Luca Cinquini wrote:
On Sep 26, 2005, at 10:03 AM, John Caron wrote:
Hi luca: you own another thank-you to julie, who forwarded your message!
I keep making that mistake...
Julie Caron wrote:
---------- Forwarded message ----------
Date: Mon, 26 Sep 2005 09:11:23 -0600
From: Luca Cinquini <luca@xxxxxxxx>
To: jcaron@xxxxxxxx
Cc: Michael Burek <mburek@xxxxxxxx>, John J.Allison
<john@xxxxxxxxxxxxx>
Subject: problem with newest netcdf java library when retrieving
netcdf file
from JOSS
Hi John,
after installing the newest NetCDF Java library on the CDP, there
seems to be a problem in generating NcML on the fly when opening a URL
that is served by the JOSS server, for example the following file:
http://chinook.joss.ucar.edu:8080/datafile/nph-get/87.004/
RF01.20041207.161000_215115.PNI.nc
Everything works ok if I place the same file on the dataportal server.
The error when opening the file from the JOSS server is the following:
java.io.IOException: Server does not support byte Ranges
at
ucar.unidata.io.http.HTTPRandomAccessFile3.<init>(HTTPRandomAccessFile
3.
java:74)
at
ucar.unidata.io.http.HTTPRandomAccessFile3.<init>(HTTPRandomAccessFile
3.
java:53)
at ucar.nc2.NetcdfFile.open(NetcdfFile.java:205)
at ucar.nc2.NetcdfFile.open(NetcdfFile.java:165)
at ucar.nc2.NetcdfFile.open(NetcdfFile.java:149)
at ncar.scd.ncml.io.NetcdfReader.read(NetcdfReader.java:84)
Which I think originates from the fact that appearently the JOSS server
does NOT send, in its response, the header "Accept-Ranges".
Now the question is: according to the WWW specification
(http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html), the
"Accept-Ranges" header is optional:
"Origin servers that accept byte-range requests MAY send
Accept-Ranges: bytes
but are not required to do so."
the functionality (and so the header) is needed if you want to read a
netcdf file over HTTP.
Yes but the JOSS server does server the netCDF file correctly - I
downloaded it to my personal laptop. The point is that, independently
wether the remote server sends or not the Header "Accept-Ranges", the
client application using the netcdf Java library MAY assume that the
remote server will support bytes transfer - if this is not the case
something else will break later on, but at least you won't loose all
those servers that don't send this optional header.
Or am I not interpreting the problem correctly ?
thanks, Luca
ok, i see what you're saying. i didnt realize that servers werent required to
have the header. I will modify to try it anyway.
Still, I would ask JOSS to add the header, I think its more standard. Also, they are down so i havent verified that they do support range bytes.
