Bugs in DAP4 Data Request Form constraint expression construction

[jgallagher59701]

Originally from https://bugs.earthdata.nasa.gov/browse/HYRAX-1070

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Overview

I found that when the DAP4 Data Request Form builds the constraint expression it has (at least!) the following two issues.

Issue: Wrong Variable Name

When the xslt/javascript writes the DAP variable name into the constraint expression the value used has had any "." characters replaced with "_". This is probably a simple fix - I think in the JavaScript code the variable name for the DAP variable uses this substitution to make the data variable name valid for a java script variable name.

Issue: Constraint expression incorrectly constructed.

When a variable or group name is included in a DAP4 constraint, and the name contains one or more "." characters (others?? Perhaps "/" , "[", and "]" are likely culprits...) then the name must be double quoted between the path separating "/" characters.

Example:

Consider a group named PM_2.5 with a child variable named PM_2.5_Sulfate_uncertainty. The child variable should appear in a DAP4 constraint like: dap4.ce=...;/"PM_2.5"/"PM_2.5_Sulfate_uncertainty";...

So we need to add some code in the appropriate place to check the variable/group names for "." (and possibly other reserved characters - Ask [~jhrg]) and when found wrap the variable/group name in double quotes as show above.

[Mikejmnez]

I ran into another a similar case, in this scenario when constructing CEs for Sequences.

Minimal Reproducible Example

Consider the URI_Avhrr sequence, which contains child variables such as year,month,day, etc. The tree hierarchy of a file avhrr.dat containing such sequence is

.avhrr.dat
└──URI_Avhrr
   ├──year
   ├──month
   ├──day
   ├──hours
   ├──minutes
   ├──seconds
   └──DODS_URL

This is a file in http://test.opendap.org/opendap/data/ff/avhrr.dat

Lets say I want to access only the variable year within sequence URI_Avhrr. I would expect from the Data Request Form:

?dap4.ce=/URI_Avhrr.year

Instead I get:

?dap4.ce=/URI_Avhrr/year