Name of file selected in file field [duplicate] - javascript

<input type="file" id="file-id" name="file_name" onchange="theimage();">
This is my upload button.
<input type="text" name="file_path" id="file-path">
This is the text field where I have to show the full path of the file.
function theimage(){
var filename = document.getElementById('file-id').value;
document.getElementById('file-path').value = filename;
alert(filename);
}
This is the JavaScript which solve my problem. But in the alert value gives me
C:\fakepath\test.csv
and Mozilla gives me:
test.csv
But I want the local fully qualified file path. How to resolve this issue?
If this is due to browser security issue then what should be the alternate way to do this?

Some browsers have a security feature that prevents JavaScript from knowing your file's local full path. It makes sense - as a client, you don't want the server to know your local machine's filesystem. It would be nice if all browsers did this.

Use
document.getElementById("file-id").files[0].name;
instead of
document.getElementById('file-id').value

I use the object FileReader on the input onchange event for your input file type! This example uses the readAsDataURL function and for that reason you should have an tag. The FileReader object also has readAsBinaryString to get the binary data, which can later be used to create the same file on your server
Example:
var input = document.getElementById("inputFile");
var fReader = new FileReader();
fReader.readAsDataURL(input.files[0]);
fReader.onloadend = function(event){
var img = document.getElementById("yourImgTag");
img.src = event.target.result;
}

If you go to Internet Explorer, Tools, Internet Option, Security, Custom, find the "Include local directory path When uploading files to a server" (it is quite a ways down) and click on "Enable" . This will work

I am happy that browsers care to save us from intrusive scripts and the like. I am not happy with IE putting something into the browser that makes a simple style-fix look like a hack-attack!
I've used a < span > to represent the file-input so that I could apply appropriate styling to the < div > instead of the < input > (once again, because of IE). Now due to this IE want's to show the User a path with a value that's just guaranteed to put them on guard and in the very least apprehensive (if not totally scare them off?!)... MORE IE-CRAP!
Anyhow, thanks to to those who posted the explanation here: IE Browser Security: Appending "fakepath" to file path in input[type="file"], I've put together a minor fixer-upper...
The code below does two things - it fixes a lte IE8 bug where the onChange event doesn't fire until the upload field's onBlur and it updates an element with a cleaned filepath that won't scare the User.
// self-calling lambda to for jQuery shorthand "$" namespace
(function($){
// document onReady wrapper
$().ready(function(){
// check for the nefarious IE
if($.browser.msie) {
// capture the file input fields
var fileInput = $('input[type="file"]');
// add presentational <span> tags "underneath" all file input fields for styling
fileInput.after(
$(document.createElement('span')).addClass('file-underlay')
);
// bind onClick to get the file-path and update the style <div>
fileInput.click(function(){
// need to capture $(this) because setTimeout() is on the
// Window keyword 'this' changes context in it
var fileContext = $(this);
// capture the timer as well as set setTimeout()
// we use setTimeout() because IE pauses timers when a file dialog opens
// in this manner we give ourselves a "pseudo-onChange" handler
var ieBugTimeout = setTimeout(function(){
// set vars
var filePath = fileContext.val(),
fileUnderlay = fileContext.siblings('.file-underlay');
// check for IE's lovely security speil
if(filePath.match(/fakepath/)) {
// update the file-path text using case-insensitive regex
filePath = filePath.replace(/C:\\fakepath\\/i, '');
}
// update the text in the file-underlay <span>
fileUnderlay.text(filePath);
// clear the timer var
clearTimeout(ieBugTimeout);
}, 10);
});
}
});
})(jQuery);

On Chrome/Chromium based apps like electron you can just use the target.files:
(I'm using React JS on this example)
const onChange = (event) => {
const value = event.target.value;
// this will return C:\fakepath\somefile.ext
console.log(value);
const files = event.target.files;
//this will return an ARRAY of File object
console.log(files);
}
return (
<input type="file" onChange={onChange} />
)
The File object I'm talking above looks like this:
{
fullName: "C:\Users\myname\Downloads\somefile.ext"
lastModified: 1593086858659
lastModifiedDate: (the date)
name: "somefile.ext"
size: 10235546
type: ""
webkitRelativePath: ""
}
So then you can just get the fullName if you wanna get the path.
Note that this would only work on chrome/chromium browsers, so if you don't have to support other browsers (like if you're building an electron project) you can use this.

