+package org.asamk.signal.manager.util;
+
+import java.net.URLDecoder;
+import java.nio.charset.StandardCharsets;
+import java.util.Base64;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+@SuppressWarnings({"java:S6218"})
+public record DataURI(String mediaType, Map<String, String> parameter, byte[] data) {
+
+ public static final Pattern DATA_URI_PATTERN = Pattern.compile(
+ "\\Adata:(?<type>.+?/.+?)?(?<parameters>;.+?=.+?)?(?<base64>;base64)?,(?<data>.+)\\z",
+ Pattern.CASE_INSENSITIVE);
+ public static final Pattern PARAMETER_PATTERN = Pattern.compile("\\G;(?<key>.+)=(?<value>.+)",
+ Pattern.CASE_INSENSITIVE);
+ public static final String DEFAULT_TYPE = "text/plain";
+
+ /**
+ * Generates a new {@link DataURI} object that follows
+ * <a href="https://datatracker.ietf.org/doc/html/rfc2397">RFC 2397</a> from the given string.
+ * <p>
+ * The {@code dataURI} must be of the form:
+ * <p>
+ * {@code
+ * data:[<mediatype>][;base64],<data>
+ * }
+ * <p>
+ * The {@code <mediatype>} is an Internet media type specification (with
+ * optional parameters.) The appearance of ";base64" means that the data
+ * is encoded as base64. Without ";base64", the data is represented using (ASCII) URL Escaped encoding.
+ * If {@code <mediatype>} is omitted, it defaults to {@link DataURI#DEFAULT_TYPE}.
+ * Parameter values should use the URL Escaped encoding.
+ *
+ * @param dataURI the data URI
+ * @return a data URI object
+ * @throws IllegalArgumentException if the given string is not a valid data URI
+ */
+ public static DataURI of(final String dataURI) {
+ final var matcher = DATA_URI_PATTERN.matcher(dataURI);
+
+ if (!matcher.find()) {
+ throw new IllegalArgumentException("The given string is not a valid data URI.");
+ }
+
+ final Map<String, String> parameters = new HashMap<>();
+ final var params = matcher.group("parameters");
+ if (params != null) {
+ final Matcher paramsMatcher = PARAMETER_PATTERN.matcher(params);
+ while (paramsMatcher.find()) {
+ final var key = paramsMatcher.group("key");
+ final var value = URLDecoder.decode(paramsMatcher.group("value"), StandardCharsets.UTF_8);
+ parameters.put(key, value);
+ }
+ }
+
+ final boolean isBase64 = matcher.group("base64") != null;
+ final byte[] data;
+ if (isBase64) {
+ data = Base64.getDecoder().decode(matcher.group("data").getBytes(StandardCharsets.UTF_8));
+ } else {
+ data = URLDecoder.decode(matcher.group("data"), StandardCharsets.UTF_8).getBytes(StandardCharsets.UTF_8);
+ }
+
+ return new DataURI(Optional.ofNullable(matcher.group("type")).orElse(DEFAULT_TYPE), parameters, data);
+ }
+}
git.nmode.ca / signal-cli / commitdiff
