Clean up correctly after API caller leaves

This gives us more accurate data types (numbers as ints/reals instead of strings)

Also adds serveRaw (raw vectors)

NAMESPACE

@@ -2,18 +2,24 @@
 
 S3method("$",reactivevalues)
 S3method("$",session_proxy)
+S3method("$",shinyapi)
 S3method("$",shinyoutput)
 S3method("$<-",reactivevalues)
 S3method("$<-",session_proxy)
+S3method("$<-",shinyapi)
 S3method("$<-",shinyoutput)
 S3method("[",reactivevalues)
+S3method("[",shinyapi)
 S3method("[",shinyoutput)
 S3method("[<-",reactivevalues)
+S3method("[<-",shinyapi)
 S3method("[<-",shinyoutput)
 S3method("[[",reactivevalues)
 S3method("[[",session_proxy)
+S3method("[[",shinyapi)
 S3method("[[",shinyoutput)
 S3method("[[<-",reactivevalues)
+S3method("[[<-",shinyapi)
 S3method("[[<-",shinyoutput)
 S3method("names<-",reactivevalues)
 S3method(as.list,reactivevalues)
@@ -194,6 +200,11 @@ export(runUrl)
 export(safeError)
 export(selectInput)
 export(selectizeInput)
+export(serveCSV)
+export(serveJSON)
+export(servePlot)
+export(serveRaw)
+export(serveText)
 export(serverInfo)
 export(setBookmarkExclude)
 export(setProgress)
@@ -267,3 +278,4 @@ import(httpuv)
 import(methods)
 import(mime)
 import(xtable)
+importFrom(utils,write.csv)

NEWS.md

@@ -7,7 +7,7 @@ Here are some highlights from this release. For more details, see the full chang
 
 ## Support for testing Shiny applications
 
-Shiny now supports automated testing of applications, with the [shinytest](https://github.com/MangoTheCat/shinytest) package. Shinytest has not yet been released on CRAN, but will be soon. ([#18](https://github.com/rstudio/shiny/issues/18), [#1464](https://github.com/rstudio/shiny/pull/1464))
+Shiny now supports automated testing of applications, with the [shinytest](https://github.com/rstudio/shinytest) package. Shinytest has not yet been released on CRAN, but will be soon. ([#18](https://github.com/rstudio/shiny/issues/18), [#1464](https://github.com/rstudio/shiny/pull/1464))
 
 ## Debounce/throttle reactives
 

R/bookmark-state.R

@@ -342,26 +342,10 @@ RestoreContext <- R6Class("RestoreContext",
       }
 
 
-      inputs <- parseQueryString(inputStr, nested = TRUE)
-      values <- parseQueryString(valueStr, nested = TRUE)
+      inputs <- parseQueryStringJSON(inputStr, nested = TRUE)
+      values <- parseQueryStringJSON(valueStr, nested = TRUE)
 
-      valuesFromJSON <- function(vals) {
-        mapply(names(vals), vals, SIMPLIFY = FALSE,
-          FUN = function(name, value) {
-            tryCatch(
-              jsonlite::fromJSON(value),
-              error = function(e) {
-                stop("Failed to parse URL parameter \"", name, "\"")
-              }
-            )
-          }
-        )
-      }
-
-      inputs <- valuesFromJSON(inputs)
       self$input <- RestoreInputSet$new(inputs)
-
-      values <- valuesFromJSON(values)
       self$values <- list2env2(values, self$values)
     }
   )