I came accross the same problem. In IE8 it could be worked-around by creating a hidden input after the file input control. The fill this with the value of it's previous sibling. In IE9 this has been fixed aswell.
My reason in wanting to get to know the full path was to create an javascript image preview before uploading. Now I have to upload the file to create a preview of the selected image.

If you really need to send the full path of the uploded file, then you'd probably have to use something like a signed java applet as there isn't any way to get this information if the browser doesn't send it.

Use file readers:
$(document).ready(function() {
$("#input-file").change(function() {
var length = this.files.length;
if (!length) {
return false;
}
useImage(this);
});
});
// Creating the function
function useImage(img) {
var file = img.files[0];
var imagefile = file.type;
var match = ["image/jpeg", "image/png", "image/jpg"];
if (!((imagefile == match[0]) || (imagefile == match[1]) || (imagefile == match[2]))) {
alert("Invalid File Extension");
} else {
var reader = new FileReader();
reader.onload = imageIsLoaded;
reader.readAsDataURL(img.files[0]);
}
function imageIsLoaded(e) {
$('div.withBckImage').css({ 'background-image': "url(" + e.target.result + ")" });
}
}

seems you can't find the full path in you localhost by js, but you can hide the fakepath to just show the file name. Use jQuery to get the file input's selected filename without the path

The best solution for this, I've found, is to use a middleware like Multer. Here's a quick rundown:
npm i multer
Add enctype="multipart/form-data" to your html form.
In your backend dock where you're making your post request, require multer (const multer = require('multer'))
In the same dock, set your upload destination: const upload = multer({dest:'uploas/'}). This will automatically create a local folder called 'uploads' where your files will be added. The code I've included shows you how to upload to your local disk storage. If you're using cloud storage (e.g. AWS, Azure, Cloudinary etc.) you can check out the Multer docs to see how to manage that. There aren't too many extra steps though.
in your post request, add 'upload.single' (for one file) or 'upload.array' (for multiple files), like this:
router.post('/new', upload.single('image'), async function(req, res) { //'image' should be the name of the input you're sending in the req.body
console.log(req.file) //note, if you're using 'upload.array', this should be 'req.files'
});
the req.file will have a full path name that you can use in your post request. For more information, check out the Multer docs:
https://www.npmjs.com/package/multer
I hope this helps!

You would be able to get at least temporary created copy of the file path on your machine. The only condition here is your input element should be within a form
What you have to do else is putting in the form an attribute enctype, e.g.:
<form id="formid" enctype="multipart/form-data" method="post" action="{{url('/add_a_note' )}}">...</form>
you can find the path string at the bottom.
It opens stream to file and then deletes it.

Hy there , in my case i am using asp.net development environment, so i was want to upload those data in asynchronus ajax request , in [webMethod] you can not catch the file uploader since it is not static element ,
so i had to make a turnover for such solution by fixing the path , than convert the wanted image into bytes to save it in DB .
Here is my javascript function ,
hope it helps you:
function FixPath(Path)
{
var HiddenPath = Path.toString();
alert(HiddenPath.indexOf("FakePath"));
if (HiddenPath.indexOf("FakePath") > 1)
{
var UnwantedLength = HiddenPath.indexOf("FakePath") + 7;
MainStringLength = HiddenPath.length - UnwantedLength;
var thisArray =[];
var i = 0;
var FinalString= "";
while (i < MainStringLength)
{
thisArray[i] = HiddenPath[UnwantedLength + i + 1];
i++;
}
var j = 0;
while (j < MainStringLength-1)
{
if (thisArray[j] != ",")
{
FinalString += thisArray[j];
}
j++;
}
FinalString = "~" + FinalString;
alert(FinalString);
return FinalString;
}
else
{
return HiddenPath;
}
}
here only for testing :
$(document).ready(function () {
FixPath("hakounaMatata:/7ekmaTa3mahaLaziz/FakePath/EnsaLmadiLiYghiz");
});
// this will give you : ~/EnsaLmadiLiYghiz

