feat: Create validation context classes from schema.meta.context

pyproject.toml

@@ -23,6 +23,9 @@ classifiers = [
 requires-python = ">=3.8"
 dependencies = [
     "bidsschematools >=0.11",
+    "typing_extensions",
+    "attrs",
+    "httpx",
 ]
 
 [project.optional-dependencies]

src/bids_validator/bidsignore.py

@@ -0,0 +1,129 @@
+"""Utilities for working with .bidsignore files."""
+
+import os
+import re
+from functools import lru_cache
+from typing import List, Protocol, Union
+
+import attrs
+
+from .types.files import FileTree
+
+
+@lru_cache
+def compile_pat(pattern: str) -> Union[re.Pattern, None]:
+    """Compile .gitignore-style ignore lines to regular expressions."""
+    orig = pattern
+    # A line starting with # serves as a comment.
+    if pattern.startswith('#'):
+        return None
+
+    # An optional prefix "!" which negates the pattern;
+    invert = pattern.startswith('!')
+
+    # Put a backslash ("\") in front of the first hash for patterns that begin with a hash.
+    # Put a backslash ("\") in front of the first "!" for patterns that begin with a literal "!"
+    if pattern.startswith((r'\#', r'\!')):
+        pattern = pattern[1:]  # Unescape
+
+    # Trailing spaces are ignored unless they are quoted with backslash ("\").
+    pattern = re.sub(r'(?<!\\) +$', '', pattern)
+
+    # A blank line matches no files, so it can serve as a separator for readability.
+    if pattern == '':
+        return None
+
+    # If there is a separator at the beginning or middle (or both) of the pattern,
+    # then the pattern is relative to the [root]
+    relative_match = pattern == '/' or '/' in pattern[:-1]
+    # If there is a separator at the end of the pattern then the pattern will only match
+    # directories, otherwise the pattern can match both files and directories.
+    directory_match = pattern.endswith('/')
+
+    # This does not handle character ranges correctly except when they are also valid regex
+    parts = [
+        '.*'
+        if part == '**'
+        else part.replace('*', '[^/]*').replace('?', '[^/]').replace('.', r'\.')
+        for part in pattern.strip('/').split('/')
+    ]
+
+    prefix = '^' if relative_match else '^(.*/|)'
+    postfix = r'/\Z' if directory_match else r'/?\Z'
+
+    # "**/" matches zero or more directories, so the separating slash needs to be optional
+    out_pattern = '/'.join(parts).replace('.*/', '.*/?')
+    out_pattern = f'{prefix}{out_pattern}{postfix}'
+
+    if invert:
+        raise ValueError(f'Inverted patterns not supported: {orig}')
+        # out_pattern = f'(?!{out_pattern})'
+
+    return re.compile(out_pattern)
+
+
+class HasMatch(Protocol):  # noqa: D101
+    def match(self, relpath: str) -> bool: ...  # noqa: D102
+
+
+@attrs.define
+class Ignore:
+    """Collection of .gitignore-style patterns.
+
+    Tracks successfully matched files for reporting.
+    """
+
+    patterns: List[str] = attrs.field(factory=list)
+    history: List[str] = attrs.field(factory=list, init=False)
+
+    @classmethod
+    def from_file(cls, pathlike: os.PathLike):
+        """Load Ignore contents from file."""
+        with open(pathlike) as fobj:
+            return cls([line.rstrip('\n') for line in fobj])
+
+    def match(self, relpath: str) -> bool:
+        """Match a relative path against a collection of ignore patterns."""
+        if any(compile_pat(pattern).match(relpath) for pattern in self.patterns):
+            self.history.append(relpath)
+            return True
+        return False
+
+
+@attrs.define
+class IgnoreMany:
+    """Match against several ignore filters."""
+
+    ignores: List[Ignore] = attrs.field()
+
+    def match(self, relpath: str) -> bool:
+        """Return true if any filters match the given file.
+
+        Will short-circuit, so ordering is significant for side-effects,
+        such as recording files ignored by a particular filter.
+        """
+        return any(ignore.match(relpath) for ignore in self.ignores)
+
+
+def filter_file_tree(filetree: FileTree) -> FileTree:
+    """Read .bidsignore and filter file tree."""
+    bidsignore = filetree.children.get('.bidsignore')
+    if not bidsignore:
+        return filetree
+    ignore = IgnoreMany([Ignore.from_file(bidsignore), Ignore(['/.bidsignore'])])
+    return _filter(filetree, ignore)
+
+
+def _filter(filetree: FileTree, ignore: HasMatch) -> FileTree:
+    items = filetree.children.items()
+    children = {
+        name: _filter(child, ignore)
+        for name, child in items
+        if not ignore.match(child.relative_path)
+    }
+
+    # XXX This check may not be worth the time. Profile this.
+    if any(children.get(name) is not child for name, child in items):
+        filetree = attrs.evolve(filetree, children=children)
+
+    return filetree

