Implement both direct and advanced lookup URIs

wkd-java/src/main/java/pgp/wkd/UserIdToWKDAddress.java

@@ -1,75 +0,0 @@
-// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package pgp.wkd;
-
-import java.net.URI;
-import java.nio.charset.StandardCharsets;
-import java.security.MessageDigest;
-import java.security.NoSuchAlgorithmException;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
-
-import org.apache.commons.codec.binary.ZBase32;
-
-public class UserIdToWKDAddress {
-
-    // RegEx for Email Addresses
-    // https://www.baeldung.com/java-email-validation-regex#regular-expression-by-rfc-5322-for-email-validation
-    // Modified by adding capture groups '()' for local and domain part
-    private static final Pattern PATTERN_EMAIL = Pattern.compile("^([a-zA-Z0-9_!#$%&'*+/=?`{|}~^.-]+)@([a-zA-Z0-9.-]+)$");
-    private static final Pattern PATTERN_USER_ID = Pattern.compile("^.*\\<([a-zA-Z0-9_!#$%&'*+/=?`{|}~^.-]+@[a-zA-Z0-9.-]+)\\>.*");
-
-    /**
-     * Extract the email address from a user-id.
-     * The user-id is expected to correspond to a RFC2822 name-addr.
-     * The email address is expected to be framed by angle brackets.
-     *
-     * @see <a href="https://datatracker.ietf.org/doc/html/rfc2822#section-3.4">RFC2822 - Internet Message Format §3.4: Address Specification</a>
-     * @param userId user-id name-addr
-     * @return WKD URI
-     *
-     * @throws IllegalArgumentException in case the user-id does not match the expected format
-     */
-    public URI userIdToUri(String userId) {
-        String lowerCase = userId.toLowerCase();
-        Matcher matcher = PATTERN_USER_ID.matcher(lowerCase);
-        if (!matcher.matches()) {
-            throw new IllegalArgumentException("User-ID does not follow excepted pattern \"Firstname Lastname <email.address> [Optional Comment]\"");
-        }
-        String email = matcher.group(1);
-        return mailToUri(email);
-    }
-
-    /**
-     * Translate an email address (localpart@domainpart) to a WKD URI.
-     *
-     * @param email email address
-     * @return WKD URI
-     * @throws IllegalArgumentException in case of a malformed email address
-     */
-    public URI mailToUri(String email) {
-        String lowerCase = email.toLowerCase();
-        Matcher matcher = PATTERN_EMAIL.matcher(lowerCase);
-        if (!matcher.matches()) {
-            throw new IllegalArgumentException("Invalid email address.");
-        }
-
-        String localPart = matcher.group(1);
-        String domainPart = matcher.group(2);
-
-        MessageDigest sha1;
-        try {
-            sha1 = MessageDigest.getInstance("SHA1");
-        } catch (NoSuchAlgorithmException e) {
-            throw new AssertionError("SHA-1 is available on all JVMs.", e);
-        }
-        sha1.update(localPart.getBytes(StandardCharsets.UTF_8));
-        byte[] digest = sha1.digest();
-
-        String base32KeyHandle = new ZBase32().encodeAsString(digest);
-
-        return URI.create("https://" + domainPart + "/.well-known/openpgpkey/hu/" + base32KeyHandle);
-    }
-}

