DAM Core module

Edition CE

License

MLA

Issues

DAM

Maven site

DAM

Latest

4.0.1

The DAM Core module is a Magnolia Maven module.

  • It has a module class (info.magnolia.dam.core.config.DamCoreConfiguration) that implements info.magnolia.module.ModuleLifecycle.

  • It contains (and registers) info.magnolia.dam.core.download.DamDownloadServlet and provides an implementation of info.magnolia.dam.api.AssetProviderRegistry.

  • The module is configured in /modules/dam/config.

Installing with Maven

Maven is the easiest way to install the module. Add the following to your bundle:

<dependency>
  <groupId>info.magnolia.dam</groupId>
  <artifactId>magnolia-dam-core</artifactId>
  <version>4.0.1</version> (1)
</dependency>
1 Should you need to specify the module version, do it using <version>.

Asset providers and renderers

In order to have a working DAM, you must have configured at least:

  • info.magnolia.dam.api.AssetProvider

  • info.magnolia.dam.api.AssetRenderer

Configuring an asset provider

To enable DAM, at least one asset provider must be configured as a subnode of /modules/dam/config/providers/.

Configuring an asset provider

Property Description

class

required

A class that must implement info.magnolia.dam.api.AssetProvider.

identifier

required

The identifier of the asset provider. Must be unique within all asset providers.

enabled

optional, default is true

Allows you to disable the provider if, for instance, it does not have the necessary credentials to access the assets.

Setting the property to false hides the related DAM subapp in the UI and prevents it from starting.

Configuring an asset renderer

info.magnolia.dam.api.AssetRenderer objects can be configured:

  • Globally

  • Per AssetProvider

When an asset rendition is requested, AssetProviderRegistry#getRendererFor(Asset asset, MediaType to) is first looking for a provider-specific renderer but will fallback to the globally defined renderer if no specific provider is found.

Configuring an asset renderer

The example configuration above has two renderers defined:

  • /modules/dam/config/providers/example-provider/renderers/imaging - configures a renderer for images specifically for the example-provider.

  • /modules/dam/config/renderers/noOp - a global fallback if a provider lacks a renderer for the requested media type.

NoOpAssetRenderer

The magnolia-dam-core module provides info.magnolia.dam.core.NoOpAssetRenderer, which can be used to define a global asset renderer. By default, the NoOpAssetRenderer only wraps the original asset.

magnolia-dam-core is not taking care about the asset provider implementation used.

Specific asset provider and renderer should rather be configured from a module which contains a specific implementation but not from the magnolia-dam-core itself.

Download servlet

info.magnolia.dam.core.download.DamDownloadServlet handles asset downloads. The main task is to retrieve an Asset Object based on the current URI:

  • If no Asset is found, an error is sent to the response.

  • If an Asset is found, the response header is set and the asset binary is put in the response.

The servlet is backwards compatible and maps static UUIDs to the new DAM format.

DamDownloadServlet is registered in the filter chain at /server/filters/servlets/DamDownloadServlet.

Download servlet configuration

Content disposition

Content-disposition is a HTTP header. If the Content-disposition field is set in a HTTP response header, the browser opens the save file as dialog instead of rendering the requested resource.

By default, the DamDownloadServlet serves assets whose Content-Disposition header is set. However, it is possible to define exceptions to omit the content disposition header.

Disabling content disposition headers per media (MIME) type

The standard DAM configuration already defines two exceptions based on media types:

  • application/x-shockwave-flash

  • video/mp4

To disable the Content-Disposition header for other content types, add their media types to /dam/config/contentDisposition/contentType/rejected.

Disabling the Content-Disposition header for other content types

Nodes and properties:

  • contentDisposition: Defines content disposition header exceptions.

    • contentType: Arbitrary node name

      • rejected: Content map of MIME types for which content disposition headers are not served.

      • class: info.magnolia.voting.voters.ResponseContentTypeVoter is a Voters that checks the content type set on the response object against a list of allowed and/or rejected content types. It is typed to Object, as it can vote on both a passed HttpServletRequest, or the current MgnlContext.webContext, if any.

    • class: info.magnolia.voting.voters.VoterSet supports a set of voters. Voting can be set, and a level returned. If the level is not set (0), the voting result is returned.

Disabling content disposition headers based on path

To disable serving Content-Disposition headers based on path:

  1. Create a new node inline under contentDisposition.

  2. Under the new content node, create three property nodes:

    • class and set the value to info.magnolia.voting.voters.URIStartsWithVoter.

    • not and set the value to true.

    • pattern and set the value to /dam/inline.

  3. Under the contentDisposition node, add the op property and set its value to and. This acts as an operator between voters and is only necessary if there are more than one voter in the set.

This will configure all files in the inline folder to be sent without content disposition headers. The new content node should look like this:

New content node

Related topics

Magnolia DAM JCR implementation

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