SVN::Web::X(3)

NAME
SVN::Web::X - exceptions for SVN::Web

SYNOPSIS
  use SVN::Web::X;

  ...

  SVN::Web::X->throw(error => '(error message %1)',
                     vars => [$var_to_interpolate]);

DESCRIPTION
SVN::Web::X implements exceptions for SVN::Web. Derived from Exception::Class, It provides a simple mechanism for throwing exceptions, catching them, and ensuring that friendly, localised error messages are generated and sent to the user's browser.

USAGE IN SVN::Web ACTIONS
If an SVN::Web action that you are writing needs to stop processing and raise an error, throw an SVN::Web::X exception.

"throw()" takes a hash with two mandatory keys.

"error"
    A string describing the error. This string should be short, and key to a longer internationalised message.

    This string may contain placeholders; %1, %2, %3, and so on. These will be replaced by the values of the variables passed in the "vars" key.

    By convention this string should be enclosed in parentheses, "(" and ")". This helps make them stand out in the interface, if localised versions of the error message have not yet been written.

"vars"
    An array reference. The first entry in the array will replace the %1 placeholder in "error", the second entry will replace the %2 placeholder, and so on.

    If there are no placeholders then pass a reference to an empty array.

EXAMPLES

  A simple exception, with no placeholders.
In the action:

  sub run {
      ...
      if(! frob_repo()) {
          SVN::Web::X->throw(error => '(frob failed)',
                             vars  => []);
      }
      ...
  }

In the en.po file for the localised text.

  msgid "(frob failed)"
  msgstr "There was a problem trying to frob the repository.  This "
  "probably indicates a permissions problem."

  An exception with placeholders
In the action:

  sub run {
      ...
      # $path is a repo path, $rev is a repo revision
      my $root = $fs->revision_root($rev);
      my $kind = $root->check_path($path);

      if($kind == $SVN::Node::none) {
          SVN::Web::X->throw(error => '(path %1 does not exist in rev %2)',
                             vars  => [$path, $rev]);
      }
  }

In the en.po file for the localised text.

  msgid "(path %1 does not exist in rev %2)"
  msgstr "The path <tt>%1</tt> could not be found in the repository "
  "at revision %2.  This may be a typo in the path or the revision "
  "number.  SVN::Web should never normally generate a link like this. "
  "If you followed a link from SVN::Web (rather than from an e-mail,
  "or similar) please report this as a bug."

As you can see, the localised text can be much friendlier and more informative to the user than the error message.