Re: [Babeldoc-devel] Enable file-based inclusion of Velocity templates?

[David K. <dav...@al...>]

Ok, I have reworked the patch slightly, as follows.

Purpose: Allow Velocity templates to be loaded from
the filesystem in addition to the classpath.

Changes (to VariableProcessor only):
- Add the FileResourceLoader to be used before the
  default ClasspathResourceLoader
- Load templates from the filesystem using the set
  of search paths provided by the EnvironmentLoader
 (Path for Velocity constructed as CSV, using the
  imported StringUtils.join method)
- Enable caching of loaded templates with a check
  for modifications every two seconds

Consequences:
- Templates for use within Babeldoc can now be placed
  and managed in the filesystem external to any jar-files
- Templates in the filesystem override templates in
  Babeldoc .jar-files having the same name
- It is now very easy to use large, complex templates
  in pipeline stages, since all that's needed is:

<stage-name>.<whatever>=#parse("path/to/template.vm")

  where the template.vm is evaluated in context of the
  pipeline stage and it's document just as an inline
  template directly specified in the property would be

  Note: it is also possible to do this:

<stage-name>.<whatever>=#include("path/to/something")

  which includes something verbatim but does NOT cause
  Velocity to actually evaluate it as a template, at
  least according to the Velocity docs

- The #parse and #include statements should also be
  possible to use inline (#parse recursively) inside
  template bodies in general, but I have not tested
  this yet (should work, though, since the default
  parse-depth of Velocity is set to 10)

- It is now possible to edit a template file and have
  the new version of it used without restarting Babeldoc,
  due to the reloading mechanism of Velocity

I have tested these changes in my setup with no ill
effects that I have been able to see, in pipelines
that use template files and pipelines that do not,
but please test it further, since it's a change in
the very core of Babeldoc, which makes me nervous.

Patch attached, for your consideration.

Regards,

David Kinnvall