App {jrc}

App class

Description

Object of this class represents the entire jrc-based app. It stores all the active connections, client-specific variables and all the global app settings.

You can create interactive apps by initializing new instances of this class and manage the apps with the methods that are described below. There are no limitations on the number of apps that can run simultaneously in one R session.

A wrapper function is also exported for almost each method (see links in the Methods section). This functions allow you to gain full control over the app without ever dealing with this class. However, in this case only a single app can run per R session. Attempt to create a new app (with openPage function) will force the existing one (if any) to stop. You can always get the App object for the currently running app with getPage function.

Methods

new(rootDirectory = NULL, startPage = NULL, onStart = NULL, onClose = NULL, connectionNumber = Inf, allowedFunctions = c(), allowedVariables = c(), sessionVars = NULL)

Creates a new instance of class App. Check openPage man page for information about arguments.

startServer(port = NULL)

Starts a local server that listens to a given port. If port = NULL, picks a random available port. See also openPage.

stopServer()

Closes all active sessions and stops a running server. See also closePage.

openPage(useViewer = TRUE, browser = NULL)

Opens a new web page either in a browser, or in the R Studio viewer. If useViewer = FALSE and browser is not selected, a default installed browser is used. If browser is specified, useViewer is ignored. This method returns a new Session object, which should correspond to the page that has been just opened. However, if someone would start a new connection at the moment when openPage method is called, it may return a wrong session. See also openPage.

getSession(sessionId = NULL)

Returns a session with the given ID or NULL if session with this ID doesn't exist. If sessionId = NULL and there is only one active session, returns it. See also getSession.

closeSession(sessionId = NULL, inactive = NULL, old = NULL)

Closes WebSocket connection of one or multiple sessions and removes all the related data from the app. For more information on the arguments, please, check closeSession man page.

getSessionIds()

Returns IDs of all currently active sessions. See also getSessionIds.

setEnvironment(envir)

Specifies the outer environment of the app, in which all the messages from the web pages will be evaluated. For more information, please, check setEnvironment.

allowFunctions(funs = NULL)

Adds function names to a list of allowed R functions. These functions can be called from a web page without authorization on the R side. If funs = NULL, returns a list of all currently allowed functions. For more information, please, check allowFunctions.

allowVariables(vars = NULL)

Adds variable names to the list of allowed variables. These variables can be changed from a web page without authorization on the R side. If vars = NULL, then returns a vector of names of all currently allowed variables. For more information, please, check allowVariables.

allowDirectories(dir = NULL)

Allows app to serve files from an existing directory. Files from the rootDirectory can always be accessed by the app. By default, the current working directory is added to the list of the allowed directories, when the app is initialized. All the subdirectories of the allowed directories can also be accessed. Attempt to request file from outside allowed directory will produce 403 Forbidden error. If dirs = NULL, then returns a vector of names of all currently allowed directories. Also see allowDirectories.

startPage(path = NULL)

Sets path to a starting web page of the app. Path can be full, relative to the app's root directory or relative to the current R working directory. If path = NULL, returns current path to the starting page.

rootDirectory(path = NULL)

Sets path to the root directory for the server. Any file, requested by the server, will be looked for in this directory. Can be a full path or a path relative to the current R working directory. If path = NULL, returns path to the current root directory.

setLimits(...)

Sets limits for memory usage, number of simultaneously active connections and amount of messages processed per second. These settings will apply for each new connection. To change memory usage for an existing session use method setLimits of class Session. For information about possible arguments, please, check setLimits.

getPort()

Returns number of the port which the running server listens to. After the app has been initialized, the port number cannot be changed.