I'm coding a webpage that needs to read some data from different csv on a path depending on the country of the user.
the path is something like this:
./csv/m2-2022-10-25_13_45_55_es.csv
m2-2022-10-25_13_45_56_fr.csv
m2-2022-10-25_13_46_04_it.csv
etc
And those files will be replaced regularly, the only that we'll always have is the country code (es, fr, it, etc).
So, what I need is to list all the files on the path to an array, and loop through the array to find if the last characters of the filename are $countryCode + ".csv", and there run some code.
But I can't find how, all the solutions I find are using Node.js, but are there a solution using only Javascript (or jQuery)?
Regards!
You cannot use pure Javascript to do that, because if you wanted to search files in your computer only using javascript, it would be a huge security breach.
You must use node.js to open files but you can make an API to your nodejs file from your javascript and you can send as a response the content of your file.
Here some links that might help you :
FS : https://nodejs.org/api/fs.html
NodeJS api : https://medium.com/swlh/how-to-create-a-simple-restful-api-in-node-js-ae4bfddea158
You can check a similar question here:
Get list of filenames in folder with Javascript
You can't access to filesystem from the frontend, this it would be a huge security breach, because anyone could access to your filesystem tree.
You have to do a function in backend to build the array you want and send it to frontend.
If you create a function in backend file that returns the array of files in the folder, you can call it from the frontend via XMLHttpRequest or Fetch to get the array in frontend and be able to use in your js file.
My requirement is to read the json file which contains some data and store in some other .js file.
I got task to read local file from local disk in Javascript , i have used file path like - D:\json\analytics.json.
(document).ready(){
($).getData("D:\json\analytics.json");
}
when i see in firebug it takes other url.
How I can do it, is it possible to read file from javascript.
I don't know javascript , i have seen some answer but i am not able to understand .
Need Solution , how I can achieve it. is there any other way to read file on jsp without using scriptlet . From server side , can send it on the jsp page.
I think Jaronmanda's answer won't work cause it will hit cross origin issue, see "Cross origin requests are only supported for HTTP." error when loading a local file.
As the page suggested, in general you need to serve that json file from a web service (same domain, or allow your domain to access), but it depends on what you really need to do. If you can control where that json file is stored, the easier way is to put that in a subdirectory of your html file, and do:
$(document).ready(function () {
$.get('<directory>/analytics.json', function (data) {
// Do your stuff
});
});
I have a Python program that generates an html page for reporting results. The html page is saved in an output directory on disk alongside a javascript file that helps with dynamic table handling. I also save a JSON file to this output directory that I would like to read in with my javascript file. This JSON file has data from the Python run (saved dictionary) that I would like to be able to access. So in an output directory on disk I have:
C:/somedirectory/output/report.html
C:/somedirectory/output/tables.js
C:/somedirectory/output/data.json
All files have been created from my program.
My html page has a table with checkboxes and if those checkboxes are selected I would like to update a second table based on data saved in the JSON file. Thus I would like to open my html report in any browser and read in the JSON file as a javascript object.
I have been trying to use ajax and .getJSON but am getting the
No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'null' is therefore not allowed access.
I have searched and seen many similar problems but have not come across anything that quite fits what I need. Thoughts and a work around would be greatly appreciated. Thanks.
Update
Since everything is run locally on the client side I have decided to embed the JSON data (python dictionary) and javascript code directly into the html report output. This way the data is internally accessible and the html file can be passed around without dependency issues. The user with the answer I selected below has a link that eludes to this solution.
JavaScript runs on the client machine, hence it can only access files on the client machine using a special setup.
If you want it to read JSON on your server, you should use the path:
http://example.com/output/data.json
Better way would be to read/write JSON file from Python and then send the table data to JavaScript as in this answer: Send data from Python to Javascript (JSON)
I'm just beginning with JavaScript and I was wondering if I can access a JSON file on the localhost without the use of any servers (like WAMP). I was planning to just read the contents of a JSON file and reflect its contents to an HTML file.
Short answer, yes you can.
Make an XMLHttpRequest against a static file such as: resources/myJSON.json (the extension is merely for organization, you can call the file whatever you want really).
Parse the response as JSON.
Obviously the file must contain a properly formatted JSON object of data, but as long as that's the case, you can load static JSON from a file to "simulate" remote connectivity to a server.
When you're browsing a file as: file:// on your system, it should treat the relative paths correctly.
I have the following problem which I'm trying to solve with javascript. I have a div with a background image specified in a css file, and I want my javascript to change that image periodically (let`s say every 5 secs).
