OOP part 19 Chaining Methods

error:Fatal error: Uncaught Error: Call to a member function save_file() on null in C:\xampp\htdocs\OOPtutorial\index.php:73 Stack trace: #0 {main} thrown in C:\xampp\htdocs\OOPtutorial\index.php on line 73

Problem:

public function sanitize($data){
foreach($data as $key =>$value){
$data[$key] = addslashes($value);
//adds lashes to the data and puts it to the same space to sanitize this data
}
}

When sanitize($data) is called in a method chain, it returns null, must return a class

Fix:

//add a line to return an object, in this case $this (as the object Signup itself)

public function sanitize($data){
foreach($data as $key =>$value){
$data[$key] = addslashes($value);
//adds lashes to the data and puts it to the same space to sanitize this data
}
return $this;
}

error: Warning: file_get_contents(mydata.json): Failed to open stream: No such file or directory in C:\xampp\htdocs\OOPtutorial\index.php on line 66

code:

public function save_file($filename){
$old_data = file_get_contents($filename);
$old_array = json_decode($old_data);

$old_array[] = $this->data;
$string = json_encode($old_array);
file_put_contents($filename, $string);
}

Trying to open a file to read it’s data but the file does not exist

Fix:

Create the file in another function and add it to the chain

public function createFile($filename){
if(!file_exists($filename)){
file_put_contents($filename, ”);
}
$this->filename = $filename;
return $this;

}

error:Fatal error: Uncaught Error: Call to a member function read() on array in C:\xampp\htdocs\OOPtutorial\index.php:91 Stack trace: #0 {main} thrown in C:\xampp\htdocs\OOPtutorial\index.php on line 91

Code:$result = $myClass->read(‘mydata.json’)->read();//typo

Fix:

$result = $myClass->create(‘my-data.json’)->read();

//Make sure to check if the file is created with create() function then read from the file

//Also make sure the filename is correct