Extend json-schema model parser

Summary

For https://gitlab.indiscale.com/caosdb/customers/3dmmto/management/-/issues/9.

This implements

• pattern properties
• type null properties
• json schema references
• and json schemas without top-level recordtype specification

for the json schema datamodel parser.

Focus

Mainly additions to the JsonSchemaParser class. We also defined a treatment for type: array properties that lack a strict items specification (i.e., could be lists of elements with mixed types, so a manual specification has to be provided -- or they are ignored altogether).

Test Environment

New unit tests. You can also test it with the chemotion json schema in nextcloud/Customers/3dmmto/example_files/testdaten_chemotion/schema.json.

Check List for the Author

Please, prepare your MR for a review. Be sure to write a summary and a focus and create gitlab comments for the reviewer. They should guide the reviewer through the changes, explain your changes and also point out open questions. For further good practices have a look at our review guidelines

• All automated tests pass
• Reference related issues
• Up-to-date CHANGELOG.md (or not necessary)
• Up-to-date JSON schema (or not necessary)
• Appropriate user and developer documentation (or not necessary)
  • How do I use the software? Assume "stupid" users.
  • How do I develop or debug the software? Assume novice developers.
• Annotations in code (Gitlab comments)
  • Intent of new code
  • Problems with old code
  • Why this implementation?

Check List for the Reviewer

• I understand the intent of this MR
• All automated tests pass
• Up-to-date CHANGELOG.md (or not necessary)
• Appropriate user and developer documentation (or not necessary)
• The test environment setup works and the intended behavior is reproducible in the test environment
• In-code documentation and comments are up-to-date.
• Check: Are there specifications? Are they satisfied?

For further good practices have a look at our review guidelines.

src/caosadvancedtools/models/parser.py

@@ -174,7+174,7 @@
         array` but without `items` specification. Default is an empty dict.
     ignore_unspecified_array_items : bool, optional
         Whether to ignore `type: array` entries the type of which is not
         specified by their `items` property or given in
         `types_for_missing_array_items`. An error is raised if they are not
         ignored. Default is False.
 
@@ -621,7+621,7 @@
     **EXPERIMENTAL:** While this calss can already be used to create data models
     from basic json schemas, there are the following limitations and missing
     features:
 
     * Due to limitations of json-schema itself, we currently do not support
       inheritance in the imported data models
     * The same goes for suggested properties of RecordTypes
@@ -639,7+639,7 @@
     """
     # @author Florian Spreckelsen
     # @date 2022-02-17
     # @review Timm Fitschen 2022-02-30
 
     def __init__(self, types_for_missing_array_items={}, ignore_unspecified_array_items=False):
         super().__init__()
@@ -683,7+683,7 @@
         top_level_recordtype : bool, optional
             Whether there is a record type defined at the top level of the
             schema. Default is true.
 
         Returns
         -------
         our : DataModel
@@ -783,7+783,7 @@
         if isinstance(elt["type"], list) and len(elt["type"]) == 2 and "null" in elt["type"]:
             elt["type"].remove("null")
             elt["type"] = elt["type"][0]
         if "enum" in elt:
             ent = self._treat_enum(elt, name)
         elif elt["type"] in JSON_SCHEMA_ATOMIC_TYPES:
             ent = db.Property(
@@ -792,7+792,7 @@
             ent = self._treat_record_type(elt, name)
         elif elt["type"] == "array":
             ent, force_list = self._treat_list(elt, name)
-        elif elt["type"] == "null":
-            # null
-            return None, force_list
         else:
             raise NotImplementedError(
                 f"Cannot parse items of type '{elt['type']}' (yet).")
@@ -917,7 +914,7 @@ class JsonSchemaParser(Parser):
         pattern_prop = self._get_pattern_prop()
         returns = []
         for ii, (key, element) in enumerate(pattern_elements.items()):
-            if not "title" in element:
+            if "title" not in element:
                 name_suffix = f"_{ii+1}" if num_patterns > 1 else ""
                 name = name_prefix + "Entry" + name_suffix
             else: