rewrote function .checkBaseUrl

[gowthamrao]

based on vignette for rex package here https://cran.r-project.org/web/packages/rex/vignettes/url_parsing.html

rex package https://cran.r-project.org/web/packages/rex/index.html

updated roxygen documentation and description file

discussion to support this change here https://github.com/OHDSI/ROhdsiWebApi/pull/28#discussion_r364924527

[codecov-io]

Codecov Report

Merging #30 into develop will decrease coverage by 0.08%. The diff coverage is 0%.

@@            Coverage Diff             @@
##           develop     #30      +/-   ##
==========================================
- Coverage     6.25%   6.16%   -0.09%     
==========================================
  Files            4       5       +1     
  Lines          448     454       +6     
==========================================
  Hits            28      28              
- Misses         420     426       +6

Impacted Files	Coverage Δ
R/WebApi.R	62.22% <ø> (+10.37%)	:arrow_up:
R/private.R	0% <0%> (ø)

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[schuemie]

A few comments:

1. It seems you have rewritten .checkBaseUrl function while maintaining its functionality. What I think you are going for is better readability of the code, but the price to pay is a dependency on the rex package. I think I prefer not having the dependency.

2. Have you made sure you can build the package? Does it pass R check? The reason I ask is that is still see %>%, which I don't think would work without having magrittr on the search path.

3. This might be a good opportunity to add a few unit tests that make sure this function works. You could test whether it detects some example malformed and well-formed URLs (see https://github.com/OHDSI/ROhdsiWebApi/blob/develop/tests/testthat/test-webapi.R)

[alondhe]

@gowthamrao I would agree with @schuemie on the first comment especially. Are there cases in which the original function does not work correctly?