Develop Reference

How Discord checks if a Javascript File is a folder on client side? [duplicate]

I haven't seen any examples that do this. Is this not allowed in the API spec?
I am searching for an easy drag-drop solution for uploading an entire folder tree of photos.

It's now possible, thanks to Chrome >= 21.
function traverseFileTree(item, path) {
path = path || "";
if (item.isFile) {
// Get file
item.file(function(file) {
console.log("File:", path + file.name);
});
} else if (item.isDirectory) {
// Get folder contents
var dirReader = item.createReader();
dirReader.readEntries(function(entries) {
for (var i=0; i<entries.length; i++) {
traverseFileTree(entries[i], path + item.name + "/");
}
});
}
}
dropArea.addEventListener("drop", function(event) {
event.preventDefault();
var items = event.dataTransfer.items;
for (var i=0; i<items.length; i++) {
// webkitGetAsEntry is where the magic happens
var item = items[i].webkitGetAsEntry();
if (item) {
traverseFileTree(item);
}
}
}, false);
More info: https://protonet.info/blog/html5-experiment-drag-drop-of-folders/
As a note (from the comments) this code is not complete if more than 100 entries are returned, some iteration is required, see https://stackoverflow.com/a/53058574/885922

Unfortunately none of the existing answers are completely correct because readEntries will not necessarily return ALL the (file or directory) entries for a given directory. This is part of the API specification (see Documentation section below).
To actually get all the files, we'll need to call readEntries repeatedly (for each directory we encounter) until it returns an empty array. If we don't, we will miss some files/sub-directories in a directory e.g. in Chrome, readEntries will only return at most 100 entries at a time.
Using Promises (await/ async) to more clearly demonstrate the correct usage of readEntries (since it's asynchronous), and breadth-first search (BFS) to traverse the directory structure:
// Drop handler function to get all files
async function getAllFileEntries(dataTransferItemList) {
let fileEntries = [];
// Use BFS to traverse entire directory/file structure
let queue = [];
// Unfortunately dataTransferItemList is not iterable i.e. no forEach
for (let i = 0; i < dataTransferItemList.length; i++) {
// Note webkitGetAsEntry a non-standard feature and may change
// Usage is necessary for handling directories
queue.push(dataTransferItemList[i].webkitGetAsEntry());
}
while (queue.length > 0) {
let entry = queue.shift();
if (entry.isFile) {
fileEntries.push(entry);
} else if (entry.isDirectory) {
queue.push(...await readAllDirectoryEntries(entry.createReader()));
}
}
return fileEntries;
}
// Get all the entries (files or sub-directories) in a directory
// by calling readEntries until it returns empty array
async function readAllDirectoryEntries(directoryReader) {
let entries = [];
let readEntries = await readEntriesPromise(directoryReader);
while (readEntries.length > 0) {
entries.push(...readEntries);
readEntries = await readEntriesPromise(directoryReader);
}
return entries;
}
// Wrap readEntries in a promise to make working with readEntries easier
// readEntries will return only some of the entries in a directory
// e.g. Chrome returns at most 100 entries at a time
async function readEntriesPromise(directoryReader) {
try {
return await new Promise((resolve, reject) => {
directoryReader.readEntries(resolve, reject);
});
} catch (err) {
console.log(err);
}
}
Complete working example on Codepen: https://codepen.io/pen/QWmvxwV
FWIW I only picked this up because I wasn't getting back all the files I expected in a directory containing 40,000 files (many directories containing well over 100 files/sub-directories) when using the accepted answer.
Documentation:
This behaviour is documented in FileSystemDirectoryReader. Excerpt with emphasis added:
readEntries()
Returns a an array containing some number of the
directory's entries. Each item in the array is an object based on
FileSystemEntry—typically either FileSystemFileEntry or
FileSystemDirectoryEntry.
But to be fair, the MDN documentation could make this clearer in other sections. The readEntries() documentation simply notes:
readEntries() method retrieves the directory entries within the directory being read and delivers them in an array to the provided callback function
And the only mention/hint that multiple calls are needed is in the description of successCallback parameter:
If there are no files left, or you've already called readEntries() on
this FileSystemDirectoryReader, the array is empty.
Arguably the API could be more intuitive as well.
It's also worth noting that DataTransferItem.webkitGetAsEntry() is a non-standard feature and may change e.g. renamed getAsEntry(). Its usage is necessary to handle uploading files nested within directories.
Related:
johnozbay comments that on Chrome, readEntries will return at most 100 entries for a directory (verified as of Chrome 64).
Xan explains the correct usage of readEntries quite well in this answer (albeit without code).
Pablo Barría Urenda's answer correctly calls readEntries in a asynchronous manner without BFS. He also notes that Firefox returns all the entries in a directory (unlike Chrome) but we can't rely on this given the specification.

