Category Archives: Programming

Material related to computer programming.

PHP Traits and Grafts

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Reading about traits and grafts in PHP: Request for Comments: Horizontal Reuse for PHP, PHP Traits, Using Traits in PHP 5.4 and PHP Traits: Good or Bad?. They mentioned the Diamond Problem.

I learned some new syntax too! E.g.:

 return $_instance ?: $_instance = new $class;

The ternary operator as a ‘binary’ operator! Cool! See here for details: Since PHP 5.3, it is possible to leave out the middle part of the ternary operator.

Running Apache as ME!

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On my development machine I want Apache to run under my user id so I can automatically generate files (and have permission to write them).

I configured Apache like this:

root@mercy:/etc/apache2# grep -R www-data .
./envvars:export APACHE_RUN_USER=www-data
./envvars:export APACHE_RUN_GROUP=www-data

root@mercy:/etc/apache2# vim envvars 

export APACHE_RUN_USER=jj5
export APACHE_RUN_GROUP=jj5

root@mercy:/etc/apache2# apache2ctl graceful
/var/lock/apache2 already exists but is not a directory owned by jj5.
Please fix manually. Aborting.

root@mercy:/etc/apache2# chown jj5:jj5 /var/lock/apache2

root@mercy:/etc/apache2# apache2ctl graceful

Easy-peasy!

Wait… that didn’t work. The problem was apache2ctl graceful didn’t pick up the new envvars file, this fixed it:

root@mercy:/etc/apache2# /etc/init.d/apache2 restart

PHP PDO MySQL Blob

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Read PHP MySQL BLOB today to learn how to work with BLOBs. Basically:

public function insertBlob($filePath,$mime){
    $blob = fopen($filePath,'rb');
 
    $sql = "INSERT INTO files(mime,data) VALUES(:mime,:data)";
    $stmt = $this->conn->prepare($sql);
 
    $stmt->bindParam(':mime',$mime);
    $stmt->bindParam(':data',$blob,PDO::PARAM_LOB);
 
    return $stmt->execute();
}

function updateBlob($id,$filePath,$mime) {
 
    $blob = fopen($filePath,'rb');
 
    $sql = "UPDATE files
            SET mime = :mime,
            data = :data
            WHERE id = :id";
 
    $stmt = $this->conn->prepare($sql);
 
    $stmt->bindParam(':mime',$mime);
    $stmt->bindParam(':data',$blob,PDO::PARAM_LOB);
    $stmt->bindParam(':id',$id);
 
    return $stmt->execute();
 
}

public function selectBlob($id) {
 
    $sql = "SELECT mime,
            data
        FROM files
        WHERE id = :id";
 
    $stmt = $this->conn->prepare($sql);
    $stmt->execute(array(":id" => $id));
    $stmt->bindColumn(1, $mime);
    $stmt->bindColumn(2, $data, PDO::PARAM_LOB);
 
    $stmt->fetch(PDO::FETCH_BOUND);
 
    return array("mime" => $mime,
             "data" => $data);
 
}