Parse's JavaScript API Now Supports Files
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Join For FreeForgive the somewhat haphazard nature of this blog post. I've got a limited amount of time before I board a plane but I didn't want to wait till the morning to post. Earlier today a reader (Arcayne - sounds like an early 80s X-Man) posted a comment that led me to discover that Parse's JavaScript API now supports Files. This wasn't possible in the past. You can read the details about it here but for folks who want to see complete demo code, keep reading.
The first thing I did was build a complete demo using their example of a file upload. I began by creating a simple HTML file:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<title></title>
<meta name="description" content="">
<meta name="viewport" content="width=device-width">
</head>
<body>
<input type="file" id="fileUploader">
<button id="fileUploadBtn">Send</button>
<script src="js/jquery-2.0.3.min.js"></script>
<script src="js/parse-1.2.8.min.js"></script>
<script src="js/app.js"></script>
</body>
</html>Note I've got the Parse library loaded. The HTML just contains a file field and a button. Here's the JavaScript code:
$(document).ready(function() {
var parseAPPID = "x";
var parseJSID = "x";
//Initialize Parse
Parse.initialize(parseAPPID,parseJSID);
$("#fileUploadBtn").on("click", function(e) {
var fileUploadControl = $("#fileUploader")[0];
if (fileUploadControl.files.length > 0) {
var file = fileUploadControl.files[0];
var name = "photo.jpg";
console.log("here goes nothing...");
var parseFile = new Parse.File(name, file);
parseFile.save().then(function() {
console.log("Woot!");
console.dir(arguments);
}, function(error) {
console.log("Error");
console.dir(error);
});
}
});
});For the most part this is just what the Parse docs have, but as a complete file, hopefully it is helpful. I can confirm this worked perfectly. In the result object I got a URL to the picture I uploaded. Of course, if I did not pick an image this wouldn't work. You do have access to the file name so in theory line 14 could easily be made dynamic.
Ok, I felt bad. The fix was one line:
var name = file.name;
In the zip I'll be sharing this is corrected. So - that would work in PhoneGap if your mobile client allows for file upload fields. I'm not sure which do. I know iOS lets you capture the camera with one, but I'm not sure if I remember if it lets you select files too. As I said, I'm in a rush.
My
real question though was if this could work with PhoneGap. I built a
test to see if I could use the Camera API and upload it to Parse. For my
first test I decided to just use Base64. That's one of the options in
PhoneGap and it works with Parse as well. Turns out this worked super
easy as well. I won't bother with the HTML, just the JavaScript, and
I'll just focus on the important part.
$("#takePicBtn").on("click", function(e) {
e.preventDefault();
navigator.camera.getPicture(gotPic, failHandler, {quality:50, destinationType:navigator.camera.DestinationType.DATA_URL, sourceType:navigator.camera.PictureSourceType.PHOTOLIBRARY});
});
function gotPic(data) {
var parseFile = new Parse.File("mypic.jpg", {base64:data});
parseFile.save().then(function() {
navigator.notification.alert("Got it!", null);
console.log("Ok");
console.log(arguments.toString());
}, function(error) {
console.log("Error");
console.log(error);
});
}
Again - I assume this is all pretty simple, but if it doesn't make sense, let me know. I specified the photo library as I was testing on the iOS simulator.
Woot. So it works. But - I've heard that using base64 for image data in PhoneGap can be a bit memory intensive. Parse supports a binary array too so I built another demo that made use of "real" files as well. That turned out to be a bit more difficult.
First - PhoneGap can save a camera image to the file system. That part is easy. But the File API is not the most... simple thing to use. The PhoneGap API returns a File URI that you have to turn into a File object that you then have to send to a File Reader. Finally you can get an array buffer object but Parse needs a real array instead. (And for that part I need to thank Si Robertson for his help on G+.)
Here is the code I used. It isn't pretty. But it works.
function gotPic(data) {
window.resolveLocalFileSystemURI(data, function(entry) {
var reader = new FileReader();
reader.onloadend = function(evt) {
var byteArray = new Uint8Array(evt.target.result);
var output = new Array( byteArray.length );
var i = 0;
var n = output.length;
while( i < n ) {
output[i] = byteArray[i];
i++;
}
var parseFile = new Parse.File("mypic.jpg", output);
parseFile.save().then(function(ob) {
navigator.notification.alert("Got it!", null);
console.log(JSON.stringify(ob));
}, function(error) {
console.log("Error");
console.log(error);
});
}
reader.onerror = function(evt) {
console.log('read error');
console.log(JSON.stringify(evt));
}
entry.file(function(s) {
reader.readAsArrayBuffer(s);
}, function(e) {
console.log('ee');
});
});
}Anyway - this is very cool and just makes the Parse/PhoneGap combination even cooler. I've attached a copy of my code with my app IDs stripped out. Enjoy!
Published at DZone with permission of Raymond Camden, DZone MVB. See the original article here.
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