This function will give you a promise for array of all dropped files, like <input type="file"/>.files:
function getFilesWebkitDataTransferItems(dataTransferItems) {
function traverseFileTreePromise(item, path='') {
return new Promise( resolve => {
if (item.isFile) {
item.file(file => {
file.filepath = path + file.name //save full path
files.push(file)
resolve(file)
})
} else if (item.isDirectory) {
let dirReader = item.createReader()
dirReader.readEntries(entries => {
let entriesPromises = []
for (let entr of entries)
entriesPromises.push(traverseFileTreePromise(entr, path + item.name + "/"))
resolve(Promise.all(entriesPromises))
})
}
})
}
let files = []
return new Promise((resolve, reject) => {
let entriesPromises = []
for (let it of dataTransferItems)
entriesPromises.push(traverseFileTreePromise(it.webkitGetAsEntry()))
Promise.all(entriesPromises)
.then(entries => {
//console.log(entries)
resolve(files)
})
})
}
Usage:
dropArea.addEventListener("drop", function(event) {
event.preventDefault();
var items = event.dataTransfer.items;
getFilesFromWebkitDataTransferItems(items)
.then(files => {
...
})
}, false);
NPM package:
https://www.npmjs.com/package/datatransfer-files-promise
Usage example:
https://github.com/grabantot/datatransfer-files-promise/blob/master/index.html

In this message to the HTML 5 mailing list Ian Hickson says:
HTML5 now has to upload many files at
once. Browsers could allow users to
pick multiple files at once, including
across multiple directories; that's a
bit out of scope of the spec.
(Also see the original feature proposal.)
So it's safe to assume he considers uploading folders using drag-and-drop also out of scope. Apparently it's up to the browser to serve individual files.
Uploading folders would also have some other difficulties, as described by Lars Gunther:
This […] proposal must have two
checks (if it is doable at all):
Max size, to stop someone from uploading a full directory of several
hundred uncompressed raw images...
Filtering even if the accept attribute is omitted. Mac OS metadata
and Windows thumbnails, etc should be
omitted. All hidden files and
directories should default to be
excluded.

Now you can upload directories with both drag and drop and input.
<input type='file' webkitdirectory >
and for drag and drop(For webkit browsers).
Handling drag and drop folders.
<div id="dropzone"></div>
<script>
var dropzone = document.getElementById('dropzone');
dropzone.ondrop = function(e) {
var length = e.dataTransfer.items.length;
for (var i = 0; i < length; i++) {
var entry = e.dataTransfer.items[i].webkitGetAsEntry();
if (entry.isFile) {
... // do whatever you want
} else if (entry.isDirectory) {
... // do whatever you want
}
}
};
</script>
Resources:
http://updates.html5rocks.com/2012/07/Drag-and-drop-a-folder-onto-Chrome-now-available

Firefox now supports folder upload, as of November 15, 2016, in v50.0: https://developer.mozilla.org/en-US/Firefox/Releases/50#Files_and_directories
You can drag and drop folders into Firefox or you can browse and select a local folder to upload. It also supports folders nested in subfolders.
That means you can now use either Chrome, Firefox, Edge or Opera to upload folders. You can't use Safari or Internet Explorer at present.

Here's a complete example of how to use the file and directory entries API:
var dropzone = document.getElementById("dropzone");
var listing = document.getElementById("listing");
function scanAndLogFiles(item, container) {
var elem = document.createElement("li");
elem.innerHTML = item.name;
container.appendChild(elem);
if (item.isDirectory) {
var directoryReader = item.createReader();
var directoryContainer = document.createElement("ul");
container.appendChild(directoryContainer);
directoryReader.readEntries(function(entries) {
entries.forEach(function(entry) {
scanAndLogFiles(entry, directoryContainer);
});
});
}
}
dropzone.addEventListener(
"dragover",
function(event) {
event.preventDefault();
},
false
);
dropzone.addEventListener(
"drop",
function(event) {
var items = event.dataTransfer.items;
event.preventDefault();
listing.innerHTML = "";
for (var i = 0; i < items.length; i++) {
var item = items[i].webkitGetAsEntry();
if (item) {
scanAndLogFiles(item, listing);
}
}
},
false
);
body {
font: 14px "Arial", sans-serif;
}
#dropzone {
text-align: center;
width: 300px;
height: 100px;
margin: 10px;
padding: 10px;
border: 4px dashed red;
border-radius: 10px;
}
#boxtitle {
display: table-cell;
vertical-align: middle;
text-align: center;
color: black;
font: bold 2em "Arial", sans-serif;
width: 300px;
height: 100px;
}
<p>Drag files and/or directories to the box below!</p>
<div id="dropzone">
<div id="boxtitle">
Drop Files Here
</div>
</div>
<h2>Directory tree:</h2>
<ul id="listing"></ul>
webkitGetAsEntry is supported by Chrome 13+, Firefox 50+ and Edge.
Source: https://developer.mozilla.org/en-US/docs/Web/API/DataTransferItem/webkitGetAsEntry

