Question

I am developing a site framework in php (codeigniter) and want to introduce image versioning on image uploads so that I can take advantage of image caching. The easiest approach would just be to md5 the image and use that as the file name but I don’t like this approach for the following reasons:

1)Not SEO friendly on the image names

2)md5 hashes seem unnecessarily long – and therefore larger database
field required.

So I am considering using an approach such as the following:

Start the filename with the entered name of the image with underscores instead of spaces then add a randomly generated integer, say 8 digits long. This will mean I have to check for an existing image by that name and then regenerate the integer if one exists (however unlikely that is).

Presumably I will also have to unique filename for every image size, so I guess the solution here would be to add a prefix representing the file size.

Now I want to get this right first time since it will be a pain to change once the framework is deployed so I am really just looking for input on

a)Whether my concerns are justified (particularly does the filename do
anything for SEO and does the length of a random string of numbers
affect it)

b)Whether there is anything else I should be concerned about or check
for with my proposed approach.

c)Is there an easier approach, perhaps a hashing algorithm which
produces much shorter results.

d) Is there already a ci lib out there that does this?

Thank you for your input and advice

Answer 1

This answers a few of your questions:

Replacing spaces with underscores is not enough to have a clean filename as you’d need to check for more weird characters, but you can use sanitize_filename() method in CI’s security library: http://ellislab.com/codeigniter/user-guide/libraries/security.html

If you do want to preserve the original filename, your approach sounds good to me. Though, 8-digit integer at the end of filename can be replaced by ‘-1’, ‘-2’, ‘-3’ by simple incremental loop checking if the file with that ending exists or not.

File Upload library is something you can check out – http://ellislab.com/codeigniter/user-guide/libraries/file_uploading.html. It is flexible and can be configured to keep the original filenames. Getting sanitize_filename() from Security lib to work along should do exactly what you need.

In all my CI applications I always use encrypted filename (this optional feature is provided by CI file upload class). At the same time I can configure the library to not overwrite already existing file by adding a number to it (if no encryption is used) or by just giving it another encrypted name (when encryption option is on). I do like it this way as it keeps the filenames consistent clean (although long and not SEO-friendly, however ALT tag gives it more exposure to search engines).