PHP Bootstrapping Basics - php

I'm writing my first PHP app. Everyone talks about having a bootstrap.php to initialize your app. This makes sense and I've put together one that I'm happy with. There's two things I don't understand, and which no one seems to mention:
Where do I call my boostrap from? Do I include it in every page? Please tell me there's a better way...
How do I make it so my bootstrap is not called more often than needed? I assume it only needs to be called either at the start of the app or the start of a new session.

1: Generally the bootstrap is in the "application" directory. It is called from the "public" directory which is in the same level as application (not inside of it). The index.php inside the public folder should include the bootstrap.php and that is where your Document_Root should be set to (note you may need to change / add some include paths for it to work)
2: It should only be included once via the index.php file in the public folder. Just including it there should be enough, if it was done correctly.
Hope that helps.

It depends on your application architecture.
If your architecture is the good old "flock of php scripts" - PHP scripts called directly from the browser - then you'll be including it at the top of each script, one way or another.
Most developers (and frameworks) these days marshall all their requests through /index.php one way or another, usually with some URL rewriting going on to make nice, pretty URLs for users to see.
In this day and age, you should probably be doing the latter, or at least thinking about it. It leads to much better organization, and even more importantly, allows you to keep all your code outside of the web server's document root, which is a good security practice for several reasons that are outside the scope of this answer.

Have a look at the singleton pattern. You can double your bootstrap class as a resource container, e.g.:
$bootstrap = Bootstrap::getInstance();
$dbConn = $bootstrap->getPdoDbh();
You can include or require the file, or use the autoloader and make sure you have a call to instantiate the object on all your pages. You might even have a call to getInstance() on the bottom of the file, after the class definition.
Or you might use URL-based routing and have all your requests go through a single index.php file, like Zend Framework does. Or better yet, use Zend Framework.
This answer assumes you're doing OOP w/ PHP >=5, which really is the way to go.

One of the more elegant means by which to bootstrap a PHP application is to do so using Composer.
Almost every PHP library uses Composer nowadays, and requiring a Bootstrap.php-like file is as simple as:
"autoload": {
"psr-4": {
"Acme\\Rocket\\": "src/"
},
"files": ["src/Bootstrap.php"]
},
Note the second property, files. (The first, psr-4, is standard PSR-4 boilerplate auto-loading, and is included only to make the example more real-world.)
Including the bootstrap file in this way doesn't make the naive assumption that the PHP application is executed in a web-server context, via index.php, or similar; the application could very well be a command-line application (or both, like Laravel/Artisan). Bootstrapping via the auto-loader makes this distinction a non-issue.

it depends on what your bootstrap file does. If it's just a file that sets some ini settings and such to create a sane execution environment and establish a database connection, then simply including it with require_once in your scripts should be enough. If it's more of a single-point of entry then you can configure your server to filter all requests to it and have it dispatch to appropriate controller scripts.

