Function parse_range_header 

pub fn parse_range_header(
    header: &str,
    resource_size: u64,
) -> Result<ByteRange, RangeError>

Parse a Range header value and resolve it against a resource size.

Supports the following formats:

• bytes=0-499 - First 500 bytes
• bytes=500-999 - Bytes 500-999
• bytes=500- - From byte 500 to end
• bytes=-500 - Last 500 bytes

Errors

Returns an error if:

• The syntax is invalid
• The unit is not “bytes”
• Multiple ranges are specified (not yet supported)
• The range is not satisfiable for the given resource size

Examples

use fastapi_http::range::parse_range_header;

// First 500 bytes of a 1000-byte resource
let range = parse_range_header("bytes=0-499", 1000).unwrap();
assert_eq!(range.start, 0);
assert_eq!(range.end, 499);
assert_eq!(range.len(), 500);

// Last 100 bytes
let range = parse_range_header("bytes=-100", 1000).unwrap();
assert_eq!(range.start, 900);
assert_eq!(range.end, 999);

// From byte 500 to end
let range = parse_range_header("bytes=500-", 1000).unwrap();
assert_eq!(range.start, 500);
assert_eq!(range.end, 999);