I want to load a json-stringified file in my javascript. The javascript reside in a html-file which I load from my local file system.
I have tried with the following code:
var xhr = new XMLHttpRequest();
xhr.open('GET', fileName, true);
xhr.responseType = 'blob';
xhr.onload = function(e) {
if (this.status == 200) {
// get binary data as a response
var blob = this.response;
alert("Yo");
}
};
But the onload event fires only once, with the status=0, then no more happens.
I have tried to use both a full path to the file as well as a local file path like "/files/the_file.txt".
It looks like the problem is related with me trying to run the html file locally. I don't want to set-up a local server as I have seen proposed in similar posts here at so.
Anyone out there with a solution to this problem?
EDIT:
This is not what I want, but this might serve to give an example of how I almost want it. This example let the user select a file, and my script can now access the content of the selected file.
HTML:
<input type="file" id="FancyInputField" onchange="doIt();">
Javascript:
function doIt(){
var selectedFile = document.getElementById('FancyInputField').files[0];
reader = new FileReader();
reader.onload = function (e) {
var output = reader.result;
var daObject = JSON.parse(output);
}
reader.readAsText(selectedFile);
}
This also works with a local html file. (No local server)
My question stands; How do I read the file(s) with no user interaction? The files reside in a sub-folder to where the html file are located. I can with no problem load and show an image from the same sub-folder, with an <img> tag. ..So why is it so difficult to load a text file?
How do I read the file(s) with no user interaction?
You can't. Those files belong to the user, not your website. You can't choose to read them.
I can with no problem load and show an image from the same sub-folder, with an <img> tag
There is a lot of difference between displaying an image to the user, and making the content of a file available to JavaScript code written by the page author.
So why is it so difficult to load a text file?
Send someone an HTML document in an email
Enjoy the JavaScript in it scooping up files from the hard disk and sending them to Joe Evil Hacker's server
It's just basic security.
Use URL.createObjectURL(file), instead of ajax.
Related
For minimal example, I have
Host: 111.222.111.123
Username: user_name
Password: pass_word
File to upload is selected with HTML input element
I can upload the file manually to the target directory on the server with a client like FileZilla.
The target directory is where the file should be uploaded. Its location on the Internet is https://nameofsite/targetdir/, so the file should be reachable on the internet for anyone as https://nameofsite/targetdir/1.html.
But is it possible to upload the file to the server with javascript?
I tried this example taking to account #mcrdy455's answer, but anyway it's not clear what the FtpConnection is:
<input id="fileForUpload" type=file onchange="upload()">
<div id="fileContents"></div>
<script>
function upload() {
var file = document.getElementById("fileForUpload").files[0];
if (file) {
var reader = new FileReader();
reader.readAsText(file, "UTF-8");
reader.onload = function (evt) {
document.getElementById("fileContents").innerHTML = evt.target.result;
var ftp = new FtpConnection("ftp://111.222.111.123/");
ftp.login("user_name", "pass_word");
ftp.put(file, "1.html");
ftp.close();
file.close();
}
}
}
</script>
Uncaught ReferenceError: FtpConnection is not defined
After searching on the Internet, I'm still not sure what project FtpConnection belongs to. Other examples use URLs instead of IP addresses (111.222.111.123).
E.g. Ftp.createCORSRequest('POST', "http://www.ftpjs.xyz/upload.aspx") in this one. I would like not to complicate things (with CORS) and use the 111.222.111.123 address.
If FileZilla can do the job, why couldn't javascript do it? How?
The JavaScript code can NOT access files from your filesystem, use an input type file, and read the file through the FileReader: You can fine more info on how to do this here, Once you have the correct file/blob object you code should work
I would like to load PDF file from URL into JavaScript variable (this file is on another domain) and then print the base64 encoded string of that file.
