Is it possible not to load the bootstrapping mechanism at every call?

Question

This is not a PHP question, but my expertise is with PHP frameworks.

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A lot of frameworks have a bootstrapping (loading of classes and files) mechanism. (Drupal, Zend Framework to name a few)

Everytime that you make a request, the complete bootloading process needs to be repeated. And it can be optimized using APC by automatically caching some intermediate code

The general question is:

For any language, is there any way to not load the complete bootstrapping process? Is there any way of "caching" the state (or starting at) at the end of the bootstraping process to not load everything again? (maybe the answer is in some other language/framework/pattern)

It looks to me as extremely inefficient.

Answer 1

In general, it's quite possible to perform bootstrap / init code once per process, instead of having to reload it for every request. In your specific case, I don't think this is possible with PHP (but my knowledge of PHP is limited). I know I have seen this as a frequently criticism of PHP's architecture... but to be fair to PHP, it's not the only language or framework that does things this way. To go into some detail...

The style of "run everything for every request" came about with "CGI" scripts (c.f. Common Gateway Interface), which were essentially just programs that got executed as a separate process by the webserver whenever a request came in matching the file, and predefined environmental variables would be set providing meta information. The file could be basically any executable, written in any language. Since this was basically the first way anyone came up with of doing server-side scripting, a number of the first languages to integrate into a webserver used the cgi interface, Perl and PHP among them.

To eliminate the inefficiency you identified, the a second method was devised, which used plugins into the webserver itself... for Apache, this includes mod_perl for Perl, and mod_python for Python (the latter now replaced by mod_wsgi for Python). Using these plugins, you could configure the server to identify a program to load once per process, which then does the requisite initialization, loads it's persistent state into memory, and offers up a single function for the server to call whenever there is a request. This can lead to some extremely fast frameworks, as well as things such as easy database connection pooling.

The other solution that was devised was to write a web server (usually stripped down) in the language required, and then use the real webserver to act as a proxy for the complicated requests, while still serving static files directly. This route is also used frequently by Python (quite often via the server provided by the 'Paste' project). It's also used by Java, through the Tomcat webserver. These servers, in turn, offer approximately the same interface as I mentioned in the last paragraph.

Answer 2

The short answer is: in PHP there's no good way to skip the bootstrapping. (Technically you could run a PHP service 24/7 that ran forked children to handle requests, but that's not going to make your life any better.)

A good framework shouldn't do much in bootstrapping. In my personal one that I use, it simply registers an autoload function for classes, loads the config settings from MemCache, and connects to a database.

At that point, it parses the request and sends it to the proper controller / action. While creating the new router object every time is a "waste," the actual process of handling the request needs to be done regardless if the bootstrapping process is magically "cached" between requests.

So I would measure the time it takes between starting the page and getting to the action method to see if it's even a problem. If the framework is doing expensive things related to configuration and class loading, you should be able to minimize that via storing the end results in memcache.

Note that you should always be using an opcode cache (e.g. APC) and a persistent SAPI (e.g., php-fpm) in production. Otherwise, there is a lot of overhead with starting up and shutting down.