• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
noaktree

[web] PHP alternative to mysql_real_escape_string

8 posts in this topic

I need to create a PHP function that does the same thing as mysql_real_escape_string. The reason being that I need to use this function more than I actually need to connect to the database. According to the PHP Manual Page, mysql_real_escape_string escapes the following characters: \x00, \n, \r, \, ', " and \x1a. Is this an equivalent function? function my_real_escape_string($value) { $search = array("\x00", "\n", "\r", "\\", "'", "\"", "\x1a"); $replace = array("\\x00", "\\n", "\\r", "\\\\" ,"\'", "\\\"", "\\\x1a"); return str_replace($search, $replace, $value); } Or is there a reason this isn't safe, etc?
0

Share this post


Link to post
Share on other sites
Nope, looks good.

PS: You can save yourself a few headaches writing that by using single quoted strings. They don't need to be escaped by backslashes. I.e:


$search = array("\x00", "\n", "\r", '\', "'", '"', "\x1a");
$replace = array('\x00', '\n', '\r', '\\' ,"\'", '\"', '\x1a');


That's especially useful if you're dealing with multiple levels of backslash escaping (e.g. in some regular expessions) where you would otherwise end up with madness like "\\\\\\\\" for a simple backslash :-)
0

Share this post


Link to post
Share on other sites
Thanks Sander,

I'm having a little bit of trouble with the new code. In the top line you have '\' and it's causing an error as it thinks there is an open ended string. An elegant solution? Or must I replace '\\' with '\\\\'?
0

Share this post


Link to post
Share on other sites
Oh, ofcourse. Silly me.

In a single quoted string, only the ' needs to be escaped. Not the rest like in double quoted strings. So the '\' should be '\\'. It's very easy to test. If you echo('\n') you will get \n as output, but when you echo("\n") you will get a newline.

See http://www.php.net/manual/en/language.types.string.php and compare single quoted strings to double quoted strings. To revise my example:


$search = array("\x00", "\n", "\r", '\\', "'", '"', "\x1a");
$replace = array('\x00', '\n', '\r', '\\\' ,"\'", '\"', '\x1a');


It does exactly the same as your code does, but IMHO it's a bit easier on the eyes. Whatever floats your boat I guess :-)
0

Share this post


Link to post
Share on other sites
Thanks again, and for the link. The echo() example really made things clear. I've always assumed that single and double quoted strings worked the same... now I know different. I didn't mean to sound picky about your code. I always appreciate smaller more readable code since that's what keeps my boat from sinking. [smile]
0

Share this post


Link to post
Share on other sites
That method won't work.

Let's say someone enters a NULL character. You want it to be stored in the string as \x00. However, your code will do this:

NULL => \x00
\x00 => \\x00

This is because calling str_replace with an array is no different from calling it multiple times. You need to use strtr.


return strtr($text, array(
"\x00" => '\x00',
"\n" => '\n',
"\r" => '\r',
'\\' => '\\\\',
"'" => "\'",
'"' => '\"',
"\x1a" => '\x1a'
));



strtr translates the biggest strings first and doesn't translates text that has already been translated. (You may want to double check that the above table is accurate.)

As an aside, I don't really recommend using this method at all. I much prefer using PDO and prepared statements.
0

Share this post


Link to post
Share on other sites
Quote:
I much prefer using PDO and prepared statements.


The OP doesn't want to use this in combination with a database. That's why he needs to roll his own.
0

Share this post


Link to post
Share on other sites
Quote:
The OP doesn't want to use this in combination with a database. That's why he needs to roll his own.
Yes I do, sometimes, want to use this for database queries. Let me explain a little..

I have my database function wrapped in a class for caching purposes.

class->sql_query($query); // Simple example

The query may contain data that has been escaped with mysql_real_escape_string.

The class uses the query string to query the database and to create an ID for caching events.

A database connection is only made when data is not found in the cache. So it seems a waste to make a connection when it is only needed for mysql_real_escape_string.

I was hoping to make a replacement function for mysql_real_escape_string to avoid unnecessary connections to my mysql server.

So should I use the strstr to implement this function? What are the dangers?
0

Share this post


Link to post
Share on other sites
Ah. In that case try lazy evaluation. If the data is in the cache then you do not need to query the database. If you do not query the batabase, you do not need to escape variables. Ergo: You only need mysql_real_escape_string() because *if* you escape something, you have a database connection.

This probably means that you need to modify your wrapper class to accept something like:

Quote:
$wrapper->sql_query('SELECT * FROM table WHERE col1=?, col2=?', $var1, $var2);


The sql_query() function checks the cache. If it's not there, make a database connection, escape $var1 and $var2, insert then in the query, run the query and cache the result.
0

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0