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add MIME encoding operation

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This commit is contained in:
skywalker 2026-06-06 19:52:35 +08:00
parent d735496641
commit ce04728a54
4 changed files with 217 additions and 2 deletions
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1
src/core/config/Categories.json
View File

@ -83,6 +83,7 @@
"Rison Decode",
"To Modhex",
"From Modhex",
"MIME Encoding",
"MIME Decoding"
]
},

149
src/core/operations/MIMEEncoding.mjs Normal file
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@ -0,0 +1,149 @@
/**
* @author skyswordw
* @copyright Crown Copyright 2026
* @license Apache-2.0
*/
import Operation from "../Operation.mjs";
import OperationError from "../errors/OperationError.mjs";
import {toBase64} from "../lib/Base64.mjs";
import cptable from "codepage";
const CHARSET_CODEPAGES = {
"UTF-8": 65001,
"US-ASCII": 20127,
"ISO-8859-1": 28591,
"ISO-8859-2": 28592,
"ISO-8859-3": 28593,
"ISO-8859-4": 28594,
"ISO-8859-5": 28595,
"ISO-8859-6": 28596,
"ISO-8859-7": 28597,
"ISO-8859-8": 28598,
"ISO-8859-9": 28599,
"ISO-8859-10": 28600,
"ISO-8859-11": 28601,
"ISO-8859-13": 28603,
"ISO-8859-14": 28604,
"ISO-8859-15": 28605,
"ISO-8859-16": 28606,
},
TRANSFER_ENCODINGS = ["Base64", "Q-encoding"],
MAX_ENCODED_WORD_LENGTH = 75;
/**
* MIME Encoding operation
*/
class MIMEEncoding extends Operation {
/**
* MIMEEncoding constructor
*/
constructor() {
super();
this.name = "MIME Encoding";
this.module = "Default";
this.description = "Encodes text as MIME encoded-words for non-ASCII email header values.";
this.infoURL = "https://tools.ietf.org/html/rfc2047";
this.inputType = "string";
this.outputType = "string";
this.args = [
{
name: "Charset",
type: "option",
value: Object.keys(CHARSET_CODEPAGES)
},
{
name: "Transfer encoding",
type: "option",
value: TRANSFER_ENCODINGS
}
];
}
/**
* @param {string} input
* @param {Object[]} args
* @returns {string}
*/
run(input, args) {
const [charset, encoding] = args,
codepage = CHARSET_CODEPAGES[charset];
if (!codepage) throw new OperationError("Invalid charset");
if (!TRANSFER_ENCODINGS.includes(encoding)) throw new OperationError("Invalid transfer encoding");
if (!input.length) return "";
return input.split(/\r\n|\n|\r/).map(line => {
return this.encodeLine(line, charset, codepage, encoding);
}).join("\r\n");
}
/**
* @param {string} input
* @param {string} charset
* @param {number} codepage
* @param {string} encoding
* @returns {string}
*/
encodeLine(input, charset, codepage, encoding) {
const encodedWords = [];
let chunk = "";
for (const char of input) {
const next = chunk + char;
if (chunk && this.encodedWord(charset, codepage, encoding, next).length > MAX_ENCODED_WORD_LENGTH) {
encodedWords.push(this.encodedWord(charset, codepage, encoding, chunk));
chunk = char;
} else {
chunk = next;
}
}
if (chunk) encodedWords.push(this.encodedWord(charset, codepage, encoding, chunk));
return encodedWords.join("\r\n ");
}
/**
* @param {string} charset
* @param {number} codepage
* @param {string} encoding
* @param {string} input
* @returns {string}
*/
encodedWord(charset, codepage, encoding, input) {
const encodedText = encoding === "Base64" ?
toBase64(cptable.utils.encode(codepage, input)) :
this.qEncode(cptable.utils.encode(codepage, input));
return `=?${charset}?${encoding === "Base64" ? "B" : "Q"}?${encodedText}?=`;
}
/**
* @param {Uint8Array|byteArray} input
* @returns {string}
*/
qEncode(input) {
let output = "";
for (const byte of input) {
if (byte === 0x20) {
output += "_";
} else if (
byte >= 0x21 &&
byte <= 0x7e &&
byte !== 0x3d &&
byte !== 0x3f &&
byte !== 0x5f
) {
output += String.fromCharCode(byte);
} else {
output += `=${byte.toString(16).toUpperCase().padStart(2, "0")}`;
}
}
return output;
}
}
export default MIMEEncoding;

