Passing a Shiny input to R markdown via Shiny Server - r

Question

I am trying to build a Shiny App and host it on my company's Shiny server that takes an inputted stock code and uses it to pull data from our database and generate a series of graphs and tables in markdown(.md) or word(.doc) format. Ideally, I would have three files for this App: server, ui, and the r markdown template.
I currently have a working App that uses SWeave, but TeX files have issues rendering Chinese characters, so I would like to use RMD.
server.r:
library(knitr)
shinyServer(function(input, output) {
output$report = downloadHandler(
filename = 'myreport.pdf',
content = function(file) {
out = knit2pdf('input.Rnw', clean = TRUE)
file.rename(out, file) # move pdf to file for downloading
},
contentType = 'application/pdf'
)
})
ui.r:
library(shiny)
shinyUI(basicPage(
textInput('stockcode', 'Stock Code:', value = '600340.SH'),
downloadButton('report')
))
input.Rnw:
\documentclass{article}
\begin{document}
\SweaveOpts{concordance=TRUE}
<<initialize, echo = FALSE, results = 'hide'>>=
library(ggplot2); library(RJDBC); library(gridExtra)
Sys.setlocale("LC_CTYPE", "chinese")
o.drv <- JDBC("oracle.jdbc.OracleDriver", classPath="C:/Oracle/instantclient_11_2/ojdbc5.jar", " ")
o.con <- dbConnect(o.drv, "database_address", "database_user", "database_pw")
stockcode <- input$stockcode
x <- dbGetQuery(o.con, "some_query")
pointLinePlot <- function(df) {
plotdata <- gather(df, metric, measure, -reportDate)
ggplot() + geom_line(data = plotdata, aes(x = reportDate, y = measure, color = metric)) +
geom_point(data = plotdata, aes(x = reportDate, y = measure, color = metric)) +
theme(legend.position="bottom", legend.title = element_blank()) +
scale_color_manual(name = "", values = c("darkred", "darkgreen", "darkblue", "orange"),
breaks = unique(plotdata$metric), labels = unique(plotdata$metric))
}
data_1.1.1 <- data.frame(reportDate = x$REPORT_PERIOD,
net_assets_f = x$`TOT_ASSETS-TOT_LIAB` / 1E4,
monetary_cap_f = x$MONETARY_CAP / 1E4,
net_cash_f = (x$MONETARY_CAP - x$ST_BORROW) / 1E4)
p1 <- pointLinePlot(data_1.1.1)
#
\begin{figure}
\centering
<<fig = TRUE, echo = FALSE>>=
print(p1)
#
\caption{Here goes the caption.}
\label{fig:p1}
\end{figure}
\begin{figure}
\centering
<<fig = TRUE, echo = FALSE>>=
print(grid.table(data_1.1.1, rows = NULL))
#
\caption{Here goes the caption.}
\label{fig:p1}
\end{figure}
\end{document}
Is there any way to pass the an input from a Shiny App directly to RMD like I have in input.Rnw with SWeave (stockcode <- input$stockcode)?

Answer 1

You do not have to pass it to the Rmd file. When the Rmd is rendered, the variable input$stockcode is taken from the current environment just like it was with the Rnw version.
server.R
library(knitr)
library(rmarkdown)
shinyServer(function(input, output) {
output$report = downloadHandler(
filename = 'myreport.pdf',
content = function(file) {
out = render('outout.Rmd')
file.rename(out, file) # move pdf to file for downloading
},
contentType = NA
)
})
input.Rmd
---
title: "Output"
output: pdf_document
---
# Test
```{r}
print(input$stockcode)
```