Develop Reference

Inserting text from remote .txt file with known URL into element

I need a way to insert the text downloaded from a .txt file from a URL into an element or variable which i can use further.
I have tried adding the URL to an object element which displays the text correctly, but I do not know how to add this text into a variable.
var storage = firebase.storage();
var storageRef = storage.ref();
var tangRef = storageRef.child('Recs');
var fileRef = tangRef.child("rec3.txt");
fileRef.getDownloadURL().then(function(url)
{
alert(url);
var para = document.getElementById('p1');
var par = document.createElement("object");
par.setAttribute('data', url);
para.appendChild(par);
}).catch(function(error)
{
console.error(error);
});

As mentionned, you can get some file through an object HTML element as you can do through a script HTML element to load a file. From these elements you won't have a same-origin policy problem, that's why your document is loaded with setAttribute and appendChild.
If you tried to access a resource by XHR or if you tried to interact with a document (both by JS), which are not from the same origin than your current resource, you will need to manage a same-origin policy mechanism see : https://developer.mozilla.org/en-US/docs/Web/Security/Same-origin_policy
You can choose XHR or choose to access the nested document from the object HTML element, in both case you will have the same-origin policy problem. This is for security reasons which are linked with JavaScript.
If you choose nested document you could do something like this :
<div id="p1"></div>
<script>
var url = "https://firebasestorage.googleapis.com/v0/b/ninjatest-1b0ab.appspot.com/o/random%20text%20file.txt?alt=media&token=c09ae3ee-6a01-4f2b-b2b3-2f57ed7ff111";
// or
// var url = "http://localhost:4000/file.txt";
var para = document.getElementById('p1');
var par = document.createElement("object");
par.setAttribute('data', url);
para.appendChild(par);
par.onload = function() {
var doc = par.contentDocument || par.contentWindow.document;
var data = doc.body.childNodes[0].innerHTML;
console.log(data);
};
</script>
If you run this code, you can see that it doesn't accept cross-origin. This is because i'm trying to get a document (nested in the HTML document) which is from another domain. The browser won't let me access it. In the other hand, if i run in local with a node server, it allows me to get it without the error.
If you choose to use XHR (XMLHttpRequest) you can do something like that :
var data;
var url = "https://firebasestorage.googleapis.com/v0/b/ninjatest-1b0ab.appspot.com/o/random%20text%20file.txt?alt=media&token=c09ae3ee-6a01-4f2b-b2b3-2f57ed7ff111";
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function () {
if (xhr.readyState === 4) {
data = xhr.responseText;
console.log(data);
}
};
xhr.open('GET', url);
xhr.send();
Again here, it won't work because of the different origin. In the two situations, it's the browser which implements a security rule. You can fix it if you have access to the server part. On the server, you could tell the browser (by HTTP header) to allows client from different origin.
With XHR you need to search about CORS.
With Nested document, you can look here :
SecurityError: Blocked a frame with origin from accessing a cross-origin frame
How Can I Bypass the X-Frame-Options: SAMEORIGIN HTTP Header?
If you don't have access to the server part, you could grab the file with a GET request from a server that you own (and so have access to the server part). In this case, you won't have the browser security issue because from your server, you will serve the file without the restriction of same-origin. It will be a proxy server solution.
With Firebase
When you create project with Firebase you can configurate the server part to allow the XHR as mention here : https://firebase.google.com/docs/storage/web/download-files#download_data_via_url
Firstly install Google Cloud SDK to have gsutil : https://cloud.google.com/storage/docs/gsutil_install#install
Then create a .json file on your computer : https://cloud.google.com/storage/docs/configuring-cors#configure-cors-bucket
Then execute this command : gsutil cors set cors.json gs://<your-cloud-storage-bucket>
JSON file example :
[
{
"origin": ["*"],
"method": ["GET"],
"maxAgeSeconds": 3600
}
]
I created a Firebase account, tried it and it works very well.
Working example with XHR (you can run it) :
var data;
var url = "https://firebasestorage.googleapis.com/v0/b/first-app-a7872.appspot.com/o/firebase.txt?alt=media&token=925fef9e-750e-40e5-aa92-bdfe8204d32e";
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function () {
if (xhr.readyState === 4) {
data = xhr.responseText;
console.log(data);
}
};
xhr.open('GET', url);
xhr.send();

