R Shiny: How to get a list of sheet names from an .xlsx file uploaded to a Shiny app using fileInput?

[Nil_07]

I have an .xlsx file with multiple sheets which I am uploading to my Shiny app using fileInput having id "file". My objective is to load a sheet using a string detect, that is if I have 3 sheets in random order names "apple", "orange" and "banana", I would like to load the "apple" sheet using string match from the list of sheets. So far I am not being able to get the list of sheets as I keep running into the error when I try to extract the sheet names using excel_sheets using readxl package-

Warning: Error in : `path` does not exist: ‘C:\Users\AppData\Local\Temp\Rtmp6dWPYS/0b16b05aa5a58cc1d1261369/0.xlsx’

The relevant server code is as follows -

    sheet_names <- reactive({
        if (!is.null(input$file)) {
            return(excel_sheets(path = input$file))
        } else {
            return(NULL)
        }
    })


apple_data <- reactive({
        req(input$file)
        inFile <- input$file
        if(is.null(inFile))
            return(NULL)
        file.rename(inFile$datapath,
                    paste(inFile$datapath, ".xlsx", sep=""))
        p<-read_excel(paste(inFile$datapath, ".xlsx", sep=""), 
    sheet = sheet_names( [str_detect(sheet_names(), regex("(apple)"))])
        

    })

After tweaking around with various functions, I eventually found a way to do it using openxlsx. Sharing the solution below -

wb<- reactive({
        req(input$file)
        inFile<- input$file
        wb<-loadWorkbook(paste(inFile$datapath, ".xlsx", sep=""))
    })
    sheetnames <- reactive({
        req(input$file)
        if (is.null(input$file)) 
            return(NULL)
        
        sheet_names<-wb()$sheet_names
        })

apple_data <- reactive({
        req(input$file)
        inFile <- input$file
        if(is.null(inFile))
            return(NULL)
        file.rename(inFile$datapath,
                    paste(inFile$datapath, ".xlsx", sep=""))
        p<-read_excel(paste(inFile$datapath, ".xlsx", sep=""), 
    sheet = sheet_names() [str_detect(sheet_names(), regex("(apple)"))]
  })