send-mail/node_modules/nodemailer/lib/base64/index.js

143 lines
3.7 KiB
JavaScript
Raw Normal View History

2020-03-01 05:01:03 +07:00
'use strict';
const Transform = require('stream').Transform;
/**
* Encodes a Buffer into a base64 encoded string
*
* @param {Buffer} buffer Buffer to convert
* @returns {String} base64 encoded string
*/
function encode(buffer) {
if (typeof buffer === 'string') {
buffer = Buffer.from(buffer, 'utf-8');
}
return buffer.toString('base64');
}
/**
* Adds soft line breaks to a base64 string
*
* @param {String} str base64 encoded string that might need line wrapping
* @param {Number} [lineLength=76] Maximum allowed length for a line
* @returns {String} Soft-wrapped base64 encoded string
*/
function wrap(str, lineLength) {
str = (str || '').toString();
lineLength = lineLength || 76;
if (str.length <= lineLength) {
return str;
}
let result = [];
let pos = 0;
let chunkLength = lineLength * 1024;
while (pos < str.length) {
let wrappedLines = str
.substr(pos, chunkLength)
.replace(new RegExp('.{' + lineLength + '}', 'g'), '$&\r\n')
.trim();
result.push(wrappedLines);
pos += chunkLength;
}
return result.join('\r\n').trim();
}
/**
* Creates a transform stream for encoding data to base64 encoding
*
* @constructor
* @param {Object} options Stream options
2022-10-21 21:52:45 +07:00
* @param {Number} [options.lineLength=76] Maximum length for lines, set to false to disable wrapping
2020-03-01 05:01:03 +07:00
*/
class Encoder extends Transform {
constructor(options) {
super();
// init Transform
this.options = options || {};
if (this.options.lineLength !== false) {
this.options.lineLength = this.options.lineLength || 76;
}
this._curLine = '';
this._remainingBytes = false;
this.inputBytes = 0;
this.outputBytes = 0;
}
_transform(chunk, encoding, done) {
if (encoding !== 'buffer') {
chunk = Buffer.from(chunk, encoding);
}
if (!chunk || !chunk.length) {
return setImmediate(done);
}
this.inputBytes += chunk.length;
if (this._remainingBytes && this._remainingBytes.length) {
chunk = Buffer.concat([this._remainingBytes, chunk], this._remainingBytes.length + chunk.length);
this._remainingBytes = false;
}
if (chunk.length % 3) {
this._remainingBytes = chunk.slice(chunk.length - (chunk.length % 3));
chunk = chunk.slice(0, chunk.length - (chunk.length % 3));
} else {
this._remainingBytes = false;
}
let b64 = this._curLine + encode(chunk);
if (this.options.lineLength) {
b64 = wrap(b64, this.options.lineLength);
// remove last line as it is still most probably incomplete
let lastLF = b64.lastIndexOf('\n');
if (lastLF < 0) {
this._curLine = b64;
b64 = '';
} else if (lastLF === b64.length - 1) {
this._curLine = '';
} else {
this._curLine = b64.substr(lastLF + 1);
b64 = b64.substr(0, lastLF + 1);
}
}
if (b64) {
this.outputBytes += b64.length;
this.push(Buffer.from(b64, 'ascii'));
}
setImmediate(done);
}
_flush(done) {
if (this._remainingBytes && this._remainingBytes.length) {
this._curLine += encode(this._remainingBytes);
}
if (this._curLine) {
this._curLine = wrap(this._curLine, this.options.lineLength);
this.outputBytes += this._curLine.length;
this.push(this._curLine, 'ascii');
this._curLine = '';
}
done();
}
}
// expose to the world
module.exports = {
encode,
wrap,
Encoder
};