A hiring assignment I had been assigned with the following description:
The following test is to evaluate the skill set of a potential candidate. The test is to be programmed in PHP, MySQL and any front end tools/frameworks you prefer to solve the following task. You may reference any material you may require on the internet or books as this is not only intended to test your ability to program but also your ability to find help should you need it. You may assume any PHP extensions are available. You may also include a list of assumptions so that we know that you are using any other libraries that are available.
Please include a
.sqlfile to initialize the database. You may assume the following properties for the database: DB name: itdept_test DB user: itdept_test DB pass: rawitdept
Create a image gallery with the following requirements:
- file uploader
- pagination
- automatic thumbnail generation
- ability to delete multiple images
- display a large version of an image on thumbnail click
Running the assignment requires a mysql database with:
- DB name: itdept_test
- DB user: itdept_test
- DB pass: rawitdept
However, there is a Makefile rule for doing this as well. To initialize a database with the required settings use
make init_db_settings
After setting up the database, just use the following line to lift the assignment
make fresh_run
In the interview, it came up that the company uses Laravel 5 and uses both NoSQL (connectors for which must have been added separately to Laravel's shipped ORM) and MySQL databases, similar to SailsJS' Waterline ORM. Using an adapter-based ORM allows you to use a unified syntax for queries. To reflect an example solution to the workflow issue of having to switch between query syntaxes for NoSQL and MySQL, I was considering, on top of building the assignment on Laravel, shipping the instance of Laravel with a different adapter-based ORM for php. Laravel's Eloquent ORM seems to be adapter-based, but it currently only has support for SQL adapters. Re: quote from https://github.com/illuminate/database --
It currently supports MySQL, Postgres, SQL Server, and SQLite
The only one I could find -- for whatever reason that others don't exist, I don't know -- was UniMapper (https://github.com/unimapper/unimapper). But since the assignment did not necessitate using a NoSQL database, I stuck with Laravel's Eloquent ORM.
It came to the choice of how I would store the images that would be uploaded. From reading a Microsoft Research paper on BLOBs I considered that upon being uploaded an image I would serialize it with PHP5's native base64_encode and use chunk_split to split the encoding of the image into 256K chunks. Since I had no reason to believe the images would later have to be modified, I was not worried about reading/writing thoroughput to be affected as in the Microsoft paper. But before using chunk_split the serialization of the image could be compressed with gzcompress. Each of the 256K chunks would be stored in the database as the BLOB type, with each chunk numbered in order so they could reassemble the original image. When it came to retrieving an image from the database, I would query the database for all of the chunks pertaining to the image I wanted, concatenate all of the chunks together, use gzuncompress to get a raw serialization of the original image, use imagecreatefromstring to create an image resource from the serialization, then imagejpeg to spit that image onto a page, notwithstanding pagination. In spite of this elaborate process for avoiding clutter in the file system, however, images were stored as files to simplify logic and due to self-imposed time-constraints.
I ended up storing all uploaded images -- the files themselves, that is -- in public/uploads and storing information of the images including their original names, hashed names, extensions, sizes, and an autoincrementing id for use as a primary key.
The following question comes to mind: why is the repository so large for an assignment with such relatively simple requirements? Basically, I wanted to give myself the challenge of using a framework I had not previously heard of, get more experience with AngularJS and Angular Material, and show the company [who had assigned the assignment] that I could pick up their framework quickly. It would have been much simpler to complete the assignment with basic HTML, CSS, JS, and PHP (with a basic framework like CodeIgniter), but it would not have felt right to hand in a hodge-podge 'hacked' solution. Of course, it's still not perfect, has some flaws, and can be improved. The next section will list such improvements and flaws.
##Improvements ######TODO: complete section
##Tools The tools and their uses include:
- Laravel 5, as the general framework
- Landish/Pagination, for customizing Laravel's Pagination Presenter to uses Angular Material's features and components
- AngularJS, for a specialized front-end framework
- Angular Material, to extend AngularJS to include Google's Material Design principles
- jQuery (version 2.1.4), for simplified DOM-accessing syntax and extending JavaScript
- Dropzone.js, for an out-of-the-box drag’n’drop file uploader
##Resources To list a few resources I used during development of the assignment:
- An issue I submitted, while configuring Laravel Homestead
- Vagrant (when I considered adding a VM to the build automation for deployment)
- The Laravel documentation
- The AngularJS documentation
- The Angular Material documentation
- StackOverflow
- The Landish/Pagination repository