Related

Need to delete file in js application but got /fakepath [duplicate]

<input type="file" id="file-id" name="file_name" onchange="theimage();">
This is my upload button.
<input type="text" name="file_path" id="file-path">
This is the text field where I have to show the full path of the file.
function theimage(){
var filename = document.getElementById('file-id').value;
document.getElementById('file-path').value = filename;
alert(filename);
}
This is the JavaScript which solve my problem. But in the alert value gives me
C:\fakepath\test.csv
and Mozilla gives me:
test.csv
But I want the local fully qualified file path. How to resolve this issue?
If this is due to browser security issue then what should be the alternate way to do this?
Some browsers have a security feature that prevents JavaScript from knowing your file's local full path. It makes sense - as a client, you don't want the server to know your local machine's filesystem. It would be nice if all browsers did this.
Use
document.getElementById("file-id").files[0].name;
instead of
document.getElementById('file-id').value
I use the object FileReader on the input onchange event for your input file type! This example uses the readAsDataURL function and for that reason you should have an tag. The FileReader object also has readAsBinaryString to get the binary data, which can later be used to create the same file on your server
Example:
var input = document.getElementById("inputFile");
var fReader = new FileReader();
fReader.readAsDataURL(input.files[0]);
fReader.onloadend = function(event){
var img = document.getElementById("yourImgTag");
img.src = event.target.result;
}
If you go to Internet Explorer, Tools, Internet Option, Security, Custom, find the "Include local directory path When uploading files to a server" (it is quite a ways down) and click on "Enable" . This will work
I am happy that browsers care to save us from intrusive scripts and the like. I am not happy with IE putting something into the browser that makes a simple style-fix look like a hack-attack!
I've used a < span > to represent the file-input so that I could apply appropriate styling to the < div > instead of the < input > (once again, because of IE). Now due to this IE want's to show the User a path with a value that's just guaranteed to put them on guard and in the very least apprehensive (if not totally scare them off?!)... MORE IE-CRAP!
Anyhow, thanks to to those who posted the explanation here: IE Browser Security: Appending "fakepath" to file path in input[type="file"], I've put together a minor fixer-upper...
The code below does two things - it fixes a lte IE8 bug where the onChange event doesn't fire until the upload field's onBlur and it updates an element with a cleaned filepath that won't scare the User.
// self-calling lambda to for jQuery shorthand "$" namespace
(function($){
// document onReady wrapper
$().ready(function(){
// check for the nefarious IE
if($.browser.msie) {
// capture the file input fields
var fileInput = $('input[type="file"]');
// add presentational <span> tags "underneath" all file input fields for styling
fileInput.after(
$(document.createElement('span')).addClass('file-underlay')
);
// bind onClick to get the file-path and update the style <div>
fileInput.click(function(){
// need to capture $(this) because setTimeout() is on the
// Window keyword 'this' changes context in it
var fileContext = $(this);
// capture the timer as well as set setTimeout()
// we use setTimeout() because IE pauses timers when a file dialog opens
// in this manner we give ourselves a "pseudo-onChange" handler
var ieBugTimeout = setTimeout(function(){
// set vars
var filePath = fileContext.val(),
fileUnderlay = fileContext.siblings('.file-underlay');
// check for IE's lovely security speil
if(filePath.match(/fakepath/)) {
// update the file-path text using case-insensitive regex
filePath = filePath.replace(/C:\\fakepath\\/i, '');
}
// update the text in the file-underlay <span>
fileUnderlay.text(filePath);
// clear the timer var
clearTimeout(ieBugTimeout);
}, 10);
});
}
});
})(jQuery);
On Chrome/Chromium based apps like electron you can just use the target.files:
(I'm using React JS on this example)
const onChange = (event) => {
const value = event.target.value;
// this will return C:\fakepath\somefile.ext
console.log(value);
const files = event.target.files;
//this will return an ARRAY of File object
console.log(files);
}
return (
<input type="file" onChange={onChange} />
)
The File object I'm talking above looks like this:
{
fullName: "C:\Users\myname\Downloads\somefile.ext"
lastModified: 1593086858659