I know how to do that, the problem is that I have a folder of images to choose from for the back image. I need to be able to read the filenames (from the image folder) into an array, change the background image of the div, delay for 5 seconds and change again.
in your javascript, use an array like
var images = [ "image1.jpg", "image2.jpg", "image3.jpg" ];
function changeImage() {
var image = document.getElementById("yourimage");
image.src=$images[changeImage.imageNumber];
changeImage.imageNumber = ++changeImage.imageNumber % images.length;
}
changeImage.imageNumber=0;
setInterval(changeImage,5000);
The values in the array should be generated by your php
You're still going to need php or asp to query the folder for files. Javascript will not be able to "remotely" inspect the file system.
You can do something like the following in jQuery:
$.ajax({
url: 'getFolderAsArrayOfNames.php',
dataType: 'json',
success: function(data) {
for(var i=0;i<data.length;i++) {
// do what you need to do
}
});
});
And in your getFolderAsArrayOfNames.php, something like this:
echo "function "
.$_GET['callback']
."() {return "
.json_encode(scandir('somepath/*.jpg'))
."}";
If you are using Apache as your
web server, and
if you can configure
it to provide a default directory
listing for your images folder (use
the appropriate options in
httpd.conf and/or .htaccess), and
if you don't care that the list of
images is available to everyone who
visits your web site,
then you don't need PHP or any other server-side processing.
You can use XMLHttpRequest (or the jQuery ajax function, which is a nice wrapper) to get the listing for the folder. The response will be HTML and it will look something like this:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<html>
<head>
<title>Index of /demo1/images</title>
</head>
<body>
<h1>Index of /demo1/images</h1>
<pre><img src="/icons/blank.gif" alt="Icon "> Name Last modified Size Description<hr><img src="/icons/back.gif" alt="[DIR]"> Parent Directory -
<img src="/icons/image2.gif" alt="[IMG]"> tree.gif 17-Mar-2009 12:58 6.2K
<img src="/icons/image2.gif" alt="[IMG]"> house.gif 17-Mar-2009 12:58 6.5K
<img src="/icons/image2.gif" alt="[IMG]"> car.gif 02-Mar-2009 15:37 8.4K
<img src="/icons/image2.gif" alt="[IMG]"> elephant.jpg 02-Mar-2009 15:37 3.4K
<hr></pre>
<address>Apache/2.0.63 (Unix) Server at zeppo Port 80</address>
</body></html>
Since this output is pretty predictable, you might try parsing out the filenames using a JavaScript regular expression, but it's probably just as easy and more robust to create a hidden DIV on your page, put the HTML response into that DIV, and then use DOM methods to find <a href>s that are after <img> tags with an alt="[IMG]" attribute. Once again, using jQuery Selectors or similar helper methods available in other toolkits will make this DOM parsing pretty easy.
Once you have the URL of the new image (parsed from the href), you can set the new CSS background for your div with the .style.backgroundImage property.
You cannot do any file IO using JavaScript mainly because of security reason, so anyway you have to create some back end service which will update you with an list of available files in your folder. You don't have to do it in a hard way, you can use AJAX to it smoothly and nicely
You can't read a folder's contents, neither on the server nor on the clientside.
What you can do is to read the folder's contents with the help of a serverside script, and load it to a JavaScript array while processing the page.
This would not be ideal but in the absence of server-side processing (which you really should be doing--either PHP or Rails or Perl or whatever your host supports), you could allow directory listing on your images folder. This has security implications.
Then loading e.g., http://mysite.com/rotatingImages should respond with a list of files. You could do this with AJAX, parse out the relevant hrefs, push them onto an array and render your rotating images in JS.
You must send the list of names along with the JavaScript and then iterate through it.
A noted above, you can not access server's system from a client's browser (which is where JavaScript runs).
You have 3 possible solutions:
Create the JavaScript file via some dynamic back-end (php or perl scripts are best for that).
The main JavaScript function could still be static but the initialization of the array used by it (either as a snippet on the main HTML page or a separate .js imported file) would be a php/perl generated URL.
A recent StackOverflow discussion of the topic is at link text
Make an XMLHttpRequest (AJAX) call from your JavaScript to a separate service (basically a URL backed by - again - php/perl backend script) returning XML/JSON/your_data_format_of_choice list of files.
This is probably a better solution if you expect/want/need to refresh a frequently-changing list of images, whereas a pre-built list of files in solution #1 is better suited when you don't care about list of files changing while the web page is loaded into the browser.
An un-orthodox solution - if browsers you care about support animated background images (gif/png), just compile your set of images, especially if they are small sized, into an animated gif/png and use that as background.