string checks

[ajoo]

Hi, 

I wish to check for a condition that a string received is not white space or false or null but it should allow the string '0'.

This must be a very simple problem but it is definitely quite confusing.

Thanks loads.

[ajoo]

Hi, 

The following seems to work but still allows for a non string 0.

(isset($str) && $str !==false && $str !==''){
.
.
.

}

Maybe I need to check for an is_string as well. I was hoping to find something simpler if it exists.

Thanks !

[gw1500se]

If I understand, you are really using the wrong approach. You really want to use preg_match and a regular expression. I am not a regexp expert so you should ask tor the expression in the regexp forum.

[requinix]

If it's a string then it won't be ===false. Because it's a string. Same for ===null.

Maybe what you're looking for is

isset($_POST["whatever"]) && trim($_POST["whatever"]) != ""

 

[ajoo]

Hi !

@ gw1500se :  While it's complicated I don't think it would require a regex since it's also basic. 

@requinix : Since this is an input received via ajax, someone can try and doctor the input to try and break the code. Hence I had the == false as well. And since a string won't be equal to false, I am thinking that it may be necessary to check that the input received is indeed a string. Wouldn't that be so ? Would you still go ahead with your code that you pasted above?

Thanks ! 

 

 

[requinix]

27 minutes ago, ajoo said:

Since this is an input received via ajax, someone can try and doctor the input to try and break the code. Hence I had the == false as well. And since a string won't be equal to false, I am thinking that it may be necessary to check that the input received is indeed a string. Wouldn't that be so ? Would you still go ahead with your code that you pasted above?

It will be either a string or an array. If you want to protect against that, a simple is_string() will suffice.

[ajoo]

hmm, 

So I can finally use 

isset($_POST["whatever"]) && is_string($_POST["whatever"]) && trim($_POST["whatever"]) != ""

because, as you said, if it's a string, it won't be false or null.

Thanks.