send-mail/node_modules/nodemailer/lib/mime-funcs/index.js
2020-11-12 16:30:46 +01:00

620 lines
23 KiB
JavaScript
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/* eslint no-control-regex:0 */
'use strict';
const base64 = require('../base64');
const qp = require('../qp');
const mimeTypes = require('./mime-types');
module.exports = {
/**
* Checks if a value is plaintext string (uses only printable 7bit chars)
*
* @param {String} value String to be tested
* @returns {Boolean} true if it is a plaintext string
*/
isPlainText(value, isParam) {
const re = isParam ? /[\x00-\x08\x0b\x0c\x0e-\x1f"\u0080-\uFFFF]/ : /[\x00-\x08\x0b\x0c\x0e-\x1f\u0080-\uFFFF]/;
if (typeof value !== 'string' || re.test(value)) {
return false;
} else {
return true;
}
},
/**
* Checks if a multi line string containes lines longer than the selected value.
*
* Useful when detecting if a mail message needs any processing at all
* if only plaintext characters are used and lines are short, then there is
* no need to encode the values in any way. If the value is plaintext but has
* longer lines then allowed, then use format=flowed
*
* @param {Number} lineLength Max line length to check for
* @returns {Boolean} Returns true if there is at least one line longer than lineLength chars
*/
hasLongerLines(str, lineLength) {
if (str.length > 128 * 1024) {
// do not test strings longer than 128kB
return true;
}
return new RegExp('^.{' + (lineLength + 1) + ',}', 'm').test(str);
},
/**
* Encodes a string or an Buffer to an UTF-8 MIME Word (rfc2047)
*
* @param {String|Buffer} data String to be encoded
* @param {String} mimeWordEncoding='Q' Encoding for the mime word, either Q or B
* @param {Number} [maxLength=0] If set, split mime words into several chunks if needed
* @return {String} Single or several mime words joined together
*/
encodeWord(data, mimeWordEncoding, maxLength) {
mimeWordEncoding = (mimeWordEncoding || 'Q').toString().toUpperCase().trim().charAt(0);
maxLength = maxLength || 0;
let encodedStr;
let toCharset = 'UTF-8';
if (maxLength && maxLength > 7 + toCharset.length) {
maxLength -= 7 + toCharset.length;
}
if (mimeWordEncoding === 'Q') {
// https://tools.ietf.org/html/rfc2047#section-5 rule (3)
encodedStr = qp.encode(data).replace(/[^a-z0-9!*+\-/=]/gi, chr => {
let ord = chr.charCodeAt(0).toString(16).toUpperCase();
if (chr === ' ') {
return '_';
} else {
return '=' + (ord.length === 1 ? '0' + ord : ord);
}
});
} else if (mimeWordEncoding === 'B') {
encodedStr = typeof data === 'string' ? data : base64.encode(data);
maxLength = maxLength ? Math.max(3, ((maxLength - (maxLength % 4)) / 4) * 3) : 0;
}
if (maxLength && (mimeWordEncoding !== 'B' ? encodedStr : base64.encode(data)).length > maxLength) {
if (mimeWordEncoding === 'Q') {
encodedStr = this.splitMimeEncodedString(encodedStr, maxLength).join('?= =?' + toCharset + '?' + mimeWordEncoding + '?');
} else {
// RFC2047 6.3 (2) states that encoded-word must include an integral number of characters, so no chopping unicode sequences
let parts = [];
let lpart = '';
for (let i = 0, len = encodedStr.length; i < len; i++) {
let chr = encodedStr.charAt(i);
// check if we can add this character to the existing string
// without breaking byte length limit
if (Buffer.byteLength(lpart + chr) <= maxLength || i === 0) {
lpart += chr;
} else {
// we hit the length limit, so push the existing string and start over
parts.push(base64.encode(lpart));
lpart = chr;
}
}
if (lpart) {
parts.push(base64.encode(lpart));
}
if (parts.length > 1) {
encodedStr = parts.join('?= =?' + toCharset + '?' + mimeWordEncoding + '?');
} else {
encodedStr = parts.join('');
}
}
} else if (mimeWordEncoding === 'B') {
encodedStr = base64.encode(data);
}
return '=?' + toCharset + '?' + mimeWordEncoding + '?' + encodedStr + (encodedStr.substr(-2) === '?=' ? '' : '?=');
},
/**
* Finds word sequences with non ascii text and converts these to mime words
*
* @param {String} value String to be encoded
* @param {String} mimeWordEncoding='Q' Encoding for the mime word, either Q or B
* @param {Number} [maxLength=0] If set, split mime words into several chunks if needed
