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();
}
Related
I've seen many partial answers to this here and elsewhere, but I am very much a novice coder and am hoping for a thorough solution. I have been able to set up recording audio from a laptop mic in Chrome Canary (v. 29.x) and can, using recorder.js, relatively easily set up recording a .wav file and saving that locally, a la:
http://webaudiodemos.appspot.com/AudioRecorder/index.html
But I need to be able to save the file onto a Linux server I have running. It's the actual sending of the blob recorded data to the server and saving it out as a .wav file that's catching me up. I don't have the requisite PHP and/or AJAX knowledge about how to save the blob to a URL and to deal, as I have been given to understand, with binaries on Linux that make saving that .wav file challenging indeed. I'd greatly welcome any pointers in the right direction.
Client side JavaScript function to upload the WAV blob:
function upload(blob) {
var xhr=new XMLHttpRequest();
xhr.onload=function(e) {
if(this.readyState === 4) {
console.log("Server returned: ",e.target.responseText);
}
};
var fd=new FormData();
fd.append("that_random_filename.wav",blob);
xhr.open("POST","<url>",true);
xhr.send(fd);
}
PHP file upload_wav.php:
<?php
// get the temporary name that PHP gave to the uploaded file
$tmp_filename=$_FILES["that_random_filename.wav"]["tmp_name"];
// rename the temporary file (because PHP deletes the file as soon as it's done with it)
rename($tmp_filename,"/tmp/uploaded_audio.wav");
?>
after which you can play the file /tmp/uploaded_audio.wav.
But remember! /tmp/uploaded_audio.wav was created by the user www-data, and (by PHP default) is not readable by the user. To automate adding the appropriate permissions, append the line
chmod("/tmp/uploaded_audio.wav",0755);
to the end of the PHP (before the PHP end tag ?>).
Hope this helps.
Easiest way, if you just want to hack that code, is go in to recorderWorker.js, and hack the exportWAV() function to something like this:
function exportWAV(type){
var bufferL = mergeBuffers(recBuffersL, recLength);
var bufferR = mergeBuffers(recBuffersR, recLength);
var interleaved = interleave(bufferL, bufferR);
var dataview = encodeWAV(interleaved);
var audioBlob = new Blob([dataview], { type: type });
var xhr=new XMLHttpRequest();
xhr.onload=function(e) {
if(this.readyState === 4) {
console.log("Server returned: ",e.target.responseText);
}
};
var fd=new FormData();
fd.append("that_random_filename.wav",audioBlob);
xhr.open("POST","<url>",true);
xhr.send(fd);
}
Then that method will save to server from inside the worker thread, rather than pushing it back to the main thread. (The complex Worker-based mechanism in RecorderJS is because a large encode should be done off-thread.)
Really, ideally, you'd just use a MediaRecorder today, and let it do the encoding, but that's a whole 'nother ball of wax.
I am doing a chrome extension capable of getting from a webpage an image, and after I got it, I'm trying to upload it to an intranet server automatically without user iteration.
I am doing this right now.
This is on Content_script.js
...
x = $(frame1).contents().find("#image");
chrome.extension.sendRequest(x[0].src);
...
This is on background.js
chrome.extension.onRequest.addListener(function(links) {
chrome.downloads.download( { url: links ,
conflictAction: "overwrite",
filename: "get_image.jpg" },
function(DescargaId) {
var formData = new FormData();
formData.append("doc", Blob, "~/Downloads/get_image.jpg");
var request = new XMLHttpRequest();
request.open("POST", "http://192.168.0.30/app_get_pictures/upload_img.php");
request.setRequestHeader("Content-Type", "multipart/form-data");
request.send(formData);
} );
This on upload_img.php
...
$uploaddir = $_SERVER['DOCUMENT_ROOT'].'/app_get_pictures/images/';
$uploadfile = $uploaddir . basename($_FILES['doc']['name']);
move_uploaded_file($_FILES['doc']['tmp_name'], $uploadfile);
...
With this, I already download the image successfully to the local machine, but can't upload the image to the server.
It is possible to do this, or even if I can upload the image to the server directly without download it first to the local machine.
Note: I don't have any tag form on a popup page in the extension solution, and I don't have a popup page neither, because as I already said, I don't need any iteration from the user.
Thanks for your help!
Thanks to https://stackoverflow.com/users/934239/xan I resolved this problem using his advise, here is the resulting working code.