Related

php - Autoloader implementation, preload all the classes

I'm new to php and inherited a website project with hundreds of pages, all procedural (when I do a text search of the files, there isn't even a function definition anywhere). I'm coming from the c# and Java worlds. I'm looking for a way to incrementally add OOP. (They want me to update the front end and I am trying to convince them of fixing the backend at the same time and they don't want to use a framework (dammit)).
While looking into autoloader... Well, here's my understanding. It's a method of registering folders where classes are stored and when you instantiate a class, trait, etc. it searches the folder based on the class/filename/namespace and loads the appropriate definitions.
I have a few questions:
Does autoloader search the folder and load the appropriate definitions on every page lifecycle (or does it cache them)?
Pre-loading:
Is there a way to use autoloader, or some alternative, to pre-load ALL class definitions into memory and make them available across all sessions?
If so, when updating class files, how would I tell this mechanism to reload everything to memory when I make changes to class files?
UPDATE TO QUESTIONS:
Thank you both for your answers and it helps a little, but... I do have a bad habit of posing the wrong question(s) on StackOverflow.
The thing I want to avoid is slowing down pages by adding classes. So let's say I add a library and register the paths with autoloader. A page instanciates a class with multiple dependencies. Let's say that the dependency graph includes 15 files. For each request lifecycle, the server loads the page and 15 other files just on that one page.
Since I am coming from compiled languages, I feel a little strange not loading these classes into memory. All the classes together should not be over say 5MB.
(Or maybe I should just create a RAM Disk and copy all the files in there on boot and just have a symlink?)
Auto loaders in PHP are lazy. When PHP encounters a the use of a class it doesn't know about, it will ask the registered autoloader (or chain of autoloaders) to go find it. It's the autoloader's job to figure out where to get the file the class is defined in and include it. Having some sort of convention for naming your classes and organizing your class files is key to having a useful autoloader, and several conventions have arisen in the PHP community, such as PSR-4.
Does autoloader search the folder and load the appropriate definitions on every page lifecycle (or does it cache them)?
The autoloader(s) is(are) called on every request, but only when the need to autoload a class arises.
Pre-loading: Is there a way to use autoloader, or some alternative, to pre-load ALL class definitions into memory and make them available across all sessions?
I don't believe so, but as the number of classes grow, this becomes more and more wasteful.
Welcome to the wonderful[citation needed] world of legacy PHP, I highly recommend you check out Modernizing Legacy Applications In PHP. It's like a strategy guide for getting from Mordor back to the Shire.
I think you may misunderstand the purpose of autoloading. It is simply instructions on what to do when your code calls for a class that PHP doesn't recognize. That's it. The autoloader just calls requires /path/to/classfile so that PHP will see the class.
Does autoloader search the folder and load the appropriate definitions
on every page lifecycle (or does it cache them)?
There is no caching across requests, so if you make a change to file, the next http request will incorporate those changes. It's just as if you changed any other instruction in your script, for example change echo 1 to echo 2
Pre-loading: Is there a way to use autoloader, or some alternative, to
pre-load ALL class definitions into memory and make them available
across all sessions?
There is no need for this. A well written autoloader has instructions for where to find any class, so loading all possible classes ahead of time is wasteful. If you're still running into undefined classes errors, you need to either improve the autoloader or place the class files in accordance with the current autoloader instructions.
If you really want to preload all your classes, use the auto_prepend_file setting in php.ini. The docs say
Specifies the name of a file that is automatically parsed before the
main file
Set it to an initialization script. In that script have something like:
//put all your class files in this folder
$dir = '/path/to/classes/folder';
$handle = opendir($dir);
//require all PHP files from classes folder
while (false !== ($item = readdir($handle))){
$path = $dir.'/'.$item;
if(is_file($path) && pathinfo($path,PATHINFO_EXTENSION)==='php')
require_once $path;
}
This is simplified. There is significant risk in just including all files in any directory into your script so I would not do this. You would also need to adjust this if you want to include files in subdirectories.
Basically, don't do this. Just have a good autoloader.
No one posted what I was looking for but it seems the best route is the OptCache that's prebuilt into php 5.5 and above (my client is using 5.3 so I didn't know about it).
https://github.com/zendtech/ZendOptimizerPlus
The Zend OPcache
The Zend OPcache provides faster PHP execution through opcode caching
and optimization. It improves PHP performance by storing precompiled
script bytecode in the shared memory. This eliminates the stages of
reading code from the disk and compiling it on future access. In
addition, it applies a few bytecode optimization patterns that make
code execution faster.

How to handle config files and default settings when using Composer?

I was wondering what the best practices were for handling configuration files for your scripts when using Composer.
To elaborate, if I have a script that has several options or settings I'd usually just add them as variables or constants in a config.php file or something similar, and then require the file my script. Or, if the script is a simple class then just use class properties... basic stuff, right?
So, my question is, with the advent of PSR-4, autoloading, Composer, etc., what is the preferred way of doing this?
It feels wrong to ask users to directly edit the file(s) in vendor/ (eg: to edit a config file or properties in a class, etc.). Plus, wouldn't those edits get overwritten on updates?
I thought about using defined() in my script to look for certain constants, which the user could set in their own config files. This would probably work fine for smaller projects, but might become cumbersome and hard to scale. For some scripts it might also be difficult to come up with sane defaults in the event that the constants aren't defined by the user.
I also thought about using one of Composer's "hooks" to trigger a script that moves a config file somewhere like the project's root directory. But then I hate to just drop a random config file in the user's project...
Am I overthinking this? How do you guys typically handle this situation?
Don't have a configuration file. Let the code which includes your project set configuration values at run time.
If you are working in object oriented php you may want to take any required configuration parameters as arguments to your constructor or factory method, and provide setter methods for optional parameters, or parameters for which a sensible default value exists.