wkd-java/src/main/java/pgp/wkd/WKDAddress.java

@@ -0,0 +1,156 @@
+// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package pgp.wkd;
+
+import java.io.UnsupportedEncodingException;
+import java.net.URI;
+import java.net.URLEncoder;
+import java.nio.charset.Charset;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.commons.codec.binary.ZBase32;
+
+/**
+ * Transform an email address into a WKD address.
+ *
+ * @see <a href="https://datatracker.ietf.org/doc/draft-koch-openpgp-webkey-service/">OpenPGP Web Key Directory</a>
+ */
+public final class WKDAddress {
+
+    // RegEx for Email Addresses.
+    // https://www.baeldung.com/java-email-validation-regex#regular-expression-by-rfc-5322-for-email-validation
+    // Modified by adding capture groups '()' for local and domain part
+    private static final Pattern PATTERN_EMAIL = Pattern.compile("^([a-zA-Z0-9_!#$%&'*+/=?`{|}~^.-]+)@([a-zA-Z0-9.-]+)$");
+
+    // Firstname Lastname <email@address> [Optional Comment]
+    // we are only interested in "email@address"
+    private static final Pattern PATTERN_USER_ID = Pattern.compile("^.*\\<([a-zA-Z0-9_!#$%&'*+/=?`{|}~^.-]+@[a-zA-Z0-9.-]+)\\>.*");
+
+    private static final ZBase32 zBase32 = new ZBase32();
+    private static final Charset utf8 = Charset.forName("UTF8");
+
+    private static final String SCHEME = "https://";
+    private static final String SUBDOMAIN = "openpgpkey";
+    private static final String PATH = "/.well-known/openpgpkey/";
+    private static final String HU = "/hu/";
+    private static final String PATH_HU = "/.well-known/openpgpkey/hu/";
+
+    private WKDAddress() {
+
+    }
+
+    public static String emailFromUserId(String userId) {
+        Matcher matcher = PATTERN_USER_ID.matcher(userId);
+        if (!matcher.matches()) {
+            throw new IllegalArgumentException("User-ID does not follow excepted pattern \"Firstname Lastname <email.address> [Optional Comment]\"");
+        }
+
+        String email = matcher.group(1);
+        return email;
+    }
+
+    public static URI directFromUserId(String userId) {
+        String email = emailFromUserId(userId);
+        return directFromEmail(email);
+    }
+
+    public static URI directFromEmail(String email) {
+        MailAddress mailAddress = parseMailAddress(email);
+
+        return URI.create(SCHEME + mailAddress.getDomainPart() + PATH_HU + mailAddress.getHashedLocalPart() + "?l=" + mailAddress.getPercentEncodedLocalPart());
+    }
+
+    /**
+     * Extract the email address from a user-id.
+     * The user-id is expected to correspond to a RFC2822 name-addr.
+     * The email address is expected to be framed by angle brackets.
+     *
+     * @see <a href="https://datatracker.ietf.org/doc/html/rfc2822#section-3.4">RFC2822 - Internet Message Format §3.4: Address Specification</a>
+     * @param userId user-id name-addr
+     * @return WKD URI
+     *
+     * @throws IllegalArgumentException in case the user-id does not match the expected format
+     */
+    public static URI advancedFromUserId(String userId) {
+        String email = emailFromUserId(userId);
+        return advancedFromEmail(email);
+    }
+
+    /**
+     * Translate an email address (localpart@domainpart) to a WKD URI.
+     *
+     * @param email email address
+     * @return WKD URI
+     * @throws IllegalArgumentException in case of a malformed email address
+     */
+    public static URI advancedFromEmail(String email) {
+        MailAddress mailAddress = parseMailAddress(email);
+
+        return URI.create(
+                SCHEME + SUBDOMAIN + "." + mailAddress.getDomainPart() + PATH + mailAddress.getDomainPart()
+                        + HU + mailAddress.getHashedLocalPart() + "?l=" + mailAddress.getPercentEncodedLocalPart()
+        );
+    }
+
+    private static MailAddress parseMailAddress(String email) {
+        Matcher matcher = PATTERN_EMAIL.matcher(email);
+        if (!matcher.matches()) {
+            throw new IllegalArgumentException("Invalid email address.");
+        }
+
+        String localPart = matcher.group(1);
+        String domainPart = matcher.group(2);
+        return new MailAddress(localPart, domainPart);
+    }
+
+    private static class MailAddress {
+        private final String localPart;
+        private final String domainPart;
+
+        MailAddress(String localPart, String domainPart) {
+            this.localPart = localPart;
+            this.domainPart = domainPart;
+        }
+
+        public String getLocalPart() {
+            return localPart;
+        }
+
+        public String getLowerCaseLocalPart() {
+            return getLocalPart().toLowerCase();
+        }
+
+        public String getPercentEncodedLocalPart() {
+            try {
+                return URLEncoder.encode(getLocalPart(), "UTF-8");
+            } catch (UnsupportedEncodingException e) {
+                // UTF8 is a MUST on JVM implementations
+                throw new AssertionError(e);
+            }
+        }
+
+        public String getHashedLocalPart() {
+            MessageDigest sha1;
+            try {
+                sha1 = MessageDigest.getInstance("SHA1");
+            } catch (NoSuchAlgorithmException e) {
+                // SHA-1 is a MUST on JVM implementations
+                throw new AssertionError(e);
+            }
+            sha1.update(getLowerCaseLocalPart().getBytes(utf8));
+            byte[] digest = sha1.digest();
+
+            String base32KeyHandle = zBase32.encodeAsString(digest);
+            return base32KeyHandle;
+        }
+
+        public String getDomainPart() {
+            return domainPart.toLowerCase();
+        }
+    }
+}

wkd-java/src/main/java/pgp/wkd/package-info.java

@@ -0,0 +1,10 @@
+// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+/**
+ * Utility classes related to the Web Key Directory Specification.
+ *
+ * @see <a href="https://datatracker.ietf.org/doc/draft-koch-openpgp-webkey-service/">OpenPGP Web Key Directory</a>
+ */
+package pgp.wkd;

