Shiny：过滤/选择变量而不从 BigQuery 表中下载所有数据

Posted 2023-03-25

【中文标题】Shiny：过滤/选择变量而不从 BigQuery 表中下载所有数据

【英文标题】：Shiny: Filter/Selection of variables without downloading all data from BigQuery table

【发布时间】：2021-10-07 02:37:10

【问题描述】：

我想在 BigQuery 的 baseball 公共数据中选择变量（year、seasonType、dayNight 和 homeFinalRuns），而不下载所有数据。我尝试使用reactive() 变量作为目标字符串的过滤器但没有成功，因为我有错误：

Complete
Billed: 0 B
Downloading first chunk of data.
First chunk includes all requested rows.

Listening on http://127.0.0.1:4784
Warning: Error in : Cannot translate a shiny reactive to SQL.
* Force evaluation in R with (e.g.) `!!foo()` or `local(foo())`
70: <Anonymous>
  Error : Cannot translate a shiny reactive to SQL.
* Force evaluation in R with (e.g.) `!!foo()` or `local(foo())

我尝试的代码是：

library(shinythemes)
library(dplyr)
library(ggplot2)
library(bigrquery)
library(DBI)

# Open a public BigQuery dataset eg. "baseball"
bq_con <- dbConnect(
  bigrquery::bigquery(),
  project = "bigquery-public-data",
  dataset = "baseball",
  billing = "my_project_id"
)
bigrquery::dbListTables(bq_con) # List all the tables in BigQuery data set
# My email google option
1
#[1] "games_post_wide" "games_wide"      "schedules"    
#

# Selection of target data set
dataset <- dplyr::tbl(bq_con, 
                      "games_wide") # connects to a table

# Selection of reactive strings 
dataset_vars <- dataset %>% distinct(year,seasonType,dayNight,homeFinalRuns)%>% 
  collect() 
dataset_vars
# Create the shiny dash
ui <- fluidPage(
  theme = shinytheme("cosmo"),
  titlePanel(title="My Baseball Dashboard"),  
  sidebarLayout(
    sidebarPanel(
      selectInput(inputId = "selectedvariable0",
                  label = "Year", 
                  choices = c(unique(dataset_vars$year)),selected = TRUE ), 
      selectInput(inputId = "selectedvariable1",
                  label = "Season", 
                  choices = c(unique(dataset_vars$seasonType)),selected = TRUE ), 
      selectInput(inputId = "selectedvariable2",
                  label = "Period", 
                  choices = c(unique(dataset_vars$dayNight)),selected = TRUE ),
      
      selectInput(inputId = "selectedvariable3",
                  label = "Final Runs", 
                  choices = c(unique(dataset_vars$homeFinalRuns)),selected = TRUE )      
    ),
    mainPanel(
      textOutput("idSaida"),
      fluidRow(
        splitLayout(plotOutput("myplot")))
    )
  )
)
server <- function(input, output)
  
  currentvariable0 <- reactive(input$selectedvariable0)
  currentvariable1 <- reactive(input$selectedvariable1)
  currentvariable2 <- reactive(input$selectedvariable2)
  currentvariable3 <- reactive(input$selectedvariable3)
  
  
  # Selection of variables for plots constructions 
  dataset_sel <- dataset %>% filter(year=currentvariable0(),homeFinalRuns==currentvariable0())%>% 
    collect() 
  
  
  observe( 
    if(currentvariable2()=="D")
      output$myplot <- renderPlot(
        
        #Create the plot
        ggplot(data=dataset_sel, aes(x=currentvariable0(), y=currentvariable3())) +
          geom_bar(stat="identity")
      )
     else 
      #Create the plot
      ggplot(data=dataset_sel, aes(x=currentvariable0(), y=currentvariable3())) +
        geom_bar(stat="identity")
      
    
  ) #end of observe function.

shinyApp(ui, server)
#

如果我在中使用!!：

  # Selection of variables for plots constructions 
  dataset_sel <- dataset %>% filter(year=!!currentvariable0(),homeFinalRuns==!!currentvariable0())%>% 
    collect() 

发生了一个新错误：

Complete
Billed: 0 B
Downloading first chunk of data.
First chunk includes all requested rows.