* @param {Boolean} [encodeAll=false] If true and the value needs encoding then encodes entire string, not just the smallest match
* @return {String} String with possible mime words
*/
encodeWords(value, mimeWordEncoding, maxLength, encodeAll) {
maxLength = maxLength || 0;
let encodedValue;
// find first word with a non-printable ascii or special symbol in it
let firstMatch = value.match(/(?:^|\s)([^\s]*["\u0080-\uFFFF])/);
if (!firstMatch) {
return value;
}
if (encodeAll) {
// if it is requested to encode everything or the string contains something that resebles encoded word, then encode everything
return this.encodeWord(value, mimeWordEncoding, maxLength);
}
// find the last word with a non-printable ascii in it
let lastMatch = value.match(/(["\u0080-\uFFFF][^\s]*)[^"\u0080-\uFFFF]*$/);
if (!lastMatch) {
// should not happen
return value;
}
let startIndex =
firstMatch.index +
(
firstMatch[0].match(/[^\s]/) || {
index: 0
}
).index;
let endIndex = lastMatch.index + (lastMatch[1] || '').length;
encodedValue =
(startIndex ? value.substr(0, startIndex) : '') +
this.encodeWord(value.substring(startIndex, endIndex), mimeWordEncoding || 'Q', maxLength) +
(endIndex < value.length ? value.substr(endIndex) : '');
return encodedValue;
},
/**
* Joins parsed header value together as 'value; param1=value1; param2=value2'
* PS: We are following RFC 822 for the list of special characters that we need to keep in quotes.
* Refer: https://www.w3.org/Protocols/rfc1341/4_Content-Type.html
* @param {Object} structured Parsed header value
* @return {String} joined header value
*/
buildHeaderValue(structured) {
let paramsArray = [];
Object.keys(structured.params || {}).forEach(param => {
// filename might include unicode characters so it is a special case
// other values probably do not
let value = structured.params[param];
if (!this.isPlainText(value, true) || value.length >= 75) {
this.buildHeaderParam(param, value, 50).forEach(encodedParam => {
if (!/[\s"\\;:/=(),<>@[\]?]|^[-']|'$/.test(encodedParam.value) || encodedParam.key.substr(-1) === '*') {
paramsArray.push(encodedParam.key + '=' + encodedParam.value);
} else {
paramsArray.push(encodedParam.key + '=' + JSON.stringify(encodedParam.value));
}
});
} else if (/[\s'"\\;:/=(),<>@[\]?]|^-/.test(value)) {
paramsArray.push(param + '=' + JSON.stringify(value));
} else {
paramsArray.push(param + '=' + value);
}
});
return structured.value + (paramsArray.length ? '; ' + paramsArray.join('; ') : '');
},
/**
* Encodes a string or an Buffer to an UTF-8 Parameter Value Continuation encoding (rfc2231)
* Useful for splitting long parameter values.
*
* For example
* title="unicode string"
* becomes
* title*0*=utf-8''unicode
* title*1*=%20string
*
* @param {String|Buffer} data String to be encoded
* @param {Number} [maxLength=50] Max length for generated chunks
* @param {String} [fromCharset='UTF-8'] Source sharacter set
* @return {Array} A list of encoded keys and headers
*/
buildHeaderParam(key, data, maxLength) {
let list = [];
let encodedStr = typeof data === 'string' ? data : (data || '').toString();
let encodedStrArr;
let chr, ord;
let line;
let startPos = 0;
let i, len;
maxLength = maxLength || 50;
// process ascii only text
if (this.isPlainText(data, true)) {
// check if conversion is even needed
if (encodedStr.length <= maxLength) {
return [
{
key,
value: encodedStr
}
];
}
encodedStr = encodedStr.replace(new RegExp('.{' + maxLength + '}', 'g'), str => {
list.push({
line: str
});
return '';
});
if (encodedStr) {
list.push({
line: encodedStr
});
}
} else {
if (/[\uD800-\uDBFF]/.test(encodedStr)) {
// string containts surrogate pairs, so normalize it to an array of bytes
encodedStrArr = [];
for (i = 0, len = encodedStr.length; i < len; i++) {
chr = encodedStr.charAt(i);
ord = chr.charCodeAt(0);
if (ord >= 0xd800 && ord <= 0xdbff && i < len - 1) {
chr += encodedStr.charAt(i + 1);
encodedStrArr.push(chr);
i++;
} else {
encodedStrArr.push(chr);
}
}
encodedStr = encodedStrArr;
}
// first line includes the charset and language info and needs to be encoded