wkd-java/src/test/java/pgp/wkd/WKDAddressTest.java

@@ -0,0 +1,76 @@
+// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package pgp.wkd;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.net.URI;
+import java.util.Arrays;
+
+import org.junit.jupiter.api.Test;
+
+public class WKDAddressTest {
+
+    @Test
+    public void testAdvancedFromUserId() {
+        String userId = "Joe Doe <Joe.Doe@Example.ORG> [Work Address]";
+        URI expectedURI = URI.create("https://openpgpkey.example.org/.well-known/openpgpkey/example.org/hu/iy9q119eutrkn8s1mk4r39qejnbu3n5q?l=Joe.Doe");
+
+        URI actual = WKDAddress.advancedFromUserId(userId);
+        assertEquals(expectedURI, actual);
+    }
+
+    @Test
+    public void testDirectFromUserId2() {
+        String userId = "<alice@pgpainless.org>";
+        URI expected = URI.create("https://pgpainless.org/.well-known/openpgpkey/hu/kei1q4tipxxu1yj79k9kfukdhfy631xe?l=alice");
+        URI actual = WKDAddress.directFromUserId(userId);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void testDirectFromEmail() {
+        String mailAddress = "Joe.Doe@Example.ORG";
+        URI expected = URI.create("https://example.org/.well-known/openpgpkey/hu/iy9q119eutrkn8s1mk4r39qejnbu3n5q?l=Joe.Doe");
+
+        URI actual = WKDAddress.directFromEmail(mailAddress);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void testAdvancedFromEmail() {
+        String mailAddress = "Joe.Doe@Example.ORG";
+        URI expected = URI.create("https://openpgpkey.example.org/.well-known/openpgpkey/example.org/hu/iy9q119eutrkn8s1mk4r39qejnbu3n5q?l=Joe.Doe");
+
+        URI actual = WKDAddress.advancedFromEmail(mailAddress);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void testFromInvalidUserid() {
+        for (String brokenUserId : Arrays.asList(
+                "Alice <alice>",
+                "Alice <alice@example.org",
+                "Alice",
+                "John Doe <john doe@example.org>",
+                "John Doe <john.doe@example org>",
+                "John Doe <john<example.org>",
+                "John Doe [The Real One]",
+                "<John Doe",
+                "Don Joeh>")) {
+            assertThrows(IllegalArgumentException.class, () -> WKDAddress.directFromUserId(brokenUserId));
+            assertThrows(IllegalArgumentException.class, () -> WKDAddress.advancedFromUserId(brokenUserId));
+        }
+    }
+
+    @Test
+    public void testFromInvalidEmail() {
+        for (String brokenEmail : Arrays.asList("john.doe", "@example.org", "john doe@example.org", "john.doe@example org")) {
+            assertThrows(IllegalArgumentException.class, () -> WKDAddress.directFromEmail(brokenEmail));
+            assertThrows(IllegalArgumentException.class, () -> WKDAddress.advancedFromEmail(brokenEmail));
+        }
+    }
+}

wkd-java/src/test/java/pgp/wkd/WKDResolverTest.java

@@ -1,42 +0,0 @@
-// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package pgp.wkd;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertThrows;
-
-import java.net.URI;
-
-import org.junit.jupiter.api.Test;
-
-public class WKDResolverTest {
-
-    @Test
-    public void testUserIdToUri() {
-        String userId = "Joe Doe <joe.doe@example.org> [Work Address]";
-        URI expectedURI = URI.create("https://example.org/.well-known/openpgpkey/hu/iy9q119eutrkn8s1mk4r39qejnbu3n5q");
-
-        URI actual = new UserIdToWKDAddress().userIdToUri(userId);
-        assertEquals(expectedURI, actual);
-    }
-
-    @Test
-    public void testMailToUri() {
-        String mailAddress = "Joe.Doe@Example.ORG";
-        URI expectedURI = URI.create("https://example.org/.well-known/openpgpkey/hu/iy9q119eutrkn8s1mk4r39qejnbu3n5q");
-
-        URI actual = new UserIdToWKDAddress().mailToUri(mailAddress);
-        assertEquals(expectedURI, actual);
-    }
-
-    @Test
-    public void testInvalidEmailToUri() {
-        UserIdToWKDAddress uid2wkd = new UserIdToWKDAddress();
-        assertThrows(IllegalArgumentException.class, () -> uid2wkd.mailToUri("john.doe"));
-        assertThrows(IllegalArgumentException.class, () -> uid2wkd.mailToUri("@example.org"));
-        assertThrows(IllegalArgumentException.class, () -> uid2wkd.mailToUri("john doe@example.org"));
-        assertThrows(IllegalArgumentException.class, () -> uid2wkd.mailToUri("john.doe@example org"));
-    }
-}