NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
Current content can be found at unidata.ucar.edu.

To learn about what's going on, see About the Archive Site.

Re: Error occurring in dods.dap.Parser


On Jan 26, 2005, at 9:30 PM, Tennessee Leeuwenburg wrote:
Unfortunately that seems to break thredds's parsing of catalogConfig.xml.
Hmmm. If you look in Java-DODS/dods/dap/parser/DDSJava.jj you can see the characters that the scanner gobbles up. I'm not really sure how the THREDDS code works.
If you have the parser generator, you could try adding '=' and ',' to the set of allowed chars. You'd need to be careful though because = and ',' are used by the CE syntax. So you can have them be part of a dataset name, but if they are a variable name the CE parser will become very confused.
A more sweeping solution (besides switching to XML, which is in the works) would be to modify the parser so that it uses a double quote (") to quote chars so any char could be part of a word (you'd do the usual thing about providing for quotes in the set of chars itself). This would be a more drastic change to the parser but would also dovetail with the current parser (I think) and not require a switch to XML (which solves the problem because it provides for robust quoting). 

James



If I convert
<dataset name="Single-level Salinity Data" urlPath="stream=ocea,param=200,DATE=20000101,TIME=0000,STEP=0,EXPVER=0o c7,CLASS=RD,TYPE=AN,NUMBER=0,METHOD=0,LEVELIST=7.000,LEVTYPE=DP,REPRES= LL,DOMAIN=G,salinity.nc"/> 

to
<dataset name="Single-level Salinity Data" urlPath="stream%3Docea,param=200,DATE=20000101,TIME=0000,STEP=0,EXPVER= 0oc7,CLASS=RD,TYPE=AN,NUMBER=0,METHOD=0,LEVELIST=7.000,LEVTYPE=DP,REPRE S=LL,DOMAIN=G,salinity.nc"/>
that is to change the first "=" to %3D, the hex code for "=", it seems to break the lookup. What I get is the error 

Error {
   code = 1;
message = "Dataset not found in catalog; urlPath= <stream=ocea,param=200,DATE=20000101,TIME=0000,STEP=0,EXPVER=0oc7,CLASS =RD,TYPE=AN,NUMBER=0,METHOD=0,LEVELIST=7.000,LEVTYPE=DP,REPRES=LL,DOMAI N=G,salinity.nc>"; 
};
It would seem that thredds is converting the %3D to "=" in its head, then failing on the string comparison. Just my guess though. 

Cheers,
-T






T,

Well. The problem is in your Dataset name:
} stream=ocea,param=200,DATE=20000101,TIME=0000,STEP=0,EXPVER=0oc7,CLA SS =RD,TYPE=AN,NUMBER=0,METHOD=0,LEVELIST=7.000,LEVTYPE=DP,REPRES=LL,DO MA IN=G,salinity.nc; 


The parser is barfing on the first "=" character (Line 58, column 9)
James? Is this in any way a legal name? If so, how does he need to "escape" the "=" (and possibly the ",") characters?
You could escape the '=' and ',' using the HTTP %<hex digit><hex digit> notation, I think. When the Java DAP 2.0 parser was written we had not encountered file names that broke the 'C identifier' mold. But that was just around the corner... Anyway, the C++ code lets just about anything be a file name. I'd try the escaping scheme and see how it works. 

James
PS. I just checked the DDS parser and it will grok the percent sign, so you should be OK using that to signal the start of the escape sequence. 




--
James Gallagher                jgallagher at opendap.org
OPeNDAP, Inc                   406.783.8663
  • 2005 messages navigation, sorted by:
    1. Thread
    2. Subject
    3. Author
    4. Date
    5. ↑ Table Of Contents
  • Search the thredds archives: