How to create a logfile in php

I want to create a logfile for my system to register/log every action they do inside the system. But I have no idea how to do it.

For example, I have this php code that does the login function.

public function hasAccess($username,$password){
    $form = array();
    $form['username'] = $username;
    $form['password'] = $password;


    $securityDAO = $this->getDAO('SecurityDAO');
    $result = $securityDAO->hasAccess($form);
    //var_dump($form);
    //var_dump($result);
    if($result[0]['success']=='1'){
        $this->Session->add('user_id', $result[0]['id']);
        //$this->Session->add('username', $result[0]['username']);
        //$this->Session->add('roleid', $result[0]['roleid']);
        return $this->status(0,true,'auth.success',$result);
    }else{
        return $this->status(0,false,'auth.failed',$result);
    }
}

now I want to create a logfile entitled ‘the date today’, then when that functions is used for loging in, it will write that user has logged in, the same with other functions. But I only want a single file for every day.

Could anyone be kind enough to guide and teach me how I should do my codes?

Answer

To write to a log file and make a new one each day, you could use date("j.n.Y") as part of the filename.

//Something to write to txt log
$log  = "User: ".$_SERVER['REMOTE_ADDR'].' - '.date("F j, Y, g:i a").PHP_EOL.
        "Attempt: ".($result[0]['success']=='1'?'Success':'Failed').PHP_EOL.
        "User: ".$username.PHP_EOL.
        "-------------------------".PHP_EOL;
//Save string to log, use FILE_APPEND to append.
file_put_contents('./log_'.date("j.n.Y").'.log', $log, FILE_APPEND);

So you would place that within your hasAccess() method.

public function hasAccess($username,$password){
    $form = array();
    $form['username'] = $username;
    $form['password'] = $password;

    $securityDAO = $this->getDAO('SecurityDAO');
    $result = $securityDAO->hasAccess($form);

    //Write action to txt log
    $log  = "User: ".$_SERVER['REMOTE_ADDR'].' - '.date("F j, Y, g:i a").PHP_EOL.
            "Attempt: ".($result[0]['success']=='1'?'Success':'Failed').PHP_EOL.
            "User: ".$username.PHP_EOL.
            "-------------------------".PHP_EOL;
    //-
    file_put_contents('./log_'.date("j.n.Y").'.txt', $log, FILE_APPEND);

    if($result[0]['success']=='1'){
        $this->Session->add('user_id', $result[0]['id']);
        //$this->Session->add('username', $result[0]['username']);
        //$this->Session->add('roleid', $result[0]['roleid']);
        return $this->status(0,true,'auth.success',$result);
    }else{
        return $this->status(0,false,'auth.failed',$result);
    }
}