downloading a CSV when a condition is satisfied - javascript

I have a code which converts JSON to CSV. And I put this through a specific condition ( if condition) I want the CSV to be downloaded automatically if the condition is met without any button click. what is the shortest/simplest way to do this?
For eg:
if( data.length == 10){
var stored_data = data;
data = [];
console.log(stored_data);
var csv_file = ConvertToCSV(stored_data); //ConvertTOCSV is a function
}
if the above condition is met, the CSV should be downloaded. Thank you
NOTE: I know this can e done easily with a button click. but i want the download to happen automatically when the condition is satisfied

Just create a "dummy" link and programmatically set its href and then click. The link shouldn't appear on the screen because it has no content.
<body>
<a href="#" id="csvDownload" download></a>
</body>
<script>
if( data.length == 10){
var lnk = document.getElementById("csvDownload");
var stored_data = data;
data = [];
console.log(stored_data);
var csv_file = ConvertToCSV(stored_data); //ConvertTOCSV is a function
lnk.href = csv_file;
lnk.click();
}
</script>

What you are trying to do is possible by changing the document location to point to your created object, but the problem that I ran into while trying to create a quick example for you, is I can't seem to give the file a usable name and extension. So everything downloaded as a file called "download" with no extension (however - the file contents are correct).
So if you want to pursue finding a way to give the stream a name and file type you could start with something like this -
document.location='data:Application/octet-stream,' +
encodeURIComponent(csv_file);
But I would say that #Scott's answer is a better way to go.

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

Extracting EXIF data (specifically dateTime and GPSLatitude and GPSLongitude) with JavaScript

I have a program where a camera is set up to constantly take pictures (about every 10 seconds or so) and the picture is sent to a folder on my server and then another program refreshes that folder constantly so that I always just have the most recent picture in that particular folder.
An HTML document exists that also constantly refreshes, and references that picture location to get and display the newest image.
What I'm trying to do is extract the EXIF data (that I've verified exists when I save the image from the active webpage and look at it's properties). I want to display the DateCreated (I believe this is DateTime) and the Latitude and Longitude (I believe is GPSLatitude and GPSLongitude).
I came across this library, exif-js, which seems like the go-to for most people trying to do this same thing in JavaScript. My code looks the same as the code at the bottom of the README.md file, except I changed out my img id="...." and variable names, (see below). It seems like it should work, but it's not producing any data. My empty span element just stays empty.
Is there an issue with the short time span that the page has before refreshing?
Thanks for any help!
Here's what my code currently looks like (just trying to get the DateTime info). I have also tried the GPSLatitude and GPSLongitude tags.
<!-- Library to extract EXIF data -->
<script src="vendors/exif-js/exif-js"></script>
<script type="text/javascript">
window.onload=getExif;
function getExif()
{
var img1 = document.getElementById("img1");
EXIF.getData(img1, function() {
var time = EXIF.getTag(this, "DateTime");
var img1Time = document.getElementById("img1Time");
img1Time.innerHTML = `${time}`;
});
var img2 = document.getElementById("img2");
EXIF.getData(img2, function() {
var allMetaData = EXIF.getALLTags(this);
var allMetaDataSpan = document.getElementById("Img2Time");
allMetaDataSpan.innerHTML = JSON.stringify(allMetaData, null, "\t");
});
}
</script>
go into ur exif.js file and then go to line 930 and then change it to
EXIF.getData = function(img, callback) {
if ((self.Image && img instanceof self.Image
|| self.HTMLImageElement && img instanceof self.HTMLImageElement)
&& !img.complete)
return false;
I know this may be already solved but I'd like to offer an alternative solution, for the people stumbling upon this question.
I'm a developer of a new library exifr you might want to try. It's maintained, actively developed library with focus on performance and works in both nodejs and browser.
async function getExif() {
let output = await exifr.parse(imgBuffer)
console.log('latitude', output.latitude) // converted by the library
console.log('longitude', output.longitude) // converted by the library
console.log('GPSLatitude', output.GPSLatitude) // raw value
console.log('GPSLongitude', output.GPSLongitude) // raw value
console.log('GPSDateStamp', output.GPSDateStamp)
console.log('DateTimeOriginal', output.DateTimeOriginal)
console.log('DateTimeDigitized', output.DateTimeDigitized)
console.log('ModifyDate', output.ModifyDate)
}
You can also try out the library's playground and experiment with images and their output, or check out the repository and docs.

