Imager

Have you ever wanted to smooth away the hassle of managing uploaded images in your Laravel 4 projects? Do you want to simplify the process of modifying and caching originally uploaded images? Look no further! Imager is a package designed to ease management of image storage, order and manipulation.

Features at a glance:

• Attach images to any eloquent model via an interface and an optionally supplied trait
• Configurable and customizable storage drivers
• Generate URIs for images based on which storage driver is in use
• Image processing chains & caching, done on retrieval not on storage
• A powerful and agnostic gallery batch processor

Setup

To get Imager ready for use in your project, take the usual steps for setting up a Laravel 4 pacakge.

• Add tippingcanoe/imager to your composer.json file.
• Run composer update at the root of your project.
• Edit your app/config/app.php file and add:
  • 'TippingCanoe\Imager\ServiceProvider', into the providers array
  • 'Imager' => 'TippingCanoe\Imager\Facade', into the aliases array
• Run the migration ./artisan migrate --package="tippingcanoe/imager"
• Take a project-level copy of the configuration ./artisan config:publish tippingcanoe/imager

Note: If you are using type-hinted dependency injection in your project, as a convenience Imager also binds the type `TippingCanoe\Imager\Service` in the container.

Configuring

Storage

If you open the copy of config.php that was created by the last step during setup, you will see it is already populated with configuration options for the most typical of setups. The TippingCanoe\Imager\Storage\Filesystem driver is the most basic which simply stores image files in your site's public directory.

Amazon S3 Driver

Replace the filesystem driver configuration in the 'config.php' file with the Amazon AWS configuration below.

[
	'storage' =>
	[
		'TippingCanoe\Imager\Storage\S3' =>
		[
			'aws_key' => 'YOUR_KEY_HERE',
			'aws_secret' => 'YOUR_SECRET_HERE',
            'aws_bucket' => 'imager-bucket'
		]
	]
]

Filters

Imager's filtering chains are a powerful feature that allow you to orchestrate arbitrary combinations of manipulations when retrieving images. When processing a chain, Imager does the following for each filter in the chain:

• Attempts to instantiate the indicated class which must implement TippingCanoe\Imager\Processing\Filter
• If the filter's configuration was an array, each key in the second index will be called as setter methods on the subclass
• Calls the method process on the subclass passing in the original image and the database entry for the image

You will most likely want to pre-configure filter chains for your project so that you don't have to repeat them over the course of retrieving variations. Imager uses a simple array schema to define filtering chains. Here's a sample of one:

[

	'TippingCanoe\Imager\Processing\FixRotation',
	
	[
		'TippingCanoe\Imager\Processing\Resize',
		[
			'width' => 300,
			'height' => 300,
			'preserve_ratio' => true
		]
	],
	
	[
		'TippingCanoe\Imager\Processing\Watermark',
		[
			'source_path' => sprintf('%s/logo.png', __DIR__),
			'anchor' => 'bottom-right'
		]
	]

]

• The array must not be keyed.
• An entry that is a string will be instantiated and run without parameters.
• An entry that is a sub-array will have the first index [0] of that array instantiated with the second index [1] converted to setters on the instance:
  • setWidth(300)
  • setHeight(300)
  • setPreserveRatio(true)
  • etc...

If you're unsure as to where you should store your filter profiles, it's suggested that you place them in the filters.php file that has also been created for you when you published Imager's configuration earlier. This will allow you to vary the filter configurations along with your environments and will make retrieval as simple as Config::get('imager::filters.filter_name')

Usage

Depending on the nature of your implementation, the means by which you will receive image files will vary. Imager makes no assumptions about your request lifecycle (or that there's even a request at all!) and only concerns itself with recieving instances of Symfony\Component\HttpFoundation\File\File.

The two optional, secondary pieces of information that Imager makes use of are Imageable to scope to a specific model and filter chains during retrieval.

Trait

If you plan on attaching images to a model (User, Item, Gallery), that model must implement the interface TippingCanoe\Imager\Model\Imageable. This will mandate a method that you can either implement yourself or conveniently keep in sync with Imager by using the trait TippingCanoe\Imager\Model\ImageableImpl.