lastModifiedDate: (the date)
name: "somefile.ext"
size: 10235546
type: ""
webkitRelativePath: ""
}
So then you can just get the fullName if you wanna get the path.
Note that this would only work on chrome/chromium browsers, so if you don't have to support other browsers (like if you're building an electron project) you can use this.
I came accross the same problem. In IE8 it could be worked-around by creating a hidden input after the file input control. The fill this with the value of it's previous sibling. In IE9 this has been fixed aswell.
My reason in wanting to get to know the full path was to create an javascript image preview before uploading. Now I have to upload the file to create a preview of the selected image.
If you really need to send the full path of the uploded file, then you'd probably have to use something like a signed java applet as there isn't any way to get this information if the browser doesn't send it.
Use file readers:
$(document).ready(function() {
$("#input-file").change(function() {
var length = this.files.length;
if (!length) {
return false;
}
useImage(this);
});
});
// Creating the function
function useImage(img) {
var file = img.files[0];
var imagefile = file.type;
var match = ["image/jpeg", "image/png", "image/jpg"];
if (!((imagefile == match[0]) || (imagefile == match[1]) || (imagefile == match[2]))) {
alert("Invalid File Extension");
} else {
var reader = new FileReader();
reader.onload = imageIsLoaded;
reader.readAsDataURL(img.files[0]);
}
function imageIsLoaded(e) {
$('div.withBckImage').css({ 'background-image': "url(" + e.target.result + ")" });
}
}
seems you can't find the full path in you localhost by js, but you can hide the fakepath to just show the file name. Use jQuery to get the file input's selected filename without the path
The best solution for this, I've found, is to use a middleware like Multer. Here's a quick rundown:
npm i multer
Add enctype="multipart/form-data" to your html form.
In your backend dock where you're making your post request, require multer (const multer = require('multer'))
In the same dock, set your upload destination: const upload = multer({dest:'uploas/'}). This will automatically create a local folder called 'uploads' where your files will be added. The code I've included shows you how to upload to your local disk storage. If you're using cloud storage (e.g. AWS, Azure, Cloudinary etc.) you can check out the Multer docs to see how to manage that. There aren't too many extra steps though.
in your post request, add 'upload.single' (for one file) or 'upload.array' (for multiple files), like this:
router.post('/new', upload.single('image'), async function(req, res) { //'image' should be the name of the input you're sending in the req.body
console.log(req.file) //note, if you're using 'upload.array', this should be 'req.files'
});
the req.file will have a full path name that you can use in your post request. For more information, check out the Multer docs:
https://www.npmjs.com/package/multer
I hope this helps!
You would be able to get at least temporary created copy of the file path on your machine. The only condition here is your input element should be within a form
What you have to do else is putting in the form an attribute enctype, e.g.:
<form id="formid" enctype="multipart/form-data" method="post" action="{{url('/add_a_note' )}}">...</form>
you can find the path string at the bottom.
It opens stream to file and then deletes it.
Hy there , in my case i am using asp.net development environment, so i was want to upload those data in asynchronus ajax request , in [webMethod] you can not catch the file uploader since it is not static element ,
so i had to make a turnover for such solution by fixing the path , than convert the wanted image into bytes to save it in DB .
Here is my javascript function ,
hope it helps you:
function FixPath(Path)
{
var HiddenPath = Path.toString();
alert(HiddenPath.indexOf("FakePath"));
if (HiddenPath.indexOf("FakePath") > 1)
{
var UnwantedLength = HiddenPath.indexOf("FakePath") + 7;
MainStringLength = HiddenPath.length - UnwantedLength;
var thisArray =[];
var i = 0;
var FinalString= "";
while (i < MainStringLength)
{
thisArray[i] = HiddenPath[UnwantedLength + i + 1];
i++;
}
var j = 0;
while (j < MainStringLength-1)
{
if (thisArray[j] != ",")
{
FinalString += thisArray[j];
}
j++;
}
FinalString = "~" + FinalString;
alert(FinalString);
return FinalString;
}
else
{
return HiddenPath;
}
}
here only for testing :
$(document).ready(function () {
FixPath("hakounaMatata:/7ekmaTa3mahaLaziz/FakePath/EnsaLmadiLiYghiz");
});
// this will give you : ~/EnsaLmadiLiYghiz

