Feature/native did web resolver

aries_cloudagent/messaging/valid.py

@@ -224,6 +224,20 @@ def __init__(self):
         )
 
 
+class DIDWeb(Regexp):
+    """Validate value against did:web specification."""
+
+    EXAMPLE = "did:web:example.com"
+    PATTERN = re.compile(r"^(did:web:)?([a-zA-Z0-9%._-]*:)*[a-zA-Z0-9%._-]+$")
+
+    def __init__(self):
+        """Initializer."""
+
+        super().__init__(
+            DIDWeb.PATTERN, error="Value {input} is not in W3C did:web format"
+        )
+
+
 class DIDPosture(OneOf):
     """Validate value against defined DID postures."""
 

aries_cloudagent/resolver/__init__.py

@@ -31,3 +31,9 @@ async def setup(context: InjectionContext):
         registry.register(indy_resolver)
     else:
         LOGGER.warning("Ledger is not configured, not loading IndyDIDResolver")
+
+    web_resolver = ClassProvider(
+        "aries_cloudagent.resolver.default.web.WebDIDResolver"
+    ).provide(context.settings, context.injector)
+    await web_resolver.setup(context)
+    registry.register(web_resolver)

aries_cloudagent/resolver/default/tests/test_web.py

@@ -0,0 +1,33 @@
+"""Test did:web Resolver."""
+
+import pytest
+from ..web import WebDIDResolver
+
+
+@pytest.fixture
+def resolver():
+    yield WebDIDResolver()
+
+
+@pytest.fixture
+def profile():
+    yield None
+
+
+def test_transformation_domain_only(resolver):
+    did = "did:web:example.com"
+    url = resolver._WebDIDResolver__transform_to_url(did)
+    assert url == "https://example.com/.well-known/did.json"
+
+
+def test_transformation_domain_with_path(resolver):
+    did = "did:web:example.com:department:example"
+    url = resolver._WebDIDResolver__transform_to_url(did)
+    assert url == "https://example.com/department/example/did.json"
+
+
+# TODO: Enable this test as soon as pyDID accepts % char in DID
+# def test_transformation_domain_with_port(resolver):
+#     did = 'did:web:localhost%3A8443'
+#     url = resolver._WebDIDResolver__transform_to_url(did)
+#     assert url == "https://localhost:443/.well-known/did.json"

aries_cloudagent/resolver/default/web.py

@@ -0,0 +1,79 @@
+"""Web DID Resolver."""
+
+from typing import Sequence, Pattern
+import aiohttp
+import urllib.parse
+
+from ...config.injection_context import InjectionContext
+from ...core.profile import Profile
+from ..base import (
+    BaseDIDResolver,
+    DIDNotFound,
+    ResolverError,
+    ResolverType,
+)
+from ...messaging.valid import DIDWeb
+from pydid import DID, DIDDocument
+
+
+class WebDIDResolver(BaseDIDResolver):
+    """Web DID Resolver."""
+
+    def __init__(self):
+        """Initialize Web DID Resolver."""
+        super().__init__(ResolverType.NATIVE)
+
+    async def setup(self, context: InjectionContext):
+        """Perform required setup for Web DID resolution."""
+
+    @property
+    def supported_did_regex(self) -> Pattern:
+        """Return supported_did_regex of Web DID Resolver."""
+        return DIDWeb.PATTERN
+
+    def supported_methods(self) -> Sequence[str]:
+        """Return list of supported methods."""
+        return ["web"]
+
+    def __transform_to_url(self, did):
+        """
+        Transform did to url.
+
+        according to
+        https://w3c-ccg.github.io/did-method-web/#read-resolve
+        """
+
+        as_did = DID(did)
+        method_specific_id = as_did.method_specific_id
+        if ":" in method_specific_id:
+            # contains path
+            url = method_specific_id.replace(":", "/")
+        else:
+            # bare domain needs /.well-known path
+            url = method_specific_id + "/.well-known"
+
+        # Support encoded ports (See: https://github.com/w3c-ccg/did-method-web/issues/7)
+        url = urllib.parse.unquote(url)
+
+        return "https://" + url + "/did.json"
+
+    async def _resolve(self, profile: Profile, did: str) -> dict:
+        """Resolve did:web DIDs."""
+
+        url = self.__transform_to_url(did)
+        async with aiohttp.ClientSession() as session:
+            async with session.get(url) as response:
+                if response.status == 200:
+                    try:
+                        # Validate DIDDoc with pyDID
+                        did_doc = DIDDocument.from_json(await response.text())
+                        return did_doc.serialize()
+                    except Exception as err:
+                        raise ResolverError(
+                            "Response was incorrectly formatted"
+                        ) from err
+                if response.status == 404:
+                    raise DIDNotFound(f"No document found for {did}")
+                raise ResolverError(
+                    "Could not find doc for {}: {}".format(did, await response.text())
+                )