ShinyApp无法发布至shinyapps.io问题求助

本地在RStudio中运行正常的ShinyApp，发布至shinyapps.io后浏览器持续显示启动错误：

An error has occurred
The application failed to start.
exit status 1

原问题代码（未声明依赖库） #

dat <- read_csv(url("https://www.dropbox.com/s/uhfstf6g36ghxwp/cces_sample_coursera.csv?raw=1")) %>%
  select(c("pid7","ideo5")) %>% drop_na()
ui <- fluidPage(sidebarLayout(
  sliderInput(inputId = "ideo5",
              label = "Select Five Point Ideology (1=Very liberal, 5=Very conservative)",
              min = min(dat[,2]),
              max = max(dat[,2]),
              value = 3),
  plotOutput("distPlot")))
server <- function(input, output) {
  output$distPlot <- renderPlot({
    c <- ggplot(dat %>% filter(ideo5 == input$ideo5), aes(pid7)) + labs(x = "7 Point Party ID, 1=Very D, 7=Very D")
    c + geom_bar()
  })
}
shinyApp(ui = ui, server = server)

问题根源 #

代码未明确声明依赖的R包，导致shinyapps.io服务器无法自动加载运行所需的库，进而引发启动失败。

修正后的完整代码 #

在代码开头添加依赖包加载语句后即可正常发布：

library(shiny)
library(tidyverse)
library(ggplot2)

dat <- read_csv(url("https://www.dropbox.com/s/uhfstf6g36ghxwp/cces_sample_coursera.csv?raw=1")) %>%
  select(c("pid7","ideo5")) %>% drop_na()
ui <- fluidPage(sidebarLayout(
  sliderInput(inputId = "ideo5",
              label = "Select Five Point Ideology (1=Very liberal, 5=Very conservative)",
              min = min(dat[,2]),
              max = max(dat[,2]),
              value = 3),
  plotOutput("distPlot")))
server <- function(input, output) {
  output$distPlot <- renderPlot({
    c <- ggplot(dat %>% filter(ideo5 == input$ideo5), aes(pid7)) + labs(x = "7 Point Party ID, 1=Very D, 7=Very D")
    c + geom_bar()
  })
}
shinyApp(ui = ui, server = server)

内容的提问来源于stack exchange，提问作者Stella Devito