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https://github.com/gchq/CyberChef.git
synced 2025-05-09 07:45:00 -04:00
adding decode mime encoded words and removing duplicate code
This commit is contained in:
bwhitn
parent
fa5d2b130f
commit
e2ee627d09
3 changed files with 43 additions and 278 deletions
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@ -55,7 +55,8 @@
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"To Braille",
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"From Braille",
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"Parse TLV",
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"Parse Internet Message Format"
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"Parse Internet Message Format",
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"Decode Mime Encoded Words"
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]
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},
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{
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36
src/core/operations/DecodeMimeEncodedWords.mjs
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36
src/core/operations/DecodeMimeEncodedWords.mjs
Normal file
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@ -0,0 +1,36 @@
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/**
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* @author bwhitn [brian.m.whitney@outlook.com]
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* @copyright Crown Copyright 2016
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* @license Apache-2.0
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*/
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import Operation from "../Operation";
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import OperationError from "../errors/OperationError";
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import Mime from "../lib/Mime";
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import Utils from "../Utils";
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class DecodeMimeEncodedWords extends Operation {
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/**
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* DecodeMimeEncodedWords constructor
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*/
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constructor() {
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super();
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this.name = "Decode Mime Encoded Words";
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this.module = "Default";
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this.description = ["Parser an IMF formatted messages following RFC5322.",
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"<br><br>",
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"Parses an IMF formated message. These often have the file extention ".eml"e; and contain the email headers and body. The output will be a file list of the headers and mime parts.",
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].join("\n");
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this.infoURL = "https://tools.ietf.org/html/rfc2047";
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this.inputType = "string";
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this.outputType = "string";
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this.args = [];
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}
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run(input, args) {
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return Mime.replaceEncodedWord(input);
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}
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}
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export default DecodeMimeEncodedWords;
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@ -6,25 +6,9 @@
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import Operation from "../Operation";
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import OperationError from "../errors/OperationError";
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import cptable from "../vendor/js-codepage/cptable.js";
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import {fromBase64} from "../lib/Base64";
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import {decodeQuotedPrintable} from "../lib/QuotedPrintable";
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import {MIME_FORMAT} from "../lib/ChrEnc";
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import Mime from "../lib/Mime";
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import Utils from "../Utils";
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/**
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*
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*
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* @constant
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* @default
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*
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const BODY_FILE_TYPE = {
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"text/plain": "txt",
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"text/html": "htm",
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"application/rtf": "rtf",
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} */
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class ParseIMF extends Operation {
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/**
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@ -34,9 +18,9 @@ class ParseIMF extends Operation {
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super();
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this.name = "Parse Internet Message Format";
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this.module = "Default";
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this.description = ["Parser an IMF formatted messages following RFC5322.",
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this.description = ["Parse an IMF formatted messages following RFC5322.",
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"<br><br>",
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"Parses an IMF formated message. These often have the file extention ".eml"e; and contain the email headers and body. The output will be a file list of the headers and mime parts.",
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"Parses an IMF formated message. These often have the file extention ".eml"e; and contain the email headers and body. The output will be a file list of the root header and decoded mime parts.",
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].join("\n");
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this.infoURL = "https://tools.ietf.org/html/rfc5322";
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this.inputType = "string";
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@ -44,7 +28,7 @@ class ParseIMF extends Operation {
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this.presentType = "html";
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this.args = [
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{
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"name": "Decode Quoted Words",
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"name": "Decode Encoded-Words",
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"type": "boolean",
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"value": false
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}
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@ -56,55 +40,6 @@ class ParseIMF extends Operation {
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return mimeObj.decodeMime(args[0]);
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}
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/**
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* Basic Email Parser that displays the header and mime sections as files.
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* Args 0 boolean decode quoted words
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*
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* @param {string} input
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* @param {Object[]} args
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* @returns {File[]}
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*
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// NOTE: Liberties taken include:
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// No checks are made to verify quoted words are valid encodings e.g. underscore vs escape
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// This attempts to decode mime reguardless if it is \r\n (correct newline) or \n (incorrect)
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// Both Base64 and QuotedPrintable is used for decode. UUEncode is not available right now
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// and is a standardized encoding format.
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run(input, args) {
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// TODO Later: no uuencode function. See if we can fix this.
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// TODO: content-type can be omitted and would mean us-ascii charset and text/plain.
