JSON – Should I Use JSON Just to Use JSON?

jsonPHP

I'm building a blogging site for learning, with a PHP/MySQl back-end. All of the user input is handled with forms sent in POST requests.

Will using JSON somehow make it cleaner, or easier to maintain or add features? Or am I just adding an interchange format for no reason?

So essentially, what functionality would be best implemented by using JSON?

Best Answer

JSON has a few advantages:

It's a structured format, which can be validated and parsed with existing, mature tools.
It can speak easily to JavaScript, which makes it very useful for AJAX communication.
It's extremely simple and lightweight. Anything you'd want to use XML data interchange for, JSON is generally a better alternative.

My rule of thumb is, if you only need to return a single semantic element from a call, send it as plain text. But if you need to return multiple pieces of information, use JSON.

Problem

Website receives a high volume of traffic and eventually crashes.

Requirements

Sustain high volume of web traffic
Display previous 150 messages
Secure communication pathway between clients

Problem Analysis

Right away it is obvious that your site is crashing because the code that opens the file is being called hundreds of thousands of times per second. Opening files and writing to them is very memory intensive.

The FILE Probem: Files do not handle concurrency very well at all. In fact, they're terrible with concurrency. Think about it like this, essentially you've opened the same file with notepad with hundreds of thousands of open windows/processes and you're changing the content in all of them simultaneously. When you try to solve a problem with this type of solution you end up with non-deterministic results. Basically, it is impossible to predict what data will be in the file.

Fortunately, there is a way to get deterministic results while still using files if you lock them properly. Unfortunately, this is not a solution to your problem. In your case, only one person would be able to send a message at a time. Surely that is NOT the solution you want!

Wait... there IS a solution:

You CAN USE a Database!

Databases are particularly good at solving this sort of concurrency issue! Depending on what database/engine you use your table may lock or only a single record might lock. In you case, I would suggest a free database like MySQL and a record-locking engine like InnoDB. If you're not a database rookie, you might want to look into MariaDB as well, it is a fork of the MySQL project by the original developer and is a binary drop in.

Basically, there is no way around it using a database for this type of solution. In fact, databases are very powerful and you can program procedures with them. From your query you can choose to select only 150 messages and then order them by most recent very easily. All users will be able to send messages at the same time with a record-locking database engine like InnoDB.

I would like to additionally point out that I would be a little troubled to find out what the code for the rest of the application looks like. It is very easy to write PHP code that looks fine but performs terribly. I'm not sure if you're familiar with asymptotic analysis or unit testing but I highly suggest that you thoroughly test your code before pushing it to production. Given the size of your userbase you should be concerned about code optimization and runtime. If your application/problem/solution was properly analyzed, designed, implemented, tested, and debugged you would have a much better handle on your problem.

It is also very easy to write code in PHP that is insecure. I would like to advise you to test your code thoroughly (try to break it) when writing modules that interact with the database. Poorly coded web applications can be very easy to exploit and given your user base of 300-400k I wouldn't doubt it if Cindy Lou Who suddenly decided to give it her own security audit. If a white hat hacker discovers the flaw in your system they will likely encourage you to fix it. If a black hat hacker discovers the flaw they will likely use it to spread malware and steal information.

MVC Framework – Content Management with Admin Panel in PHP

I solved this when I started using service providers with a dependency injection container to implement a module system.

Treating modules as service providers for the application is what worked best, whether they are providing new services or providing to data to existing services, like routes.

The admin panel has itself become a module that simply provides admin related routes and services to the container. Any other modules can do the same thing.

Default routes in the config look like this in JSON format:

{
    "/:controller/:action/:params": {
        "namespace": "Darya\\Core\\Controllers"
    },
    "/:controller/:params": {
        "namespace": "Darya\\Core\\Controllers"
    },
    "/:page?/:subpage?": "Darya\\Core\\Controllers\\IndexController"
}

Module routes can look like this when defined in a module class (a service provider):

// Route path to namespace prefixes:
// "/admin/info" would become "Darya\Module\Admin\Controllers\InfoController"
$router->add(array(
    '/admin/:controller/:action/:params'  => 'Darya\Module\Admin\Controllers',
    '/admin/:controller/:params'          => 'Darya\Module\Admin\Controllers',
    '/:controller/:action/:params'        => 'Darya\Module\Controllers'
    '/:controller/:params'                => 'Darya\Module\Controllers'
));

This way all the URLs of the application are nice and extensible. The next problem is deciding on route priorities, but that becomes off topic.

Dependency injection is your friend. :)