R/middleware-shiny.R

@@ -41,3 +41,229 @@ sessionHandler <- function(req) {
     shinysession$handleRequest(subreq)
   })
 }
+
+apiHandler <- function(serverFuncSource) {
+  function(req) {
+    path <- req$PATH_INFO
+    if (is.null(path))
+      return(NULL)
+
+    matches <- regmatches(path, regexec('^/api/(.*)$', path))
+    if (length(matches[[1]]) == 0)
+      return(NULL)
+
+    apiName <- matches[[1]][2]
+
+    sharedSecret <- getOption('shiny.sharedSecret')
+    if (!is.null(sharedSecret)
+      && !identical(sharedSecret, req$HTTP_SHINY_SHARED_SECRET)) {
+      stop("Incorrect shared secret")
+    }
+
+    if (!is.null(getOption("shiny.observer.error", NULL))) {
+      warning(
+        call. = FALSE,
+        "options(shiny.observer.error) is no longer supported; please unset it!"
+      )
+      stopApp()
+    }
+
+    # need to give a fake websocket to the session
+    ws <- list(
+      request = req,
+      sendMessage = function(...) {
+        #print(list(...))
+      }
+    )
+
+    # Accept JSON query string and/or JSON body as input values
+    inputVals <- c(
+      parseQueryStringJSON(req$QUERY_STRING),
+      parseJSONBody(req)
+    )
+
+    shinysession <- ShinySession$new(ws)
+    on.exit({
+      try({
+        # Clean up the session. Very important, so that observers
+        # and such don't hang around, and to let memory get gc'd.
+        shinysession$wsClosed()
+        appsByToken$remove(shinysession$token)
+      })
+    }, add = TRUE)
+    appsByToken$set(shinysession$token, shinysession)
+    shinysession$setShowcase(.globals$showcaseDefault)
+
+    serverFunc <- withReactiveDomain(NULL, serverFuncSource())
+
+    tryCatch({
+      withReactiveDomain(shinysession, {
+        shinysession$manageInputs(inputVals)
+        do.call(serverFunc, argsForServerFunc(serverFunc, shinysession))
+        result <- NULL
+        shinysession$enableApi(apiName, function(value) {
+          result <<- try(withLogErrors(value), silent = TRUE)
+        })
+        flushReact()
+        resultToResponse(result)
+      })
+    }, error = function(e) {
+      return(httpResponse(
+        status=500,
+        content=htmlEscape(conditionMessage(e))
+      ))
+    })
+  }
+}
+
+apiWsHandler <- function(serverFuncSource) {
+  function(ws) {
+    path <- ws$request$PATH_INFO
+    if (is.null(path))
+      return(NULL)
+
+    matches <- regmatches(path, regexec('^/api/(.*)$', path))
+    if (length(matches[[1]]) == 0)
+      return(NULL)
+
+    apiName <- matches[[1]][2]
+
+    sharedSecret <- getOption('shiny.sharedSecret')
+    if (!is.null(sharedSecret)
+      && !identical(sharedSecret, ws$request$HTTP_SHINY_SHARED_SECRET)) {
+      ws$close()
+      return(TRUE)
+    }
+
+    if (!is.null(getOption("shiny.observer.error", NULL))) {
+      warning(
+        call. = FALSE,
+        "options(shiny.observer.error) is no longer supported; please unset it!"
+      )
+      stopApp()
+    }
+
+    inputVals <- parseQueryStringJSON(ws$request$QUERY_STRING)
+
+    # Give a fake websocket to suppress messages from session
+    shinysession <- ShinySession$new(list(
+      request = ws$request,
+      sendMessage = function(...) {
+        #print(list(...))
+      }
+    ))
+    appsByToken$set(shinysession$token, shinysession)
+    shinysession$setShowcase(.globals$showcaseDefault)
+
