ng-file-upload-mem-leak-fix

#### File preview
`html
ngf-src="file" //To preview the selected file, sets src attribute to the file data url.
ngf-background="file" //sets background-image style to the file data url.
ngf-default-src="'placeholder.jpg'" // default src in case no file is available
ngf-default-background="'placeholder.jpg'" // default background-image style in case no file is available
ngf-no-object-url="true or false" // see #887 to force base64 url generation instead of object url. Default false
ngf-accept="'.pdf,.jpg'" // comma separated wildcard to filter files allowed
ngf-validate="validate($file)" // custom validation, to reject return false or non-empty string for file.$error
ngf-min-size='10' // minimum acceptable file size in bytes
ngf-max-size='1000' // maximum acceptable file size in bytes
>
`

#### Upload service:
`js
var upload = Upload.upload({
*url: 'server/upload/url', // upload.php script, node.js route, or servlet url
*file: file, // single file or an array of files (array is for html5 only)
method: 'POST' or 'PUT'(html5), default POST,
headers: {'Authorization': 'xxx'}, // only for html5
fileName: 'doc.jpg' or ['1.jpg', '2.jpg', ...], // to modify the name of the file(s)
/*
file formData name ('Content-Disposition'), server side request form name could be
an array of names for multiple files (html5). Default is 'file' */
fileFormDataName: 'myFile' or ['file[0]', 'file[1]', ...],
/*
map of extra form data fields to send along with file. each field will be sent as a form field.
The values are converted to json string or jsob blob or nested form depending on 'sendFieldsAs' option. */
fields: {key: $scope.myValue, ...},
/*
default is 'json', sends each field as json string plain text content type, 'json-blob' sends object fields
as a blob object with content type 'application/json', 'form' sends fields as nested form fields. see #784 */
sendFieldsAs: json|json-blob|form,
/ customize how data is added to the formData. See #40#issuecomment-28612000 for sample code. /
formDataAppender: function(formData, key, val){},
/*
data will be sent as a separate form data field called "data".*/
data: {}.
withCredentials: true|false,
... and all other angular $http() options could be used here.
}).progress(function(evt) {
console.log('progress: ' + parseInt(100.0 * evt.loaded / evt.total) + '% file :'+ evt.config.file.name);
}).success(function(data, status, headers, config) {
// file is uploaded successfully
console.log('file ' + config.file.name + 'is uploaded successfully. Response: ' + data);
}).error(function(data, status, headers, config) {
// handle error
}).xhr(function(xhr){
//access or attach event listeners to the underlying XMLHttpRequest
xhr.upload.addEventListener(...)
});
/* return $http promise then,catch or finally.
Note that this promise does NOT have progress, abort or xhr functions */
var promise = upload.then(success, error, progress);
upload.catch(errorCallback);
upload.finally(callback, notifyCallback);

/ cancel/abort the upload in progress. /
upload.abort();

/* alternative way of uploading, send the file binary with the file's content-type.
Could be used to upload files to CouchDB, imgur, etc... html5 FileReader is needed.
It could also be used to enable progress for regualr angular $http() post/put requests.
*/
Upload.http({
url: '/server/upload/url',
headers : {
'Content-Type': file.type
},
data: file
})

/* Set the default values for ngf-select and ngf-drop directives
*/
Upload.setDefaults({ngfMinSize: 20000, ngfMaxSize:20000000, ...})

/* Convert the file to base64 data url
*/
Upload.dataUrl(file, callback, disallowObjectUrl);
`
ng-model
The model value will be a single file instead of an array if all of the followings are true:
* ngf-multiple is not set or is resolved to false.
* multiple attribute is not set on the element
* ngf-keep is not set or is resolved to false.

Upload multiple files: Only for HTML5 FormData browsers (not IE8-9) if you pass an array of files to file option it will upload all of them together in one request. In this case the fileFormDataName could be an array of names or a single string. For Rails or depending on your server append square brackets to the end (i.e. file[]).
Non-html5 browsers due to flash limitation will still upload array of files one by one in a separate request. You should iterate over files and send them one by one if you want cross browser solution.

Upload.http():
This is equivalent to angular $http() but allow you to listen to the progress event for HTML5 browsers.

drag and drop styling: For file drag and drop, ngf-drag-over-class could be used to style the drop zone. It can be a function that returns a class name based on the $event. Default is "dragover" string.
Only in chrome It could be a json object {accept: 'a', 'reject': 'r', delay: 10} that specify the class name for the accepted or rejected drag overs. The validation ngf-accept could only check the file type since that is the only property of the file that is reported by the browser on drag. So you cannot validate the file size or name on drag. There is also some limitation on some file types which are not reported by Chrome.
delay param is there to fix css3 transition issues from dragging over/out/over #277.

ngf-reset-on-click and ngf-reset-model-on-click:
These two options are for testing purposes or rare cases, be aware that they might make the file select behave differently on different browsers.
By default since there is no cross-browser way to detect cancel on the file popup everytime you click on the file select it would create a new element and click on that and the model value will be reset to empty. This would also allow selecting the same file again which normally will not trigger a change event.
Setting this to false would not create a new element, and browsers will behave differently when the user cancels the popup, for example for chrome you would receive a change event with empty files but in FireFox there will be no event fired. This could be helpful in some rare cases or for testing when you want to keep the original elements without replacing them. Setting ngf-reset-model-on-click will not reset the model when you click on the file select, that would make reseting model when the user cancels the select popup impossible in some browsers.

ng-model-rejected:
You can find the reason for rejection using file.$error which would be one of these values accept, minSize, maxSize, validate, or a custom error returned by ngf-validate function.
accept is for the case the file doesn't match the ngf-accept criteria.
validate is for the case when the ngf-validate function returns false for that file.

