Stream file to server from Cordova app

Question

I have cordova app where the user must be able to select an image off their phone and upload it to AWS S3. I'm using cordova-plugin-camera and the S3 SDK for this. I have code that works fine (see below), but requires the entire image to be pulled into memory inside a base64 encoded string (per Camera.DestinationType.DATA_URL) and then again into a Buffer.

I'd prefer to have this streamed off the phone's hard drive to mitigate potential memory issues. The cordova-plugin-camera website even has a warning about this:

/** * Warning: Using DATA_URL is not recommended! The DATA_URL destination * type is very memory intensive, even with a low quality setting. Using it * can result in out of memory errors and application crashes. Use FILE_URI * or NATIVE_URI instead. */

So is there any way to stream the photo straight from the disk up to S3 using FILE_URI or NATIVE_URI or any other technique?

Here's my current code:

doTheThing() {
    let options = {
        quality: 50,
        destinationType: Camera.DestinationType.DATA_URL,
        sourceType: Camera.PictureSourceType.PHOTOLIBRARY,
        encodingType: Camera.EncodingType.JPG
    };

    navigator.camera.getPicture(imgData => {
       this.uploadToS3(imgData);
    }, options);


    uploadToS3(data) {
        let AWS = require('aws-sdk');

        AWS.config = new AWS.Config();
        AWS.config.accessKeyId = 'noway';
        AWS.config.secretAccessKey = 'jose';
        AWS.config.region = 'us-east-2';

        let s3 = new AWS.S3();
        let uploadParams = { Bucket: 'iamkule/f1/f2', Key: '', Body: new Buffer(data, 'base64') };
        uploadParams.Key = 'myfile.jpg';

        s3.upload(uploadParams, function (err, data) {
           if (data) {
              console.log('yay!');
           }
        });
    }
}

user_2004532 · Answer

This should get you started. Please forgive my pseudo code. Feel free to edit it as needed.

Device saves image to disk:

function takePicture(urlCallback){
    let options = {
        quality: 50,
        destinationType: Camera.DestinationType.FILE_URI,// <--
        sourceType: Camera.PictureSourceType.PHOTOLIBRARY,
        encodingType: Camera.EncodingType.JPG
    };
    navigator.camera.getPicture(urlCallback, onFail, options);  
    function onFail(message) {
        alert('Failed because: ' + message);
    }
}

Get the image from disk as a blob:

function getImageAsBlob(url, blobCallback) {
    var xhr = new XMLHttpRequest();
    xhr.open( "GET", url, true );
    xhr.responseType = "arraybuffer";
    xhr.onload = function( ev ) {
        // Obtain a blob: URL for the image data.
        var arrayBufferView = new Uint8Array( this.response );
        var blob = new Blob( [ arrayBufferView ], { type: "image/jpeg" } );
        blobCallback(blob);
    };
    xhr.send();
}

Upload the blob to S3:

function uploadToS3(blob, callback) {
    let AWS = require('aws-sdk');
    AWS.config = new AWS.Config();
    AWS.config.accessKeyId = 'noway';
    AWS.config.secretAccessKey = 'jose';
    AWS.config.region = 'us-east-2';
    let s3 = new AWS.S3();
    let options = { Bucket: 'iamkule/f1/f2', Key: 'myfile.jpg', Body: blob };// <--
    s3.upload(options, callback);
}

Putting it all together:

takePicture(function(url){
    getImageAsBlob(url, function(blob){
        uploadToS3(blob, function (err, data) {
            if (data) console.log('yay!');
        });
    });
});

S3 info came from here. Photo capture info came from here. Happy Coding!

Stream file to server from Cordova app

1 Answers