How to check if input contains one of array?

Question

I have an input like this:

<input name='postImg' type='text'><?php if(isset($error)){ echo $_POST['postImg'];}?></input>

I would like PHP to check if the input text contains: .png or .jpeg or .gif etc. To make sure its a image. But it has to be input name (so no upload).

How can I do this best?

note that matching filenames isn't a reliable way of checking "is this an image"? ren nastyvirus.exe cutekittens.jpg, for one... — Marc B
– Marc B, Commented Oct 20, 2014 at 15:56

Community · Accepted Answer · 2020-06-20 09:12:55Z

2

You could use a regular expression. This will check that the extension is correct; matching (.png, .jpeg, .jpg, .gif) the end of the string

if( preg_match("/\.(png|jpeg|jpg|gif)$/", $_POST['postImg']) ) {
   //Yep.
}

Example: https://eval.in/208018

Edit

if( strlen($postImg) > 0 AND preg_match("/\.(png|jpeg|jpg|gif)$/", $postImg) == FALSE) {
   $error[] = 'Wrong image format.';
}

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Oct 20, 2014 at 15:45

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6 Comments

MrDikke Over a year ago

For some reason it isnt working. My other statements aren't working anymore. Here is the full code: pastebin.com/hF6p9fVA

ʰᵈˑ Over a year ago

Try something like: pastebin.com/SiEeGU3U (You are also trying to insert into the database even if there were errors. I've switched the logic on that for you, too)

MrDikke Over a year ago

Ok, that's working. Thanks. But could you add something that it is also possible to leave postImg empty?

ʰᵈˑ Over a year ago

Sure, add an OR clause within the if logic. if( empty($_POST['postImg']) OR ...

ʰᵈˑ Over a year ago

if( empty($postImg) OR preg_match("/\.(png|jpeg|jpg|gif)$/", $postImg) == FALSE) {} If the string is blank OR the regular expression brings no matches.

|

DrRoach · Accepted Answer · 2014-10-20 15:43:52Z

0

Try:

if(strpos($_POST['postImg'], '.png') || strpos($_POST['postImg'], '.jpeg') || strpos($_POST['postImg'], '.gif')) {
    echo 'It exists';
}

answered Oct 20, 2014 at 15:43

DrRoach

1,3569 silver badges16 bronze badges

1 Comment

ʰᵈˑ Over a year ago

This will allow input.png.exe, which isn't an image. You'd need to match the extension, not the contents of the string.

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