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Introduction to movexplR6

movexplR6.Rmd

Overview

movexplR6 is a Shiny app-package for exploring a movie database that combines Rotten Tomatoes and IMDb data. It modernizes the classic 051-movie-explorer Shiny example by:

  • Replacing ggvis with ggplot2 + plotly for interactive scatter plots.
  • Replacing wellPanel layouts with bslib (page_sidebar, card).
  • Wrapping all database and filter logic in an R6 class (MovieData).

The MovieData R6 class

MovieData owns the database connection and exposes two public methods: $filter() for querying the in-memory data, and $finalize() for cleaning up the connection.

Connecting and loading data 

md <- MovieData$new(db_path)
#> INFO [2026-08-07 19:49:48] Connecting to database: /home/runner/.cache/R/renv/library/movexplR6-8fe87c7d/linux-ubuntu-noble/R-4.6/x86_64-pc-linux-gnu/movexplR6/extdata/movies.db
#> INFO [2026-08-07 19:49:48] Database connection established
#> INFO [2026-08-07 19:49:49] Loaded 12569 movies into memory

On initialization the class:

  1. Opens a DBI connection to the SQLite file.
  2. Joins the omdb and tomatoes tables.
  3. Collects the result into $all_movies (an in-memory data frame).
dim(md$all_movies)
#> [1] 12569    26
names(md$all_movies)
#>  [1] "ID"          "imdbID"      "Title"       "Year"        "Rating_m"   
#>  [6] "Runtime"     "Genre"       "Released"    "Director"    "Writer"     
#> [11] "imdbRating"  "imdbVotes"   "Language"    "Country"     "Oscars"     
#> [16] "Rating"      "Meter"       "Reviews"     "Fresh"       "Rotten"     
#> [21] "userMeter"   "userRating"  "userReviews" "BoxOffice"   "Production" 
#> [26] "Cast"

Filtering

$filter() accepts the same parameters exposed by the Shiny sidebar and returns a filtered data frame with an added has_oscar column.

defaults <- md$filter()
nrow(defaults)
#> [1] 4181

Filter by minimum reviews:

strict <- md$filter(reviews = 200)
nrow(strict)
#> [1] 306

Filter by genre:

drama <- md$filter(genre = "Drama")
nrow(drama)
#> [1] 2195
head(drama[, c("Title", "Year", "Genre", "Oscars", "has_oscar")], 5)
#>                       Title Year                 Genre Oscars has_oscar
#> 1 Diary of a Country Priest 1951                 Drama      0        No
#> 2 The Man in the White Suit 1951 Comedy, Sci-Fi, Drama      0        No
#> 3           Little Fugitive 1953         Drama, Family      0        No
#> 4                 Le amiche 1955        Drama, Romance      0        No
#> 5                Breathless 1960 Crime, Drama, Romance      0        No

Filter by year range:

nineties <- md$filter(year = c(1990, 1999))
range(nineties$Year)
#> [1] 1990 1999

Filter by box-office range (millions):

blockbusters <- md$filter(boxoffice = c(200, 800))
nrow(blockbusters)
#> [1] 106

Filter by director (partial, case-insensitive):

spielberg <- md$filter(director = "Spielberg")
unique(spielberg$Director)
#> [1] "Steven Spielberg"

Combining filters:

combined <- md$filter(
  genre    = "Action",
  oscars   = 1,
  year     = c(2000, 2014),
  director = "Nolan"
)
combined[, c("Title", "Year", "Director", "Oscars")]
#>             Title Year          Director Oscars
#> 1 The Dark Knight 2008 Christopher Nolan      2
#> 2       Inception 2010 Christopher Nolan      4

The has_oscar column

$filter() always appends a has_oscar character column ("Yes" / "No") derived from the Oscars count. The scatter plot uses this for color encoding.

table(defaults$has_oscar)
#> 
#>   No  Yes 
#> 4023  158

Disconnecting

Call $disconnect() to explicitly close the database connection. This is also called automatically via shiny::onStop() inside movies_server(). The private finalize() method delegates to $disconnect() so the connection is also closed when the object is garbage collected.

md$disconnect()
#> INFO [2026-08-07 19:49:50] Database connection closed
DBI::dbIsValid(md$con)
#> [1] FALSE

Axis variables

axis_vars is a named character vector mapping display labels to column names. Both mod_filters_ui() and mod_plot_server() use it to populate the axis selector inputs.

axis_vars
#>          Tomato Meter        Numeric Rating     Number of reviews 
#>               "Meter"              "Rating"             "Reviews" 
#> Dollars at box office                  Year      Length (minutes) 
#>           "BoxOffice"                "Year"             "Runtime"

Shiny modules

mod_filters

mod_filters_ui(id) renders two bslib::card elements inside the sidebar: one for filter controls and one for axis selectors. mod_filters_server(id) returns a reactive list of the current selections.

mod_plot

mod_plot_ui(id) renders a bslib::card containing a plotly scatter plot and a movie count line. mod_plot_server(id, movies, filters) accepts the filtered data reactive and the filter selections reactive, and renders the plot. Hover tooltips show the movie title, year, and box-office gross.

Running the app 

movexplR6::launch_app()