PHP 5.3 has a new feature called PHAR similar to JAR in JAVA. It\'s basically a archive of PHP files. What are its advantages
Any tool that works on a single file "suddenly" works with all files of an application at once.
E.g. transport: You can upload the entire application through a single input/file element without additional steps.
E.g. signing an application: checksum/sign the file -> checksum/signature for the whole application.
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There are tremendous benefits for open source projects (in no particular order).
Easier deployment means easier adoption. Imagine: You install a CMS, forum, or blog system on your website by dragging it into your FTP client. That's it.
Easier deployment means easier security. Updating to the latest version of a software package will be much less complicated if you have only one file to worry about.
Faster deployment. If your webhost doesn't give you shell access, you don't need to unzip before uploading, which cuts out per-file transfer overhead.
Innate compartmentalization. Files that are part of the package are clearly distinguished from additions or customizations. You know you can easily replace the archive but you need to backup your config and custom templates (and they aren't all mixed together).
Easier libraries. You don't need to figure out how to use the PEAR installer, or find out whether this or that library has a nested directory structure, or whether you have to include X, Y, or Z (in that order?). Just upload, include archive, start coding.
Easier to maintain. Not sure whether updating a library will break your application? Just replace it. Broken? Revert one file. You don't even need to touch your application.
What you see is what you get. Chances are, someone is not going to go to the trouble of fudging with an archive, so if you see one installed on a system you maintain, you can be fairly confident that it doesn't have someone's subtly buggy random hacks thrown in. And a hash can quickly tell you what version it is or whether it's been changed.
Don't poo-poo making it easier to deploy things. It won't make any difference for homegrown SaaS, but for anyone shipping or installing PHP software packages it's a game-changer.
The advantage is mainly ease of deployment. You deploy an entire application by just copying one file.
Libraries can also be used without being expanded.
In theory it should also improve loading speed. If you have alot of files which need to be included, replacing it with single include will save you time on file opening operations.
In my experience, loosely packaged PHP source files sitting in a production environment invite tinkering with live code when a fix is needed. Deploying in a .phar file discourages this behaviour and helps reinforce better practices, i.e. build and test in a local environment, then deploy to production.