+    serverFunc <- withReactiveDomain(NULL, serverFuncSource())
+
+    tryCatch({
+      withReactiveDomain(shinysession, {
+        shinysession$manageInputs(inputVals)
+        do.call(serverFunc, argsForServerFunc(serverFunc, shinysession))
+        shinysession$enableApi(apiName, function(value) {
+          resp <- resultToResponse(value)
+          if (resp$status != 200L) {
+            warning("Error: ", responseToContent(resp))
+            ws$close()
+          } else {
+            content <- responseToContent(resp)
+            if (grepl("^image/", resp$content_type)) {
+              content <- paste0("data:", resp$content_type, ";base64,",
+                httpuv::rawToBase64(content))
+            }
+            try(ws$send(content), silent=TRUE)
+          }
+        })
+        flushReact()
+      })
+    }, error = function(e) {
+      ws$close()
+    })
+
+    ws$onClose(function() {
+      # Clean up the session. Very important, so that observers
+      # and such don't hang around, and to let memory get gc'd.
+      shinysession$wsClosed()
+      appsByToken$remove(shinysession$token)
+    })
+
+    # TODO: What to do on ws$onMessage?
+  }
+}
+
+parseJSONBody <- function(req) {
+  if (identical(req[["REQUEST_METHOD"]], "POST")) {
+    if (isTRUE(grepl(perl=TRUE, "^(text|application)/json(;\\s*charset\\s*=\\s*utf-8)?$", req[["HTTP_CONTENT_TYPE"]]))) {
+      tmp <- file("", "w+b")
+      on.exit(close(tmp))
+
+      input_file <- req[["rook.input"]]
+      while (TRUE) {
+        chunk <- input_file$read(8192L)
+        if (length(chunk) == 0)
+          break
+        writeBin(chunk, tmp)
+      }
+
+      return(jsonlite::fromJSON(tmp))
+    }
+
+    if (is.null(req[["HTTP_CONTENT_TYPE"]])) {
+      if (!is.null(req[["rook.input"]]) && length(req[["rook.input"]]$read(1L)) > 0) {
+        stop("Invalid POST request (body provided without content type)")
+      }
+      return()
+    }
+
+    stop("Invalid POST request (content type not supported)")
+  }
+}
+
+resultToResponse <- function(result) {
+  if (inherits(result, "httpResponse")) {
+    return(result)
+  } else if (inherits(result, "try-error")) {
+    return(httpResponse(
+      status=500,
+      content_type="text/plain",
+      content=conditionMessage(attr(result, "condition"))
+    ))
+  } else if (!is.null(attr(result, "content.type"))) {
+    return(httpResponse(
+      status=200L,
+      content_type=attr(result, "content.type"),
+      content=result
+    ))
+  } else {
+    return(httpResponse(
+      status=200L,
+      content_type="application/json",
+      content=toJSON(result, pretty=TRUE)
+    ))
+  }
+}
+
+responseToContent <- function(result) {
+  ct <- result$content_type
+  textMode <- grepl("^text/", ct) || ct == "application/json" ||
+    grepl("^application/xml($|\\+)", ct)
+
+  # TODO: Make sure text is UTF-8
+
+  if ("file" %in% names(result$content)) {
+    filename <- result$content$file
+    if ("owned" %in% names(result$content) && result$content$owned) {
+      on.exit(unlink(filename), add = TRUE)
+    }
+    if (textMode)
+      return(paste(readLines(filename), collapse = "\n"))
+    else
+      return(readBin(filename, raw(), file.info(filename)$size))
+  } else {
+    if (textMode)
+      return(paste(result$content, collapse = "\n"))
+    else
+      return(result$content)
+  }
+}