This script allows me to browse file on my computer and then it prints base64 string into browser console:
<input id="inputFile" type="file" onchange="convertToBase64();" />
<script type="text/javascript">
function convertToBase64() {
//Read File
var selectedFile = document.getElementById("inputFile").files;
//Check File is not Empty
if (selectedFile.length > 0) {
// Select the very first file from list
var fileToLoad = selectedFile[0];
// FileReader function for read the file.
var fileReader = new FileReader();
var base64;
// Onload of file read the file content
fileReader.onload = function(fileLoadedEvent) {
base64 = fileLoadedEvent.target.result;
// Print data in console
console.log(base64);
};
// Convert data to base64
fileReader.readAsDataURL(fileToLoad);
}
}
</script>
I would like to completely remove the input button from this script and pass my file to variable var selectedFile from URL (for example: http://www.example.com/docs/document.pdf).
I'd need a help how to realize this, because I am not sure if XMLHttpRequest() works cross domain and scripts I've found with Ajax/jQuery method operated mainly with JSON file, which is something different that I need.
Thank you very much for help.
You cannot do this in normal browser-based JavaScript* if the other side (http://www.example.com in your case) doesn't allow cross-origin requests from your origin.
If the other side does let you do this, then yes, you'd use XMLHttpRequest (or jQuery's wrappers for it, such as ajax or get) to request the data and transform/display it as you see fit.
A fairly typical way to work around that if the other side doesn't is to use your own server in-between: Make the request to your server, have it make the request to the other side (server-side code doesn't have the Same Origin Policy blocks that browsers impose), and then have your server respond to your request with the data from the other server.
* "normal browser-based JavaScript" - e.g., without starting the browser with special flags that disable security, or getting people to install an extension, etc.
I'm just trying on the task, file manipulation system using java script. As I was referred from W3C File API( https://www.w3.org/TR/FileAPI/ ), we can only read local files like
var file = "test.txt";
function readTextFile(file) {
var readFile;
if(window.XMLHttpRequest){
// for new browsers
readFile = new XMLHttpRequest();
}else{
//for old browsers like IE5 or IE6
readFile = new ActiveXObject("Microsoft.XMLHTTP");
}
readFile.open("GET", file, true);
readFile.onreadystatechange = function() {
if(readFile.readyState === 4) {
if(readFile.status === 200 || readFile.status == 0) {
//text will be displayed that read from the file
console.log(readFile.responseText);
}
}
}
readFile.send(null);
}
but it looks there is no options to write on file without server. I was tried to fetch solutions from the websites like http://www.stackoverflow.com/, the study says almost there is no possibilities.
For an example what I got is
from https://gist.github.com/Arahnoid/9925725
It shows error "TypeError: file.open is not a function."
So my question is, Is there any possible to file manipulations(asking only about Write file) for local files without using server-side scripting or is any extensions like available?
We can do file manipulations using server scripting languages such as PHP, Node.js.
Thanks in advance.
In your code, it's not reading from the local file (test.txt), it's sending Ajax GET request to server and read file in server side.
To read local file (files that stored in machine where browser is installed), you need to use FileAPI, which is not used in current code.
To write file to local, it's impossible to write it directly using JavaScript. Otherwise, it would be a huge security vulnerability. However, you can generate a URL from File object, and use that URL as the href attribute of <a> tag, so that user can download and "write to local" manually.
Here is a code snippet to read & "write" local file:
var inputElement = document.getElementById("input");
var reader = new FileReader();
var downloadLink = document.getElementById('downloadLink');
reader.onloadend = function(){
console.log(reader.result);
}
inputElement.addEventListener("change", handleFiles, false);
function handleFiles() {
var fileSelected = this.files[0]; /* now you can work with the file list */
reader.readAsBinaryString(fileSelected);
downloadLink.href = window.URL.createObjectURL(fileSelected);
}
<input type="file" id="input">
<a id="downloadLink" download>Download</a>
I have a standard folder structure for a web app.
css
js
img
asetts
lib
index.html
Inside my assets folder I have a bunch of plain text files and I would like to first be able to list the filenames using Javascript, so I can store the URI's in the model, and read from them later on the in the application. I want all of this happening client side.
