The Blog of a Programmer
PHP
Generating Thumbnails from FLV using FFMPEG
Mar 15th
I had to make some modifications to a zenGallery system which was going to hold a lot of flash video files and I was too lazy to create a thumbnail for each image so for awhile it had the default thumbnail.
After a few, “what’s with the thumbnails?” I decided to write a script that executed ffmpeg to create a thumbnail for each video (from the frame 10 seconds into the video) and write out a jpg image.
The filename currently just replaces .flv with .jpg and my settings for the call are pretty generic. If anyone has questions about this feel free to ask.
Grab the .phps file from here: Generate Thumbnails from FLV files using FFMPEG
MD5 with Dynamic Salt Class
Sep 25th
Remember my post about MD5 Hashing and Salt? Well I’ve taken some time to develop a PHP class which helps very easily implement dynamic salt when using MD5. This class can be easily expanded or modified to use a different hash function. Take a look at it and let me know if it becomes useful to anyone!
You can download the PasswordWithSalt.class.php file here. Also I setup a VERY simple demo of how this works. I’m still working on developing this but comments and advice will definately be useful here.
The following is the rough text and instructions I’ve written for my “readme.txt” file.
The only thing you need to do in order to properly configure this class is set the location you want to store your salts at. For example in the class set $storageLocation = “/home/user/salts/”; and give permissions for your server to write to that folder (777 will work). I recommend the folder to be one outside your normal webroot.
The following demonstrates how to store salt for your user, then generate the hash using those salts. Don’t forget to store the final hash so you can compare against it later!
<?php
require(“PasswordWithSalt.class.php”);//Init the class
$SaltPlease = new PasswordWithSalt();//Store generated salts for user “admin”
$SaltPlease->storeSalt(“admin”);//Get hash for user admin, password is “password”
$hash = $SaltPlease->createHash(“admin”, “password”);
?>
The following demonstrates how to duplicate the hash for a user who already has salt. $dbhash should be filled with the hash you have stored before.
<?php
require(“PasswordWithSalt.class.php”);//Init the class
$SaltPlease = new PasswordWithSalt();//Get hash for user admin, password is “password”
$hash = $SaltPlease->createHash(“admin”, “password”);//Check to see if the generated hash match.
if($dbhash == $hash) {
echo “Password Hashes Match.”;
} else {
echo “Password Hashes DO NOT Match”;
}
?>
MD5 Hashing and Salt
Sep 13th
I just read a great post by Marcel Oelke who runs http://md5.rednoize.com/. He’s got a great way to access his webservice and then check if a user’s password is insecure. Even if you are using MD5 before storing the password, I certianly hope people aren’t storing passwords in cleartext, it may not be secure. More >
Image Resizing Using PHP and the GD library
Nov 26th
I’m developing a new system core, can’t really say what it’s about but I’m having some fun doing it. Coding it is interesting, I’m getting to pull out and update some of my php code. Below is some code for image resizing, I use config files to set some default information like directories to save to and max width/height requirements. Also the entire system uses language files so I don’t output the text directly either, except for what I’m going to remove which is the uploaded file information.
Resize JPG images using the GD library and PHP.
function get_image_information($key) {
global $thumbnail_dest, $image_dest, $thumb_max_height, $thumb_max_width, $image_max_height, $image_max_width;
$filename = $_FILES[$key]["name"];
$file_type = $_FILES[$key]["type"];
$file_tmpname = $_FILES[$key]["tmp_name"];
$file_error = $_FILES[$key]["error"];
$file_size = $_FILES[$key]["size"];if($file_error == 0 && $file_size > 0) {
if($file_type == “image/pjpeg” $file_type == “image/jpeg” $file_type == “image/jpg”) {
$image_name = md5(time() . rand(1001,10000)) . “.jpg”;
$thumb_dest = $thumbnail_dest . $image_name;
$image_dest = $image_dest . $image_name;
create_image($file_tmpname, $thumb_max_height, $thumb_max_width, $thumb_dest);
create_image($file_tmpname, $image_max_height, $image_max_width, $image_dest);
return “thumbs/” . $image_name;
} else {
$success .= file_upload_success_1 . $filename . file_upload_success_2 . “
“;
$success .= “We can only accept jpg uploads. Upload Failed.”;
return $success;
}
} else {
if($file_error == 1) {
echo $file_upload_fail_1;
} elseif($file_error == 2) {
echo $file_upload_fail_2;
} elseif($file_error == 3) {
echo $file_upload_fail_3;
} elseif($file_error == 4) {
echo $file_upload_fail_4;
} elseif($file_error == 6) {
echo $file_upload_fail_6;
}
return false;
}
}
function create_image($image, $max_width, $max_height, $dest) {
$image = imagecreatefromjpeg($image);
if ($image === false) {
die (‘Unable to open image’);
}$width = imagesx($image);
$height = imagesy($image);if($width < $max_width && $height < $max_height) {
$new_width = $width;
$new_height = $height;
} else {
$scale = min($max_width/$width, $max_height/$height);
$new_width = floor($scale * $width);
$new_height = floor($scale * $height);
}$image_resized = imagecreatetruecolor($new_width, $new_height);
imagecopyresampled($image_resized, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);
imagejpeg($image_resized, $dest, 90);
}
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