Does HTML5 allow drag-drop upload of folders or a folder tree?
Only Chrome supports this feature. It has failed to have any traction and is likely to be removed.
Ref : https://developer.mozilla.org/en/docs/Web/API/DirectoryReader#readEntries

UPDATE: Since 2012 a lot has changed, see answers above instead. I leave this answer here for the sake of archeology.
The HTML5 spec does NOT say that when selecting a folder for upload, the browser should upload all contained files recursively.
Actually, in Chrome/Chromium, you can upload a folder, but when you do it, it just uploads a meaningless 4KB file, which represents the directory. Some servers-side applications like Alfresco can detect this, and warn the user that folders can not be uploaded:

Recently stumbled upon the need to implement this in two of my projects so I created a bunch of utility functions to help with this.
One creates a data-structure representing all the folders, files and relationship between them, like so 👇
{
folders: [
{
name: string,
folders: Array,
files: Array
},
/* ... */
],
files: Array
}
While the other just returns an Array of all the files (in all folders and sub-folders).
Here's the link to the package: https://www.npmjs.com/package/file-system-utils

I had been happy copy/pasting #grabantot 's solution until I met the 100 file limit issue.
#xlm 's solution overcomes the 100-file-limit, and it returns an array of FileEntry objects.
However in my project I need to extract the file paths from fileEntry objects.
This works if you have access to the ChromeFileSystem api:
const getAllPaths = async (dataTransferItems) =>{
async function getAllFileEntries(dataTransferItemList) {
let fileEntries = [];
// Use BFS to traverse entire directory/file structure
let queue = [];
for (let i = 0; i < dataTransferItemList.length; i++) {
queue.push(dataTransferItemList[i].webkitGetAsEntry());
}
while (queue.length > 0) {
let entry = queue.shift();
if (entry.isFile) {
fileEntries.push(entry);
} else if (entry.isDirectory) {
queue.push(...await readAllDirectoryEntries(entry.createReader()));
}
}
return fileEntries;
}
// Get all the entries (files or sub-directories) in a directory
// by calling readEntries until it returns empty array
async function readAllDirectoryEntries(directoryReader) {
let entries = [];
let readEntries = await readEntriesPromise(directoryReader);
while (readEntries.length > 0) {
entries.push(...readEntries);
readEntries = await readEntriesPromise(directoryReader);
}
return entries;
}
// Wrap readEntries in a promise to make working with readEntries easier
// readEntries will return only some of the entries in a directory
// e.g. Chrome returns at most 100 entries at a time
async function readEntriesPromise(directoryReader) {
try {
return await new Promise((resolve, reject) => {
directoryReader.readEntries(resolve, reject);
});
} catch (err) {
console.log(err);
}
}
const getDisplayPath = (entry)=>{
return new Promise((resolve, reject) =>{
chrome.fileSystem.getDisplayPath(entry, (path)=>{
if(chrome.runtime.lastError) {
reject(chrome.runtime.lastError)
}else {
resolve(path);
}
})
})
}
const fileEnties = await getAllFileEntries(dataTransferItems);
const files = await Promise.all(fileEnties.map(async(x)=>{
return (await getDisplayPath(x))
}))
return files;
}

How would I assign a Javascript variable to another Javascript variable? (a little confusing, i know)