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if (!input) {
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return [];
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}
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let emlObj = ParseIMF.splitParse(input);
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if (!emlObj.body) { throw new OperationError("No body was found");}
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if (args[0]) {
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emlObj.rawHeader = ParseIMF.replaceDecodeWord(emlObj.rawHeader);
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}
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let retval = [new File([emlObj.rawHeader], "Header", {type: "text/plain"})];
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let retfiles = ParseIMF.walkMime(emlObj, input.indexOf("\r") >= 0);
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retfiles.forEach(function(fileObj){
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let file = null;
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if (fileObj.name !== null) {
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file = new File([fileObj.data], fileObj.name, {type: fileObj.type});
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} else {
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let name = null;
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if ("subject" in emlObj.header) {
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name = emlObj.header["subject"][0].concat(".");
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} else {
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name = "Undefined.";
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}
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if (fileObj.type in BODY_FILE_TYPE) {
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name = name.concat(BODY_FILE_TYPE[fileObj.type]);
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} else {
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name = name.concat("bin");
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}
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file = new File([fileObj.data], name, {type: fileObj.type});
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}
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retval.push(file);
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});
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return retval;
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} */
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/**
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* Displays the files in HTML for web apps.
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*
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@ -114,213 +49,6 @@ class ParseIMF extends Operation {
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async present(files) {
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return await Utils.displayFilesAsHTML(files);
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}
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/**
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* Walks a MIME document and returns an array of Mime data and header objects.
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*
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* @param {string} input
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* @param {object} header
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* @returns {object[]}
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*
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static walkMime(parentObj, rn) {
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let new_line_length = rn ? 2 : 1;
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let contType = null, fileName = null, charEnc = null, contDispoObj = null;
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if (parentObj.header.hasOwnProperty("content-type")) {
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let contTypeObj = ParseIMF.decodeComplexField(parentObj.header["content-type"][0]);
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if (parentObj.header.hasOwnProperty("content-disposition")) {
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contDispoObj = ParseIMF.decodeComplexField(parentObj.header["content-disposition"][0])
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if (contDispoObj != null && contDispoObj.hasOwnProperty("filename")) {
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fileName = contDispoObj.filename;
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}
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}
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if (contTypeObj != null) {
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if (contTypeObj.hasOwnProperty("value")) {
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contType = contTypeObj.value[0];
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}
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if (contTypeObj.hasOwnProperty("charset")) {
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charEnc = contTypeObj.charset;
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}
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if (fileName == null && contTypeObj.hasOwnProperty("name")) {
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fileName = contTypeObj.name;
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}
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}
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if (contType.startsWith("multipart/")) {
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let content_boundary = null;
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let output_sections = [];
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if (contTypeObj.hasOwnProperty("boundary")) {
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content_boundary = contTypeObj.boundary;
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}
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let mime_parts = ParseIMF.splitMultipart(parentObj.body, content_boundary, new_line_length);
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mime_parts.forEach(function(mime_part){
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let mimeObj = ParseIMF.splitParse(mime_part);
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if (!mimeObj.body) {
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return [];
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}
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let parts = ParseIMF.walkMime(mimeObj, rn);
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parts.forEach(function(part){
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output_sections.push(part);
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});
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});
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return output_sections;
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}
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if (parentObj.header.hasOwnProperty("content-transfer-encoding")) {
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let contEncObj = ParseIMF.decodeComplexField(parentObj.header["content-transfer-encoding"][0]);
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let contTran = null;
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if (contEncObj != null && contEncObj.hasOwnProperty("value")) {
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contTran = contEncObj.value[0];
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}
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if (contTran != null) {
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parentObj.body = ParseIMF.decodeMimeData(parentObj.body, charEnc, contTran);
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}
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}
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return [{type: contType, data: parentObj.body, name: fileName}];
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}
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throw new OperationError("Invalid Mime section");
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}
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/**
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* Takes a string and decodes quoted words inside them
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* These take the form of =?utf-8?Q?Hello?=
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*
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* @param {string} input
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* @returns {string}
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*
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static replaceDecodeWord(input) {
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return input.replace(/=\?([^?]+)\?(Q|B)\?([^?]+)\?=/g, function (a, charEnc, contEnc, input) {
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contEnc = (contEnc === "B") ? "base64" : "quoted-printable";
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if (contEnc === "quoted-printable") {
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input = input.replace(/_/g, " ");
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}
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return ParseIMF.decodeMimeData(input, charEnc, contEnc);
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});
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}
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/**
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* Breaks the header from the body and parses the header. The returns an
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* object or null. The object contains the raw header, decoded body, and
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* parsed header object.
