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Standalone fully-featured Whatsapp Web API for Java and Kotlin
package it.auties.whatsapp.binary;
import it.auties.bytes.Bytes;
import it.auties.whatsapp.model.contact.ContactJid;
import it.auties.whatsapp.model.request.Node;
import java.nio.charset.StandardCharsets;
import java.util.Collection;
import java.util.List;
import java.util.Objects;
import static it.auties.whatsapp.binary.Tag.*;
// TODO: Switch off my bad Bytes class to a better lib so buffer can be final
public class Encoder {
private static final int UNSIGNED_BYTE_MAX_VALUE = 256;
private static final int UNSIGNED_SHORT_MAX_VALUE = 65536;
private static final int INT_20_MAX_VALUE = 1048576;
private Bytes buffer;
private final List singleByteTokens;
private final List doubleByteTokens;
public Encoder(){
this(Tokens.SINGLE_BYTE, Tokens.DOUBLE_BYTE);
}
public Encoder(List singleByteTokens, List doubleByteTokens){
this.singleByteTokens = singleByteTokens;
this.doubleByteTokens = doubleByteTokens;
}
public byte[] encode(Node node) {
this.buffer = Bytes.newBuffer();
var encoded = writeNode(node);
var result = new byte[1 + encoded.length];
result[0] = 0;
System.arraycopy(encoded, 0, result, 1, encoded.length);
return result;
}
private void writeString(String input, Tag token) {
this.buffer = buffer.append(token.data());
writeStringLength(input);
for (int charCode = 0, index = 0; index < input.length(); index++) {
var stringCodePoint = Character.codePointAt(input, index);
var binaryCodePoint = getStringCodePoint(token, stringCodePoint);
if (index % 2 != 0) {
this.buffer = buffer.append(charCode |= binaryCodePoint);
continue;
}
charCode = binaryCodePoint << 4;
if (index != input.length() - 1) {
continue;
}
this.buffer = buffer.append(charCode |= 15);
}
}
private int getStringCodePoint(Tag token, int codePoint) {
if (codePoint >= 48 && codePoint <= 57) {
return codePoint - 48;
}
if (token == NIBBLE_8 && codePoint == 45) {
return 10;
}
if (token == NIBBLE_8 && codePoint == 46) {
return 11;
}
if (token == HEX_8 && codePoint >= 65 && codePoint <= 70) {
return codePoint - 55;
}
throw new IllegalArgumentException("Cannot parse codepoint %s with token %s".formatted(codePoint, token));
}
private void writeStringLength(String input) {
var roundedLength = (int) Math.ceil(input.length() / 2F);
if (input.length() % 2 == 1) {
this.buffer = buffer.append(roundedLength | 128);
return;
}
this.buffer = buffer.append(roundedLength);
}
private void writeLong(long input) {
if (input < UNSIGNED_BYTE_MAX_VALUE) {
this.buffer = buffer.append(BINARY_8.data());
this.buffer = buffer.append((int) input);
return;
}
if (input < INT_20_MAX_VALUE) {
this.buffer = buffer.append(BINARY_20.data());
this.buffer = buffer.append((int) ((input >>> 16) & 255));
this.buffer = buffer.append((int) ((input >>> 8) & 255));
this.buffer = buffer.append((int) (255 & input));
return;
}
this.buffer = buffer.append(BINARY_32.data());
buffer.appendLong(input);
}
private void writeString(String input) {
if (input.isEmpty()) {
this.buffer = buffer.append(BINARY_8.data());
this.buffer = buffer.append(LIST_EMPTY.data());
return;
}
var tokenIndex = singleByteTokens.indexOf(input);
if (tokenIndex != -1) {
this.buffer = buffer.append(tokenIndex + 1);
return;
}
if (writeDoubleByteString(input)) {
return;
}
var length = length(input);
if (length < 128 && !Tokens.anyMatch(input, Tokens.NUMBERS_REGEX)) {
writeString(input, NIBBLE_8);
return;
}
if (length < 128 && !Tokens.anyMatch(input, Tokens.HEX_REGEX)) {
writeString(input, HEX_8);
return;
}
writeLong(length);
this.buffer = buffer.append(input.getBytes(StandardCharsets.UTF_8));
}
private boolean writeDoubleByteString(String input) {
if (!doubleByteTokens.contains(input)) {
return false;
}
var index = doubleByteTokens.indexOf(input);
this.buffer = buffer.append(doubleByteStringTag(index).data());
this.buffer = buffer.append(index % (doubleByteTokens.size() / 4));
return true;
}
private Tag doubleByteStringTag(int index) {
return switch (index / (doubleByteTokens.size() / 4)) {
case 0 -> DICTIONARY_0;
case 1 -> DICTIONARY_1;
case 2 -> DICTIONARY_2;
case 3 -> DICTIONARY_3;
default -> throw new IllegalArgumentException("Cannot find tag for quadrant %s".formatted(index));
};
}
private byte[] writeNode(Node input) {
if (input.description().equals("0")) {
this.buffer = buffer.append(LIST_8.data());
this.buffer = buffer.append(LIST_EMPTY.data());
return buffer.toByteArray();
}
writeInt(input.size());
writeString(input.description());
writeAttributes(input);
if (input.hasContent()) {
write(input.content());
}
return buffer.toByteArray();
}
private void writeAttributes(Node input) {
input.attributes().toMap().forEach((key, value) -> {
writeString(key);
write(value);
});
}
private void writeInt(int size) {
if (size < UNSIGNED_BYTE_MAX_VALUE) {
this.buffer = buffer.append(LIST_8.data());
this.buffer = buffer.append(size);
return;
}
if (size < UNSIGNED_SHORT_MAX_VALUE) {
this.buffer = buffer.append(LIST_16.data());
buffer.appendShort(size);
return;
}
throw new IllegalArgumentException("Cannot write int %s: overflow".formatted(size));
}
private void write(Object input) {
switch (input) {
case null -> this.buffer = buffer.append(LIST_EMPTY.data());
case String str -> writeString(str);
case Boolean bool -> writeString(Boolean.toString(bool));
case Number number -> writeString(number.toString());
case byte[] bytes -> writeBytes(bytes);
case ContactJid jid -> writeJid(jid);
case Collection collection -> writeList(collection);
case Enum serializable -> writeString(Objects.toString(serializable));
case Node ignored ->
throw new IllegalArgumentException("Invalid payload type(nodes should be wrapped by a collection): %s".formatted(input));
default -> throw new IllegalArgumentException("Invalid payload type(%s): %s".formatted(input.getClass()
.getName(), input));
}
}
private void writeList(Collection collection) {
writeInt(collection.size());
collection.stream().filter(entry -> entry instanceof Node).map(entry -> (Node) entry).forEach(this::writeNode);
}
private void writeBytes(byte[] bytes) {
writeLong(bytes.length);
this.buffer = buffer.append(bytes);
}
private void writeJid(ContactJid jid) {
if (jid.isCompanion()) {
this.buffer = buffer.append(COMPANION_JID.data());
this.buffer = buffer.append(jid.agent());
this.buffer = buffer.append(jid.device());
writeString(jid.user());
return;
}
this.buffer = buffer.append(JID_PAIR.data());
if (jid.user() != null) {
writeString(jid.user());
writeString(jid.server().address());
return;
}
this.buffer = buffer.append(LIST_EMPTY.data());
writeString(jid.server().address());
}
private int length(String input) {
return input.getBytes(StandardCharsets.UTF_8).length;
}
}