src/bids_validator/context.py

@@ -0,0 +1,38 @@
+"""Validation context for schema-based BIDS validation."""
+
+from .context_generator import get_schema, load_schema_into_namespace
+
+schema = get_schema()
+load_schema_into_namespace(schema['meta']['context'], globals(), 'Context')
+
+
+__all__ = [  # noqa: F822
+    'Context',
+    'Schema',
+    'Dataset',
+    'DatasetDescription',
+    'Tree',
+    'Subjects',
+    'Subject',
+    'Sessions',
+    'Entities',
+    'Sidecar',
+    'Associations',
+    'Events',
+    'Aslcontext',
+    'M0scan',
+    'Magnitude',
+    'Magnitude1',
+    'Bval',
+    'Bvec',
+    'Channels',
+    'Coordsystem',
+    'Columns',
+    'Json',
+    'Gzip',
+    'NiftiHeader',
+    'DimInfo',
+    'XyztUnits',
+    'Ome',
+    'Tiff',
+]

src/bids_validator/context_generator.py

@@ -0,0 +1,214 @@
+"""Utilities for generating validation context classes from a BIDS schema.
+
+For default contexts based on the installed BIDS schema, use the `context` module.
+These functions allow generating classes from alternative schemas.
+
+Basic usage:
+
+.. python::
+
+    from bids_validator.context_generator import get_schema, load_schema_into_namespace
+
+    schema = get_schema('https://bids-specification.readthedocs.io/en/stable/schema.json')
+    load_schema_into_namespace(schema['meta']['context']['context'], globals(), 'Context')
+"""
+
+import json
+from typing import Any, Dict, List, Union
+
+import attrs
+import bidsschematools as bst
+import bidsschematools.schema
+import httpx
+
+LATEST_SCHEMA_URL = 'https://bids-specification.readthedocs.io/en/latest/schema.json'
+STABLE_SCHEMA_URL = 'https://bids-specification.readthedocs.io/en/stable/schema.json'
+
+
+def get_schema(url: Union[str, None] = None) -> Dict[str, Any]:
+    """Load a BIDS schema from a URL or return the bundled schema if no URL is provided.
+
+    Parameters
+    ----------
+    url : str | None
+        The URL to load the schema from. If None, the bundled schema is returned.
+        The strings 'latest' and 'stable' are also accepted as shortcuts.
+
+    Returns
+    -------
+    Dict[str, Any]
+        The loaded schema as a dictionary.
+
+    """
+    if url is None:
+        return bst.schema.load_schema()
+
+    if url == 'latest':
+        url = LATEST_SCHEMA_URL
+    elif url == 'stable':
+        url = STABLE_SCHEMA_URL
+
+    with httpx.Client() as client:
+        return client.get(url).json()
+
+
+def snake_to_pascal(val: str):
+    """Convert snake_case string to PascalCase."""
+    return ''.join(sub.capitalize() for sub in val.split('_'))
+
+
+def typespec_to_type(name: str, typespec: Dict[str, Any]):
+    """Convert JSON-schema style specification to type and metadata dictionary."""
+    tp = typespec.get('type')
+    if not tp:
+        raise ValueError(f'Invalid typespec: {json.dumps(typespec)}')
+    metadata = {key: typespec[key] for key in ('name', 'description') if key in typespec}
+    if tp == 'object':
+        properties = typespec.get('properties')
+        if properties:
+            type_ = create_attrs_class(name, properties=properties, metadata=metadata)
+        else:
+            type_ = Dict[str, Any]
+    elif tp == 'array':
+        if 'items' in typespec:
+            subtype, md = typespec_to_type(name, typespec['items'])
+        else:
+            subtype = Any
+        type_ = List[subtype]
+    else:
+        type_ = {
+            'number': float,
+            'float': float,  # Fix in schema
+            'string': str,
+            'integer': int,
+            'int': int,  # Fix in schema
+        }[tp]
+    return type_, metadata
+
+
