nmode's Git Repositories - signal-cli/blob - lib/src/main/java/org/asamk/signal/manager/util/DataURI.java

   1 package org.asamk.signal.manager.util;
   2
   3 import java.net.URLDecoder;
   4 import java.nio.charset.StandardCharsets;
   5 import java.util.Base64;
   6 import java.util.HashMap;
   7 import java.util.Map;
   8 import java.util.Optional;
   9 import java.util.regex.Matcher;
  10 import java.util.regex.Pattern;
  11
  12 @SuppressWarnings({"java:S6218"})
  13 public record DataURI(String mediaType, Map<String, String> parameter, byte[] data) {
  14
  15     public static final Pattern DATA_URI_PATTERN = Pattern.compile(
  16             "\\Adata:(?<type>.+?/.+?)?(?<parameters>;.+?=.+?)?(?<base64>;base64)?,(?<data>.+)\\z",
  17             Pattern.CASE_INSENSITIVE);
  18     public static final Pattern PARAMETER_PATTERN = Pattern.compile("\\G;(?<key>.+)=(?<value>.+)",
  19             Pattern.CASE_INSENSITIVE);
  20
  21     /**
  22      * Generates a new {@link DataURI} object that follows
  23      * <a href="https://datatracker.ietf.org/doc/html/rfc2397">RFC 2397</a> from the given string.
  24      * <p>
  25      * The {@code dataURI} must be of the form:
  26      * <p>
  27      * {@code
  28      * data:[<mediatype>][;base64],<data>
  29      * }
  30      * <p>
  31      * The {@code <mediatype>} is an Internet media type specification (with
  32      * optional parameters.) The appearance of ";base64" means that the data
  33      * is encoded as base64. Without ";base64", the data is represented using (ASCII) URL Escaped encoding.
  34      * If {@code <mediatype>} is omitted, it defaults to {@link MimeUtils#PLAIN_TEXT}.
  35      * Parameter values should use the URL Escaped encoding.
  36      *
  37      * @param dataURI the data URI
  38      * @return a data URI object
  39      * @throws IllegalArgumentException if the given string is not a valid data URI
  40      */
  41     public static DataURI of(final String dataURI) {
  42         final var matcher = DATA_URI_PATTERN.matcher(dataURI);
  43
  44         if (!matcher.find()) {
  45             throw new IllegalArgumentException("The given string is not a valid data URI.");
  46         }
  47
  48         final Map<String, String> parameters = new HashMap<>();
  49         final var params = matcher.group("parameters");
  50         if (params != null) {
  51             final Matcher paramsMatcher = PARAMETER_PATTERN.matcher(params);
  52             while (paramsMatcher.find()) {
  53                 final var key = paramsMatcher.group("key");
  54                 final var value = URLDecoder.decode(paramsMatcher.group("value"), StandardCharsets.UTF_8);
  55                 parameters.put(key, value);
  56             }
  57         }
  58
  59         final boolean isBase64 = matcher.group("base64") != null;
  60         final byte[] data;
  61         if (isBase64) {
  62             data = Base64.getDecoder().decode(matcher.group("data").getBytes(StandardCharsets.UTF_8));
  63         } else {
  64             data = URLDecoder.decode(matcher.group("data"), StandardCharsets.UTF_8).getBytes(StandardCharsets.UTF_8);
  65         }
  66
  67         return new DataURI(Optional.ofNullable(matcher.group("type")).orElse(MimeUtils.PLAIN_TEXT), parameters, data);
  68     }
  69 }