How to get item attachment size in JavaScript

Question

I have a SharePoint list with attachments in its items. Now I want to show the attachment size in the item View Form and Edit form. But I cannot find a JavaScript API to get the attachment size.

I tried the OData service but it only returns the file name. Apparently I cannot download these files... _api/web/lists/getbytitle('My%20Documents')/items(1)/AttachmentFiles

So in short, How can I get item attachment size in JavaScript? (I am using SharePoint 2013)

Answer 1

You can grab the serverrelativeurl of the file from your request. Pass it to another request like so: _api/web/getfilebyserverrelativeurl('/Lists/TestList/Attachments/1/blabla.xlsx'). This will give you the file length in Bytes.

Answer 2

Use below REST API example

url: "<app web url>/_api/SP.AppContextSite(@target)/web
    /getfilebyserverrelativeurl('/Shared Documents/filename.docx')/Length

For more info: MSDN