range header does not work per spec

[jmgurney]

I needed a test WebDAV server, so I decided to attempt to use the package, but it appears that this software does not implement the range header properly. The RFC https://tools.ietf.org/html/rfc2616#section-14.35 states that the ranges is inclusive:

The last-byte-pos value gives the
   byte-offset of the last byte in the range; that is, the byte
   positions specified are inclusive. Byte offsets start at zero.

In the request, this does not appear to be the case. This is a log from a request:

>>> GET /somefile HTTP/1.1
>>> Host: 127.0.0.1:5555
>>> Accept: */*
>>> User-Agent: test libfetch/2.0
>>> Range: bytes=2-21
>>> Connection: close
>>> 
<<< HTTP/1.0 206 Partial Content
<<< Server: DAV/0.9.14 Python/3.7.7
<<< Date: Fri, 09 Oct 2020 21:46:08 GMT
<<< Content-type: application/octet-stream
<<< Transfer-Encoding: chunked
<<< Date: Fri, 09 Oct 2020 21:46:08 GMT
<<< DAV: 1,2
<<< Last-Modified: Fri, 09 Oct 2020 21:43:02 GMT
<<< Keep-Alive: timeout=15, max=86
last modified: [2020-10-09 21:43:02]
<<< Connection: Keep-Alive
<<< Content-Length: 19
<<< Content-Type: application/octet-stream
content length: [19]
<<< 
offset 0, length -1, size -1, clength 19

The request requests 20 bytes, (21 - 2 + 1), but as you can see, the reply only includes 19 bytes.

It also looks like it does not honor range, as if I manually do the request:

 $ telnet 0 5555
Trying 0.0.0.0...
Connected to 0.
Escape character is '^]'.
GET /somefile HTTP/1.1
Host: 127.0.0.1:5555
Accept: */*
User-Agent: test libfetch/2.0
Range: bytes=2-21
Connection: close

HTTP/1.0 206 Partial Content
Server: DAV/0.9.14 Python/3.7.7
Date: Fri, 09 Oct 2020 21:51:20 GMT
Content-type: application/octet-stream
Transfer-Encoding: chunked
Date: Fri, 09 Oct 2020 21:51:20 GMT
DAV: 1,2
Last-Modified: Fri, 09 Oct 2020 21:43:02 GMT
Keep-Alive: timeout=15, max=86
Connection: Keep-Alive
Content-Length: 19
Content-Type: application/octet-stream

1f400
is is a test to give some bogus data at first

1f400

1f400

1f400

1f400

1f400

1f400

1f400

5ffe

0

^]
telnet> quit
Connection closed.

A lot more data is included than the specified range:

freebsd@generic:~/lf.test $ echo -n 'is is a test to give some bogus data at first' | wc
       0      11      45

The data was a simple file that contained the above string, and zero padded to 1MB.

[andrewleech]

Thanks for the testing and clear reporting. I'm not actively working on this project though, to be honest I only ever created it as a test tool for a WebDAV client I used to work on.

I'm more than happy to merge and release any patches though if you're interested in fixing the issue!