Accept-Ranges
The HTTP Accept-Ranges response header is sent by the server to indicate that it accepts requests for partial file downloads.
Usage
The HTTP Accept-Ranges response header is used by servers to indicate that they accept requests for partial resources, such as files that are available for download. A common use is the resumption of a previously interrupted file transfer. If part of the file had already been transferred before the connection had been interrupted, then clients can resume by specifying a range.
A range unit can be specified, however the only unit available is bytes. If the none directive is returned then range requests are not supported. Effectively, this is the same as omitting the HTTP header.
Example
In this example, the server responds to a previous HTTP request that was made by the client. As part of it, the HTTP Accept-Ranges response header is included to indicate that the function is supported.
Response
HTTP/1.1 200 OK
Accept-Ranges: bytes
Takeaway
The HTTP Accept-Ranges response header is sent by a server to inform clients that range requests are supported, which can be used to resume an interrupted file transfer.