====== Islandora/Fedora requirements ======


  * Islandora openseadragon starting from "Commits on Jul 26, 2017"

  * Openseadragon 2.2.1

  * Apache reverse proxy on front-end (Islandora)

<WRAP prewrap center>
<code>
a2enmod headers
service apache2 restart

nano -w /etc/apache2/sites-enabled/archive.digibess.eu.conf


        AllowEncodedSlashes On
        ProxyRequests Off
        ProxyPreserveHost On
        <Proxy *>
                Order deny,allow
                Allow from all
        </Proxy>

+        RequestHeader set X-Forwarded-Path /iiif-server
+        ProxyPass /iiif-server http://123.123.123.123:8182 nocanon
+        ProxyPassReverse /iiif-server http://123.123.123.123:8182
</code>
</WRAP>
  * Islandora viewers Openseadragon settings (admin/islandora/islandora_viewers/openseadragon)
<WRAP prewrap center>
<code>
Image Server = IIIF Image server

IIIF Image Server Base URL = http://archive.digibess.eu/iiif-server/iiif/2
</code>
</WRAP>

  * Fedora policy update [not sure we need this]

If yuo plan to redirect Tile source URL from front-end to directly back-end, you need to add Image Server IP to /usr/local/fedora/data/fedora-xacml-policies/repository-policies/default/deny-apim-if-not-localhost.xml

  * Redirect Openseadragon tile source to fedora

By default tile source point to front-end server to download JP2. In some case pointing directly to fedora may result in better performance.
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To modify how this works you can add to your theme template.php this function to override tile source URL for islandora openseadragon (Many thanks Nigel!!):
<WRAP prewrap center>
<code php>
function beginning_preprocess_islandora_openseadragon_viewer(array &$variables) {
  module_load_include('inc', 'islandora_openseadragon', 'includes/utilities');
  $pid =  $variables['settings']['pid'];
  $matches = array();
  preg_match('/datastream%2[fF](.*)%2[fF]view/', $variables['settings']['options']['tileSources'][0], $matches);
  $dsid = isset($matches[1]) ? $matches[1] : NULL;
  $identifier = "http://FEDORA_IP_or_FQDN:8080/fedora/objects/".$pid."/datastreams/".$dsid."/content";
  $variables['settings']['options']['tileSources'] = islandora_openseadragon_identifier_tile_source($identifier);
}
</code>
</WRAP>
This function replaces tile source URL and remove token, so IIIF server download directly from fedora avoiding network loop with front-end.
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**NOTE: UPGRADE to CANTALOUPE 3.4**
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  * remove function to override tile source URL for islandora openseadragon from your theme template.php
  * openseadragon >= 2.3.1 (wget https://github.com/openseadragon/openseadragon/releases/download/v2.3.1/openseadragon-bin-2.3.1.tar.gz)
  * drupal module token (drush -v -u 1 dl token / drush -v -u 1 en token)
  * islandora_openseadragon HEAD or from commit cfb005b Nov 20, 2017
  * configure islandora openseadragon new options (i.e. Add token as header:NO ; IIIF Identifier: http://repo.digibess.eu/fedora/objects/[islandora_openseadragon:pid]/datastreams/[islandora_openseadragon:dsid]/content)