如何通过AWS Cognito使用ng-file-upload进行上传？

Question

I have AWS Cognito installed for my Angular application, and I am trying to hook in the s3.putObject some how into the ng-file-upload Upload service.

I want to use ng-file-upload's Upload.upload() method, but I don't know how to use the existing authenticated connection with Cognito. The idea is to use ng-file-upload's drag and drop and then the upload will use the existing Cognito connection to upload to s3. How can I do this? The reason why I want to use ng-file-upload's Upload.upload() method is to help retain some of the functionality like progress bars (please correct me if this is incorrect).

Answer 1

I assume you are trying to upload to S3 bucket directly from your client in Single Page App. If so, you can start by pre signing S3 URL and then try using it in ng-file-upload. A pre-signed URL allows you to give one-off access to other users who may not have direct access to execute the operations. Pre-signing generates a valid URL signed with your credentials that any user can access. By Default the URL's generated by the SDK expire after 15 minutes.

To generate a simple pre-signed URL that allows any user to put object in a bucket you own, you can use the following call to getSignedUrl():

//Initialize the SDK with Cognito Credentials
var s3 = new AWS.S3();
var params = {Bucket: 'myBucket', Key: 'myKey'};
var url = s3.getSignedUrl('putObject', params);
console.log("Use this url in ng-file-upload", url);

For more information on getting pre signed URL, refer to this wiki http://docs.aws.amazon.com/AWSJavaScriptSDK/guide/node-examples.html#Amazon_S3__Getting_a_pre-signed_URL_for_a_PUT_operation_with_a_specific_payload and consult ng-file-upload documentation