Re: Error occurring in dods.dap.Parser

On Jan 27, 2005, at 8:52 AM, James Gallagher wrote:

> 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).

I am concerned that if Tennessee's modifies his code (especially our  
parser) to handle these names then he will be generating DDS's that no  
one else can parse...




> James
>
>
> > If I convert
> > <dataset name="Single-level Salinity Data"  
> > urlPath="stream=ocea,param=200,DATE=20000101,TIME=0000,STEP=0,EXPVER=0 
> > oc7,CLASS=RD,TYPE=AN,NUMBER=0,METHOD=0,LEVELIST=7.000,LEVTYPE=DP,REPRE 
> > S=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,REP 
> > RES=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,CLAS 
> > S=RD,TYPE=AN,NUMBER=0,METHOD=0,LEVELIST=7.000,LEVTYPE=DP,REPRES=LL,DOM 
> > AIN=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,CL 
> > > > > ASS  
> > > > > =RD,TYPE=AN,NUMBER=0,METHOD=0,LEVELIST=7.000,LEVTYPE=DP,REPRES=LL,D 
> > > > > OMA 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
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Nathan Potter              Oregon State University, COAS
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