...
// With this I can download or get content image into var blob
var xhr = new XMLHttpRequest();
var kima = $(frame1).contents().find("#image");
xhr.open('GET',kima[0].src,true);
xhr.responseType = 'blob';
xhr.onload = function(e) {
if (this.status == 200) {
var blob = new Blob([this.response], {type: 'image/png'});
send_image(blob);
}
};
xhr.send();
....
// After the image is loaded into var blob, it can be send
// to the server side
function send_image(x){
var formData = new FormData();
formData.append("doc", x);
var request = new XMLHttpRequest();
request.open("POST", "http://192.168.0.30/app_get_image/upload_img.php");
request.send(formData);
}
All this code into the content_script of the chrome extension. Also the code of the background using API download isn't needed anymore.
Hope this could works for anybody else.
Thanks again.
Besides the fact that the callback of downloads.download does NOT indicate that the file is already downloaded (only that the download is queued)..
formData.append("doc", Blob, "~/Downloads/get_image.jpg");
What do you think this code does? Documentation, for reference.
The second parameter is supposed to hold the data of the file; the third parameter is just the file name for the purposes of naming anonymous data (e.g. in a Blob)
Instead, you pass the Blob object itself; not an instance of Blob with the data.
In fact, with this architecture, you won't be able to upload the file, since at no point does chrome.downloads API give you access to the file's contents, and you can't just access a file on a disk by filename (which is what I think you thought this code would do).
To actually access the data, you need to request it yourself with XHR (or Fetch API if you want to be "modern"). Then, you get the response object which you can request to be a Blob. Then, you can both upload the blob and invoke chrome.downloads together with createObjectURL to "download" it from your extension's memory.
I have an XHR object that downloads 1GB file.
function getFile(callback)
{
var xhr = new XMLHttpRequest();
xhr.onload = function () {
if (xhr.status == 200) {
callback.apply(xhr);
}else{
console.log("Request error: " + xhr.statusText);
}
};
xhr.open('GET', 'download', true);
xhr.onprogress = updateProgress;
xhr.responseType = "arraybuffer";
xhr.send();
}
But the File API can't load all that into memory even from a worker
it throws out of memory...
btn.addEventListener('click', function() {
getFile(function() {
var worker = new Worker("js/saving.worker.js");
worker.onmessage = function(e) {
saveAs(e.data); // FileSaver.js it creates URL from blob... but its too large
};
worker.postMessage(this.response);
});
});
Web Worker
onmessage = function (e) {
var view = new DataView(e.data, 0);
var file = new File([view], 'file.zip', {type: "application/zip"});
postMessage('file');
};
I'm not trying to compress the file, this file is already compressed from server.
I thought storing it first on indexedDB but i i'll have to load blob or file anyway, even if i do request by range bytes, soon or late i will have to build this giant blob..
I want to create blob: url and send it to user after been downloaded by browser
I'll use FileSystem API for Google Chrome, but i want make something for firefox, i looked into File Handle Api but nothing...
Do i have to build an extension for firefox, in order to do the same thing as FileSystem does for google chrome?
Ubuntu 32 bits
Loading 1gb+ with ajax isn't convenient just for monitoring download progress and filling up the memory.
Instead I would just send the file with a Content-Disposition header to save the file.
There are however ways to go around it to monitor the progress. Option one is to have a second websocket that signals how much you have downloaded while you are downloading normally with a get request. the other option will be described later in the bottom
I know you talked about using Blinks sandboxed filesystem in the conversation. but it has some drawbacks. It may need permission if using persistent storage. It only allows 20% of the available disk that are left. And if chrome needs to free some space then it will throw away any others domains temporary storage that was last used for the most recent file. Beside it doesn't work in private mode.
