feat: Add did:web resolver support

Signed-off-by: Colton Wolkins (Indicio work address) <colton@indicio.tech>

Author: TheTechmage

didcomm_messaging/resolver/web.py

@@ -0,0 +1,117 @@
+"""did:web resolver.
+
+Resolve did:web style dids to a did document. did:web spec:
+https://w3c-ccg.github.io/did-method-web/
+"""
+
+from . import DIDResolver, DIDNotFound, DIDResolutionError
+from pydid import DID
+from urllib.parse import urlparse
+from datetime import datetime, timedelta
+import urllib.request as url_request
+import re
+import json
+import urllib
+
+domain_regex = (
+    r"((?!-))(xn--)?[a-z0-9][a-z0-9-_]{0,61}[a-z0-9]{0,1}"
+    r"\.(xn--)?([a-z0-9\._-]{1,61}|[a-z0-9-]{1,30})"
+    r"(%3[aA]\d+)?"  # Port
+    r"(:[a-zA-Z]+)*"  # Path
+)
+did_web_pattern = re.compile(rf"^did:web:{domain_regex}$")
+cache = {}
+TIME_TO_CACHE = 1800  # 30 minutes
+
+
+class DIDWeb(DIDResolver):
+    """Utility functions for building and interacting with did:web."""
+
+    async def resolve(self, did: str) -> dict:
+        """Resolve a did:web to a did document via http request."""
+
+        # Check to see if we've seen the did recently
+        if did in cache:
+            if cache[did]["timestamp"] > datetime.now() + timedelta(
+                seconds=-TIME_TO_CACHE
+            ):
+                return cache[did]["doc"]
+            else:
+                del cache[did]
+
+        uri = DIDWeb._did_to_uri(did)
+        headers = {
+            "User-Agent": "DIDCommRelay/1.0",
+        }
+        request = url_request.Request(url=uri, method="GET", headers=headers)
+        try:
+            with url_request.urlopen(request) as response:
+                doc = json.loads(response.read().decode())
+                cache[did] = {
+                    "timestamp": datetime.now(),
+                    "doc": doc,
+                }
+                return doc
+        except urllib.error.HTTPError as e:
+            if e.code == 404:
+                raise DIDNotFound(
+                    f"The did:web {did} returned a 404 not found while resolving"
+                )
+            else:
+                raise DIDResolutionError(
+                    f"Unknown server error ({e.code}) while resolving did:web: {did}"
+                )
+        except json.decoder.JSONDecodeError as e:
+            msg = str(e)
+            raise DIDNotFound(f"The did:web {did} returned invalid JSON {msg}")
+        except Exception as e:
+            raise DIDResolutionError("Failed to fetch did document") from e
+
+    @staticmethod
+    def _did_to_uri(did: str) -> str:
+        # Split the did by it's segments
+        did_segments = did.split(":")
+
+        # Get the hostname & port
+        hostname = did_segments[2].lower()
+        hostname = hostname.replace("%3a", ":")
+
+        # Resolve the path portion of the DID, if there is no path, default to
+        # a .well-known address
+        path = ".well-known"
+        if len(did_segments) > 3:
+            path = "/".join(did_segments[3:])
+
+        # Assemble the URI
+        did_uri = f"https://{hostname}/{path}/did.json"
+
+        return did_uri
+
+    async def is_resolvable(self, did: str) -> bool:
+        """Determine if the did is a valid did:web did that can be resolved."""
+        if DID.is_valid(did) and did_web_pattern.match(did):
+            return True
+        return False
+
+    @staticmethod
+    def did_from_url(url: str) -> DID:
+        """Convert a URL into a did:web did."""
+
+        # Make sure that the URL starts with a scheme
+        if not url.startswith("http"):
+            url = f"https://{url}"
+
+        # Parse it out to we can grab pieces
+        parsed_url = urlparse(url)
+
+        # Assemble the domain portion of the DID
+        did = "did:web:%s" % parsed_url.netloc.replace(":", "%3A")
+
+        # Cleanup the path
+        path = parsed_url.path.replace(".well-known/did.json", "")
+        path = path.replace("/did.json", "")
+
+        # Add the path portion of the did
+        if len(path) > 1:
+            did += path.replace("/", ":")
+        return did