+def _type_name(tp: type) -> str:
+    try:
+        return tp.__name__
+    except AttributeError:
+        return str(tp)
+
+
+def create_attrs_class(
+    class_name: str,
+    properties: Dict[str, Any],
+    metadata: Dict[str, Any],
+) -> type:
+    """Dynamically create an attrs class with the given properties.
+
+    Parameters
+    ----------
+    class_name
+        The name of the class to create.
+    properties
+        A dictionary of property names and their corresponding schema information.
+        If a nested object is encountered, a nested class is created.
+    metadata
+        A short description of the class, included in the docstring.
+
+    Returns
+    -------
+    cls : type
+        The dynamically created attrs class.
+
+    """
+    attributes = {}
+    for prop_name, prop_info in properties.items():
+        type_, md = typespec_to_type(prop_name, prop_info)
+        attributes[prop_name] = attrs.field(
+            type=type_, repr=prop_name != 'schema', default=None, metadata=md
+        )
+
+    return attrs.make_class(
+        snake_to_pascal(class_name),
+        attributes,
+        class_body={
+            '__doc__': f"""\
+{metadata.get('description', '')}
+
+attrs data class auto-generated from BIDS schema
+
+Attributes
+----------
+"""
+            + '\n'.join(
+                [
+                    f'{k}: {_type_name(v.type)}\n\t{v.metadata["description"]}'
+                    for k, v in attributes.items()
+                ]
+            ),
+        },
+    )
+
+
+def generate_attrs_classes_from_schema(
+    schema: Dict[str, Any],
+    root_class_name: str,
+) -> type:
+    """Generate attrs classes from a JSON schema.
+
+    Parameters
+    ----------
+    schema : Dict[str, Any]
+        The JSON schema to generate classes from. Must contain a 'properties' field.
+    root_class_name : str
+        The name of the root class to create.
+
+    Returns
+    -------
+    cls : type
+        The root class created from the schema.
+
+    """
+    if 'properties' not in schema:
+        raise ValueError("Invalid schema: 'properties' field is required")
+
+    type_, _ = typespec_to_type(root_class_name, schema)
+    return type_
+
+
+def populate_namespace(attrs_class: type, namespace: Dict[str, Any]) -> None:
+    """Populate a namespace with nested attrs classes.
+
+    Parameters
+    ----------
+    attrs_class : type
+        The root attrs class to add to the namespace.
+    namespace : Dict[str, Any]
+        The namespace to populate with nested classes.
+
+    """
+    for attr in attrs_class.__attrs_attrs__:
+        attr_type = attr.type
+
+        if isinstance(attr_type, type) and hasattr(attr_type, '__attrs_attrs__'):
+            namespace[attr_type.__name__] = attr_type
+            populate_namespace(attr_type, namespace)
+
+
+def load_schema_into_namespace(
+    schema: Dict[str, Any],
+    namespace: Dict[str, Any],
+    root_class_name: str,
+) -> None:
+    """Load a JSON schema into a namespace as attrs classes.
+
+    Intended to be used with globals() or locals() to create classes in the current module.
+
+    Parameters
+    ----------
+    schema : Dict[str, Any]
+        The JSON schema to load into the namespace.
+    namespace : Dict[str, Any]
+        The namespace to load the schema into.
+    root_class_name : str
+        The name of the root class to create.
+
+    """
+    attrs_class = generate_attrs_classes_from_schema(schema, root_class_name)
+    namespace[root_class_name] = attrs_class
+    populate_namespace(attrs_class, namespace)

src/bids_validator/types/__init__.py

@@ -0,0 +1 @@
+"""Modules for providing types."""