+package org.asamk.signal.manager.api;
+
+import org.signal.core.util.Base64;
+import org.whispersystems.signalservice.api.push.UsernameLinkComponents;
+import org.whispersystems.signalservice.api.util.UuidUtil;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.regex.Pattern;
+
+public final class UsernameLinkUrl {
+
+ private static final Pattern URL_REGEX = Pattern.compile("(https://)?signal.me/?#eu/([a-zA-Z0-9+\\-_/]+)");
+
+ private static final String BASE_URL = "https://signal.me/#eu/";
+
+ private final String url;
+ private final UsernameLinkComponents usernameLinkComponents;
+
+ public static UsernameLinkUrl fromUri(String url) throws InvalidUsernameLinkException {
+ final var matcher = URL_REGEX.matcher(url);
+ if (!matcher.matches()) {
+ throw new InvalidUsernameLinkException("Invalid username link");
+ }
+ final var path = matcher.group(2);
+ final byte[] allBytes;
+ try {
+ allBytes = Base64.decode(path);
+ } catch (IOException e) {
+ throw new InvalidUsernameLinkException("Invalid base64 encoding");
+ }
+
+ if (allBytes.length != 48) {
+ throw new InvalidUsernameLinkException("Invalid username link");
+ }
+
+ final var entropy = Arrays.copyOfRange(allBytes, 0, 32);
+ final var serverId = Arrays.copyOfRange(allBytes, 32, allBytes.length);
+ final var serverIdUuid = UuidUtil.parseOrNull(serverId);
+ if (serverIdUuid == null) {
+ throw new InvalidUsernameLinkException("Invalid serverId");
+ }
+
+ return new UsernameLinkUrl(new UsernameLinkComponents(entropy, serverIdUuid));
+ }
+
+ public UsernameLinkUrl(UsernameLinkComponents usernameLinkComponents) {
+ this.usernameLinkComponents = usernameLinkComponents;
+ this.url = createUrl(usernameLinkComponents);
+ }
+
+ private static String createUrl(UsernameLinkComponents usernameLinkComponents) {
+ final var entropy = usernameLinkComponents.getEntropy();
+ final var serverId = UuidUtil.toByteArray(usernameLinkComponents.getServerId());
+
+ final var combined = new byte[entropy.length + serverId.length];
+ System.arraycopy(entropy, 0, combined, 0, entropy.length);
+ System.arraycopy(serverId, 0, combined, entropy.length, serverId.length);
+
+ final var base64 = Base64.encodeUrlSafeWithoutPadding(combined);
+ return BASE_URL + base64;
+ }
+
+ public String getUrl() {
+ return url;
+ }
+
+ public UsernameLinkComponents getComponents() {
+ return usernameLinkComponents;
+ }
+
+ public static final class InvalidUsernameLinkException extends Exception {
+
+ public InvalidUsernameLinkException(String message) {
+ super(message);
+ }
+
+ public InvalidUsernameLinkException(Throwable cause) {
+ super(cause);
+ }
+ }
+}
git.nmode.ca / signal-cli / commitdiff