So, I have had a problem recently!
I was trying to assign a value to a variables value (a little confusing, i know). I was trying to make a library system for my Discord bot, which uses JavaScript (Node.js)!
So, here's a part of the code that I was struggling with:
flist.forEach(item1 => {
liblist.forEach(item => {
eval(item1 = require(item));
});
});
OK, so basically item1 has to be replaced with a library file's name (if a file is named cmdh, I use that as a variable name to assign require(item) to it)
Edit: the item1 is the file name, by the way.
Edit 2: Here's a part of the file util.js:
const Discord = require("discord.js");
const fs = require("fs");
function genEmbed(title, desc, col) {
return new Discord.MessageEmbed().setTitle(title).setDescription(desc).setColor(col);
};
function log(inp) {
console.log(`[UTIL] ${inp}`);
};
function loadDef() {
log("Loading libraries...");
dirlist = [];
liblist = [];
flist = [];
fs.readdir("./libraries", (err, dirs) => {
if(err) console.error(err);
dirs.forEach(dir => {
dirlist.push("./libraries/" + dir);
});
dirlist.forEach(dir => {
fs.readdir(dir, (err, files) => {
if(err) console.error(err);
files.forEach(file => {
if(file.includes(".")) {
liblist.push(require(dir + "/" + file));
filename = file.split(".")[0];
flist.push(filename);
} else {
log(`${file} is a directory, ignoring...`)
};
});
});
});
});
flist.forEach(item1 => {
liblist.forEach(item => {
eval(item1 = require(item));
});
});
log("Libraries loaded!");
};
module.exports = {
genEmbed,
loadDef
};

If you are trying to assign a new value for each element in an array and return a new array with the updated values, you should use map instead of forEach.
If you want to return an array with the required libraries from liblist and store the result in flist, your code should look as follows:
flist = liblist.map(item => require(item));
Essentially, map takes each value from an array, applies a function to it (in your case, require), and then returns a new array with the results of the function.
It should be noted that you also need to replace fs.readdir with fs.readdirSync, otherwise liblist will be empty when the code is called.
After our discussion on the chat I understood that you want to set the variables as globals in your main file. However, this is a bit hackish. To do that you need to modify the global object.
Note: I would advise you to statically require via const libraryName = require('./libraries/fileName.js') instead, as this way of dynamically defining libraries has no advantage in this case and only makes the code more complicated. Dynamically requiring libraries only makes sense when you, for example, add listeners via your libraries, but then you do not need to store them as globals.
Your full code for the utils file should now look as follows:
const Discord = require("discord.js");
const fs = require("fs");
function genEmbed(title, desc, col) {
return new Discord.MessageEmbed().setTitle(title).setDescription(desc).setColor(col);
};
function log(inp) {
console.log(`[UTIL] ${inp}`);
};
function loadDef() {
log("Loading libraries...");
libraries = {};
const dirlist = fs.readdirSync("./libraries").map(dir => "./libraries/" + dir)
dirlist.forEach(dir => {
const files = fs.readdirSync(dir)
files.forEach(file => {
if(file.includes(".")) {
filename = file.split(".")[0];
libraries[filename] = require(dir + "/" + file);
} else {
log(`${file} is a directory, ignoring...`)
};
});
});
log("Libraries loaded!");
return libraries;
};
module.exports = {
genEmbed,
loadDef
};
Now you still need to modify the code in your main file, as follows:
const libraries = loadDef()
global = Object.assign(global, libraries) // assign libraries to global variables

Webpack add files before compiling through plugin

I am trying to build a webpack plugin and I want to add some files to be processed before the whole compilation step.
My intention is to add some files from a folder to be passed by the normal build process using the desired plugins and loaders.
I realize that if I create a new asset I can do this:
SomePlugin.prototype.apply = function(compiler) {
compiler.plugin("emit", function(compilation, callback) {
compilation.assets['newAsset.js'] = {
source: function() {
return 'content';
},
size: function() {
return 'content'.length;
}
};
callback();
});
}
But I don't know how to add for example a .scss on the list of files to be processed so webpack can handle the scss file based on the loaders.

Turns out that using what webpack internally uses can do the trick, suppose you want to add a markdown called test.md to be bundled with the same stuff that you are using, basing it the EntryOptionPlugin (What is used to decide how to bundle deppending on the entry options). You can do it like this
MyPlugin.prototype.apply = function(compiler) {
compiler.plugin("entry-option", function(context, entry) {
function itemToPlugin(item, name) {
if(Array.isArray(item))
return new MultiEntryPlugin(context, item, name);
else
return new SingleEntryPlugin(context, item, name);
}
if(typeof entry=== 'string'){
entry = [entry,__dirname+'/test.md']
}
else if (Array.isArray(entry)){
entry.push(__dirname+'/test.md')
}
else{
entry['SOME_KEY'] = __dirname+'/test.md'
}
if( Array.isArray(entry)) {
compiler.apply(itemToPlugin(entry, "main"));
} else if(typeof entry === "object") {
Object.keys(entry).forEach(function(name) {
compiler.apply(itemToPlugin(entry[name], name));
});
}
return true;
});
}
The resulting file will be shimmed on your pipeline and handled by the loaders and plugins that you already included.