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*
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* @param {string} input
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* @returns {object}
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*
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static splitParse(input) {
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const emlRegex = /(?:\r?\n){2}/g;
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let matchobj = emlRegex.exec(input);
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if (matchobj) {
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let splitEmail = [input.substring(0,matchobj.index), input.substring(emlRegex.lastIndex)];
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const sectionRegex = /([A-Za-z-]+):\s+([\x00-\xff]+?)(?=$|\r?\n\S)/g;
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let headerObj = {}, section;
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while ((section = sectionRegex.exec(splitEmail[0]))) {
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let fieldName = section[1].toLowerCase();
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let fieldValue = ParseIMF.replaceDecodeWord(section[2].replace(/\n|\r/g, " "));
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if (fieldName in headerObj) {
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headerObj[fieldName].push(fieldValue);
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} else {
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headerObj[fieldName] = [fieldValue];
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}
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}
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return {rawHeader:splitEmail[0], body: splitEmail[1], header: headerObj};
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}
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return null;
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}
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/**
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* Return decoded MIME data given the character encoding and content encoding.
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*
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* @param {string} input
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* @param {string} charEnc
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* @param {string} contEnc
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* @returns {string}
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*
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static decodeMimeData(input, charEnc, contEnc) {
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switch (contEnc) {
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case "base64":
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input = fromBase64(input);
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break;
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case "quoted-printable":
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input = Utils.byteArrayToUtf8(decodeQuotedPrintable(input));
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break;
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}
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if (charEnc && MIME_FORMAT.hasOwnProperty(charEnc.toLowerCase())) {
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input = cptable.utils.decode(MIME_FORMAT[charEnc.toLowerCase()], input);
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}
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return input;
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}
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/**
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* Parses a complex header field and returns an object that contains
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* normalized keys with corresponding values along with single values under
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* a value array.
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*
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* @param {string} field
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* @returns {object}
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*
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static decodeComplexField(field) {
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let fieldSplit = field.split(/;\s+/g);
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let retVal = {};
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fieldSplit.forEach(function(item){
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if (item.indexOf("=") >= 0) {
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let eq = item.indexOf("=");
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let kv = null;
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if (item.length > eq) {
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kv = [item.substring(0, eq), item.substring(eq + 1).trim()];
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} else {
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throw OperationError("Not a valid header entry");
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}
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if ((kv[1].startsWith("\'") && kv[1].endsWith("\'"))
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|| (kv[1].startsWith("\"") && kv[1].endsWith("\""))) {
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kv[1] = (/(['"])(.+)\1/.exec(kv[1]))[2];
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}
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retVal[kv[0].toLowerCase()] = kv[1];
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} else {
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item = item.trim().toLowerCase();
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if (retVal.hasOwnProperty("value")) {
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retVal.value.push(item);
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} else {
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retVal.value = [item];
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}
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}
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});
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return retVal;
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}
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/**
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* Splits a Mime document by the current boundaries and attempts to account
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* for the current new line size which can be either the standard \r\n or \n.
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*
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* @param {string} input
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* @param {string} boundary
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* @param {string} new_line_length
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* @return {string[]}
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*
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static splitMultipart(input, boundary, new_line_length) {
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let output = [];
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let newline = new_line_length === 2 ? "\r\n" : "\n";
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const boundary_str = "--".concat(boundary, newline);
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let last = input.indexOf("--".concat(boundary, "--", newline)) - new_line_length;
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if (last < 0) {
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last = input.indexOf("--".concat(boundary, "--")) - new_line_length;
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}
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let start = 0;
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while(true) {
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let start = input.indexOf(boundary_str, start);
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if (start >= 0) {
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start = start + boundary_str.length;
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} else {
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break;
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}
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let end = input.indexOf(boundary_str, start) - new_line_length;
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if (end > start) {
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output.push(input.substring(start, end));
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} else {
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output.push(input.substring(start, last));
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break;
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}
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start = end;
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}
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return output;
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} */
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}
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export default ParseIMF
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export default ParseIMF;
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