How to keep relative filepaths intact, even though I'm bootstrapping

I'm trying to include a premade messageboard, Phorum, into one of my Zend projects. Phorum is a relatively large and intricate web of PHP includes. My website already has a signup, so I'm trying to combine the two login systems into one.
What I've done is to make a controller that includes the Phorum index.php. This will let me use the authentication system I've set up. My problem is that, since I'm bootstrapping, all the relative filepaths within Phorum's index.php seem to try to begin at my Zend project's index.php, meaning they all seem to break.
Is there a way around this? Should I include? Render? Something better?
All help is appreciated.
Adding the appropriate chdir (back to Phorums include path root) in your Bootstrap file should do it. Then you have to of course take care that you Zend App uses application specific and not relative paths.
You can use the include_path setting, which can be set at runtime using set_include_path(). This doesn't require you to change the working directory, but makes PHP search for includes in all the directories specified in this setting.

What is the best way to set up shared php script files on a webserver?

I'm running the same php script on many domains on an apache2 server. Only some of the files change between domains, and the rest are always the same. Right now, every time I set up a new domain, I copy all the files, but I'd really like to have these common files in one place so any changes would affect all domains.
I've thought of using a bunch of symlinks to point at common files. Is this an ok approach, or are there some simple edits I can make to the php scripts or apache configuration files to make this more efficient?
Thanks!
The way I do this kind of thing is to create a "common" directory, where I place all the file that can be shared between each site. Then I simply include them wherever they are needed.
This is pretty good because allows to add features across multiple sites.
I'd suggest abstracting the common code into a set of 'library' scripts. Placing these in a common directory, and making that available by modifying PHP's include_path variable. This means you most likely won't have to modify your current scripts, while still removing the need to have more than one copy.
This path could (and probably should) be outside of your public directories. This enhances the security of your websites by not making them directly available to outside users.
This can be a bit tricky, as the application almost needs to know you're doing this. IME, it works best when you can divide the app into common code and instance code in two separate directory trees. The common code also needs to not do anything silly like include a file that has to be in the instance tree.
A single point of entry to load the common code is also a big bonus because then you can chain a few very small files: the instance code includes one in it's own directory; that file includes a file outside the instance code; that file then either loads the entry point file for the common code, or loads another that does. Now this is only one way to do it, but it means you have just one file that needs to know where the common code is (so you can move it if you have to with minimal effort), and if you do it right, all the various instance code trees load it, albeit indirectly.
You could have a library directory that sits above all of your sites, and a config file that states which library files your sites should include by default. You can then have another config file within each site that overrides the global config. These config files can be used to generate include('../../lib/*.php') statements to build the basic function toolkit needed for each site.
some_high_level_directory/
-> lib/
->*.php (library files)
-> config.php (global library includes)
-> site_1/
-> config.php (library includes that only relate to site_1)
-> www/
-> site_2/
-> config.php (library includes that only relate to site_2)
-> www/
-> etc, etc
Hopefully that makes sense... :)