R/server.R

@@ -189,6 +189,7 @@ createAppHandlers <- function(httpHandlers, serverFuncSource) {
   appHandlers <- list(
     http = joinHandlers(c(
       sessionHandler,
+      apiHandler(serverFuncSource),
       httpHandlers,
       sys.www.root,
       resourcePathHandler,
@@ -200,6 +201,11 @@ createAppHandlers <- function(httpHandlers, serverFuncSource) {
         return(TRUE)
       }
 
+      if (grepl("^/api/", ws$request$PATH_INFO)) {
+        apiWsHandler(serverFuncSource)(ws)
+        return(TRUE)
+      }
+
       if (!is.null(getOption("shiny.observer.error", NULL))) {
         warning(
           call. = FALSE,

R/shiny.R

@@ -405,6 +405,7 @@ ShinySession <- R6Class(
     fileUploadContext = 'FileUploadContext',
     .input      = 'ANY', # Internal ReactiveValues object for normal input sent from client
     .clientData = 'ANY', # Internal ReactiveValues object for other data sent from the client
+    apiObservers = list(),
     busyCount = 0L, # Number of observer callbacks that are pending. When 0, we are idle
     closedCallbacks = 'Callbacks',
     flushCallbacks = 'Callbacks',
@@ -689,6 +690,7 @@ ShinySession <- R6Class(
     progressStack = 'Stack', # Stack of progress objects
     input       = 'reactivevalues', # Externally-usable S3 wrapper object for .input
     output      = 'ANY',    # Externally-usable S3 wrapper object for .outputs
+    api         = 'ANY',    # Externally-usable S3 wrapper object for APIs
     clientData  = 'reactivevalues', # Externally-usable S3 wrapper object for .clientData
     token = 'character',  # Used to identify this instance in URLs
     files = 'Map',        # For keeping track of files sent to client
@@ -725,6 +727,7 @@ ShinySession <- R6Class(
       .setLabel(self$clientData, 'clientData')
 
       self$output <- .createOutputWriter(self)
+      self$api <- .createApiWriter(self)
 
       self$token <- createUniqueId(16)
       private$.outputs <- list()
@@ -1632,6 +1635,19 @@ ShinySession <- R6Class(
                      workerId(),
                      URLencode(createUniqueId(8), TRUE)))
     },
+    registerApi = function(name, func) {
+      private$apiObservers[[name]] <- func
+    },
+    enableApi = function(name, callback) {
+      rexpr <- private$apiObservers[[name]]
+      if (is.null(rexpr)) {
+        stop("API not found")
+      }
+
+      observe({
+        callback(..stacktraceon..(rexpr()))
+      }, ..stacktraceon = FALSE)
+    },
     # This function suspends observers for hidden outputs and resumes observers
     # for un-hidden outputs.
     manageHiddenOutputs = function() {
@@ -1809,7 +1825,6 @@ outputOptions <- function(x, name, ...) {
   .subset2(x, 'impl')$outputOptions(name, ...)
 }
 
-
 #' Add callbacks for Shiny session events
 #'
 #' These functions are for registering callbacks on Shiny session events.
@@ -1865,3 +1880,47 @@ flushAllSessions <- function() {
     NULL
   })
 }
+
+.createApiWriter <- function(shinysession, ns = identity) {
+  structure(list(impl=shinysession, ns=ns), class='shinyapi')
+}
+
+#' @export
+`$<-.shinyapi` <- function(x, name, value) {
+  name <- .subset2(x, 'ns')(name)
+
+  label <- deparse(substitute(value))
+  if (length(substitute(value)) > 1) {
+    # value is an object consisting of a call and its arguments. Here we want
+    # to find the source references for the first argument (if there are
+    # arguments), which generally corresponds to the reactive expression--
+    # e.g. in renderTable({ x }), { x } is the expression to trace.
+    attr(label, "srcref") <- srcrefFromShinyCall(substitute(value)[[2]])
+    srcref <- attr(substitute(value)[[2]], "srcref")
+    if (length(srcref) > 0)
+      attr(label, "srcfile") <- srcFileOfRef(srcref[[1]])
+  }
+  .subset2(x, 'impl')$registerApi(name, value)
+  return(invisible(x))
+}
+
+#' @export
+`[[<-.shinyapi` <- `$<-.shinyapi`
+
+#' @export
+`$.shinyapi` <- function(x, name) {
+  stop("Reading objects from shinyapi object not allowed.")
+}
+
+#' @export
+`[[.shinyapi` <- `$.shinyapi`
+
+#' @export
+`[.shinyapi` <- function(values, name) {
+  stop("Single-bracket indexing of shinyapi object is not allowed.")
+}
+
+#' @export
+`[<-.shinyapi` <- function(values, name, value) {
+  stop("Single-bracket indexing of shinyapi object is not allowed.")
+}

R/shinywrappers.R

@@ -354,6 +354,98 @@ renderUI <- function(expr, env=parent.frame(), quoted=FALSE,
   markRenderFunction(uiOutput, renderFunc, outputArgs = outputArgs)
 }
 
