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Laravel Report: Dynamic Page Size

March 06, 2021

I work on the reporting service of a large SaaS application where we offer analytics-as-a-service. One of the biggest challenge in this type of application is that reporting is extremely customizable. With this post I’m interested in starting a new series of Laravel Report where I will introduce a few key aspects of how I achieve repetitive functionality across several reporting APIs by standarizing important features. The simplest feature I could think of to kickstart this series is user-controlled page size.

Reporting Context

When working with reporting-as-a-service, I noticed that there are usually 2 types of report and 1 derivative:

  • Aggregate
  • Stack
  • Detail (Derivative)

An aggregate report is one that compute COUNT, SUM, AVG, etc on a dataset. Examples could be total number of sales in the last 15 days for brand MyBrand. Total revenue in transactions on the last 24 hours on a specific country. Average time to close support tickets for the last quarter for Level 1 Support employees.

More often than not, when users navegate these aggregate numbers they end up interested in double-checking the underlying data that makes up such a number. These are referenced in this post as a derivative report. The dataset is exactly the same as the primary report with a slight difference that instead of doing a COUNT, SUM or AVG, we will instead do a paginate on the entire dataset and let the user navigate through it.

Dynamic Page Size

After building several dozens of derivative reports that requires dynamic page size, I came up with a system that I’m very happy with that allows the API caller to have some control over the aspect of the reporting capabilities without losing the ability to prevent shady users from abusing said control.

Let’s start by defining a Service Provider where we’ll standarize how we receive the information about the page size.

    public function register()
    {
        $this->app->bind(Page::class, function () {
            $request = $this->app->make(Request::class);

            return new Page((int) $request->input('per_page', Page::DEFAULT));
        });
    } 

Now let’s define the Page input.

<?php declare(strict_types=1);

namespace App\Components\Report\Input\Page;

final class Page
{
    public const DEFAULT = 25;

    public const LIMIT = 1000;

    public function __construct(private int $size) {}

    public function size(): int
    {
        return min($this->size, self::LIMIT);
    }
}

With just these two classes I’m now able to inject a new object into any Repository class in my application that will instruct my Query Builder how many records the pagination should use.

    public function __construct(private Account $account, private Page $page) {}
    
    public function accounts(): Collection
    {
        return $this->account->newQuery()
            ->paginate($this->page->size());
    }

Conclusion

This process has 2 main advantages for me. The first is the standard parameter that becomes the project-wide format to define page size. This will allow several dozen of reports to be consistent in a per_page input responsible for defining how many records to retrieve at a time. The 2nd advantage is that the Repository is still isolated from the Http context since the Page object act as a Data Transfer Object. I know this probably looks more complex than it needs for a small accomplishment, but as I extend on this series for more reporting functionality it will become clearer that having this standard can help a vast set of reporting APIs to share common capabilities.

As always, hit me up on Twitter with any questions.

Cheers.


Marco Aurélio Deleu

Marco Aurélio Deleu
Writing bad code for 10 years. Passionate about Laravel and AWS.

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