cell clicked works locally but not on remote shiny server --DT - ajax

Question

I have an application that listens for a cell click in a DT in any cell and then updates a plot accordingly. The program works perfectly when I runApp() locally. However when I depoloy the app on a shiny server, the click no longer triggers any actions. This discepancy does not exists for other action listeners such as a simple refresh button, as I have demonstrated in the code below. You can see how the discrepancy between remote and local does not exist for the refresh button condition input$refreshButton!=0, but there is a discrepancy using the length(input$table_cell_clicked)>0 trigger condition.
I have done some research into this error and this is what I know so far:
1) I am getting the warning "Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience." in the console when the app is deployed remotely. I am told this has something to do with a setting in a file in my shiny server called javascript.min.js and jquery.min.js that says c.async="false" I have searched for every file on my serer with that name or containing the string async="false", and changed the setting to sync="true". However I did not find any files with the exact string c.async="true". I can see the file with this string in the browser console, which gives a location relative to server::port/, but I do not know where that file actually lives on my system, and I suspect it is just a file made on the fly by shiny services.
2) It is possible that this could be fixed with something related to the selectize functionality in some shiny inputs, which may cause the code to execute asynchronously(?). I have tried a few different things but couldn't get any to solve the problem.
3) There is a commonly known annoyance with shiny that it is generally hard to debug. In my case, it would be extremely helpful if I could see the output of the server.R functions as I would when using runApp() locally. Using a call to browser, options(shiny.trace = T) were both recommended, but when I add them to the code below, nothing apprears in the console output. I even tried using sink in order to save to output to some file on the remote server, and it rusn without error, but I do not see any file in the location indicated. If I could at least see the output of this file, or the request/response messages between the server and the client it would go a long way towards debugging this.
So the two questions are: how can I see these messages/output when the app is deployed remotely? And more importantly, how can I implement a fix so that all of my hard work on this project (unfortunately can't disclose any details) will not be a waste.
The basic code for my shiny app is below.
server.R:
server <- function(input, output, session) {
options(shiny.trace = T)
browser()
sink("~/outputfile.txt",append = T,type = "output",split = T)
end_date=as.character(as.Date(Sys.Date()-10))
library(DT)
library(data.table)
library(xtable)
library(zoo)
library(lattice)
library(RSQLite)
output$table = DT::renderDataTable({
thisTable = head(iris)
return(thisTable)
},server = T,options = list(target = 'cell'))
output$plot1 <- renderPlot({
cell= as.numeric(input$table_cell_clicked)
print(cell)
row = as.numeric(input$transtable_row_last_clicked)
print(paste0("last row clicked: ",row))
print(paste0("timestamp: ",Sys.time()))
(cell, file = "/home/plintilhac/cell_file.txt") ## causes error that dumps SND and REC messages to javascript console
# if (length(input$row_last_clicked)>0){ ##works remotely and locally
# if (input$refreshButton!=0){ ##works remotely and locally
if (length(cell)>0){ #works locally, but doesn't work remotely
plot(0,0,xlim = c(-1,1),ylim = c(-1,1))
}
else{return(plot(0,1,xlim = c(-1,1),ylim = c(-1,1)))}}
)
output$text1 <- renderText({
if (input$refreshButton!=0){
"clicked"
}
else{"unclicked"}
})
}
ui.R
shinyUI(
fluidPage(
fluidRow(plotOutput("plot1",click = "plot_click"),theme = "bootstrap.css"),
mainPanel(
DT::dataTableOutput('table'),
fluidRow(
actionButton("refreshButton", "refresh")
)
)
))
EDIT:
I was able to get some output by placing an erroneous line of code right after the cell variable is defined, causing the shiny server to dump output to the javascript console. At this time this is the only way I know how to capture any output. However, the output is quite informative, as it shows that the table_cell_clicked attribute is not being exported on the remote server at all, whereas other attributes such as row_last_clicked are.