// even if it does not contain any unicode characters
line = 'utf-8\x27\x27';
let encoded = true;
startPos = 0;
// process text with unicode or special chars
for (i = 0, len = encodedStr.length; i < len; i++) {
chr = encodedStr[i];
if (encoded) {
chr = this.safeEncodeURIComponent(chr);
} else {
// try to urlencode current char
chr = chr === ' ' ? chr : this.safeEncodeURIComponent(chr);
// By default it is not required to encode a line, the need
// only appears when the string contains unicode or special chars
// in this case we start processing the line over and encode all chars
if (chr !== encodedStr[i]) {
// Check if it is even possible to add the encoded char to the line
// If not, there is no reason to use this line, just push it to the list
// and start a new line with the char that needs encoding
if ((this.safeEncodeURIComponent(line) + chr).length >= maxLength) {
list.push({
line,
encoded
});
line = '';
startPos = i - 1;
} else {
encoded = true;
i = startPos;
line = '';
continue;
}
}
}
// if the line is already too long, push it to the list and start a new one
if ((line + chr).length >= maxLength) {
list.push({
line,
encoded
});
line = chr = encodedStr[i] === ' ' ? ' ' : this.safeEncodeURIComponent(encodedStr[i]);
if (chr === encodedStr[i]) {
encoded = false;
startPos = i - 1;
} else {
encoded = true;
}
} else {
line += chr;
}
}
if (line) {
list.push({
line,
encoded
});
}
}
return list.map((item, i) => ({
// encoded lines: {name}*{part}*
// unencoded lines: {name}*{part}
// if any line needs to be encoded then the first line (part==0) is always encoded
key: key + '*' + i + (item.encoded ? '*' : ''),
value: item.line
}));
},
/**
* Parses a header value with key=value arguments into a structured
* object.
*
* parseHeaderValue('content-type: text/plain; CHARSET='UTF-8'') ->
* {
* 'value': 'text/plain',
* 'params': {
* 'charset': 'UTF-8'
* }
* }
*
* @param {String} str Header value
* @return {Object} Header value as a parsed structure
*/
parseHeaderValue(str) {
let response = {
value: false,
params: {}
};
let key = false;
let value = '';
let type = 'value';
let quote = false;
let escaped = false;
let chr;
for (let i = 0, len = str.length; i < len; i++) {
chr = str.charAt(i);
if (type === 'key') {
if (chr === '=') {
key = value.trim().toLowerCase();
type = 'value';
value = '';
continue;
}
value += chr;
} else {
if (escaped) {
value += chr;
} else if (chr === '\\') {
escaped = true;
continue;
} else if (quote && chr === quote) {
quote = false;
} else if (!quote && chr === '"') {
quote = chr;
} else if (!quote && chr === ';') {
if (key === false) {
response.value = value.trim();
} else {
response.params[key] = value.trim();
}
type = 'key';
value = '';
} else {
value += chr;
}
escaped = false;
}
}
if (type === 'value') {
if (key === false) {
response.value = value.trim();
} else {
response.params[key] = value.trim();
}
} else if (value.trim()) {
response.params[value.trim().toLowerCase()] = '';
}
// handle parameter value continuations
// https://tools.ietf.org/html/rfc2231#section-3
// preprocess values
Object.keys(response.params).forEach(key => {
let actualKey, nr, match, value;
if ((match = key.match(/(\*(\d+)|\*(\d+)\*|\*)$/))) {
actualKey = key.substr(0, match.index);
nr = Number(match[2] || match[3]) || 0;
if (!response.params[actualKey] || typeof response.params[actualKey] !== 'object') {
response.params[actualKey] = {
charset: false,
values: []
};
}
value = response.params[key];
if (nr === 0 && match[0].substr(-1) === '*' && (match = value.match(/^([^']*)'[^']*'(.*)$/))) {
response.params[actualKey].charset = match[1] || 'iso-8859-1';
value = match[2];
}
response.params[actualKey].values[nr] = value;
// remove the old reference
delete response.params[key];
}
});
// concatenate split rfc2231 strings and convert encoded strings to mime encoded words
Object.keys(response.params).forEach(key => {
let value;
if (response.params[key] && Array.isArray(response.params[key].values)) {
value = response.params[key].values.map(val => val || '').join('');
if (response.params[key].charset) {
// convert "%AB" to "=?charset?Q?=AB?="
