Session {jrc} | R Documentation |
Session class
Description
Objects of this class handle all the incoming and outgoing messages for one active connection.
Please, avoid creating instances of this class manually. Each Session
object is created when
a WebSocket is opened and serves as a wrapper around it. A manually created object will not have
a WebSocket connection and thus are not functional.
All sessions are stored within an object of class App
and cannot exist and function without it.
One can manipulate a session directly, using its methods described below, via methods of the corresponding
App
object or the provided wrapper function (links to them can be found in the Methods section).
Fields
id
-
Automatically generated ID for this session. ID is a random combination of 6 letters or numbers. Please, do not change the value of this field.
lastActive
-
Time of the last received message from the session's WebSocket. The timestamp is generated by the
Sys.time
function. startTime
-
Time when this session has been started (generated by the
Sys.time
function).
Methods
getMessageIds()
-
Returns IDs of all currently stored messages. ID is a combination of 6 random letters and numbers generated when the message is stored. See also
getMessageIds
. authorize(messageId = NULL, show = FALSE)
-
Authorizes evaluation of a message. Check
authorize
for more information. removeMessage(messageId = NULL)
-
Removes a stored message. This can also be done with the
authorize
function (setshow = TRUE
and then select the “Ignore message” option). See alsoremoveMessage
. sendCommand(command, wait = 0)
-
Sends a JavaScript command to be evaluated on the web page. Check
sendCommand
for more information. callFunction(name, arguments = NULL, assignTo = NULL, wait = 0, thisArg = NULL, ...)
-
Calls an existing JavaScript function on the web page. Check
callFunction
for more information. sendData(variableName, variable, wait = 0, keepAsVector = FALSE, rowwise = TRUE)
-
Sends data and assigns it to a variable on the web page. Check
sendData
for more information. sendHTML(html, wait = 0)
-
Sends HTML code that will be appended to the web page. Check
sendHTML
for more information. sessionVariables(vars = NULL, varName = NULL, remove = NULL)
-
Sets or returns variables that are used (read or modified) only by this session. If both arguments are
NULL
, returns environment for this session. Ifvars
is a named list, adds this variables to the session environment. IfvarName
is a character, returns a variable with this name how it is seen from the session. If the variable doesn't exist, throws an error. Ifremove
is a vector of characters, removes variables with these names from the session environment. One can add variables to the session environment, get one back and remove variables with a single function call. ChecksetSessionVariables
,getSessionVariable
,removeSessionVariables
for more information. setLimits(limits)
-
Sets limits for memory usage, number of simultaneously active connections and amount of messages processed per second. For information about possible arguments, please, check
setLimits
. This method accepts all the same arguments, but they should be supplied in a form of list.
Note, that Session
class has some other public methods that are not mentioned in this list. These methods are
intended to be used only by other functions of jrc
package and therefore are not documented.