2

I'm trying to manually decrypt my owncloud's files to test it, but I don't know the PHP language well.

The problem I'm facing is:

PHP Fatal Error: Using $this when not in object context

I looked around for some time, but all I came across was using $this wrongly along with static methods. But, there aren't any static methods in the files I'm editing.

There's a file 'script.php' where I'm calling another file's (crypt.php) methods.

script.php:

<?php 
namespace OCA\Files_Encryption\Crypto;
use OCA\Files_Encryption\Crypto\Crypt;
require_once 'crypt.php';

.
.
.

$decryptedUserKey = Crypt::decryptPrivateKey($encryptedUserKey, $userPassword);

.
.
.

Here's the other crypt.php file, where the fatal error occurs crypt.php

<?php
namespace OCA\Files_Encryption\Crypto;

class Crypt {

.
.
.

public function decryptedPrivateKey($privateKey, $password = '', $uid = '') {
    $header = $this->parseHeader($privateKey);
.
.
.
}

}

The last line of code throws the fatal error. Any ideas?

dbf
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Ashish Patil
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2 Answers2

3

You may not have defined decryptPrivateKey as static, but that is how you are using it.

It is then going forward and using $this when it isn't actually part of an instantiated object.

Try using this in script.php

$crypt = new Crypt();
$decryptedUserKey = $crypt->decryptPrivateKey($encryptedUserKey, $userPassword);
Tom Wright
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3

You can not use $this in static call. Because $this is refer current object and you haven't created any object for class Crypt.

Also you haven't declared decryptedPrivateKey method as static.

You can call class method by two ways. You can use Tom Wright's suggested way

(1) Call with object

$crypt = new Crypt(); // create class object
$decryptedUserKey = $crypt->decryptPrivateKey($encryptedUserKey, $userPassword); // call class method via object

OR

(2) Call without object (static call)

a) You should define method as static.

b) You should use self keyword and call another static method,

public static function decryptedPrivateKey($privateKey, $password = '', $uid = '') {
    $header = self::parseHeader($privateKey);
}

public static function parseHeader() { // static parseHeader
  // stuff
}

In above case, parseHeader method must be static as well.

So you have two options:-

i) Either declare parseHeader method also static OR

ii) create object of current class and call non static method parseHeader 

public static function decryptedPrivateKey($privateKey, $password = '', $uid = '') {
     $obj = new self(); // create object of current class
     $header = $obj->parseHeader($privateKey); // call method via object
}

public function parseHeader() { // Non static parseHeader
  // stuff
}

Hope it will help you :-)

Community
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Ravi Hirani
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  • Thanks, I have a better idea now. What about for calls like $this->abc->def(); ? – Ashish Patil Jun 03 '16 at 09:30
  • You are welcome :-) It is object chaining. see this link http://stackoverflow.com/questions/3724112/php-method-chaining – Ravi Hirani Jun 03 '16 at 09:35
  • Thanks again! What I meant was, how should I modify such method chaining calls? I tried using the same method as you mentioned by declaring the methods as static and doing this: self::abc->def() but that did not work. – Ashish Patil Jun 03 '16 at 09:38
  • You can use self and call self::abc()->def() only if you will create class object in abc() method and return $this. then only it is possible. – Ravi Hirani Jun 03 '16 at 09:50
  • Yeah, that makes sense. Thanks again @Ravi Hirani – Ashish Patil Jun 03 '16 at 09:54