Get File Path From Drop Event

I have some javascript code that allows users to drag and drop files in IE.
The problem I have is that they would like the file deleted after being dragged, but I can't seem to get the file path, just the name.
I have seen many references to e.dataTransfer.files[0].path, but it always comes back as 'undefined' when I try it.
Any ideas why e.dataTransfer.files[0].path does not work, or how I can get the file path?
$(document).ready(function (ex) {
var holder = document.getElementById('holder');
holder.ondragover = function () { this.className = 'hover'; return false; };
holder.ondrop = function (e) {
e.preventDefault();
var file = e.dataTransfer.files[0];
var path = e.dataTransfer.files[0].path;
fileArray.push(file);
//alert(e.target.id);
var reader = new FileReader();
reader.readAsDataURL(file);
};
});
that's not possible for a web app, but if your users would run an app on their machine, you could build an electron app. inside electron you get the e.dataTransfer.files[0].path property, which you can then use to delete the file.
https://www.electronjs.org/
The file doesn't have property path.
You can experiment with it here and the complete list of file properties can be found here.
To read the file one uses FileReader as you did, without using the path explicitly.
After trying everything I could find, I am of the opinion that it is not possible.

JS/JQuery get (local) file path [duplicate]

<input type="file" id="file-id" name="file_name" onchange="theimage();">
This is my upload button.
<input type="text" name="file_path" id="file-path">
This is the text field where I have to show the full path of the file.
function theimage(){
var filename = document.getElementById('file-id').value;
document.getElementById('file-path').value = filename;
alert(filename);
}
This is the JavaScript which solve my problem. But in the alert value gives me
C:\fakepath\test.csv
and Mozilla gives me:
test.csv
But I want the local fully qualified file path. How to resolve this issue?
If this is due to browser security issue then what should be the alternate way to do this?
Some browsers have a security feature that prevents JavaScript from knowing your file's local full path. It makes sense - as a client, you don't want the server to know your local machine's filesystem. It would be nice if all browsers did this.
Use
document.getElementById("file-id").files[0].name;
instead of
document.getElementById('file-id').value
I use the object FileReader on the input onchange event for your input file type! This example uses the readAsDataURL function and for that reason you should have an tag. The FileReader object also has readAsBinaryString to get the binary data, which can later be used to create the same file on your server
Example:
var input = document.getElementById("inputFile");
var fReader = new FileReader();
fReader.readAsDataURL(input.files[0]);
fReader.onloadend = function(event){
var img = document.getElementById("yourImgTag");
img.src = event.target.result;
}
If you go to Internet Explorer, Tools, Internet Option, Security, Custom, find the "Include local directory path When uploading files to a server" (it is quite a ways down) and click on "Enable" . This will work
I am happy that browsers care to save us from intrusive scripts and the like. I am not happy with IE putting something into the browser that makes a simple style-fix look like a hack-attack!
I've used a < span > to represent the file-input so that I could apply appropriate styling to the < div > instead of the < input > (once again, because of IE). Now due to this IE want's to show the User a path with a value that's just guaranteed to put them on guard and in the very least apprehensive (if not totally scare them off?!)... MORE IE-CRAP!
Anyhow, thanks to to those who posted the explanation here: IE Browser Security: Appending "fakepath" to file path in input[type="file"], I've put together a minor fixer-upper...
The code below does two things - it fixes a lte IE8 bug where the onChange event doesn't fire until the upload field's onBlur and it updates an element with a cleaned filepath that won't scare the User.
// self-calling lambda to for jQuery shorthand "$" namespace
(function($){
// document onReady wrapper
$().ready(function(){
// check for the nefarious IE
if($.browser.msie) {
// capture the file input fields
var fileInput = $('input[type="file"]');
// add presentational <span> tags "underneath" all file input fields for styling
fileInput.after(
$(document.createElement('span')).addClass('file-underlay')
);
// bind onClick to get the file-path and update the style <div>
fileInput.click(function(){
// need to capture $(this) because setTimeout() is on the
// Window keyword 'this' changes context in it
var fileContext = $(this);
// capture the timer as well as set setTimeout()
// we use setTimeout() because IE pauses timers when a file dialog opens
// in this manner we give ourselves a "pseudo-onChange" handler
var ieBugTimeout = setTimeout(function(){
// set vars
var filePath = fileContext.val(),
fileUnderlay = fileContext.siblings('.file-underlay');
// check for IE's lovely security speil
if(filePath.match(/fakepath/)) {
// update the file-path text using case-insensitive regex
filePath = filePath.replace(/C:\\fakepath\\/i, '');
}