Listening on http://127.0.0.1:4784
Warning: Error in : Operation not allowed without an active reactive context.
* You tried to do something that can only be done from inside a reactive consumer.
  60: <Anonymous>
Error : Operation not allowed without an active reactive context.
* You tried to do something that can only be done from inside a reactive consumer.

如果我通过以下查询方法进行更改：

var1 <- currentvariable0()
var2 <- currentvariable3()
sqlInput <- paste("SELECT",var1,"as year, 'REG' as seasonType,'N' as dayNight,",var2,"as homeFinalRuns FROM games_wide LIMIT 30")
dataset_sel <- dbGetQuery(bq_con, sqlInput, stringsAsFactors = T)

也不行：

Warning: Error in : Operation not allowed without an active reactive context.
* You tried to do something that can only be done from inside a reactive consumer.
  55: <Anonymous>
Error : Operation not allowed without an active reactive context.
* You tried to do something that can only be done from inside a reactive consumer.

请帮忙解决一下？

【参考方案1】：

问题解决了，没有更多错误了！！选择数据集也必须是reactive()，并且第一个选择中的选择元素是查询 paste("SELECT",var1,"as year, 'REG' as seasonType,'N' as dayNight,",var2,"as homeFinalRuns FROM games_wide LIMIT 30")。

library(shinythemes)
library(dplyr)
library(ggplot2)
library(bigrquery)
library(DBI)

# Open a public BigQuery dataset eg. "baseball"
bq_con <- dbConnect(
  bigrquery::bigquery(),
  project = "bigquery-public-data",
  dataset = "baseball",
  billing = "my_project_id"
)
bigrquery::dbListTables(bq_con) # List all the tables in BigQuery data set

#[1] "games_post_wide" "games_wide"      "schedules"    
#

# Selection of target data set
dataset <- dplyr::tbl(bq_con, 
                      "games_wide") # connects to a table
# My email google option
2

# Selection of reactive strings 
dataset_vars <- dataset %>% distinct(year,seasonType,dayNight,homeFinalRuns)%>% 
  collect() 
dataset_vars


# Create the shiny dash
ui <- fluidPage(
  theme = shinytheme("cosmo"),
  titlePanel(title="My Baseball Dashboard"),  
  sidebarLayout(
    sidebarPanel(
      selectInput(inputId = "selectedvariable0",
                  label = "Year", 
                  choices = c(unique(dataset_vars$year)),selected = TRUE ), 
      selectInput(inputId = "selectedvariable1",
                  label = "Season", 
                  choices = c(unique(dataset_vars$seasonType)),selected = TRUE ), 
      selectInput(inputId = "selectedvariable2",
                  label = "Period", 
                  choices = c(unique(dataset_vars$dayNight)),selected = TRUE ),
      
      selectInput(inputId = "selectedvariable3",
                  label = "Final Runs", 
                  choices = c(unique(dataset_vars$homeFinalRuns)),selected = TRUE )      
    ),
    mainPanel(
      textOutput("idSaida"),
      fluidRow(
        splitLayout(plotOutput("myplot")))
    )
  )
)
server <- function(input, output)
  
  currentvariable0 <- reactive(input$selectedvariable0)
  currentvariable1 <- reactive(input$selectedvariable1)
  currentvariable2 <- reactive(input$selectedvariable2)
  currentvariable3 <- reactive(input$selectedvariable3)

  
  # # Selection of variables for plots constructions
   
  dataset_sel <- reactive( 
    var1 <- currentvariable0()
    var2 <- currentvariable3()
    sqlInput <- paste("SELECT",var1,"as year, 'REG' as seasonType,'N' as dayNight,",var2,"as homeFinalRuns FROM games_wide LIMIT 30")
    dbGetQuery(bq_con, sqlInput, stringsAsFactors = T))


  observe(
    if(currentvariable2()=="D")
      output$myplot <- renderPlot(

        #Create the plot
        ggplot(data=dataset_sel(), aes(x=year, y=homeFinalRuns)) +
          geom_bar(stat="identity")
      )
     else 
      #Create the plot
      ggplot(data=dataset_sel(), aes(x=year, y=homeFinalRuns)) +
        geom_bar(stat="identity")

    
  ) #end of observe function.

shinyApp(ui, server)
#