tests/conftest.py

@@ -0,0 +1,24 @@
+import pytest
+
+
+def pytest_addoption(parser):
+    parser.addoption(
+        "--runexternal",
+        action="store_true",
+        default=False,
+        help="run tests that make external requests",
+    )
+
+
+def pytest_configure(config):
+    config.addinivalue_line("markers", "external_fetch: mark test as slow to run")
+
+
+def pytest_collection_modifyitems(config, items):
+    if config.getoption("--runexternal"):
+        # --runslow given in cli: do not skip slow tests
+        return
+    skip_external = pytest.mark.skip(reason="need --runexternal option to run")
+    for item in items:
+        if "external_fetch" in item.keywords:
+            item.add_marker(skip_external)

tests/test_didweb.py

@@ -0,0 +1,106 @@
+import pytest
+
+
+from didcomm_messaging.resolver.web import DIDWeb
+
+DIDWEB = "did:web:example.com"
+DIDWEB_URI = "https://example.com/.well-known/did.json"
+DIDWEB_COMPLEX = "did:web:example.com%3A4443:DIDs:alice:relay"
+DIDWEB_COMPLEX_URI = "https://example.com:4443/DIDs/alice/relay/did.json"
+
+
+@pytest.mark.asyncio
+async def test_didweb_from_didurl_domain():
+    did = DIDWeb.did_from_url("example.com")
+    assert did
+    assert did == DIDWEB
+
+
+@pytest.mark.asyncio
+async def test_didweb_from_didurl_schema_and_domain():
+    did = DIDWeb.did_from_url("https://example.com")
+    assert did
+    assert did == DIDWEB
+
+
+@pytest.mark.asyncio
+async def test_didweb_from_didurl_schema_and_domain_slash():
+    did = DIDWeb.did_from_url("https://example.com/")
+    assert did
+    assert did == DIDWEB
+
+
+@pytest.mark.asyncio
+async def test_didweb_from_didurl_schema_and_domain_path():
+    did = DIDWeb.did_from_url("https://example.com/did.json")
+    assert did
+    assert did == DIDWEB
+
+
+@pytest.mark.asyncio
+async def test_didweb_from_didurl_schema_and_domain_wellknown():
+    did = DIDWeb.did_from_url("https://example.com/.well-known/did.json")
+    assert did
+    assert did == DIDWEB
+
+
+@pytest.mark.asyncio
+async def test_didweb_from_didurl_schema_and_domain_port_wellknown():
+    did = DIDWeb.did_from_url("https://example.com:443/.well-known/did.json")
+    assert did
+    assert did == DIDWEB + "%3A443"
+
+
+@pytest.mark.asyncio
+async def test_didweb_from_didurl_schema_and_complex_domain_path():
+    did = DIDWeb.did_from_url("https://example.com:4443/DIDs/alice/relay/did.json")
+    assert did
+    assert did == DIDWEB_COMPLEX
+
+
+@pytest.mark.asyncio
+async def test_didweb_to_url():
+    uri = DIDWeb._did_to_uri(DIDWEB)
+    assert uri
+    assert uri == DIDWEB_URI
+
+
+@pytest.mark.asyncio
+async def test_didweb_to_url_complex():
+    uri = DIDWeb._did_to_uri(DIDWEB_COMPLEX)
+    assert uri
+    assert uri == DIDWEB_COMPLEX_URI
+
+
+@pytest.mark.asyncio
+async def test_didweb_is_resolvable():
+    resolver = DIDWeb()
+    resolvable = await resolver.is_resolvable(DIDWEB)
+    assert resolvable
+    resolvable_complex = await resolver.is_resolvable(DIDWEB_COMPLEX)
+    assert resolvable_complex
+
+
+@pytest.mark.external_fetch
+@pytest.mark.asyncio
+async def test_didweb_fetch():
+    did_web = "did:web:colton.wolkins.net"
+    resolver = DIDWeb()
+    uri = await resolver.resolve(did_web)
+    print(uri)
+    assert uri
+    assert isinstance(uri, dict)
+
+
+@pytest.mark.external_fetch
+@pytest.mark.asyncio
+async def test_didweb_double_fetch():
+    did_web = "did:web:colton.wolkins.net"
+    resolver = DIDWeb()
+    uri = await resolver.resolve(did_web)
+    print(uri)
+    assert uri
+    assert isinstance(uri, dict)
+    uri = await resolver.resolve(did_web)
+    assert uri
+    assert isinstance(uri, dict)