# angular-download

Service for downloading browser-generated data to disk.

Motivation
----------

This service provides methods for downloading content generated in JavaScript (text, images, etc.) as files.
It relies on the `<a download>` functionality supported in current browsers and does not require any server
handling or flash plugins.

Installing the Module
---------------------
Installation can be done through bower:
``` shell
bower install angular-download
```

In your page add:
```html
  <script src="bower_components/angular-download/angular-download.js"></script>
```

You can also use npm to install it:

``` shell
npm install angular-download --save
```

Loading the Module
------------------

This service is part of the `download` module:

```javascript
var app = angular.module('myApp', [..., 'download']);
```

Using the download service
--------------------------

Inject the `download` service:

```javascript
function MyController($scope, download, ...) {
    $scope.downloadFile = function() {
        download.fromData("contents of the file", "text/plain", "file.txt");
    }
}
```

Method: fromData(data, mimeType, fileName)
------------------------------------------

Downloads a file containing string `data` as type `mimeType` named `fileName`.

```javascript
function MyController($scope, download) {
    $scope.downloadAsJson = function(someData) {
        download.fromData(JSON.stringify(someData), "application/json", "download.json");
    }
}
```

Method: fromBase64(dataBase64, mimeType, fileName)
--------------------------------------------

Downloads a file containing Base64-encoded string `dataBase64` as type `mimeType` named `fileName`.

```javascript
function MyController($scope, download) {
    $scope.downloadAsJson = function(someData) {
        download.dataBase64(JSON.stringify(btoa(someData)), "application/json", "download.json");
    }
}
```

Method: fromDataURL(dataUrl, fileName)
--------------------------------------

Downloads a file with contents defined by the `dataUrl` named `fileName`.  This is useful for downloading binary
data, such as client-generated images.

```javascript
function MyController($scope, download) {
    $scope.downloadImage = function(img) {
        download.fromDataURL(getImageDataURL(img), "download.png");
    }
}

// Create a dataURL from an img element
function getImageDataURL(img) {
    // Create an empty canvas element
    var canvas = document.createElement("canvas");

    // Copy the image contents to the canvas
    canvas.width = img.width;
    canvas.height = img.height;
    var ctx = canvas.getContext("2d");
    ctx.drawImage(img, 0, 0);

    return canvas.toDataURL("image/png");
}
```

Method: fromBlob(dataBlob, fileName)
----------------------------------------

Downloads a `Blob` with contents defined by the `dataBlob` named `fileName`.  This is useful for downloading binary
data, such as client-generated images.

```javascript
function MyController($scope, download) {
    $scope.downloadImage = function(img) {
        getImageDataBlob(function(blob) {
            download.fromBlob(blob, "download.png");
        });
    }
}

// Create a PNG Blob from an img element
function downloadImage(img, cb) {
    // Create an empty canvas element
    var canvas = document.createElement("canvas");

    // Copy the image contents to the canvas
    canvas.width = img.width;
    canvas.height = img.height;
    var ctx = canvas.getContext("2d");
    ctx.drawImage(img, 0, 0);

    if (canvas.msToBlob) {
        // On IE, the msToBlob method returns the Blob value
        cb(canvas.msToBlob);
    } else {
        // On standard browsers, the toBlob method calls the callback
        canvas.toBlob(cb);
    }
}
```

Copyright & License
-------------------

Copyright 2015 Stepan Riha. All Rights Reserved.

This may be redistributed under the MIT licence. For the full license terms, see the LICENSE file which
should be alongside this readme.