here is the output I get when the server is run locally ithout the erroneous line (note it includes table_cell_clicked as a feature):
SEND
{"config":{"workerId":"","sessionId":"ef292cd0c98baee4afa504aa8330b49e"}}
RECV
{"method":"init","data":{"refreshButton:shiny.action":0,".clientdata_output_plot1_width":873,".clientdata_output_plot1_height":400,".clientdata_output_plot1_hidden":false,".clientdata_output_table_hidden":false,".clientdata_pixelratio":1.100000023841858,".clientdata_url_protocol":"http:",".clientdata_url_hostname":"d2rm01",".clientdata_url_port":"8787",".clientdata_url_pathname":"/p/4944/",".clientdata_url_search":"",".clientdata_url_hash_initial":"",".clientdata_singletons":"",".clientdata_allowDataUriScheme":true}}
SEND
{"errors":[],"values":{"table":{"x":{"filter":"none","container":"<table
class=\"display\">\n <thead>\n <tr>\n <th> </th>\n
<th>Sepal.Length</th>\n <th>Sepal.Width</th>\n
<th>Petal.Length</th>\n <th>Petal.Width</th>\n
<th>Species</th>\n </tr>\n
</thead>\n</table>","options":{"target":"cell","selectize":true,"columnDefs":[{"className":"dt-right","targets":[1,2,3,4]},{"orderable":false,"targets":0}],"order":[],"autoWidth":false,"orderClasses":false,"ajax":{"url":"session/ef292cd0c98baee4afa504aa8330b49e/dataobj/table?w=","type":"POST","data":"function(d)
{\nd.search.caseInsensitive = true;\nd.escape = true;\nvar encodeAmp
= function(x) { x.value = x.value.replace(/&/g, \"%26\"); }\nencodeAmp(d.search);\n$.each(d.columns, function(i, v)
{encodeAmp(v.search);});\n}"},"serverSide":true,"processing":true},"selection":{"mode":"multiple","selected":null,"target":"row"}},"evals":["options.ajax.data"],"deps":[{"name":"datatables","version":"1.10.7","src":{"file":"/home/plintilhac/R/x86_64-pc-linux-gnu-library/3.2/DT/htmlwidgets/lib/datatables/js","href":"datatables-1.10.7"},"meta":null,"script":"jquery.dataTables.min.js","stylesheet":null,"head":null,"attachment":null},{"name":"datatables-default","version":"1.10.7","src":{"file":"/home/plintilhac/R/x86_64-pc-linux-gnu-library/3.2/DT/htmlwidgets/lib/datatables/css/default","href":"datatables-default-1.10.7"},"meta":null,"script":[],"stylesheet":["dataTables.extra.css","jquery.dataTables.min.css"],"head":null,"attachment":null}]},"plot1":{"src":"data:image/png;[base64
data]","width":873,"height":400,"coordmap":[{"domain":{"left":-1.08,"right":1.08,"bottom":-1.08,"top":1.08},"range":{"left":58.9093125,"right":842.8269375,"bottom":325.745454545455,"top":57.8909090909091},"log":{"x":null,"y":null},"mapping":{}}]}},"inputMessages":[]}
RECV
{"method":"update","data":{"table_rows_selected":[],"table_rows_current":[],"table_rows_all":[],"table_state":null,"table_search":"","table_cell_clicked":{}}}
SEND {"progress":{"type":"binding","message":{"id":"plot1"}}} SEND
{"errors":[],"values":{"plot1":{"src":"data:image/png;[base64
data]","width":873,"height":400,"coordmap":[{"domain":{"left":-1.08,"right":1.08,"bottom":-1.08,"top":1.08},"range":{"left":58.9093125,"right":842.8269375,"bottom":325.745454545455,"top":57.8909090909091},"log":{"x":null,"y":null},"mapping":{}}]}},"inputMessages":[]}
RECV
{"method":"update","data":{"table_rows_current":[1,2,3,4,5,6],"table_rows_all":[1,2,3,4,5,6]}}
RECV {"method":"update","data":{"plot_click":null}} RECV
{"method":"update","data":{"table_cell_clicked":{"row":1,"col":2,"value":3.5},"table_rows_selected":[1],"table_row_last_clicked":1}}
SEND {"progress":{"type":"binding","message":{"id":"plot1"}}} SEND
{"errors":[],"values":{"plot1":{"src":"data:image/png;[base64
data]","width":873,"height":400,"coordmap":[{"domain":{"left":-1.08,"right":1.08,"bottom":-1.08,"top":1.08},"range":{"left":58.9093125,"right":842.8269375,"bottom":325.745454545455,"top":57.8909090909091},"log":{"x":null,"y":null},"mapping":{}}]}},"inputMessages":[]}
