kopia lustrzana https://github.com/miklobit/TiddlyWiki5
108 wiersze
3.3 KiB
JavaScript
108 wiersze
3.3 KiB
JavaScript
/*\
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title: js/FileRetriever.js
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FileRetriever can asynchronously retrieve files from HTTP URLs or the local file system. Files are treated as utf-8 text or, if the filepath ends in one of the recognised binary extensions, as a base64 encoded binary string
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\*/
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(function(){
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/*jslint node: true */
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"use strict";
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var fs = require("fs"),
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path = require("path"),
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url = require("url"),
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util = require("util"),
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http = require("http"),
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https = require("https");
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var FileRetriever = exports;
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// These are the file extensions that we'll recognise as binary.
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FileRetriever.binaryFileExtensions = [".jpg",".jpeg",".png",".gif"];
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// Retrieve a local file and invoke callback(err,data) in the usual way
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var fileRequest = function fileRequest(filepath,callback) {
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fs.readFile(filepath, function (err,data) {
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if(err) {
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callback(err);
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} else {
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// Check if we need to base64 encode the file
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if(FileRetriever.binaryFileExtensions.indexOf(path.extname(filepath)) !== -1) {
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callback(err,data.toString("base64"));
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} else {
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callback(err,data.toString("utf8"));
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}
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}
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});
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};
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// Retrieve a file over HTTP and invoke callback(err,data) in the usual way
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var httpRequest = function(fileurl,callback) {
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var opts = url.parse(fileurl),
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httpLib = opts.protocol === "http:" ? http : https,
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encoding = (FileRetriever.binaryFileExtensions.indexOf(path.extname(fileurl)) !== -1) ? "binary" : "utf8";
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var request = httpLib.get(opts,function(res) {
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if(res.statusCode != 200) {
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var err = new Error("HTTP error");
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err.code = res.statusCode.toString();
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callback(err);
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} else {
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var data = [];
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res.setEncoding(encoding);
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res.on("data", function(chunk) {
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data.push(chunk);
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});
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res.on("end", function() {
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if(encoding === "binary") {
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callback(null,(new Buffer(data.join(""),"binary")).toString("base64"));
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} else {
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callback(null,data.join(""));
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}
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});
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}
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});
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request.addListener("error", function(err) {
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callback(err);
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});
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request.end();
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};
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// Retrieve a file given a filepath specifier and a base directory. If the filepath isn't an absolute
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// filepath or an absolute URL, then it is interpreted relative to the base directory, which can also be
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// a local directory or a URL. On completion, the callback function is called as callback(err,data). The
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// data hashmap is as follows:
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// text: full text of file
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// path: full path used to reach the file
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// basename: the basename of the file
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// extname: the extension of the file
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FileRetriever.retrieveFile = function(filepath,baseDir,callback) {
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var httpRegExp = /^(https?:\/\/)/gi,
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result = {},
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filepathIsHttp = httpRegExp.test(filepath),
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baseDirIsHttp = httpRegExp.test(baseDir),
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requester;
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if(baseDirIsHttp || filepathIsHttp) {
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// If we've got a full HTTP URI then we're good to go
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result.path = url.resolve(baseDir,filepath);
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var parsedPath = url.parse(result.path);
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result.extname = path.extname(parsedPath.pathname);
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result.basename = path.basename(parsedPath.extname);
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requester = httpRequest;
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} else {
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// It's a file requested in a file context
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result.path = path.resolve(baseDir,filepath);
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result.extname = path.extname(result.path);
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result.basename = path.basename(result.path,result.extname);
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requester = fileRequest;
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}
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requester(result.path,function(err,data) {
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if(!err) {
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result.text = data;
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}
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callback(err,result);
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});
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};
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})();
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