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Workspace Filter

One of the most important meta files of a vault checkout or a content package is the filter.xml which is present in the META-INF/vault directory. The filter.xml is used to load and initialize the WorkspaceFilter. The workspace filter defines what parts of the JCR repository are imported or exported during the respective operations through vlt or package management.

General Structure

The filter.xml consists of a set of filter elements, each with a root attribute and an optional list of include and exclude child elements.

Example:

<workspaceFilter version="1.0">
    <filter root="/apps/project1" />
    <filter root="/etc/project1">
        <exclude pattern=".*\.gif" />
        <include pattern="/etc/project1/static(/.*)?" />
    </filter>
    <filter root="/etc/map" mode="merge" />
</workspaceFilter>

filter elements

The filter elements are independent of each other and define include and exclude patters for subtrees. The root of a subtree is defined by the root attribute, which must be an absolute path.

The filter element can have an optional mode attribute which specified the import mode used when importing content. the following values are possible:

“replace”
This is the normal behavior. Existing content is replaced completely by the imported content, i.e. is overridden or deleted accordingly.
“merge”
Existing content is not modified, i.e. only new content is added and none is deleted or modified.
“update”
Existing content is updated, new content is added and none is deleted.

include and exclude elements

the include and exclude elements allow more fine grained filtering of the subtree during import and export. they have a mandatory pattern attribute which has the format of a regexp. the regexp is matched against the path of the respective or potential JCR node, thus can be relative or absolute.

order

the order of the include and exclude elements is important. the paths are tested in a sequential order against all patterns and the type of the last matching element determines if the path is included or not. One caveat is, that the type of the first pattern defines the default behavior, so that the filter is more natural to write. If the first pattern is include, then the default is exclude and vice versa.

The following example only includes the nodes in /tmp that end with .gif.

<filter root="/tmp">
    <include pattern=".*\.gif"/>
</filter>

The following example includes all nodes in /tmp except those that end with .gif.

<filter root="/tmp">
    <exclude pattern=".*\.gif"/>
</filter>

Usage for export

When exporting content into the filesystem or a content package, the workspace filter defines which nodes are serialized. It is important to know, that only the nodes that match the filter are actually traversed, which can lead to unexpected results.

for example:

<filter root="/tmp">
    <include pattern="/tmp/a(/.*)?"/>
    <include pattern="/tmp/b/c(/.*)?"/>
</filter>

Will include the /tmp/a subtree, but not the /tmp/b/c subtree, since /tmp/b does not match the filter and is therefor not traversed.

There is one exception, if all the pattern are relative (i.e. don’t start with a slash), then the algorithm is:

  1. start at the filter root
  2. traverse all child nodes recursively
  3. if the path of the child node matches the regexp, include it in the export