(Client-side) JavaScript does not have access to the file system like that.
This is not possible without some kind of browser plugin.
You can read the textfiles in the local folder.
function read()
{
var xHR = new XMLHttpRequest();
//replace textfile_url with the relative url of your text file
xHR.open("GET", "textfile_url", true);
xHR.onreadystatechange = function ()
{
if(xHR.readyState === 4)
{
//all your text is in the next line
var text = xHR.responseText;
}
}
xHR.send();
}
I am trying to read a local file and have each line as an index in an array using JavaScript. I have been searching for the past 20 minutes and either I'm stupid or there really isn't an answer that pertains to my problem (...but it's probably the former :P). I am really new to JavaScript so if you have an answer could you please comment the code just to I know what's going on?
Also, from the searching I've done on the internet some people said JavaScript can't read local file for security reasons so if that is correct is there another language I can use? I'm a bit familiar with PHP if that is an option, which I doubt it is.
EDIT
As per thg435's question, I'll explain what I am trying to accomplish.
My project is to analyze a BUNCH of water quality data that has been collected by the Ontario gov't (which I've done) and display it in some way. I have chosen to display it on a webpage using the Google Maps API. I currently have a file of chemicals that were found. Each line is a different chemical. I would like to read the file in an array then create an option menu displaying the chemicals in the array.
Also, the local file I would like to read will the be the same name and location all the time. I have seen people have boxes where the user clicks and chooses their file or to drag and drop but that's not what I'm looking for.
I don't think I explained this properly. I have a file in the same directory as my HTML and JavaScript files that contains words. Example:
Line 1: "Iron"
Line 2: "Aluminum"
Line 3: "Steel"
etc...
I would like to read the file and parse each line into a different index in an array. I don't want the user to be able to choose which file to read using the <input ... /> thing.
You're going to want to take a look at the FileReader API. This should allow you to read the text of a local file via readAsText(). This won't work in every browser but should work in all modern browser. You can see which browsers support it here.
Example:
<input id="file" type="file" />
var filesInput = document.getElementById("file");
filesInput.addEventListener("change", function (event) {
var files = event.target.files;
var file = files[0];
var reader = new FileReader();
reader.addEventListener("load", function (event) {
var textFile = event.target;
alert(textFile.result);
});
reader.readAsText(file);
});
It's not possible to invoke the FileReader API without user interaction. Consequently, your user would have to select whatever file to load in order for it to be read in pure JS. Since I'm assuming this will be up on a server, why not just put the list of chemicals also up on the server and GET the JSON encoded array of the results. Then you can decode them with Javascript.
You can access local files in 2 ways that I know of. The first way is making the user drag-and-drop the files onto the page, and using an <input type="file"> tag.
For the former, you would need to do the following:
addEventListener('dragover', function(e){e.preventDefault();});
addEventListener('drop', function(e) {
eventHandler.call(e.dataTransfer||e.clipboardData);
e.preventDefault();
});
For the latter, you'd need to add an event listener for the change event on the input:
document.getElementById('upload').addEventListener('change', eventHandler)
And for both, you'd need to have this as a basic callback function:
function eventHandler() {
var file = this.files[0]; //get the files
var reader = new FileReader(); //initiate reader
reader.onloadend = callbackFn; //set event handler
reader.readAsText(file); //initiate reading of files
if (this.id) { //only run if this is the input
var id = this.id;
this.outerHTML = this.outerHTML; //this resets the input
document.getElementById(id).addEventListener('change', eventHandler); //reattach event handler
}
function callbackFn(e) {
document.getElementById('output').value = e.target.result; //output it to a textarea
}
}
Here is a demo where the text contents (that what you see when opening it in notepad) of any file you drop in it, or any file you select from the input, is put in the textarea.
For more information, see https://developer.mozilla.org/en-US/docs/Using_files_from_web_applications.