Saving

Saving images is done via the Imager service which can either be accessed via the facade or through dependency injection.

	/** @var \Symfony\Component\HttpFoundation\File\File $file */
	/** @var \TippingCanoe\Imager\Model\Imageable $imageable */

	$attributes = [
		'slot' => 1
	];

	/** @var \TippingCanoe\Imager\Model\Image $image */
	$image = Imager::saveFromFile($file, $imageable, $attributes);

Imager will return an instance of TippingCanoe\Imager\Model\Image upon a successful save. If you supplied one, the image record will be associated with an imageable. Any additional attributes will be passed through to the save as well.

Retrieval

When retrieving an individual image, you will need a way to identify it:

• The image's id
• The image's imageable and a slot
• An imageable's images() relation

Most of the time you will have at least one of these three pieces of information which will then allow you to obtain a URI to the physical file of the image.

	Imager::getPublicUri($image, $filters);
	Imager::getPublicUriBySlot($slot, $imageable, $filters);
	Imager::getPublicUriById($id, $filters);

When retrieving images from imager, it's helpful to remember that anywhere you see "imageable" is optional and omitting it or providing null means "global". Similarly, "filters" is also optional and omitting this value, providing null or an empty array will mean "the original image".

Slots

Imager features a concept known as slots which at it's very core is just a string value. Slots are used to order and/or key images by their imageable. There are helper scopes on the TippingCanoe\Imager\Model\Image class to help with retrieving images based on their slot values.

Note: When storing images without an imageable (globally), keep in mind that they are all sharing the same slot scope and cannot have duplicates.

A sample use case for slots would be an "Item" class that can have an image gallery as well as a "primary" image. Images belonging to the gallery would have slots that are numeric so that they can be kept in a specific order while the primary image is in a named slot that can be queried directly.

Batches

It's common for implementations to require a way to submit multiple changes to an imageable's images in a single pass. These changes can sometimes present conflicts and be challenging to resolve.

As a convenience, Imager supplies a batch method off the service that allows these bulk operations to be performed. The operations are scoped by imageable and performed slot-by-slot in a safe order.

The structure of the schema is caller agnostic and in the unavoidable case of a conflict will null-out the slot of any images being displaced.

Here's a sample of the schema used when performing batch operations:

	$operations = [
		1 => 2,
		3 => 'thumbnail',
		4 => null,
		5 => 'http://placehold.it/200x200&text=Imager'
	];

	/** @var \Symfony\Component\HttpFoundation\File\File[] $newFiles */
	/** @var \TippingCanoe\Imager\Model\Imageable $imageable */

	Imager::batch($operations, $newFiles, $imageable);

In this example, the following actions would be taken - in order:

• The images in slot 1 and 2 are swapped
• The image in slot 3 is moved to the 'thumbnail' slot
• The image in slot 4 will be deleted
• The image found at the URI will be downloaded and inserted into slot 5

The file array $newFiles will be keyed by slot and could in theory contain new a new image for slot 4.

When an image is told to move to a new slot, if there is one aready in the target slot, they are swapped. If an uploaded image attempts to go into an already-occupied slot, the image currently in the slot will have it's slot nulled out.

It's important to note that slot keys cannot be duplicated in this schema, so it's in your best interest to submit the simplest batch list possible.

Drivers

More drivers will be added over time and we are always interested in hearing suggestions for new ones or receiving pull requests with your own ideas. Creating a driver is as simple as implementing the interface TippingCanoe\Imager\Storage\Driver which is fully documented. You can also use TippingCanoe\Imager\Storage\Filesystem as a reference.

Filters

It's very easy to create your own filters within your own project or packages. You're also more than welcome to use whatever image processing libraries and/or algorithms you wish.

The only rule is that filter subclasses must perform their manipulations to the file provided without moving, renaming or deleting it - overwriting is fine. The process method is not expected to return a value.

Meta

If you encounter any issues, find a bug or have any questions, feel free to open a ticket in the issue tracker.

Credits

Imager is created and maintained by Alexander Trauzzi at Tipping Canoe.