identity: normalize DID doc handles; try harder to find valid handles

atproto/identity/identity.go

···
 func (i *Identity) DeclaredHandle() (syntax.Handle, error) {
 	for _, u := range i.AlsoKnownAs {
 		if strings.HasPrefix(u, "at://") && len(u) > len("at://") {
-			return syntax.ParseHandle(u[5:])
+			hdl, err := syntax.ParseHandle(u[5:])
+			if err != nil {
+				continue
+			}
+			return hdl.Normalize(), nil
 		}
 	}
 	return "", ErrHandleNotDeclared

atproto/identity/identity_test.go

···
+package identity
+
+import (
+	"encoding/json"
+	"io"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// Tests parsing and normalizing handles from DID documents
+func TestHandleExtraction(t *testing.T) {
+	assert := assert.New(t)
+	f, err := os.Open("testdata/did_plc_doc.json")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f.Close()
+
+	docBytes, err := io.ReadAll(f)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var doc DIDDocument
+	err = json.Unmarshal(docBytes, &doc)
+	assert.NoError(err)
+
+	{
+		ident := ParseIdentity(&doc)
+		hdl, err := ident.DeclaredHandle()
+		assert.NoError(err)
+		assert.Equal("atproto.com", hdl.String())
+	}
+
+	{
+		doc.AlsoKnownAs = []string{
+			"at://BLAH.com",
+			"at://other.org",
+		}
+		ident := ParseIdentity(&doc)
+		hdl, err := ident.DeclaredHandle()
+		assert.NoError(err)
+		assert.Equal("blah.com", hdl.String())
+	}
+
+	{
+		doc.AlsoKnownAs = []string{
+			"https://http.example.com",
+			"at://under_example_com",
+			"at://correct.EXAMPLE.com",
+			"at://other.example.com",
+		}
+		ident := ParseIdentity(&doc)
+		hdl, err := ident.DeclaredHandle()
+		assert.NoError(err)
+		assert.Equal("correct.example.com", hdl.String())
+	}
+
+	{
+		doc.AlsoKnownAs = []string{
+			"https://http.example.com",
+		}
+		ident := ParseIdentity(&doc)
+		_, err := ident.DeclaredHandle()
+		assert.Error(err)
+		assert.Equal("handle.invalid", ident.Handle.String())
+	}
+}