// update the text in the file-underlay <span>
fileUnderlay.text(filePath);
// clear the timer var
clearTimeout(ieBugTimeout);
}, 10);
});
}
});
})(jQuery);
On Chrome/Chromium based apps like electron you can just use the target.files:
(I'm using React JS on this example)
const onChange = (event) => {
const value = event.target.value;
// this will return C:\fakepath\somefile.ext
console.log(value);
const files = event.target.files;
//this will return an ARRAY of File object
console.log(files);
}
return (
<input type="file" onChange={onChange} />
)
The File object I'm talking above looks like this:
{
fullName: "C:\Users\myname\Downloads\somefile.ext"
lastModified: 1593086858659
lastModifiedDate: (the date)
name: "somefile.ext"
size: 10235546
type: ""
webkitRelativePath: ""
}
So then you can just get the fullName if you wanna get the path.
Note that this would only work on chrome/chromium browsers, so if you don't have to support other browsers (like if you're building an electron project) you can use this.
I came accross the same problem. In IE8 it could be worked-around by creating a hidden input after the file input control. The fill this with the value of it's previous sibling. In IE9 this has been fixed aswell.
My reason in wanting to get to know the full path was to create an javascript image preview before uploading. Now I have to upload the file to create a preview of the selected image.
If you really need to send the full path of the uploded file, then you'd probably have to use something like a signed java applet as there isn't any way to get this information if the browser doesn't send it.
Use file readers:
$(document).ready(function() {
$("#input-file").change(function() {
var length = this.files.length;
if (!length) {
return false;
}
useImage(this);
});
});
// Creating the function
function useImage(img) {
var file = img.files[0];
var imagefile = file.type;
var match = ["image/jpeg", "image/png", "image/jpg"];
if (!((imagefile == match[0]) || (imagefile == match[1]) || (imagefile == match[2]))) {
alert("Invalid File Extension");
} else {
var reader = new FileReader();
reader.onload = imageIsLoaded;
reader.readAsDataURL(img.files[0]);
}
function imageIsLoaded(e) {
$('div.withBckImage').css({ 'background-image': "url(" + e.target.result + ")" });
}
}
seems you can't find the full path in you localhost by js, but you can hide the fakepath to just show the file name. Use jQuery to get the file input's selected filename without the path
The best solution for this, I've found, is to use a middleware like Multer. Here's a quick rundown:
npm i multer
Add enctype="multipart/form-data" to your html form.
In your backend dock where you're making your post request, require multer (const multer = require('multer'))
In the same dock, set your upload destination: const upload = multer({dest:'uploas/'}). This will automatically create a local folder called 'uploads' where your files will be added. The code I've included shows you how to upload to your local disk storage. If you're using cloud storage (e.g. AWS, Azure, Cloudinary etc.) you can check out the Multer docs to see how to manage that. There aren't too many extra steps though.
in your post request, add 'upload.single' (for one file) or 'upload.array' (for multiple files), like this:
router.post('/new', upload.single('image'), async function(req, res) { //'image' should be the name of the input you're sending in the req.body
console.log(req.file) //note, if you're using 'upload.array', this should be 'req.files'
});
the req.file will have a full path name that you can use in your post request. For more information, check out the Multer docs:
https://www.npmjs.com/package/multer
I hope this helps!
You would be able to get at least temporary created copy of the file path on your machine. The only condition here is your input element should be within a form
What you have to do else is putting in the form an attribute enctype, e.g.:
<form id="formid" enctype="multipart/form-data" method="post" action="{{url('/add_a_note' )}}">...</form>
you can find the path string at the bottom.
It opens stream to file and then deletes it.
Hy there , in my case i am using asp.net development environment, so i was want to upload those data in asynchronus ajax request , in [webMethod] you can not catch the file uploader since it is not static element ,
so i had to make a turnover for such solution by fixing the path , than convert the wanted image into bytes to save it in DB .
Here is my javascript function ,
hope it helps you:
function FixPath(Path)
{
var HiddenPath = Path.toString();
alert(HiddenPath.indexOf("FakePath"));
if (HiddenPath.indexOf("FakePath") > 1)
{
var UnwantedLength = HiddenPath.indexOf("FakePath") + 7;
MainStringLength = HiddenPath.length - UnwantedLength;
var thisArray =[];
var i = 0;
var FinalString= "";
while (i < MainStringLength)
{
thisArray[i] = HiddenPath[UnwantedLength + i + 1];
i++;
}
var j = 0;
while (j < MainStringLength-1)
{
if (thisArray[j] != ",")
{
FinalString += thisArray[j];
}
j++;
}
FinalString = "~" + FinalString;
alert(FinalString);
return FinalString;
}
else
{
return HiddenPath;
}
}
here only for testing :
$(document).ready(function () {
FixPath("hakounaMatata:/7ekmaTa3mahaLaziz/FakePath/EnsaLmadiLiYghiz");
});
// this will give you : ~/EnsaLmadiLiYghiz