+#' @export
+serveJSON <- function(expr, env=parent.frame(), quoted=FALSE) {
+  installExprFunction(expr, "func", env, quoted)
+  function() {
+    structure(
+      toJSON(func(), pretty = TRUE),
+      content.type = "application/json"
+    )
+  }
+}
+
+#' @export
+servePlot <- function(expr, env=parent.frame(), quoted=FALSE,
+  defaultWidth = 600, defaultHeight = 400) {
+
+  if (!is.function(defaultWidth))
+    defaultWidth <- valueToFunc(defaultWidth)
+  if (!is.function(defaultHeight))
+    defaultHeight <- valueToFunc(defaultHeight)
+
+  installExprFunction(expr, "func", env, quoted)
+  function() {
+    input <- getDefaultReactiveDomain()$input
+    w <- if (!is.null(input$`plot-width`)) as.numeric(input$`plot-width`) else defaultWidth()
+    h <- if (!is.null(input$`plot-height`)) as.numeric(input$`plot-height`) else defaultHeight()
+
+    pngfile <- plotPNG(function() {
+      result <- withVisible(func())
+      if (result$visible) {
+        # Use capture.output to squelch printing to the actual console; we
+        # are only interested in plot output
+        utils::capture.output({
+          # The value needs to be printed just in case it's an object that
+          # requires printing to generate plot output, similar to ggplot2. But
+          # for base graphics, it would already have been rendered when func was
+          # called above, and the print should have no effect.
+          print(result$value)
+        })
+      }
+    }, width = w, height = h)
+
+    structure(
+      list(file = pngfile, owned = TRUE),
+      content.type = "image/png"
+    )
+  }
+}
+
+#' @importFrom utils write.csv
+#' @export
+serveCSV <- function(expr, env=parent.frame(), quoted=FALSE, row.names=FALSE) {
+  installExprFunction(expr, "func", env, quoted)
+  function() {
+    tmp <- tempfile(".csv")
+    write.csv(func(), tmp, row.names=row.names)
+    structure(
+      list(file = tmp, owned = TRUE),
+      content.type = "text/csv"
+    )
+  }
+}
+
+#' @export
+serveText <- function(expr, env=parent.frame(), quoted=FALSE) {
+  installExprFunction(expr, "func", env, quoted)
+  function() {
+    structure(
+      paste(func(), collapse = "\n"),
+      content.type = "text/plain"
+    )
+  }
+}
+
+#' @export
+serveRaw <- function(expr, env=parent.frame(), quoted=FALSE, contentType) {
+
+  if (!is.function(contentType))
+    contentType <- valueToFunc(contentType)
+
+  installExprFunction(expr, "func", env, quoted)
+  function() {
+    bytes <- func()
+    if (!is.raw(bytes)) {
+      stop("serveRaw expects raw vector data")
+    }
+    structure(
+      bytes,
+      content.type = contentType()
+    )
+  }
+}
+
 #' File Downloads
 #'
 #' Allows content from the Shiny application to be made available to the user as

R/utils.R

@@ -576,6 +576,20 @@ parseQueryString <- function(str, nested = FALSE) {
   res
 }
 
+parseQueryStringJSON <- function(str, nested = FALSE) {
+  vals <- parseQueryString(str, nested)
+  mapply(names(vals), vals, SIMPLIFY = FALSE,
+    FUN = function(name, value) {
+      tryCatch(
+        jsonlite::fromJSON(value),
+        error = function(e) {
+          stop("Failed to parse URL parameter \"", name, "\"")
+        }
+      )
+    }
+  )
+}
+
 # Assign value to the bottom element of the list x using recursive indices idx
 assignNestedList <- function(x = list(), idx, value) {
   for (i in seq_along(idx)) {
@@ -1585,3 +1599,9 @@ Mutable <- R6Class("Mutable",
     get = function() { private$value }
   )
 )
+
+# Turn a value into a no-arg function that returns that value
+valueToFunc <- function(val) {
+  force(val)
+  function() val
+}