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     public static final String DEFAULT_TYPE = "text/plain";
  21
  22     /**
  23      * Generates a new {@link DataURI} object that follows
  24      * <a href="https://datatracker.ietf.org/doc/html/rfc2397">RFC 2397</a> from the given string.
  25      * <p>
  26      * The {@code dataURI} must be of the form:
  27      * <p>
  28      * {@code
  29      * data:[<mediatype>][;base64],<data>
  30      * }
  31      * <p>
  32      * The {@code <mediatype>} is an Internet media type specification (with
  33      * optional parameters.) The appearance of ";base64" means that the data
  34      * is encoded as base64. Without ";base64", the data is represented using (ASCII) URL Escaped encoding.
  35      * If {@code <mediatype>} is omitted, it defaults to {@link DataURI#DEFAULT_TYPE}.
  36      * Parameter values should use the URL Escaped encoding.
  37      *
  38      * @param dataURI the data URI
  39      * @return a data URI object
  40      * @throws IllegalArgumentException if the given string is not a valid data URI
  41      */
  42     public static DataURI of(final String dataURI) {
  43         final var matcher = DATA_URI_PATTERN.matcher(dataURI);
  44
  45         if (!matcher.find()) {
  46             throw new IllegalArgumentException("The given string is not a valid data URI.");
  47         }
  48
  49         final Map<String, String> parameters = new HashMap<>();
  50         final var params = matcher.group("parameters");
  51         if (params != null) {
  52             final Matcher paramsMatcher = PARAMETER_PATTERN.matcher(params);
  53             while (paramsMatcher.find()) {
  54                 final var key = paramsMatcher.group("key");
  55                 final var value = URLDecoder.decode(paramsMatcher.group("value"), StandardCharsets.UTF_8);
  56                 parameters.put(key, value);
  57             }
  58         }
  59
  60         final boolean isBase64 = matcher.group("base64") != null;
  61         final byte[] data;
  62         if (isBase64) {
  63             data = Base64.getDecoder().decode(matcher.group("data").getBytes(StandardCharsets.UTF_8));
  64         } else {
  65             data = URLDecoder.decode(matcher.group("data"), StandardCharsets.UTF_8).getBytes(StandardCharsets.UTF_8);
  66         }
  67
  68         return new DataURI(Optional.ofNullable(matcher.group("type")).orElse(DEFAULT_TYPE), parameters, data);
  69     }
  70 }