Check if file has changed using HTML5 File API

Okay, so I have a program which outputs some specific data to a tab separated variable file.
I had been using Excel to open and view the file contents, however I found excel's insistence on locking every file it opens to be incredibly annoying as my program would crash if I left the file open in Excel... but I would really like the data to neatly update after each run of the program, so I don't have to close and re-open the file all the time.
So, I decided it would be easiest to use Javascript to parse the file and display it in a html table, and it was. I knocked something together in no time. Now my program doesn't crash if I leave the file on display, however, it still doesn't update... and I have to open the newly generated file each time.
So, I was wondering if there was a mechanism by which my Javascript could be somehow notified of a change to the file by another process? I know this is unlikely, but I would like to avoid simply polling the file for obvious reasons.
I am very familiar with JS, but HTML5 and the new APIs are all new to me.
I don't believe the File API has any event for the file changing, just progress events and the like.
Update August 2020: The alternative below no longer works, and the specification specifically disallows it by saying that the File object's information must reflect the state of the underlying file as of when it was selected. From the spec:
User agents should endeavor to have a File object’s snapshot state set to the state of the underlying storage on disk at the time the reference is taken. If the file is modified on disk following the time a reference has been taken, the File's snapshot state will differ from the state of the underlying storage.
You could use polling. Remember the lastModifiedDate of the File, and then when your polling function fires, get a new File instance for the input and see if the lastModifiedDate has changed.
This works for me on Chrome, for instance: Live Copy | Source
(function() {
var input;
var lastMod;
document.getElementById('btnStart').onclick = function() {
startWatching();
};
function startWatching() {
var file;
if (typeof window.FileReader !== 'function') {
display("The file API isn't supported on this browser yet.");
return;
}
input = document.getElementById('filename');
if (!input) {
display("Um, couldn't find the filename element.");
}
else if (!input.files) {
display("This browser doesn't seem to support the `files` property of file inputs.");
}
else if (!input.files[0]) {
display("Please select a file before clicking 'Show Size'");
}
else {
file = input.files[0];
lastMod = file.lastModifiedDate;
display("Last modified date: " + lastMod);
display("Change the file");
setInterval(tick, 250);
}
}
function tick() {
var file = input.files && input.files[0];
if (file && lastMod && file.lastModifiedDate.getTime() !== lastMod.getTime()) {
lastMod = file.lastModifiedDate;
display("File changed: " + lastMod);
}
}
function display(msg) {
var p = document.createElement('p');
p.innerHTML = msg;
document.body.appendChild(p);
}
})();
<input type='file' id='filename'>
<input type='button' id='btnStart' value='Start'>
There is two solutions to this problem, and <input type="file"> is not one of them. according to the spec, it creates a "snapshot" of the file.
Native File System
This api is experimental and requires flags to be enabled in blink (aka chromium browsers). The idea is that you get a file handle and when you need the file then you call the async "getFile" function to retrieve the actual file.
This feature is a "power feature" and require your site to be secure, and it can't work in sandboxed iframes.
So without testing here is some "code in the dark":
// triggerd on click
async function pickFile () {
const handle = showOpenFilePicker()
let lastModificationTime = 0
async function compare () {
const file = await handle.getFile()
if (file.lastModified > lastModificationTime) {
lastModificationTime = +file.lastModified
console.log(await file.text())
}
}
setInterval(compare, 1000)
}
Get Entry from Drag and drop
Similar to the native file system you can also retrieve a file handle and do the same thing, but this feature works in all browsers today. but this code snippet don't work in stackoverflow since it use some sandboxing do making it incompatible, so here is a fiddle with few comments
function drop(event) {
event.stopPropagation();
event.preventDefault();
// get the file as an fileEntry (aka file handle)
const fileEntry = event.dataTransfer.items[0].webkitGetAsEntry()
let lastModificationTime = 0
async function read (file) {
// use the new async read method on blobs.
console.log(await file.text())
}
function compare (meta) {
if (meta.modificationTime > lastModificationTime) {
lastModificationTime = meta.modificationTime
fileEntry.file(read)
}
}
setInterval(fileEntry.getMetadata.bind(fileEntry, compare), 1000)
}
Edit: there is now also a way to get drag and dropped files as a FileSystemFileHandle that is much nicer to work with
elem.addEventListener('dragover', evt => {
// Prevent navigation.
evt.preventDefault()
})
elem.addEventListener('drop', async evt => {
// Prevent navigation.
evt.preventDefault()
// Process all of the items.
for (const item of evt.dataTransfer.items) {
// kind will be 'file' for file/directory entries.
if (item.kind === 'file') {
const entry = await item.getAsFileSystemHandle();
if (entry.kind === 'file') {
// use same solution as the first Native File System solution
}
}
}
})
While T.J. Crowder's answer is correct, Chrome's implementation appears to break the spec.
Each Blob must have an internal snapshot state, which must be initially set to the state of the underlying storage, if any such underlying storage exists, and must be preserved through structured clone. Further normative definition of snapshot state can be found for files.
When a file is selected the input has a snapshot of the contents at that point. Local changes on disk don't update the snapshot.