Update HTML object with node.js and javascript

I'm new to nodejs and jquery, and I'm trying to update one single html object using a script.
I am using a Raspberry pi 2 and a ultrasonic sensor, to measure distance. I want to measure continuous, and update the html document at the same time with the real time values.
When I try to run my code it behaves like a server and not a client. Everything that i console.log() prints in the cmd and not in the browesers' console. When I run my code now i do it with "sudo node surveyor.js", but nothing happens in the html-document. I have linked it properly to the script. I have also tried document.getElementsByTagName("h6").innerHTML = distance.toFixed(2), but the error is "document is not defiend".
Is there any easy way to fix this?
My code this far is:
var statistics = require('math-statistics');
var usonic = require('r-pi-usonic');
var fs = require("fs");
var path = require("path");
var jsdom = require("jsdom");
var htmlSource = fs.readFileSync("../index.html", "utf8");
var init = function(config) {
usonic.init(function (error) {
if (error) {
console.log('error');
} else {
var sensor = usonic.createSensor(config.echoPin, config.triggerPin, config.timeout);
//console.log(config);
var distances;
(function measure() {
if (!distances || distances.length === config.rate) {
if (distances) {
print(distances);
}
distances = [];
}
setTimeout(function() {
distances.push(sensor());
measure();
}, config.delay);
}());
}
});
};
var print = function(distances) {
var distance = statistics.median(distances);
process.stdout.clearLine();
process.stdout.cursorTo(0);
if (distance < 0) {
process.stdout.write('Error: Measurement timeout.\n');
} else {
process.stdout.write('Distance: ' + distance.toFixed(2) + ' cm');
call_jsdom(htmlSource, function (window) {
var $ = window.$;
$("h6").replaceWith(distance.toFixed(2));
console.log(documentToSource(window.document));
});
}
};
function documentToSource(doc) {
// The non-standard window.document.outerHTML also exists,
// but currently does not preserve source code structure as well
// The following two operations are non-standard
return doc.doctype.toString()+doc.innerHTML;
}
function call_jsdom(source, callback) {
jsdom.env(
source,
[ 'jquery-1.7.1.min.js' ],
function(errors, window) {
process.nextTick(
function () {
if (errors) {
throw new Error("There were errors: "+errors);
}
callback(window);
}
);
}
);
}
init({
echoPin: 15, //Echo pin
triggerPin: 14, //Trigger pin
timeout: 1000, //Measurement timeout in µs
delay: 60, //Measurement delay in ms
rate: 5 //Measurements per sample
});

Node.js is a server-side implementation of JavaScript. It's ok to do all the sensors operations and calculations on server-side, but you need some mechanism to provide the results to your clients. If they are going to use your application by using a web browser, you must run a HTTP server, like Express.js, and create a route (something like http://localhost/surveyor or just http://localhost/) that calls a method you have implemented on server-side and do something with the result. One possible way to return this resulting data to the clients is by rendering an HTML page that shows them. For that you should use a Template Engine.
Any DOM manipulation should be done on client-side (you could, for example, include a <script> tag inside your template HTML just to try and understand how it works, but it is not recommended to do this in production environments).
Try searching google for Node.js examples and tutorials and you will get it :)

AngularJS and Restangular, trying to convert update method to API

I'm trying to convert my basic crud operations into an API that multiple components of my application can use.
I have successfully converted all methods, except the update one because it calls for each property on the object to be declared before the put request can be executed.
controller
$scope.update = function(testimonial, id) {
var data = {
name: testimonial.name,
message: testimonial.message
};
dataService.update(uri, data, $scope.id).then(function(response) {
console.log('Successfully updated!');
},
function(error) {
console.log('Error updating.');
});
}
dataService
dataService.update = function(uri, data, id) {
var rest = Restangular.one(uri, id);
angular.forEach(data, function(value, key) {
// needs to be in the format below
// rest.key = data.key
});
// needs to output something like this, depending on what the data is passed
// rest.name = data.name;
// rest.message = data.message;
return rest.put();
}
I tried to describe the problem in the codes comments, but to reiterate I cannot figure out how to generate something like rest.name = data.name; without specifying the name property because the update function shouldn't need to know the object properties.
Here is what the update method looked like before I started trying to make it usable by any of my components (this works)
Testimonial.update = function(testimonial, id) {
var rest = Restangular.one('testimonials', id);
rest.name = testimonial.name;
rest.message = testimonial.message;
return rest.put();
}
How can I recreate this without any specific properties parameters hard-coded in?
Also, my project has included lo-dash, if that helps, I don't know where to start with this problem. Thanks a ton for any advice!

Try like
angular.extend(rest,testimonial)
https://docs.angularjs.org/api/ng/function/angular.extend