response.params[key] =
'=?' +
response.params[key].charset +
'?Q?' +
value
// fix invalidly encoded chars
.replace(/[=?_\s]/g, s => {
let c = s.charCodeAt(0).toString(16);
if (s === ' ') {
return '_';
} else {
return '%' + (c.length < 2 ? '0' : '') + c;
}
})
// change from urlencoding to percent encoding
.replace(/%/g, '=') +
'?=';
} else {
response.params[key] = value;
}
}
});
return response;
},
/**
* Returns file extension for a content type string. If no suitable extensions
* are found, 'bin' is used as the default extension
*
* @param {String} mimeType Content type to be checked for
* @return {String} File extension
*/
detectExtension: mimeType => mimeTypes.detectExtension(mimeType),
/**
* Returns content type for a file extension. If no suitable content types
* are found, 'application/octet-stream' is used as the default content type
*
* @param {String} extension Extension to be checked for
* @return {String} File extension
*/
detectMimeType: extension => mimeTypes.detectMimeType(extension),
/**
* Folds long lines, useful for folding header lines (afterSpace=false) and
* flowed text (afterSpace=true)
*
* @param {String} str String to be folded
* @param {Number} [lineLength=76] Maximum length of a line
* @param {Boolean} afterSpace If true, leave a space in th end of a line
* @return {String} String with folded lines
*/
foldLines(str, lineLength, afterSpace) {
str = (str || '').toString();
lineLength = lineLength || 76;
let pos = 0,
len = str.length,
result = '',
line,
match;
while (pos < len) {
line = str.substr(pos, lineLength);
if (line.length < lineLength) {
result += line;
break;
}
if ((match = line.match(/^[^\n\r]*(\r?\n|\r)/))) {
line = match[0];
result += line;
pos += line.length;
continue;
} else if ((match = line.match(/(\s+)[^\s]*$/)) && match[0].length - (afterSpace ? (match[1] || '').length : 0) < line.length) {
line = line.substr(0, line.length - (match[0].length - (afterSpace ? (match[1] || '').length : 0)));
} else if ((match = str.substr(pos + line.length).match(/^[^\s]+(\s*)/))) {
line = line + match[0].substr(0, match[0].length - (!afterSpace ? (match[1] || '').length : 0));
}
result += line;
pos += line.length;
if (pos < len) {
result += '\r\n';
}
}
return result;
},
/**
* Splits a mime encoded string. Needed for dividing mime words into smaller chunks
*
* @param {String} str Mime encoded string to be split up
* @param {Number} maxlen Maximum length of characters for one part (minimum 12)
* @return {Array} Split string
*/
splitMimeEncodedString: (str, maxlen) => {
let curLine,
match,
chr,
done,
lines = [];
// require at least 12 symbols to fit possible 4 octet UTF-8 sequences
maxlen = Math.max(maxlen || 0, 12);
while (str.length) {
curLine = str.substr(0, maxlen);
// move incomplete escaped char back to main
if ((match = curLine.match(/[=][0-9A-F]?$/i))) {
curLine = curLine.substr(0, match.index);
}
done = false;
while (!done) {
done = true;
// check if not middle of a unicode char sequence
if ((match = str.substr(curLine.length).match(/^[=]([0-9A-F]{2})/i))) {
chr = parseInt(match[1], 16);
// invalid sequence, move one char back anc recheck
if (chr < 0xc2 && chr > 0x7f) {
curLine = curLine.substr(0, curLine.length - 3);
done = false;
}
}
}
if (curLine.length) {
lines.push(curLine);
}
str = str.substr(curLine.length);
}
return lines;
},
encodeURICharComponent: chr => {
let res = '';
let ord = chr.charCodeAt(0).toString(16).toUpperCase();
if (ord.length % 2) {
ord = '0' + ord;
}
if (ord.length > 2) {
for (let i = 0, len = ord.length / 2; i < len; i++) {
res += '%' + ord.substr(i, 2);
}
} else {
res += '%' + ord;
}
return res;
},
safeEncodeURIComponent(str) {
str = (str || '').toString();
try {
// might throw if we try to encode invalid sequences, eg. partial emoji
str = encodeURIComponent(str);
} catch (E) {
// should never run
return str.replace(/[^\x00-\x1F *'()<>@,;:\\"[\]?=\u007F-\uFFFF]+/g, '');
}
// ensure chars that are not handled by encodeURICompent are converted as well
return str.replace(/[\x00-\x1F *'()<>@,;:\\"[\]?=\u007F-\uFFFF]/g, chr => this.encodeURICharComponent(chr));
}
};