Not to mention that it has been dropping support for it and may never end up in other browsers - but they will most likely not remove it since many sites still depend on it
The only way to process this large file is with streams. That is why I have created a StreamSaver. This is only going to work in Blink (chrome & opera) ATM but it will eventually be supported by other browsers with the whatwg spec to back it up as a standard.
fetch(url).then(res => {
// One idea is to get the filename from Content-Disposition header...
const size = ~~res.headers.get('Content-Length')
const fileStream = streamSaver.createWriteStream('filename.zip', size)
const writeStream = fileStream.getWriter()
// Later you will be able to just simply do
// res.body.pipeTo(fileStream)
// instead of pumping
const reader = res.body.getReader()
const pump = () => reader.read()
.then(({ value, done }) => {
// here you know how large the value (chunk) is and you can
// figure out the download speed/progress when comparing it to the size
return done
? writeStream.close()
: writeStream.write(value).then(pump)
)
// Start the reader
pump().then(() =>
console.log('Closed the stream, Done writing')
)
})
This will not take up any memory
I have a theory that is if you split the file into chunks and store them in the indexedDB and then later merge them together it will work
A blob isn't made of data... it's more like pointers to where a file can be read from
Meaning if you store them in indexedDB and then do something like this (using FileSaver or alternative)
finalBlob = new Blob([blob_A_fromDB, blob_B_fromDB])
saveAs(finalBlob, 'filename.zip')
But i can't confirm this since i haven't tested it, would be good if someone else could
Blob is cool until you want to download a large file, there is a 600MB limit(chrome) for blob since it stores everything in memory.
My custom server embeds meta data about an image in the PNG meta data fields. The image is loaded via a regular img tag. I'd like to access the meta data from JavaScript - any way to achieve this?
If not, what are the alternatives for serving additional information for an image? The images are generated on the fly and are relatively expensive to produce, so I'd like to serve the meta data and the image data in a single round trip to the server.
i had a similar task. I had to write physical dimensions and additional metadata to PNG files. I have found some solutions and combined it into one small library.
png-metadata
it could read PNG metadata from NodeJS Buffers, and create a new Buffers with new metadata.
Here how you can read PNG metadata in the Browser:
function loadFileAsBlob(url){
return new Promise((resolve, reject) => {
var xhr = new XMLHttpRequest();
xhr.open('GET', url, true);
xhr.responseType = 'blob';
xhr.onload = function(e) {
if (this.status === 200) {
resolve(this.response);
// myBlob is now the blob that the object URL pointed to.
}else{
reject(this.response);
}
};
xhr.send();
})
};
const blob = await loadFileAsBlob('1000ppcm.png');
metadata = readMetadataB(blob);
A couple of solutions I can think of:
Pass the metadata as headers, use XMLHttpRequest to load the image and display it by converting the raw bytes to a data uri, as talked about here. Looks roughly like this:
var xhr = new XMLHttpRequest();
xhr.responseType = 'blob';
xhr.onload = function() {
var metadata = xhr.getResponseHeader("my-custom-header");
image.src = window.URL.createObjectURL(xhr.response);
}
xhr.open('GET', 'http://whatever.com/wherever');
xhr.send();
Alternatively, write a little png parser in js (or compile libpng to javascript using something like emscripten), and do basically the same thing as above.
It probably wouldn't be too hard to write actually; since you don't care about the image data, you'd just have to write the chunk-traversing code. Read up on how chunks are laid out here, and figure out what chunk type you're storing the metadata in. Still, don't really recommend this if you can just use headers...
there is many examples of reading local files using html5 but by choosing from list of files , my problem is that i want to create the file object manually , think about i have a file with the link
file:///G:/Users/txt.txt
i want the browser to open it ,
i think it have to File f=new File('file:///G:/Users/txt.txt');
my question is how to create/initialize the file object using file path ?!
I have used below workaround since File inherits blob interface.
var getFileBlob = function (url, cb) {
var xhr = new XMLHttpRequest();
xhr.open("GET", url);
xhr.responseType = "blob";
xhr.addEventListener('load', function() {
cb(xhr.response);
});
xhr.send();
};
var blobToFile = function (blob, name) {
blob.lastModifiedDate = new Date();
blob.name = name;
return blob;
};
var getFileObject = function(filePathOrUrl, cb) {
getFileBlob(filePathOrUrl, function (blob) {
cb(blobToFile(blob, 'test.jpg'));
});
};
getFileObject('img/test.jpg', function (fileObject) {
console.log(fileObject);
});
There really is no way to create a file without permission from the user. A button or something will need to be pressed. You would need to create a data:uri in order for it to save. You can find more information using a web search or checking out http://en.wikipedia.org/wiki/Data_URI_scheme (not a complete source but can show what is possible). This is very limited depending on phone and OS. Data URI are limited while using IE.
When it is triggered for download, it saves to t he default location or user specified. You may also want to look into vendor/OS specific API Calls that can do as you are describing. But may need to verify permissions prior to actually allowing access.