trigger progress event on fileupload progress

README.md

@@ -206,7 +206,7 @@ $('#myS3Uploader').bind 's3_uploads_start', (e) ->
   alert("Uploads have started")
 ```
 
-#### Successfull upload
+#### Successful upload
 When a file has been successfully uploaded to S3, the `s3_upload_complete` is triggered on the form. A `content` object is passed along with the following attributes :
 
 * `url`       The full URL to the uploaded file on S3.
@@ -221,6 +221,15 @@ $('#myS3Uploader').bind "s3_upload_complete", (e, content) ->
   $('#someHiddenField').val(content.url)
 ```
 
+#### Upload Progress
+When uploading to S3, we receive periodic progress events that expose the percentage of the file(s) uploaded to s3. This is how we update the progress bar. This could be useful for displaying more fine-grained information about the upload, like an ETA or rate.
+
+```coffeescript
+$('#myS3Uploader').bind "s3_upload_progress", (e, data) ->
+  remaining_time = (data.total - data.loaded) / data.bitrate
+  $('#someHiddenField').val(remaining_time)
+```
+
 #### Failed upload
 When an error occured during the transferm the `s3_upload_failed` is triggered on the form with the same `content` object is passed for the successful upload with the addition of the `error_thrown` attribute. The most basic way to handle this error would be to display an alert message to the user in case the upload fails :
 ```coffeescript

app/assets/javascripts/s3_direct_upload.js.coffee

@@ -60,6 +60,7 @@ $.fn.S3Uploader = (options) ->
 
       progress: (e, data) ->
         if data.context
+          $uploadForm.trigger("s3_uploads_progress", [e, data])
           progress = parseInt(data.loaded / data.total * 100, 10)
           data.context.find('.bar').css('width', progress + '%')