Integrating external scripts with Zend Framework

What is the best way to integrate an external script into the Zend Framework? Let me explain because I may be asking this the wrong way. I have a script that downloads and parses an XML file. This script, which runs as a daily cron job, needs to dump its data into the database.
I am using Zend Framework for the site which uses this script and it seems to me that it would be best to use my subclassed model of Zend_Db_Abstract to do the adding and updating of the database. How does one go about doing this? Does my script go in the library next to the Zend Components (i.e. library/Mine/Xmlparse.php) and thus have access to the various ZF components? Do I simply need to include the correct model files and the Zend DB component in the file itself? What is the best way to handle this sort of integration?
Yes, you should put your own classes that maybe inherit Zend Framework classes or add further classes into your own folder next to the Zend Framework folder in library.
When you have Zend_Loader s auto-loading enabled, the class names will automatically map to the class you created, e.g.:
My_Db_Abstract will map to My/Db/Abstract.php .
In your library directory you should have your own library next to the Zend library folder. Whatever you call it (Mylib, Project, ...) you should include it into the Zend Autoloader and that's done as follows:
require_once 'Zend/Loader/Autoloader.php';
$loader = Zend_Loader_Autoloader::getInstance();
$loader->registerNamespace('Project_');
$loader->setFallbackAutoloader(true);
if ($configSection == 'development')
{
$loader->suppressNotFoundWarnings(false);
}
In order for you library to integrate nicely with ZF and the Autoloader you should stick to the ZF naming conventions. This means two things:
if you extend an existing ZF class, replicate the ZF folder structure so that your file has the same path and name except for the library name. E.g. /library/Zend/Db/Abstract.php => /library/Project/Db/Abstract.php.
if you write your own classes, still stick to the ZF naming conventions for the autoloader to find them.
I just came across something that may be germane to this question. This IBM developerWorks article.
The author recommends simply creating a scripts folder in the ZF hierarchy and the using it as one normally would within ZF (though he does set the ini path and call autoload). Is it that simple? Does simply being in the hierarchy of the framework and including the path and autoloader grant your script access to all of the goodies?
I'm not 100% sure what you're trying to ask but I will try to help. If at any point you add a reference to "/path/to/zend/framework" into your php include path then you have in essence enabled the Zend Framework. From there if you do:
require_once('Zend/Loader.php');
Zend_Loader::registerAutoload();
Then at any point in your script you can pretty much just create new Zend Framework objects and Zend_Loader will handle the rest.
One of the big things about the Zend Framework though is not forcing you to do things a certain way. That's why sometimes there are several ways to accomplish the same thing. So, if you feel you need to make your script use the Zend Framework just for the sake of doing so this is not really necessary. But if you think it may improve your script in some way then go for it.
I usually put custom stuff that I think could be used across projects in a custom folder in the library. So I have a library/Ak33m folder that has scripts that may be outside of the framework.
As a ZF noob myself, I think I understand some of what the OP is trying to figure out. So, I'll just explain a bit of what I understand in the hope that it is helpful either to the OP (or more likely, to a future reader, since the original question is so old and I imagine that OP is now a ZF guru).
I understand that ZF claims to be largely "use at will", so that you need no buy into an entire structure, like the Zend_Application, the Zend_Bootstrap class, the entire MVC approach, etc.
Further, I understand conventions for class naming and file locations that enable easy autoloading. Ex: class App_Model_User resides in a folder App/Model/User.php
I think what can be potentially confusing is that in the script context, where you have not yet
done the .htaccess magic that pushes all request to public/index.php
set your APPLICATION_PATH and include paths in public/index.php
created your Application or Bootstrap object tied to a config file
it can be a little bit unclear how best to avail yourself of most of the ZF goodness we get in that context and want in another context.
I guess my answer to the original question would be that the usual entry point sequence of
http request -> .htaccess -> index.php -> config
sets up much of our environment for us, we would need to duplicate some of that for different entry path.
So, for your script, my first instinct would be to create a common include file that mirrors much of what happens in index.php - set the include paths, the APPLICATION_PATH, instantiates and calls a bootstrap, and then does your script-specific processing.
Even better, it might be desirable to create a single entry point for all your scripts, like we do in the http/web context. Extend Zend_Application for your own script purposes so that $application->run(); no longer starts up the MVC router-controller-dispatch processing, but rather does your own stuff. In that way, this single script entry point would look almost identical to the web entry point, the only difference being which application object gets instantiated. Then pass the name of your desired Application class as a command line parameter to the script.
But here I confess to being less confident and just throwing out ideas.
Hope all this helps someone. It actually helped me to write it all down. Thanks and cheers!
Update 2009-09-29: Just ran across this article: Using Zend Framework from the Command Line
Update 2009-11-20: And another article: Cron jobs in Zend Framework | GS Design
Update 2010-02-25: Easy command line scripts with Zend Application - David Caunt

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