hi duncan, Thank you, it refreshed my memories on "local", cool. About the dummy function to load packages, it lets Rstudio bring them in the Namespace, kind of a tradeoff because of the warning I get in NAMESPACE after building the documentation: >>> # Generated by roxygen2: do not edit by hand
regards frederic On Fri, Aug 4, 2017 at 4:19 PM Duncan Murdoch <murdoch.dun...@gmail.com> wrote: > On 04/08/2017 5:51 AM, frédéric Clement wrote: > > Hello, > > > > I want to use a package to load and set up a working environment (Only > > intern used). It has function, but also create a connection object > > (RPostgreSQL) to make dplyr::tbl implicitely use this connection. > > > > After trying to save the connection object in "Data\"... and failed. I > made > > the following work around. > > > > Is it the right way to do it, or should it be solved in other ways. > > > > PS: This is my first attent at package development experience, I mainly > > follow http://r-pkgs.had.co.nz/ > > > > regards > > > > frederic Clement > > > > ----- the script---- > > > > .onAttach <- function(libname = find.package("dbName"), pkgname = > "dbName") > > { > > packageStartupMessage("Intranet Company required") > > > > dbNameConPool = dbName_create_pool() > > assign("dbNameConPool", dbNameConPool, envir = > > as.environment("package:dbName")) > > } > > Usually you should use .onLoad, not .onAttach. If someone who hasn't > attached your package calls one of the functions using dbName::fn(...), > your package will be loaded but not attached. Similarly if another > package imports one of your functions. > > > > > > > > ## This is a function so that I can call it in .onAttach > > ## > > dbName_create_pool = function(){ > > > > DBI::dbConnect(drv = RPostgreSQL::PostgreSQL(), > > user = "dbName", > > password = .rs.askForPassword("Enter password:"), > > port = 0000, > > host = "dbName-int.company.com") > > } > > However, for this particular use, it might be bad to put the code even > in .onLoad. A better way to go would be to have a function in your > package that calls dbName_create_pool the first time you call it, and > just returns the same value on subsequent calls. For example, > > getcon <- local({ > con <- NULL > function() { > if (is.null(con)) > con <<- dbName_create_pool() > con > }}) > > > This way nobody is prompted for a password unless they actually need to > access the database. > > > > > #' Dummy function > > #' > > #' Only used for package build purpose > > #' to import the usefull function. > > #' @return NULL > > #' @export > > #' @import dplyr dbplyr DBI magrittr RPostgreSQL tidyr > > #' > > #' @examples > > #' fun_import() > > fun_import <- function(){ > > NULL > > } > > Not sure why you'd want these 13 lines instead of editing your NAMESPACE > file, but that's your choice... > > Duncan Murdoch > > > > > --- session > > > > R version 3.4.1 (2017-06-30) > > Platform: i386-w64-mingw32/i386 (32-bit) > > Running under: Windows >= 8 x64 (build 9200) > > > > Matrix products: default > > > > locale: > > [1] LC_COLLATE=German_Germany.1252 LC_CTYPE=German_Germany.1252 > > LC_MONETARY=German_Germany.1252 LC_NUMERIC=C > > LC_TIME=German_Germany.1252 > > > > attached base packages: > > [1] stats graphics grDevices utils datasets methods base > > > > loaded via a namespace (and not attached): > > [1] compiler_3.4.1 tools_3.4.1 > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-package-devel@r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-package-devel > > > > [[alternative HTML version deleted]] ______________________________________________ R-package-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-package-devel
