Allow BLOB columns with utf8mb3 charset

[juan-ferrer-toribio]

Fixes #143

[rhwinter]

I was running into this issue when using @rodrigogs/mysql-events. Since I don't have access to configure the MySQL server, which is likely the culprit of the issue (wrong charset encoding settings).

The following error would be thrown when something changed in certain databases/tables/columns:

Error: Encoding not recognized: 'utf8mb3' (searched as: 'utf8mb3')
      at Object.getCodec (_____/node_modules/iconv-lite/lib/index.js:106:23)
      at Object.getDecoder (_____/node_modules/iconv-lite/lib/index.js:127:23)
      at Object.decode (_____/node_modules/iconv-lite/lib/index.js:40:25)
      at exports.readMysqlValue (_____/node_modules/@rodrigogs/zongji/lib/common.js:461:24)
      at readRow (_____/node_modules/@rodrigogs/zongji/lib/rows_event.js:111:16)
      at RowsEvent._fetchOneRow (_____/node_modules/@rodrigogs/zongji/lib/rows_event.js:93:10)
      at DeleteRows.RowsEvent (_____/node_modules/@rodrigogs/zongji/lib/rows_event.js:62:27)
      at new DeleteRows (_____/node_modules/@rodrigogs/zongji/lib/rows_event.js:128:13)
      at BinlogHeader.parse (_____/node_modules/@rodrigogs/zongji/lib/packet/binlog_header.js:47:23)
      at Protocol._parsePacket (_____/node_modules/mysql/lib/protocol/Protocol.js:272:12)

which would be followed by a mysql-events connection error:

Error: Packets out of order. Got: 161 Expected: 42
      at Parser._tryReadPacketHeader (_____/node_modules/mysql/lib/protocol/Parser.js:470:15)
      at Parser.write (_____/node_modules/mysql/lib/protocol/Parser.js:33:29)
      at Protocol.write (_____/node_modules/mysql/lib/protocol/Protocol.js:38:16)
      at Socket.<anonymous> (_____/node_modules/mysql/lib/Connection.js:88:28)
      at Socket.<anonymous> (_____/node_modules/mysql/lib/Connection.js:526:10)
      at Socket.emit (node:events:511:28)
      at Socket.emit (node:domain:489:12)
      at Readable.read (node:internal/streams/readable:547:10)
      at Socket.read (node:net:765:39)
      at flow (node:internal/streams/readable:1031:34)
      --------------------
      at Protocol._enqueue (_____/node_modules/mysql/lib/protocol/Protocol.js:144:48)
      at Immediate._start (_____/node_modules/@rodrigogs/zongji/index.js:240:31)
      at process.processImmediate (node:internal/timers:478:21) {
    code: 'PROTOCOL_PACKETS_OUT_OF_ORDER',
    fatal: true
  }

I patched @rodrigogs/zongji's common.js as follows:

diff --git a/node_modules/@rodrigogs/zongji/lib/common.js b/node_modules/@rodrigogs/zongji/lib/common.js
index 89bf7ed..1cb9c6f 100644
--- a/node_modules/@rodrigogs/zongji/lib/common.js
+++ b/node_modules/@rodrigogs/zongji/lib/common.js
@@ -440,7 +440,7 @@ exports.readMysqlValue = function(
       } else {
         if (column.charset !== null) {
           // Javascript UTF8 always allows up to 4 bytes per character
-          column.charset = column.charset === 'utf8mb4' ? 'utf8' : column.charset;
+          column.charset = column.charset.startsWith('utf8mb') ? 'utf8' : column.charset;
           parser._encoding = column.charset;
         }
         result = parser.parseString(size);
@@ -457,7 +457,7 @@ exports.readMysqlValue = function(
       // e.g. TINYTEXT, MEDIUMTEXT, LONGTEXT, TEXT data types
       if (column.charset !== null) {
         // Javascript UTF8 always allows up to 4 bytes per character
-        column.charset = column.charset === 'utf8mb4' ? 'utf8' : column.charset;
+        column.charset = column.charset.startsWith('utf8mb') ? 'utf8' : column.charset;
         result = iconv.decode(result, column.charset);
       }
       break;

Maybe this can be of help to someone out there (I couldn't find any information about these errors and issue).