如何在R中列出mongodb集合

Question

I have been trying to list collections within a mongo database in R. I have realized that this feature is still in the to do list in the mongolite package ( https://github.com/jeroen/mongolite/issues/86 ). There seemed to be a package, rmongodb , which did the trick ( Unable to see all collections from a mongodb remote server using mongolite ). However, it is no longer a part of CRAN.

Can anyone, please, suggest a way to list all collection in a database?

The mongodb is remote, so I guess using the mongoshell with combination with system() is not an option. At least not a straightforward one.

Thanks

Answer 1

The solution I came up with is the following:

ListMongoCollections <- function(db, mongoConString) {

  result <- system(glue::glue(
    "
    mongo --host <<mongoConString>> --eval \"
      db.getMongo().getDBNames().forEach(
        function(v, i) {if (v.valueOf() === '<<db>>') {
          print(db.getSiblingDB(v).getCollectionNames().join('%%%'))
        }}
      )
    \"
    ",
    .open = "<<",
    .close = ">>"
    ),
    intern = T
  )

  collections <- result %>% stringr::str_detect("%%%")

  result <- result[collections] %>% 
    stringr::str_split(pattern = "%%%", simplify = T) %>% 
    as.character()

  result

}