https://codepen.io/anon/pen/JmoqQY?editors=1010
In HTML file:
<div id="p1">
</div>
script
url = "https://firebasestorage.googleapis.com/v0/b/ninjatest-1b0ab.appspot.com/o/random%20text%20file.txt?alt=media&token=c09ae3ee-6a01-4f2b-b2b3-2f57ed7ff111"
var para = document.getElementById('p1');
var par = document.createElement("object");
par.setAttribute('data', url);
para.appendChild(par);
EDIT: I made a stackblitz to try to see if I could extract the data in the text file into a variable for manipulation.
https://stackblitz.com/edit/angular-eyhaj5
I was unable to find a way. Problem is that because of CORS policy in browsers you are not supposed to open files outside of your own site.
To get around this you have to either have to send the URL to a function on your server that downloads the textFile and then makes it accessible in a folder.
Or you could set up a proxy server that allows cors. Or you could ask the owner of the text file to make it into an API.
Possibly it was a bad idea to put the textfile in firestorage in the first place. If you are the owner of the text file, it would maybe be better to put the text in a firestore database rather than save it as a textfile.

Load a binary asset file into Chrome App

I'm trying to make a Chrome app that will have some animated objects in it.
I can load textures by using: new Image() and then setting the image's src property to the name of a file in my app's root directory. (This will load the texture)
Is it possible to do a similar thing for binary files that contain my proprietary animation data? I've looked and looked but I don't seem to find anything that lets me load a binary file that has NOT been picked by the user or dragged and dropped by the user.
If this is something that is not allowed, (presumably for security issues) anyone got any clever workarounds?

For files inside the app's package, it should be as simple as loading the file with XHR.
Use the fully-qualified URL to be on the safe side, obtained with chrome.runtime.getURL(pathRelativeToRoot)

This was what worked for me:
function reqError() {
console.log("Got an error");
}
function reqListener() {
var buffer = this.response;
console.log("Load complete! Length = ", buffer.byteLength);
}
function LoadBinaryFile(fileName) {
var path = chrome.runtime.getURL(fileName);
var oReq = new XMLHttpRequest();
oReq.onload = reqListener;
oReq.onerror = reqError;
oReq.open("GET", path, true);
oReq.responseType = "arraybuffer";
oReq.send();
}

Sourcing a <p> from a .txt file. HTML

I'm currently coding a website on which I need to have a picture file and a txt file displayed on a HTML page that will vary by the date. I've got the picture set up, but I need to be able to show the contents of a txt file. I have it set up so that it will target a folder that is the number of the current month, then it will target a file that is the date. i.e. The variable image = "calendar/2/28.jpg" Here's the code, thanks:
http://pastebin.com/2LCT1qiG
*Note I'd rather not use anything besides javascript, HTML and CSS, but if jQuery or another language is necessary I will use that.

You can use ajax to fetch text file:
without jQuery it will be:
var request = new XMLHttpRequest();
request.onreadystatechange = function () {
var DONE = this.DONE || 4;
if (this.readyState === DONE){
document.getElementById("dailyText").innerHTML = request.responseText;
}
};
request.open('GET', 'calendar/'+today+'.txt', true);
request.setRequestHeader('X-Requested-With', 'XMLHttpRequest');
request.send(null);
if you use jQuery the code will be much shorter:
$.get('calendar/'+today+'.txt', function(text) {
$('#dailyText').html(text);
});

How to load a PDF into a blob so it can be uploaded?