RECV {"method":"update","data":{"table_rows_selected":[]}}
while this is the output when it is run remotely with the erroneous line (note table_cell_clicked is not being received):
Loading required package: DBI
SEND {"errors":[],"values":{"table":{"x":{"container":"<table class=\"display\">\n <thead>\n <tr>\n <th> </th>\n <th>Sepal.Length</th>\n <th>Sepal.Width</th>\n <th>Petal.Length</th>\n <th>Petal.Width</th>\n <th>Species</th>\n </tr>\n </thead>\n</table>","options":{"target":"cell","selectize":true,"columnDefs":[{"className":"dt-right","targets":[1,2,3,4]},{"orderable":false,"targets":0}],"order":[],"autoWidth":false,"orderClasses":false,"ajax":{"url":"session/07190712bb533d7cf1929522b19e436a/dataobj/table?w=","type":"POST","data":"function(d) {\nd.search.caseInsensitive = true;\nd.escape = true;\n}"},"serverSide":true,"processing":true},"callback":null,"filter":"none","selection":"multiple"},"evals":["options.ajax.data"],"deps":[{"name":"datatables","version":"1.10.7","src":{"file":"/usr/local/lib/R/site-library/DT/htmlwidgets/lib/datatables/js","href":"datatables-1.10.7"},"meta":null,"script":"jquery.dataTables.min.js","stylesheet":null,"head":null,"attachment":null},{"name":"datatables-default","version":"1.10.7","src":{"file":"/usr/local/lib/R/site-library/DT/htmlwidgets/lib/datatables/css/default","href":"datatables-default-1.10.7"},"meta":null,"script":[],"stylesheet":["dataTables.extra.css","jquery.dataTables.min.css"],"head":null,"attachment":null}]},"plot1":{"src":"data:image/png;[base64 data]","width":1745,"height":400,"coordmap":[{"domain":{"left":-1.08,"right":1.08,"bottom":-1.08,"top":1.08},"range":{"left":58.9062532569046,"right":1714.82850442939,"bottom":325.745454545455,"top":57.8909090909091},"log":{"x":null,"y":null},"mapping":{}}]}},"inputMessages":[]}
RECV {"method":"update","data":{"table_rows_selected":[],"table_rows_current":[],"table_rows_all":[],"table_state":null,"table_search":""}}
RECV {"method":"update","data":{"table_rows_current":["1","2","3","4","5","6"],"table_rows_all":["1","2","3","4","5","6"]}}
RECV {"method":"update","data":{"table_rows_selected":["3"],"table_row_last_clicked":"3"}}
RECV {"method":"update","data":{".clientdata_output_plot1_width":463}}
SEND {"progress":{"type":"binding","message":{"id":"plot1"}}}
SEND {"errors":[],"values":{"plot1":{"src":"data:image/png;[base64 data]","width":463,"height":400,"coordmap":[{"domain":{"left":-1.08,"right":1.08,"bottom":-1.08,"top":1.08},"range":{"left":58.9256188605108,"right":432.81858546169,"bottom":325.745454545455,"top":57.8909090909091},"log":{"x":null,"y":null},"mapping":{}}]}},"inputMessages":[]}
RECV {"method":"update","data":{"plot_click":null}}
SEND {"config":{"workerId":"","sessionId":"7b20c500ee810e198324a75b6512a353"}}
RECV {"method":"init","data":{"refreshButton:shiny.action":0,"ss-net-opt-websocket":true,"ss-net-opt-xdr-streaming":true,"ss-net-opt-xhr-streaming":true,"ss-net-opt-iframe-eventsource":true,"ss-net-opt-iframe-htmlfile":true,"ss-net-opt-xdr-polling":true,"ss-net-opt-xhr-polling":true,"ss-net-opt-iframe-xhr-polling":true,"ss-net-opt-jsonp-polling":true,".clientdata_output_plot1_width":463,".clientdata_output_plot1_height":400,".clientdata_output_plot1_hidden":false,".clientdata_output_table_hidden":false,".clientdata_pixelratio":1.100000023841858,".clientdata_url_protocol":"http:",".clientdata_url_hostname":"d2rm01",".clientdata_url_port":"3838",".clientdata_url_pathname":"/testFunnel/",".clientdata_url_search":"",".clientdata_url_hash_initial":"",".clientdata_singletons":"",".clientdata_allowDataUriScheme":true}}
Error in source(file, ..., keep.source = TRUE, encoding = checkEncoding(file)) :
/srv/shiny-server/testFunnel/server.R:38:10: unexpected ','
37: #print(paste0("timestamp: ",Sys.time()))
38: (cell,