acdh-oeaw/aksearch-ext

A sample extension module for VuFind/AkSearch

2.4.6 2023-01-11 11:46 UTC

README

Extensions of the VuFind/AkSearch for the ACDH deployment of AkSearch.

Can also serve as an example of extending VuFind with your own module being loaded using Composer (see intstructions below).

What is being added by this module

  • Tuned version of the SolrMarc class (aksearchExt\SolrMarc)
  • Tuned version of the ILS driver class (aksearchExt\Alma)
  • Additional record view tab (aksearchExt\RecordTab\Exemplarspezifika)
  • Tuned version of the VuFindSearch\Backend\Solr\LuceneSyntaxHelper class resolving the search with slash issue.
    • As it can't be easily overriden with a new code, it is copied to {FuVindDir}/module/VuFindSearch/src/VuFindSearch/Backend/Solr/LuceneSyntaxHelper.php by the Dockerfile creating the deployment docker image (which is admitedly very ugly but avoids overriding of the whole VuFind/AkSearch Solr search backend classes stack).

The detailed description of particular features is included in the docs folder.

How does it work?

Remark - description below applies to the current AkSearch which is based on VuFind 6. Some stuff will change with Vufind >= 7 which migrated from Zend2 to Laminas.

Making the code loadable by Zend2

VuFind/AkSearch are written using Zend2 framework and extending/adjusting them goes down to implementation of you own Zend2 module(s).

To get your code recognized and properly loaded by a Zend2 you must:

  • Choose your module name (here it's aksearchExt).
  • Implement a {my module name}\Module class implementing getAutoloaderConfig() and getConfig() methods.
    • The getAutoloaderConfig() should just return an empty array (as composer will deal with autoloading for us and we don't need Zend2 for that).
    • The getConfig() class should return a Zend2/VuFind module configuration (an empty one is perfectly valid for starters).
    • The minimal implementation of the aksearchExt module (making it Zend2-loadable but nothing more than that) would look as follows:
      class aksearchExt\Module {
          public function getAutoloaderConfig() {
              return [];
          }
          public function getConfig() {
              return [];
          }
      }
  • Create a composer.json for your module so you can publish it as a composer package. Don't forget to define autoloading properly. If you need an example, just look at the composer.json in this repo root (it publishes this module as a acdh-oeaw/aksearch-ext composer package).
  • Publish your code as a composer package (put it into a publicly reachable git repo and then publish on https://packagist.org/).

Setting up VuFind/AkSearch to actually load your code

This is done by adjusting the AkSearchWeb repository content.

  • If you didn't to it so far, clone the repository.
  • Add your composer package to the list of composer dependencies either by running composer require your-organization/your-composer-package-name in the repository's root directory or adding your package name to the require section of the composer.json manually.
  • Include your Zend2 module name in the list of modules being loaded by the VuFind/AkSearch.
    • Append your module's name (namespace) at the end of the VUFIND_LOCAL_MODULES environment variable defined in the last line of the Dockerfile in the repository root directory.
    • Append your module's name (namespace) at the end of the VUFIND_LOCAL_MODULES environment variable in the docker-compose.yaml in the repository root directory (so people deploying with just docker-compose up have it as well).
  • Try to build the image locally by running docker build -t acdhch/aksearch-web . in the repository root directory and then try to deploy with docker-composer up. Finally check if everything stil works by opening http://127.0.0.1/vufind in your browser.
  • If everything's fine, commit changes and push the repository to the GitHub.

Congratulations! Now your module is deployed along with the AkSearchWeb and will be used (or not) depending on the VUFIND_LOCAL_MODULES runtime environment variable value (precisely if its name is included in the env var value).

Overriding actual VuFind/AkSearch code

The most tricky part is to find out the right place to plug in your own adjustment.

The good thing is it's all done by adjusting what your module's Module::getConfig() method returns (denoted below as $cfg).

The difficult part is you can plug your code in hundreds of places. See e.g. all class mappings provided in VuFind's main module config or overrides defined by AkSearch's AkSearch module config. Be aware that despite providing a class alias you may also need to define factories and/or delegators for your class - see just mentioned examples and the src/aksearchExt/Module.php file in this repository.

Live development

To be able to live test your module:

  • Include it into the AkSearchWeb deployment as described in the How does it work? section above.
  • Run the aksearch-web container with:
    • Your module's code mounted under /usr/local/vufind/vendor/{your-organization}/{your-composer-package-name}.
    • APPLICATION_ENV set to development (which would turn off Zend2 classmap caching and save you a lot of headache).