PHP 检查图像 mime 类型

Question

This should be so simple, but I have no idea why this is not working.

I send a URL to my server, and I want to check whether this is an image. Then I want to check whether it's a JPEG or PNG.

if(! $image = @getimagesize( $url ) ) {

    return $this->buildResponse( false, 'No image exists at that location' );
}

So I return some JSON response if it isn't an image. This works.

I then want to check it's extension.

if( $image['mime']!= 'image/jpeg' || $image['mime']!= 'image/png') {

    return $this->buildResponse( false, 'File must be of type jpeg or png' );
}

So basically I'm checking whether the mime is equal to either of these, if it isn't then I don't want it.

Okay that should work, but I always get the File must be of type jpeg or png response back.

A var_dump($image) :

array(7) {
 [0] 1366
 [1] 854
 [2] 2
 [3] "width="
 ["bits"] 8
 ["channels"] 3
 ["mime"] "image/jpeg"
}

And a var_dump($image['mime']) :

string(10) "image/jpeg"

Am I being stupid, going mad or missing something stupidly obvious here.

Answer 1

if( $image['mime'] != 'image/jpeg' || $image['mime'] != 'image/png')

这永远是真的

Answer 2

I understand how this can be a little confusing when you've been struggling on it for a while, so I'll explain the logic behind it. You're stating two conditions of which you want one to be satisfied. Yet the if-block triggers an error when either of them doesn't satisfy. Because the two conditions are mutually exclusive, this is always the case. Instead you want the if to check whether they both don't satisfy, thus replacing your current OR-operator with an AND-operator.

Answer 3

Change the or to an and conditional and it will work.

if( $image['mime']!= 'image/jpeg' && $image['mime']!= 'image/png')