Upload.setDefaults():
If you have many file selects or drops you can set the default values for the directives by calling Upload.setDefaults(options). options would be a json object with directive names in camelcase and their default values.

## Old browsers

For browsers not supporting HTML5 FormData (IE8, IE9, ...) FileAPI module is used.
Note: You need Flash installed on your browser since FileAPI uses Flash to upload files.

These two files FileAPI.min.js, FileAPI.flash.swf will be loaded by the module on demand (no need to be included in the html) if the browser does not supports HTML5 FormData to avoid extra load for HTML5 browsers.
You can place these two files beside angular-file-upload-shim(.min).js on your server to be loaded automatically from the same path or you can specify the path to those files if they are in a different path using the following script:
`html

...
`
Old browsers known issues:
* Because of a Flash limitation/bug if the server doesn't send any response body the status code of the response will be always 204 'No Content'. So if you have access to your server upload code at least return a character in the response for the status code to work properly.
* Custom headers will not work due to a Flash limitation #111 #224 #129
* Due to Flash bug #92 Server HTTP error code 400 will be returned as 200 to the client. So avoid returning 400 on your server side for upload response otherwise it will be treated as a success response on the client side.
* In case of an error response (http code >= 400) the custom error message returned from the server may not be available. For some error codes flash just provide a generic error message and ignores the response text. #310
* Older browsers won't allow PUT requests. #261

##Server Side

* Java
You can find the sample server code in Java/GAE here
* Spring MVC
Wiki Sample provided by zouroto
* Node.js
Wiki Sample provided by chovy.
Another wiki using Express 4.0 and the Multiparty provided by Jonathan White
* Rails
* Wiki Sample provided by guptapriyank.
* Blog post
provided by Coshx Labs.
* Rails progress event: If your server is Rails and Apache you may need to modify server configurations for the server to support upload progress. See #207
* PHP
[Wiki Sample] (https://github.com/danialfarid/ng-file-upload/wiki/PHP-Example) and related issue [only one file in $_FILES when uploading multiple files] (https://github.com/danialfarid/ng-file-upload/issues/475)
* .Net
Sample client and server code [demo/C#] (https://github.com/danialfarid/ng-file-upload/tree/master/demo/C%23) provided by AtomStar

##CORS
To support CORS upload your server needs to allow cross domain requests. You can achive that by having a filter or interceptor on your upload file server to add CORS headers to the response similar to this:
(sample java code)
`java
httpResp.setHeader("Access-Control-Allow-Methods", "POST, PUT, OPTIONS");
httpResp.setHeader("Access-Control-Allow-Origin", "your.other.server.com");
httpResp.setHeader("Access-Control-Allow-Headers", "Content-Type"));
`
For non-HTML5 IE8-9 browsers you would also need a crossdomain.xml file at the root of your server to allow CORS for flash:
(sample xml)
`xml





`

#### Amazon AWS S3 Upload
The demo page has an option to upload to S3.
Here is a sample config options:
`
Upload.upload({
url: 'https://angular-file-upload.s3.amazonaws.com/', //S3 upload url including bucket name
method: 'POST',
fields : {
key: file.name, // the key to store the file on S3, could be file name or customized
AWSAccessKeyId: ,
acl: 'private', // sets the access to the uploaded file in the bucket: private or public
policy: $scope.policy, // base64-encoded json policy (see article below)
signature: $scope.signature, // base64-encoded signature based on policy string (see article below)
"Content-Type": file.type != '' ? file.type : 'application/octet-stream', // content type of the file (NotEmpty)
filename: file.name // this is needed for Flash polyfill IE8-9
},
file: file,
});
`
This article explains more about these fields and provides instructions on how to generate the policy and signature using a server side tool.
These two values are generated from the json policy document which looks like this:
`
{"expiration": "2020-01-01T00:00:00Z",
"conditions": [
{"bucket": "angular-file-upload"},
["starts-with", "$key", ""],
{"acl": "private"},
["starts-with", "$Content-Type", ""],
["starts-with", "$filename", ""],
["content-length-range", 0, 524288000]
]
}
`
The demo page provide a helper tool to generate the policy and signature from you from the json policy document. Note: Please use https protocol to access demo page if you are using this tool to generate signature and policy to protect your aws secret key which should never be shared.

Make sure that you provide upload and CORS post to your bucket at AWS -> S3 -> bucket name -> Properties -> Edit bucket policy and Edit CORS Configuration. Samples of these two files:
`
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "UploadFile",
"Effect": "Allow",
"Principal": {
"AWS": "arn:aws:iam::xxxx:user/xxx"
},
"Action": [
"s3:GetObject",
"s3:PutObject"
],
"Resource": "arn:aws:s3:::angular-file-upload/*"
},
{
"Sid": "crossdomainAccess",
"Effect": "Allow",
"Principal": "*",
"Action": "s3:GetObject",
"Resource": "arn:aws:s3:::angular-file-upload/crossdomain.xml"
}
]
}
`
`



http://angular-file-upload.appspot.com
POST
GET
HEAD
3000
*


``

For IE8-9 flash polyfill you need to have a crossdomain.xml file at the root of you S3 bucket. Make sure the content-type of crossdomain.xml is text/xml and you provide read access to this file in your bucket policy.

You can also have a look at https://github.com/nukulb/s3-angular-file-upload for another example with this fix.