8
tests/node/tests/operations.mjs
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@ -681,6 +681,13 @@ WWFkYSBZYWRh\r
assert.strictEqual(chef.LZNT1Decompress("\x1a\xb0\x00compress\x00edtestda\x04ta\x07\x88alot").toString(), "compressedtestdatacompressedalot");
}),
it("MIME Encoding", () => {
assert.strictEqual(chef.MIMEEncoding("Keld Jørn Simonsen", {
charset: "ISO-8859-1",
transferEncoding: "Q-encoding",
}).toString(), "=?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?=");
}),
it("MD6", () => {
assert.strictEqual(chef.MD6("Head Over Heels", {key: "arty"}).toString(), "d8f7fe4931fbaa37316f76283d5f615f50ddd54afdc794b61da522556aee99ad");
}),
@ -1178,4 +1185,3 @@ ExifImageHeight: 57`);
]);

61
tests/operations/tests/MIMEDecoding.mjs
View File

@ -1,5 +1,5 @@
/**
* MIME Header Decoding tests
* MIME Header Encoding and Decoding tests
*
* @author mshwed [m@ttshwed.com]
* @copyright Crown Copyright 2019
@ -9,6 +9,65 @@
import TestRegister from "../../lib/TestRegister.mjs";
TestRegister.addTests([
{
name: "MIME Encoding: UTF-8 Base64",
input: "Éric <eric@example.org>",
expectedOutput: "=?UTF-8?B?w4lyaWMgPGVyaWNAZXhhbXBsZS5vcmc+?=",
recipeConfig: [
{
"op": "MIME Encoding",
"args": ["UTF-8", "Base64"]
}
]
},
{
name: "MIME Encoding: UTF-8 Q-encoding",
input: "Éric <eric@example.org>",
expectedOutput: "=?UTF-8?Q?=C3=89ric_<eric@example.org>?=",
recipeConfig: [
{
"op": "MIME Encoding",
"args": ["UTF-8", "Q-encoding"]
}
]
},
{
name: "MIME Encoding: ISO-8859-1 Q-encoding",
input: "Keld Jørn Simonsen",
expectedOutput: "=?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?=",
recipeConfig: [
{
"op": "MIME Encoding",
"args": ["ISO-8859-1", "Q-encoding"]
}
]
},
{
name: "MIME Encoding: long Q-encoded header round trip",
input: "This is a deliberately long MIME header value with Éric and Anaïs in it.",
expectedOutput: "This is a deliberately long MIME header value with Éric and Anaïs in it.",
recipeConfig: [
{
"op": "MIME Encoding",
"args": ["UTF-8", "Q-encoding"]
},
{
"op": "MIME Decoding",
"args": []
}
]
},
{
name: "MIME Encoding: long Base64 header is folded",
input: "This is a deliberately long MIME header value with Eric and Anais in it.",
expectedOutput: "=?US-ASCII?B?VGhpcyBpcyBhIGRlbGliZXJhdGVseSBsb25nIE1JTUUgaGVhZGVyIHZhbHVl?=\r\n =?US-ASCII?B?IHdpdGggRXJpYyBhbmQgQW5haXMgaW4gaXQu?=",
recipeConfig: [
{
"op": "MIME Encoding",
"args": ["US-ASCII", "Base64"]
}
]
},
{
name: "Encoded comments",
input: "(=?ISO-8859-1?Q?a?=)",