ImageMagick as a microservice.
- Install
imagemagick. On Ubuntu, this can be done withsudo apt-get install imagemagick. If you want extra image delegates (for example JPEG2000) you may have to compile from source. - Clone this repository somewhere in your web root.
- Install
composer. Install instructions here. $ cd /path/to/Houdiniand run$ composer install- Then either
- For production, configure your web server appropriately (e.g. add a VirtualHost for Houdini in Apache) OR
- For development, run the PHP built-in web server
$ php -S localhost:8888 -t srcfrom Houdini root.
If your imagemagick installation is not on your path, then you can configure Houdini to use a specific executable by editing executable entry in config.yaml.
You also will need to set the fedora base url entry to point to your Fedora installation.
In order to work on larger images, be sure post_max_size is sufficiently large and max_execution_time is set to 0 in your PHP installation's ini file. You can determine which ini file is getting used by running the command $ php --ini.
The location specified in the Houdini configuration file for the log must be writable by the web server.
Houdini sets up two endpoints:
- /identify/
- /convert/
Houdini is meant for use with API-X, and accepts GET and OPTIONS requests to those endpoints. The OPTIONS requests are for use with the API-X service loading mechanism, and return RDF describing the
service for API-X. The GET requests are used to execute the services, and must contain the URI to an image in Fedora in the ApixLdpResource header.
This runs the imagemagick identify command on the specified resource and returns the results as JSON with the MIME type application/json.
For example, suppose if you have a TIFF in Fedora at http://localhost:8080/fcrepo/rest/foo/bar. If running the PHP built-in server command described in the Installation section:
$ curl -H "Authorization: Bearer blabhlahblah" -H "Apix-Ldp-Resource: http://localhost:8080/fcrepo/rest/foo/bar" "localhost:8888/identify"
But you're probably going to use Houdini through API-X, which exposes this service as svc:identify. Assuming your API-X proxy is on port 8081, you can access the service with
$ curl -H "Authorization: Bearer blabhlahblah" "http://localhost:8081/services/foo/bar/svc:identify"
This runs the imagemagick convert command on the specified resource. The output format is decided by the Accept header sent along with the request. A default output format can also be selected in the configuration.
For example, suppose if you have an image in Fedora at http://localhost:8080/fcrepo/rest/foo/bar. If running the PHP built-in server command described in the Installation section:
$ curl -H "Authorization: Bearer blabhlahblah" -H "Apix-Ldp-Resource: http://localhost:8080/fcrepo/rest/foo/bar" -H "Accept: image/png" "localhost:8888/convert/foo/bar"
This will return the TIFF converted into a PNG file.
Additional arguments can be specified using the X-Islandora-Args header. For example to resize to 10% the size use:
$ curl -H "Authorization: Bearer blabhlahblah" -H "Apix-Ldp-Resource: http://localhost:8080/fcrepo/rest/foo/bar" -H "X-Islandora-Args: -resize 10%" "localhost:8888/convert/foo/bar"
But you're probably going to use Houdini through API-X, which exposes this service as svc:convert. Assuming your API-X proxy is on port 8081, you can access the service with
$ curl -H "Authorization: Bearer blabhlahblah" "http://localhost:8081/services/foo/bar/svc:convert"
Current maintainers:
If you would like to contribute, please get involved by attending our weekly Tech Call. We love to hear from you!
If you would like to contribute code to the project, you need to be covered by an Islandora Foundation Contributor License Agreement or Corporate Contributor License Agreement. Please see the Contributors pages on Islandora.ca for more information.
We recommend using the islandora-playbook to get started.