Draft: ENH: file system: link

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• All automated tests pass
• Up-to-date CHANGELOG.md (or not necessary)
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src/caosdb/common/models.py

@@ -115,6 +115,7 @@ class Entity(object):
         self.parents = _Parents()
         self.path = None
         self.file = None
+        self.link_target = None
         self.unit = None
         self.acl = None
         self.permissions = None
@@ -297,6 +298,17 @@ class Entity(object):
 
         return self._wrapped_entity.path
 
+    @link_target.setter
+    def link_target(self, new_link_target):
+        self.__link_target = new_link_target
+
+    @property
+    def link_target(self):
+        if self.__link_target is not None or self._wrapped_entity is None:
+            return self.__link_target
+
+        return self._wrapped_entity.link_target
+
     @path.setter
     def path(self, new_path):
         self.__path = new_path
@@ -1063,6 +1075,9 @@ class Entity(object):
         if self.file is not None and local_serialization:
             xml.set("file", self.file)
 
+        if self.link_target is not None:
+            xml.set("linktarget", self.link_target)
+
         if self.checksum is not None:
             xml.set("checksum", self.checksum)
 
@@ -1817,6 +1832,38 @@ class Record(Entity):
         return Entity.to_xml(self, xml, add_properties=ALL)
 
 
+class Link(Entity):
+    """This class represents CaosDB's link entities."""
+
+    def __init__(self, name=None, id=None, description=None, path=None, target=None)
+        Record.__init__(self, id=id, name=name, description=description)
+        self.role = "Link"
+        self.datatype = None
+        self.link_target = target
+
+        # location in the fileserver
+        self.path = path
+
+    def to_xml(self, xml=None, add_properties=ALL, local_serialization=False):
+        """Convert this Link to an xml element.
+
+        @return: xml element
+        """
+
+        if xml is None:
+            xml = etree.Element("Link")
+
+        return Entity.to_xml(self, xml=xml, add_properties=add_properties,
+                             local_serialization=local_serialization)
+
+    def add_property(self, property=None, id=None, name=None, description=None, datatype=None,
+                     value=None, unit=None, importance=FIX, inheritance=FIX):
+
+        return super().add_property(
+            property=property, id=id, name=name, description=description, datatype=datatype,
+            value=value, unit=unit, importance=importance, inheritance=inheritance)
+
+
 class Directory(Record):
     """This class represents CaosDB's directory entities."""
 
@@ -2510,6 +2557,7 @@ def _basic_sync(e_local, e_remote):
     e_local.name = e_remote.name
     e_local.description = e_remote.description
     e_local.path = e_remote.path
+    e_local.link_target = e_remote.link_target
     e_local._checksum = e_remote._checksum
     e_local._size = e_remote._size
     e_local.datatype = e_remote.datatype
@@ -4415,6 +4463,7 @@ def _parse_single_xml_element(elem):
         'property': Property,
         'file': File,
         'directory': Directory,
+        'link': Link,
         'parent': Parent,
         'entity': Entity}