I'm working on a testing framework that needs to pass files to the drop listener of a PLUpload instance. I need to create blob objects to pass inside a Data Transfer Object of the sort generated on a Drag / Drop event. I have it working fine for text files and image files. I would like to add support for PDF's, but it seems that I can't get the encoding right after retrieving the response. The response is coming back as text because I'm using Sahi to retrieve it in order to avoid Cross-Domain issues.
In short: the string I'm receiving is UTF-8 encoded and therefore the content looks like you opened a PDF with a text editor. I am wondering how to convert this back into the necessary format to create a blob, so that after the document gets uploaded everything looks okay.
What steps do I need to go through to convert the UTF-8 string into the proper blob object? (Yes, I am aware I could submit an XHR request and change the responseType property and (maybe) get closer, however due to complications with the way Sahi operates I'm not going to explain here why I would prefer not to go this route).
Also, I'm not familiar enough but I have a hunch maybe I lose data by retrieving it as a string? If that's the case I'll find another approach.
The existing code and the most recent approach I have tried is here:
var data = '%PDF-1.7%����115 0 obj<</Linearized 1/L ...'
var arr = [];
var utf8 = unescape(encodeURIComponent(data));
for (var i = 0; i < utf8.length; i++) {
arr.push(utf8.charCodeAt(i));
}
var file = new Blob(arr, {type: 'application/pdf'});

It looks like you were close. I just did this for a site which needed to read a PDF from another website and drop it into a fileuploader plugin. Here is what worked for me:
var url = "http://some-websites.com/Pdf/";
//You may not need this part if you have the PDF data locally already
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function () {
if (this.readyState == 4 && this.status == 200) {
//console.log(this.response, typeof this.response);
//now convert your Blob from the response into a File and give it a name
var fileOfBlob = new File([this.response], 'your_file.pdf');
// Now do something with the File
// for filuploader (blueimp), just use the add method
$('#fileupload').fileupload('add', {
files: [ fileOfBlob ],
fileInput: $(this)
});
}
}
xhr.open('GET', url);
xhr.responseType = 'blob';
xhr.send();
I found help on the XHR as blob here. Then this SO answer helped me with naming the File. You might be able to use the Blob by itself, but you won't be able to give it a name unless its passed into a File.

How send file on javascript?

var photo = 'http://cs323230.vk.me/u172317140/d_5828c26f.jpg';
var upload_url = 'http://cs9458.vk.com/upload.php?act=do_add&mid=62..';
var xmlhttp = getXmlHttp();
var params = 'photo=' + encodeURIComponent(photo);
xmlhttp.open("POST", upload_url, true);
xmlhttp.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState == 4) {
if(xmlhttp.status == 200) {
var answer2 = xmlhttp.responseText;
console.log(answer2);
alert(answer2);
}
}
};
xmlhttp.send(params);
I need to change the photo URL on the contents of the file
./DirectoryImage/imagetest.jpg
and send contents of the file
./DirectoryImage/imagetest.jpg
on upload_url.
But I don't know how send the contents of the file on upload_url in javascript...
Is it possible?
Does anyone know how make it?

Yes, you can, but it's not easy. The trick is using the FileReader object. Here's some sample code I put together for uploading an image after it's dropped into a <div>.
I'm pretty sure you can do the same with any file, as long as you can make the FileReader object from whatever your user inputs.
YourNamespace.uploadImg = function(evt) {
// Get the first file, if a stack of files has been dropped
// (to transfer the whole stack just repeat the process)
var file = evt.dataTransfer.files[0];
// Make a FileReader object
var reader = new FileReader();
// Build an AJAX request to send the file once the browser has received it.
// The FileReader will call this onload event when it's finished.
reader.onload = function(evtLoad) {
var req = new XMLHttpRequest();
req.open('POST', '/foo/bar.php', true);
req.onreadystatechange = function() {
if (req.readyState == 4 && req.status == 200) {
alert("success");
}
};
// Encode the file stream properly, set the appropriate header, and send.
var params = "foo=bar&data=" + encodeURIComponent(evtLoad.target.result);
req.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
req.send(params);
};
// This starts the whole process: read in the file as a data URL.
// When it's finished it calls the onload() that was defined above.
reader.readAsDataURL(file);
};
The MDN pages are very helpful on this whole topic, such as the FileReader object API.
Also I seem to remember browser support is poor for the usual suspects (IE6-7, etc).
It's worth mentioning that this is difficult because Javascript in browsers was not designed to talk to the server, for security purposes. Javascript is usually client-side only. File transfers and such should usually be handled with a server-side script in PHP, Perl, Ruby, etc.