R from a text loading bar to a shiny loading bar - r

Question

I use a function with a text loading bar (get_reddit()) in a Shiny app and I would like to display the progression not in the R console but in the app. Does anyone know how I could do that?
For now I have an empty progress bar in the app (not surprising since I don't have any incProgress() to go with the withProgress()) and an active text bar in my RStudio console.
library(shiny)
library(RedditExtractoR)
ui <- fluidPage(actionButton("go", "GO !"),
tableOutput("reddit"))
server <- function(input, output) {
get_data <- eventReactive(input$go, {
withProgress(message = 'Work in progress', value = 0, {
df <-
get_reddit(
search_terms = "Lyon",
regex_filter = "",
subreddit = "france",
cn_threshold = 1,
page_threshold = 1,
sort_by = "comments",
wait_time = 2
)
df
})
})
output$reddit <- renderTable({
df <- get_data()
df[1:5, 1:5]
})
}
shinyApp(ui = ui, server = server)
Thank you for your help!

Answer 1

A simple solution is to edit the function in the RedditExtractoR package responsible for the progress bar, which is reddit_content. This function is called from within the get_reddit function, so this function has to be updated too.
library(shiny)
library(RedditExtractoR)
source("get_reddit2.R") # source the new get_reddit2 function (see below)
source("reddit_content2.R") # source the new reddit_content2 function (see below)
ui <- fluidPage(actionButton("go", "GO !"),
tableOutput("reddit"))
server <- function(input, output) {
get_data <- eventReactive(input$go, {
df <- get_reddit2(
search_terms = "science",
subreddit = "science")
})
output$reddit <- renderTable({
df <- get_data()
df[1:5, 1:5]
})
}
shinyApp(ui = ui, server = server)
Put the following function in a separate file called get_reddit2.R which you source from the app (see above):
get_reddit2 <- function (
search_terms = NA,
regex_filter = "",
subreddit = NA,
cn_threshold = 1,
page_threshold = 1,
sort_by = "comments",
wait_time = 2)
{
URL = unique(as.character(
reddit_urls(
search_terms,
regex_filter,
subreddit,
cn_threshold,
page_threshold,
sort_by,
wait_time
)$URL
))
retrieved_data = reddit_content2(URL, wait_time)
return(retrieved_data)
}
Put also the following function in a separate file called reddit_content2.R (see above):
reddit_content2 <- function (URL, wait_time = 2)
{
if (is.null(URL) | length(URL) == 0 | !is.character(URL)) {
stop("invalid URL parameter")
}
GetAttribute = function(node, feature) {
Attribute = node$data[[feature]]
replies = node$data$replies
reply.nodes = if (is.list(replies))
replies$data$children
else
NULL
return(list(Attribute, lapply(reply.nodes, function(x) {
GetAttribute(x, feature)
})))
}
get.structure = function(node, depth = 0) {
if (is.null(node)) {
return(list())
}
filter = is.null(node$data$author)
replies = node$data$replies
reply.nodes = if (is.list(replies))
replies$data$children
else
NULL
return(list(
paste0(filter, " ", depth),
lapply(1:length(reply.nodes),
function(x)
get.structure(reply.nodes[[x]], paste0(depth,
"_", x)))
))
}
data_extract = data.frame(
id = numeric(),
structure = character(),
post_date = as.Date(character()),
comm_date = as.Date(character()),
num_comments = numeric(),
subreddit = character(),
upvote_prop = numeric(),
post_score = numeric(),
author = character(),
user = character(),
comment_score = numeric(),
controversiality = numeric(),
comment = character(),
title = character(),
post_text = character(),
link = character(),
domain = character(),
URL = character()
)
# pb = utils::txtProgressBar(min = 0,
# max = length(URL),
# style = 3)
withProgress(message = 'Work in progress', value = 0, {
for (i in seq(URL)) {
if (!grepl("^https?://(.*)", URL[i]))
URL[i] = paste0("https://www.", gsub("^.*(reddit\\..*$)",
"\\1", URL[i]))
if (!grepl("\\?ref=search_posts$", URL[i]))
URL[i] = paste0(gsub("/$", "", URL[i]), "/?ref=search_posts")
X = paste0(gsub("\\?ref=search_posts$", "", URL[i]),
".json?limit=500")
raw_data = tryCatch(
RJSONIO::fromJSON(readLines(X, warn = FALSE)),
error = function(e)
NULL
)
if (is.null(raw_data)) {
Sys.sleep(min(1, wait_time))
raw_data = tryCatch(
RJSONIO::fromJSON(readLines(X,
warn = FALSE)),
error = function(e)
NULL
)
}
if (is.null(raw_data) == FALSE) {
meta.node = raw_data[[1]]$data$children[[1]]$data
main.node = raw_data[[2]]$data$children
if (min(length(meta.node), length(main.node)) > 0) {
structure = unlist(lapply(1:length(main.node),
function(x)
get.structure(main.node[[x]], x)))
TEMP = data.frame(
id = NA,
structure = gsub("FALSE ",
"", structure[!grepl("TRUE", structure)]),
post_date = format(as.Date(
as.POSIXct(meta.node$created_utc,
origin = "1970-01-01")
), "%d-%m-%y"),
comm_date = format(as.Date(
as.POSIXct(unlist(lapply(main.node,
function(x) {
GetAttribute(x, "created_utc")
})), origin = "1970-01-01")
), "%d-%m-%y"),
num_comments = meta.node$num_comments,
subreddit = ifelse(
is.null(meta.node$subreddit),
"UNKNOWN",
meta.node$subreddit
),
upvote_prop = meta.node$upvote_ratio,
post_score = meta.node$score,
author = meta.node$author,
user = unlist(lapply(main.node, function(x) {
GetAttribute(x, "author")
})),
comment_score = unlist(lapply(main.node,
function(x) {
GetAttribute(x, "score")
})),
controversiality = unlist(lapply(main.node,
function(x) {
GetAttribute(x, "controversiality")
})),
comment = unlist(lapply(main.node, function(x) {
GetAttribute(x, "body")
})),
title = meta.node$title,
post_text = meta.node$selftext,
link = meta.node$url,
domain = meta.node$domain,
URL = URL[i],
stringsAsFactors = FALSE
)
TEMP$id = 1:nrow(TEMP)
if (dim(TEMP)[1] > 0 & dim(TEMP)[2] > 0)
data_extract = rbind(TEMP, data_extract)
else
print(paste("missed", i, ":", URL[i]))
}
}
# utils::setTxtProgressBar(pb, i)
incProgress()
Sys.sleep(min(2, wait_time))
}
# close(pb)
})
return(data_extract)
}
Now the loading bar is shown in Shiny instead of the console.