Shiny app crash, issue with leaflet Shiny RStudio

Question

i'm building shiny app, used leaflet to plot a map with markers and polygons.

At this point i have a map, with some markers and one polygon at time

This is part of my code, with this i can render a Polygon in leaflet map but only if com <- mongo$find('{"id" : "Temuco"}') have one name (Temuco or Santiago), if i put '{"id" : {"$in":["Temuco", "Santiago"]}}' all crashed with this error: 'options' must be a fully named list, or have no names (NULL)

    com <- mongo_comunas$find('{"nombre": {"$in":["Temuco", "Santiago", "etcetcetc"]}}')
    build_list <- split(com, com$id)
    build_list <- lapply(build_list, function(x){x["id"]<- NULL;x})
    build_list <- lapply(build_list, function(x){x["order"]<- NULL;x})
    build_list <- lapply(build_list, function(x){x["hole"]<- NULL;x})
    build_list <- lapply(build_list, function(x){x["piece"]<- NULL;x})
    build_list <- lapply(build_list, function(x){x["group"]<- NULL;x})
    ps <- lapply(build_list, Polygon)
    ps <- Polygons(ps, ID = 1)
    ps <- SpatialPolygons(list(ps), proj4string =CRS("+proj=longlat"))


  output$mymap <- renderLeaflet({
    leaflet(data = ps) %>% addTiles() %>% addPolygons())       

  })

with only com <- mongo$find('{"id" : "Temuco"}') (or another id) all its good. I used ggplot with that function and render two or three or more polygons at time but with leaflet all crashed.

data stored in mongo like:

        long      lat    order  hole piece   id      group
    1 -72.8012 -38.8337 914361 FALSE   1     Temuco Temuco.1
    .
    .
    .
  200 -72.5503 -38.7324 919738 FALSE   1     Santiago Santiago.1

I appreciate if anyone can guide me in this problem

Answer 1

First

Are you using

mongo$find(...)

or

mongo_comunas$find(...)

?

Because the mongo command cannot be used to query your db. It is used to establish the connection to your mongodb.

You would need something along the lines of this:

mongoConnection <- mongo(collection = "test", db = "test", url = "mongodb://localhost",
  verbose = FALSE, options = ssl_options())

See ?mongo for help.

Then you can call this connection for your find, aggregate, etc. queries

com <- mongoConnection$find(...)

I am guessing that the connection is what you have assigned to mongo_comunas but without seeing more of your code I don't know for sure.

Second

Does the data you are pulling in contain any arrays? If so, you will need to use the $unwind command to un-nest these arrays.

You may also need to use "flatten" from the jsonlite package to further flatten out your data into a non-nested dataframe.