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Notes for Developers

Configuration

The config file is turned into a dictionary of dictionaries at startup, e.g.:

[loris.Loris]
cache_dp=/tmp/loris/cache
tmp_dp=/tmp/loris
...
[resolver.Resolver]
src_img_root=/usr/local/share/images

yields

config = {
	'loris.Loris': {
		'cache_dp' : '/tmp/loris/cache',
		'tmp_dp' : '/tmp/loris'
	},

	'resolver.Resolver' {
		'src_img_root' : '/usr/local/share/images'
	}
}

which is then available in the config attribute of the application. The sub-dictionaries are then used to configure other objects, by passing the values of individual entries or just the entire dict, depending on how complex the situation is. Generally, the naming conventions and principals behind how this is intended to work should be clear.

N.B.: When developing or extending, i.e., instantiating the application instance in debug mode (by calling webapp.create_app(debug=True)), some properties in etc/loris.conf are overridden in the create_app function. This is done so that we can calculate some locations based on the application directory. Therefore, if you need to add additional configuration, e.g. in your resolver or transformations, you may need to add/set them in two places if you want an option to be different when developing/running tests: in etc/loris.conf and in the first if block of webapp.create_app.

Running Tests

To run the tests, you need to install test dependencies:

$ pip install -r requirements_test.txt

Then, in the root of the repository, run:

$ coverage run -m py.test tests/*.py
$ coverage report

This will run the tests, and print coverage information for the loris directory. If you'd like to run a specific test, pass a filename to coverage run. For example:

$ coverage run -m py.test tests/parameters_t.py

Using the Development Server

loris/webapp.py is executable, and will start a development server at localhost:5004. From there you can work with the images that are included for testing by plugging any of these into the identifier slot:

  • 01%2F02%2F0001.jp2
  • 01%2F03%2F0001.jpg
  • 01%2F02%2Fgray.jp2
  • 01%2F04%2F0001.tif
  • 47102787.jp2 # use this one to make sure color profile mapping is working.

Image Transformations

Loris is designed to make it possible for you to implement image transformations using any libraries or utilities you choose. The transformers are loaded dynamically at startup, and are configured in etc/loris.conf. See transforms.py for details. Transformers for JPEG, TIFF, GIF, and JP2 (JP2 as long as you provide the Kakadu dependencies) using Pillow are provided.

More about this. Every _AbstractTransformer implementation must implement a transform() method that receives the path to the source file (src_fp), the path to where the output file should go (target_fp), and an instance of an img.ImageRequest object. This object should contain all of the attributes you could ever possbily need for working with an image library. See img.ImageRequest.__slots__ for details.

[transforms][[{fmt}]] is the naming convention for of these sections in etc/loris.conf. This MUST be followed, and {fmy} MUST be one of the extension strings listed in the IIIF Image API specification.

Every section requires an impl key, and any other options provided will be automatically be available to the impl in its config dictionary.

At least for now, all implementation must be in (or aliased in) the transforms module.

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