File transfer source and target are specified using Fragment elements.
Fragments are children of the ProtocolFragment element and have child elements that specify the parameters such as the authentication method, connection type and proxy.
Fragments are protocol specific - that is, there is a fragment element defined in the XSD schema for each file transfer protocol. This enables the properties of each protocol to be reflected in the schema and allows dependencies and incompatibilities to be defined. A trivial example is that a PassiveMode element can be specified for an FTPFragment but not for an FTPSFragment.
Any number of Fragments can be specified within a file transfer configuration.
Individual Fragments are mainly referenced from the Profile Branch (see .... TODO) of the configuration.
Operation-dependent source and target elements specify how a Fragment is to be used. For example:
- A Copy operation requires that CopySource and CopyTarget elements are specified.
- The CopySource and CopyTarget elements in turn require that CopySourceFragmentRef and CopytargetFragmentRef elements are defined, that respectively specify the Fragments to be used for both parts of the operation.
The advantage of this approach - which may at first seen somewhat complex - is that fragments can flexibly reused within the otherwise strict XML hierarchy and that configurations can be validated against an XSD schema to greatly reduce the possibility of configuration errors.
A Fragment can be used as a source or as a target within the one Configuration.
ProtocolFragments can also be referenced from other fragments:
- AlternativeFragments elements can specify a number of Fragments. These fragments will be applied in order, should, for example a server not be available. For example, it is conceivable that in some situations a less secure protocol is tried if a secure one is not available.