120 lines
3.4 KiB
JavaScript
120 lines
3.4 KiB
JavaScript
'use strict';
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// Expose to the world
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module.exports.parseHeader = parseHeader;
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module.exports.generateHeader = generateHeader;
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module.exports.formatCharset = formatCharset;
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module.exports.foldLine = foldLine;
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/**
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* Parses a header string into an object of key-value pairs
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*
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* @param {String} str Header string
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* @return {Object} An object of key-value pairs
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*/
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function parseHeader(str) {
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var lines = (str || '').split('\n'),
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headers = {};
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lines.forEach(function(line) {
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var parts = line.trim().split(':'),
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key = (parts.shift() || '').trim().toLowerCase(),
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value = parts.join(':').trim();
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if (!key) {
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return;
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}
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headers[key] = value;
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});
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return headers;
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}
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/**
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* Convert first letters after - to uppercase, other lowercase
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*
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* @param {String} str String to be updated
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* @return {String} A string with uppercase words
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*/
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function upperCaseWords(str) {
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return (str || '').toLowerCase().trim().replace(/^(MIME|POT?(?=\-)|[a-z])|\-[a-z]/gi, function(str) {
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return str.toUpperCase();
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});
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}
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/**
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* Joins a header object of key value pairs into a header string
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*
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* @param {Object} header Object of key value pairs
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* @return {String} Header string
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*/
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function generateHeader(header) {
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var lines = [];
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Object.keys(header || {}).forEach(function(key) {
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if (key) {
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lines.push(upperCaseWords(key) + ': ' + (header[key] || '').trim());
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}
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});
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return lines.join('\n') + (lines.length ? '\n' : '');
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}
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/**
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* Normalizes charset name. Converts utf8 to utf-8, WIN1257 to windows-1257 etc.
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*
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* @param {String} charset Charset name
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* @return {String} Normalized charset name
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*/
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function formatCharset(charset, defaultCharset) {
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return (charset || 'iso-8859-1').toString().toLowerCase().
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replace(/^utf[\-_]?(\d+)$/, 'utf-$1').
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replace(/^win(?:dows)?[\-_]?(\d+)$/, 'windows-$1').
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replace(/^latin[\-_]?(\d+)$/, 'iso-8859-$1').
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replace(/^(us[\-_]?)?ascii$/, 'ascii').
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replace(/^charset$/, defaultCharset || 'iso-8859-1').
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trim();
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}
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/**
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* Folds long lines according to PO format
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*
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* @param {String} str PO formatted string to be folded
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* @param {Number} [maxLen=76] Maximum allowed length for folded lines
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* @return {Array} An array of lines
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*/
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function foldLine(str, maxLen) {
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maxLen = maxLen || 76;
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var lines = [],
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curLine = '',
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pos = 0,
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len = str.length,
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match;
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while (pos < len) {
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curLine = str.substr(pos, maxLen);
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// ensure that the line never ends with a partial escaping
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// make longer lines if needed
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while (curLine.substr(-1) === '\\' && pos + curLine.length < len) {
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curLine += str.charAt(pos + curLine.length);
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}
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// ensure that if possible, line breaks are done at reasonable places
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if ((match = curLine.match(/\\n/))) {
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curLine = curLine.substr(0, match.index + 2);
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} else if (pos + curLine.length < len) {
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if ((match = curLine.match(/(\s+)[^\s]*$/)) && match.index > 0) {
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curLine = curLine.substr(0, match.index + match[1].length);
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} else if ((match = curLine.match(/([\x21-\x40\x5b-\x60\x7b-\x7e]+)[^\x21-\x40\x5b-\x60\x7b-\x7e]*$/)) && match.index > 0) {
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curLine = curLine.substr(0, match.index + match[1].length);
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}
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}
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lines.push(curLine);
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pos += curLine.length;
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}
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return lines;
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} |