When using plupload HOWTO duplicate file object when selected & submit it separately for a related server-side processing

I am using plupload to let users upload images. But I also want to generate thumbnails for preview before they finally decide to keep it. I understand currently "Image preview" feature is not present in plupload. So to work around this I decided to submit a new form containing just one file for each image added, & let the server process it & return a thumbnail.
Now my question is how do I get the handle on the file object from the plupload so that I can create an "input" file field dynamically.
Currently I iterate over uploader.files & set input.name but I dont know how to set the input.value field, since I cant seem to get the complete file path of the file added.
I am up for any suggestions (in addition to replacing this approach completely), I just need thumbnail of the file selected for upload.
Maybe my answer is a bit late, but I searched today for a similar solution and came up with the following approach. It will only work with the HTML5 Runtime.
As there is no way to get the file objects from plupload, I changed the onchange event of the dynamically created input field and store the file objects for myself. This is done by binding to the PostInit-Event.
After that I can show the image to the user by using the FileReader API introduced with HTML 5. So there is no need to send the image to the server. See my FilesAdded Listener below.
// Currently added File Objects
var nativeFiles = {};
var uploader = new plupload.Uploader({
runtimes : 'html5,html4',
// Your settings...
});
uploader.bind('PostInit', function(up, params) {
// Initialize Preview.
if(uploader.runtime == "html5") {
var inputFile = document.getElementById(uploader.id + '_html5');
var oldFunction = inputFile.onchange;
inputFile.onchange = function() {
nativeFiles = this.files;
oldFunction.call(inputFile);
}
}
});
uploader.bind('FilesAdded', function(up, files) {
for (var i in files) {
// Your code...
// Load Preview
if(uploader.runtime == "html5") {
var fileObject = uploader.getFile(files[i].id);
var reader = new FileReader();
reader.onload = (function(file, id) {
return function(e) {
var span = document.getElementById('thumb_'+id);
span.innerHTML = "<img src='"+e.target.result+"'/>";
};
})(nativeFiles[i], files[i].id);
reader.readAsDataURL(nativeFiles[i]);
}
}
});

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