forked from zhurui/management
96 lines
2.8 KiB
JavaScript
96 lines
2.8 KiB
JavaScript
'use strict';
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/**
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* @param typeMap [Object] Map of MIME type -> Array[extensions]
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* @param ...
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*/
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function Mime() {
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this._types = Object.create(null);
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this._extensions = Object.create(null);
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for (var i = 0; i < arguments.length; i++) {
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this.define(arguments[i]);
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}
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this.define = this.define.bind(this);
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this.getType = this.getType.bind(this);
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this.getExtension = this.getExtension.bind(this);
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}
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/**
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* Define mimetype -> extension mappings. Each key is a mime-type that maps
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* to an array of extensions associated with the type. The first extension is
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* used as the default extension for the type.
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*
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* e.g. mime.define({'audio/ogg', ['oga', 'ogg', 'spx']});
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*
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* If a type declares an extension that has already been defined, an error will
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* be thrown. To suppress this error and force the extension to be associated
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* with the new type, pass `force`=true. Alternatively, you may prefix the
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* extension with "*" to map the type to extension, without mapping the
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* extension to the type.
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*
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* e.g. mime.define({'audio/wav', ['wav']}, {'audio/x-wav', ['*wav']});
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*
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*
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* @param map (Object) type definitions
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* @param force (Boolean) if true, force overriding of existing definitions
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*/
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Mime.prototype.define = function(typeMap, force) {
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for (var type in typeMap) {
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var extensions = typeMap[type].map(function(t) {return t.toLowerCase()});
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type = type.toLowerCase();
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for (var i = 0; i < extensions.length; i++) {
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var ext = extensions[i];
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// '*' prefix = not the preferred type for this extension. So fixup the
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// extension, and skip it.
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if (ext[0] == '*') {
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continue;
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}
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if (!force && (ext in this._types)) {
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throw new Error(
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'Attempt to change mapping for "' + ext +
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'" extension from "' + this._types[ext] + '" to "' + type +
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'". Pass `force=true` to allow this, otherwise remove "' + ext +
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'" from the list of extensions for "' + type + '".'
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);
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}
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this._types[ext] = type;
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}
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// Use first extension as default
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if (force || !this._extensions[type]) {
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var ext = extensions[0];
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this._extensions[type] = (ext[0] != '*') ? ext : ext.substr(1)
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}
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}
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};
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/**
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* Lookup a mime type based on extension
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*/
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Mime.prototype.getType = function(path) {
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path = String(path);
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var last = path.replace(/^.*[/\\]/, '').toLowerCase();
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var ext = last.replace(/^.*\./, '').toLowerCase();
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var hasPath = last.length < path.length;
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var hasDot = ext.length < last.length - 1;
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return (hasDot || !hasPath) && this._types[ext] || null;
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};
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/**
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* Return file extension associated with a mime type
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*/
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Mime.prototype.getExtension = function(type) {
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type = /^\s*([^;\s]*)/.test(type) && RegExp.$1;
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return type && this._extensions[type.toLowerCase()] || null;
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};
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module.exports = Mime;
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