In order for the Europeana Collections portal to access and display media resources coming from providers’ servers, the latter must support Cross-Origin Resource Sharing (CORS). This is because web browsers restrict resources on a web page to be requested from another domain outside the domain it was served (Collections in this case). The CORS standard is needed because it allows servers to specify not only who can access its resources but also how these resources can be accessed.
This is especially important for providers who share resources via IIIF as CORS is essential for our IIIF viewer to perform the image information requests and to obtain the presentation manifests. Without CORS, although the IIIF resources will be displayed in the provider’s website, it won’t be possible to be viewed in the Europeana Collections portal.
More information about CORS and how to implement it can be found here.
Providers of IIIF resources are encouraged to deliver their resources over HTTPS so that they can be included in our web page without issue.
Embedding of media resources
In order for an item to be embedded in the Europeana Collections portal, there must be a valid oEmbed endpoint (see example from SketchFab) available where the media referred to in the item is displayed using a third party viewer or player. An exception is made for some data partners that do not support oEmbed.
On the metadata side, a link to a webpage where the item can be displayed and which can be mappable to an oEmbed URL is provided within edm:isShownBy. In order to do this and because there is no information in the metadata that relates the webpage link to the oEmbed endpoint, the Europeana Collections portal has to apply an additional logic to convert the URL provided in edm:isShownBy into an oEmbed URL that can be used for embedding. For this, it uses an internal registry of oEmbed endpoints which consists of both a public list and manual additions made by the Collections development team (which also includes the Europeana oEmbed implementations to cover the exceptions). This means that whenever a new dataset is added that uses a different oEmbed endpoint it will need to be added to this registry.