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

how to load data from text file to javascript array?

i have an array called items=["apple","mango","cherry"];
i wonder how i can load the array data from text file instead of declaring it?the text file data is stored like this "apple","mango","cherry",...
furthermore, how to add to the end of this this text file an item for example add "orange" after "cherry"?
items=["apple","mango","cherry"];
if (items.indexOf(myVariable2) == -1) {
// not found, so output it
t++;
document.myform3.outputtext3.value +=myVariable2+"\n";
}
With jQuery you can do something like this
$.get("textFile.txt", function(data) {
var items = data.split(',');
});
You may need something like this though
var items = data.replace(/"/g, '').split(',');
This is a start.
If this is a user input file then you may need to upload it before you work with it.
Sorry, but I don't believe it's quite that simple. Browsers restrict access to local drives (and to server drives) for security reasons.
But one way to access the text file using jQuery would be
jQuery.get('http://localhost/foo.txt', function(data) {
var myvar = data;
});
var file = event.target.file;
var reader = new FileReader();
var txt=reader.readAsText(file);
var items=txt.split(",");

Changing image extension with javascript/jquery only?

I'm making a simple slider to show off artwork for a friend of mine. I'm really only familiar with javascript/jquery, so I'm not 100% comfortable using something else right now.
Since my friend doesn't have any programming knowledge, I'm trying to keep this really simple for her to update (i.e., automating creating new images whenever she adds a new one to the folder). She will upload images to a folder and will have to number them (i.e., 1.jpg, 2.jpg). My javascript uses a for loop to loop through numbers (she will have to update the loop whenever she adds a new image) and insert them into the file name. HOWEVER this limits her to only uploading one type of file. Is there someway to change the extension only using javascript?
This is what I have so far:
function callImages(){
//create the image div
$('.artslider').append('<div class="image"></div>');
//create the files array
var files = [];
//start the loop, starting position will have to be updated as images are added
for (i=8;i>=0;i--){
//create the img src for a jpg img
var imgJPG = 'arts/'+i+'.jpg';
//find the natural width of the image after it loads to see if it actually exists
var imgWidth = $('imgJPG').load().naturalWidth;
//if the width is undefined, replace the jpg extension with gif
if (imgWidth===undefined){
var imgGIF = imgJPG.replace('jpg', 'gif');
files[i] = '<img src="'+imgGIF+'" class="artsliderimg"/>';
}
//otherwise keep the jpg extension
else {
files[i] = '<img src="'+imgJPG+'" class="artsliderimg"/>';
}
//then add the images to the img div
$('.image').append(files[i]);
}
};
The problem with this if/else is that it will only create a gif image. If you switch the order, it will only create a jpg image.
edit: here's what this code produces: https://googledrive.com/host/0B1lNgklCWTGwV1N5cWNlNUJqMzg/index.html
The problem is with this bit of code:
var imgJPG = 'arts/'+i+'.jpg';
var imgWidth = $('imgJPG').load().naturalWidth;
imgWidth will always be undefined.
Firstly you are passing in the string 'imgJPG' instead of the parameter imgJPG. Secondly I think you have misunderstood jQuery selectors, this is used for selecting HTML elements, inputting a file path into here will not achieve anything. Thirdly I think you have misunderstood the load function, this is used for loading data from the server into a HTML element.
I would suggest using a function like below to check if the image exists:
function urlExists(url) {
var http = jQuery.ajax({
type:"HEAD",
url: url,
async: false
});
return http.status == 200;
}
Then in your code:
if (!urlExists(imgJPG)){
var imgGIF = imgJPG.replace('jpg', 'gif');
files[i] = '<img src="'+imgGIF+'" class="artsliderimg"/>';
}
else {
files[i] = '<img src="'+imgJPG+'" class="artsliderimg"/>';
}

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