CodeIgniter.php

Constructor.

Handles some basic app and environment setup.

Checks system for missing required PHP extensions.

Initializes Kint

Launch the application! This is "the loop" if you will. The main entry point into the script that gets the required class instances, fires off the filters, tries to route the response, loads the controller and generally makes all the pieces work together.

Run required before filters.

Run required after filters.

Invoked via php-cli command?

Web access?

Disables Controller Filters.

Handles the main request logic and fires the controller.

You can load different configurations depending on your current environment. Setting the environment also influences things like logging and error reporting. This can be set to anything, but default usage is: development testing production

Load any custom boot files based upon the current environment. If no boot file exists, we shouldn't continue because something is wrong. At the very least, they should have error reporting setup.

Start the Benchmark The timer is used to display total script execution both in the debug toolbar, and potentially on the displayed page.

Sets a Request object to be used for this request. Used when running certain tests.

Get our Request object, (either IncomingRequest or CLIRequest).

Get our Response object, and set some default values, including the HTTP protocol version and a default successful response.

Force Secure Site Access? If the config value 'forceGlobalSecureRequests' is true, will enforce that all requests to this site are made through HTTPS. Will redirect the user to the current page with HTTPS, as well as set the HTTP Strict Transport Security header for those browsers that support it. should be enforced for this URL.

Determines if a response has been cached for the given URI.

Tells the app that the final output should be cached.

Caches the full response from the current request. Used for full-page caching for very high performance.

Returns an array with our basic performance stats collected.

Generates the cache name to use for our full-page caching.

Replaces the elapsed_time and memory_usage tag.

Try to Route It - As it sounds like, works with the router to match a route against the current URI. If the route is a "redirect route", will also handle the redirect. of the config file.

Determines the path to use for us to try to route to, based on the CLI/IncomingRequest path.

Now that everything has been setup, this method attempts to run the controller method and make the script go. If it's not able to, will show the appropriate Page Not Found error.

Instantiates the controller class.

Runs the controller, allowing for _remap methods to function. CI4 supports three types of requests: 1. Web: URI segments become parameters, sent to Controllers via Routes, output controlled by Headers to browser 2. PHP CLI: accessed by CLI via php public/index.php, arguments become URI segments, sent to Controllers via Routes, output varies

Displays a 404 Page Not Found error. If set, will try to call the 404Override controller/method that was set in routing config.

Gathers the script output from the buffer, replaces some execution time tag in the output and displays the debug toolbar, if required.

If we have a session object to use, store the current URI as the previous URI. This is called just prior to sending the response to the client, and will make it available next request. This helps provider safer, more reliable previous_url() detection.

Modifies the Request Object to use a different method if a POST variable called _method is found.

Sends the output of this request back to the client. This is what they've been waiting for!

Exits the application, setting the exit code for CLI-based applications that might be watching. Made into a separate method so that it can be mocked during testing without actually stopping script execution.

Sets the app context.