Merge pull request #24 from labthings/autodiscovery

mDNS Autodiscovery

Author: jtc42

examples/builder.py

@@ -21,6 +21,7 @@ def cleanup():
     title="My Lab Device API",
     description="Test LabThing-based API",
     version="0.1.0",
+    types=["org.labthings.examples.builder"],
 )
 
 # Attach an instance of our component

labthings/server/decorators.py

@@ -286,7 +286,10 @@ def __init__(self, code, description=None, mimetype=None, **kwargs):
 
         if self.mimetype:
             self.response_dict.update(
-                {"responses": {self.code: {"content": {self.mimetype: {}}}}}
+                {
+                    "responses": {self.code: {"content": {self.mimetype: {}}}},
+                    "_content_type": self.mimetype,
+                }
             )
 
     def __call__(self, f):

labthings/server/find.py

@@ -4,22 +4,23 @@
 from . import EXTENSION_NAME
 
 
-def current_labthing():
+def current_labthing(app=None):
     """The LabThing instance handling current requests.
     
     Searches for a valid LabThing extension attached to the current Flask context.
     """
     # We use _get_current_object so that Task threads can still
     # reach the Flask app object. Just using current_app returns
     # a wrapper, which breaks it's use in Task threads
-    app = current_app._get_current_object()  # skipcq: PYL-W0212
+    if not app:
+        app = current_app._get_current_object()  # skipcq: PYL-W0212
     if not app:
         return None
     logging.debug("Active app extensions:")
     logging.debug(app.extensions)
     logging.debug("Active labthing:")
     logging.debug(app.extensions[EXTENSION_NAME])
-    return app.extensions[EXTENSION_NAME]
+    return app.extensions.get(EXTENSION_NAME, None)
 
 
 def registered_extensions(labthing_instance=None):

labthings/server/labthing.py

@@ -28,6 +28,7 @@ def __init__(
         prefix: str = "",
         title: str = "",
         description: str = "",
+        types: list = [],
         version: str = "0.0.0",
     ):
         self.app = app  # Becomes a Flask app
@@ -46,6 +47,14 @@ def __init__(
         self.endpoints = set()
 
         self.url_prefix = prefix
+
+        for t in types:
+            if ";" in t:
+                raise ValueError(
+                    f'Error in type value "{t}". Thing types cannot contain ; character.'
+                )
+        self.types = types
+
         self._description = description
         self._title = title
         self._version = version

labthings/server/quick.py

@@ -11,6 +11,7 @@ def create_app(
     prefix: str = "",
     title: str = "",
     description: str = "",
+    types: list = [],
     version: str = "0.0.0",
     handle_errors: bool = True,
     handle_cors: bool = True,
@@ -52,7 +53,12 @@ def create_app(
 
     # Create a LabThing
     labthing = LabThing(
-        app, prefix=prefix, title=title, description=description, version=str(version)
+        app,
+        prefix=prefix,
+        title=title,
+        description=description,
+        types=types,
+        version=str(version),
     )
 
     # Store references to added-in handlers

labthings/server/sockets/eventlet.py

@@ -3,7 +3,7 @@
 
 from ..view import View
 
-from .utilities import get_spec, convert_schema, schema_to_json
+from .utilities import get_spec, convert_schema, schema_to_json, get_topmost_spec_attr
 from .paths import rule_to_params, rule_to_path
 
 from ..find import current_labthing
@@ -79,12 +79,17 @@ def add_link(self, view, rel, kwargs=None, params=None):
     def to_dict(self):
         return {
             "@context": "https://www.w3.org/2019/wot/td/v1",
+            "@type": current_labthing().types,
             "id": url_for("root", _external=True),
+            "base": url_for("root", _external=True),
             "title": current_labthing().title,
             "description": current_labthing().description,
             "properties": self.properties,
             "actions": self.actions,
             "links": self.links,
+            # TODO: Add proper security schemes
+            "securityDefinitions": {"nosec_sc": {"scheme": "nosec"}},
+            "security": ["nosec_sc"],
         }
 
     def view_to_thing_property(self, rules: list, view: View):
@@ -104,6 +109,7 @@ def view_to_thing_property(self, rules: list, view: View):
             "writeOnly": not hasattr(view, "get"),
             # TODO: Make URLs absolute
             "links": [{"href": f"{url}"} for url in prop_urls],
+            "forms": self.view_to_thing_property_forms(rules, view),
             "uriVariables": {},
         }
 
@@ -134,6 +140,20 @@ def view_to_thing_property(self, rules: list, view: View):
 
         return prop_description
 
+    def view_to_thing_property_forms(self, rules: list, view: View):
+        readable = (
+            hasattr(view, "post") or hasattr(view, "put") or hasattr(view, "delete")
+        )
+        writeable = hasattr(view, "get")
+
+        op = []
+        if readable:
+            op.append("readproperty")
+        if writeable:
+            op.append("writeproperty")
+
+        return self.build_forms_for_view(rules, view, op=op)
+
     def view_to_thing_action(self, rules: list, view: View):
         action_urls = [rule_to_path(rule) for rule in rules]
 
@@ -145,14 +165,31 @@ def view_to_thing_action(self, rules: list, view: View):
             or (get_docstring(view.post) if hasattr(view, "post") else ""),
             # TODO: Make URLs absolute
             "links": [{"href": f"{url}"} for url in action_urls],
+            "forms": self.view_to_thing_action_forms(rules, view),
         }
 
         return action_description
 
+    def view_to_thing_action_forms(self, rules: list, view: View):
+        return self.build_forms_for_view(rules, view, op=["invokeaction"])
+
     def property(self, rules: list, view: View):
         key = snake_to_camel(view.endpoint)
         self.properties[key] = self.view_to_thing_property(rules, view)
 
     def action(self, rules: list, view: View):
         key = snake_to_camel(view.endpoint)
         self.actions[key] = self.view_to_thing_action(rules, view)
+
+    def build_forms_for_view(self, rules: list, view: View, op: list):
+        forms = []
+        prop_urls = [rule_to_path(rule) for rule in rules]
+
+        content_type = (
+            get_topmost_spec_attr(view, "_content_type") or "application/json"
+        )
+
+        for url in prop_urls:
+            forms.append({"op": op, "href": url, "contentType": content_type})
+
+        return forms

labthings/server/spec/td.py

@@ -32,10 +32,35 @@ def get_spec(obj):
     Returns:
         dict: API spec dictionary. Returns empty dictionary if no spec is found.
     """
+    if not obj:
+        return {}
     obj.__apispec__ = obj.__dict__.get("__apispec__", {})
     return obj.__apispec__ or {}
 
 
+def get_topmost_spec_attr(view, spec_key: str):
+    """
+    Get the __apispec__ value corresponding to spec_key, from first the root view,
+    falling back to GET, POST, and PUT in that descending order of priority
+
+    Args:
+        obj: Python object
+
+    Returns:
+        spec value corresponding to spec_key
+    """
+    spec = get_spec(view)
+    value = spec.get(spec_key)
+
+    if not value:
+        for meth in ["get", "post", "put"]:
+            spec = get_spec(getattr(view, meth, None))
+            value = spec.get(spec_key)
+            if value:
+                break
+    return value
+
+
 def convert_schema(schema, spec: APISpec):
     """
     Ensure that a given schema is either a real Marshmallow schema,