need for an if to skip to the switch's default value?

I have a configuration table for different authentication methods for a http request, with an option not to set the value to default to a plain http request:

if(!isset($type)) {
    $type = "default";
}

switch ($type) {
   case "oauth":
       #instantinate an oauth class here
       break;
   case "http":
       #instantinate http auth class here
       break;
   default:
       #do an unprotected http request
       break;
}

I have no issue with the functionality, but I would like a cleaner solution to switch on an optional variable, is there any way to achieve that? Thanks!

Note that you do not need to set it to "default" - you could put that code in a function and use syntax function funcName($type = "") which would set it to "" if a null value was passed ib. — andrewb
– andrewb, Commented Sep 23, 2013 at 23:53
Interesting catch there @andrewb It's almost a little misleading in the code that the value if unset is set to the literal string 'default' and then execution in switch fall through to the 'default case'. default: is php syntax for an unmatched switch case. you may as well set $type to "" or "barbecuebits". — Billy left SE for Codidact
– Billy left SE for Codidact, Commented Apr 11, 2020 at 19:03
Yeah that was sort of the issue. I just had to set $type to something as if it wasn't set, I'd end up with an error. To this day I'm not sure I know a better solution.. — kachnitel
– kachnitel, Commented Apr 13, 2020 at 6:38

unxed · Accepted Answer · 2019-11-29 01:09:54Z

4

Just

switch ($type??'') {
    case "oauth":
        #instantinate an oauth class here
        break;
    case "http":
        #instantinate http auth class here
        break;
    default:
        #do an unprotected http request
        break;    
}

is enough on php >= 7

answered Nov 29, 2019 at 1:09

unxed

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Comments

edditor · Accepted Answer · 2013-09-23 23:58:55Z

4

You don't need to set the variable to "default". The default-case will be executed if the variable is not set or has any different value from all other defined cases. But remember: if the variable is not set and you use it in the switch, you will get a notice "Notice: Undefined variable". So if you don't want to disable notices you have to do the check if the variable is set.

answered Sep 23, 2013 at 23:58

edditor

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4 Comments

kachnitel Over a year ago

I have failed to mention I need to avoid getting a Notice, so it seems there's no way to get around it without additional code, thanks.

musicin3d Over a year ago

While it may be frowned upon, you can suppress the Notice by placing @ in front of the variable.

edditor Over a year ago

@musicin3d This is not a good practice. You should not use the @ to supress errors etc. stackoverflow.com/questions/5573426/…

musicin3d Over a year ago

See, I understand it's bad practice to suppress errors, and it's usually bad to suppress anything. But this is a Notice, akin to a linter warning... about something we're already handling (with default:). And IMO switch(@ $var){...} is MUCH more readable than wrapping the whole block in if(isset($var)){...}. I mean, the "variable not set" Notice is the only use for the @ in this case, so you know exactly why it's there and it reduces indentation and clutter. This seems like one legitimate use case to me.

Arian Faurtosh · Accepted Answer · 2013-09-24 00:35:33Z

1

If you want to simplify it without getting a notice. Try the following:

if(!isset($type)) {
    #do an unprotected http request
}else{
    switch ($type) {
       case "oauth":
           #instantinate an oauth class here
           break;
       case "http":
           #instantinate http auth class here
           break;
    }
}

answered Sep 24, 2013 at 0:35

Arian Faurtosh

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Comments

boojer · Accepted Answer · 2013-09-23 23:50:46Z

-1

The default case is a catch-all if none of the previous cases are found, so your check for whether the variable isset and assigning it to "default" is unnecessary.

answered Sep 23, 2013 at 23:50

boojer

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