Read values in dropdown menu element with RSelenium

Question

I am using RSelenium to navigate to sites and interact with the elements.

Question: using RSelenium, how can I read the list of options in a dropdown menu so that I can identify the latest month available and use that to set the dropdown to the correct value?

On a certain site a dropdown menu is provided for the user to set the month of the year, thus defining the end point of a date range used in turn to display or download monthly data. As additional months of data become available through the year, the options in the dropdown change.

By the end of July the dropdown will have 6 options, January to June. Note that the data for a particular month is released about 4-6 weeks after the end of that month, so you do not get June's data until late July, and so on. I can set the values using numbers 1 to 12 without any problems, provided that the dropdown actually contains the corresponding option.

If, for example, the data for July has not yet been published (that is, if July has not yet appeared in the dropdown list of options) and if I try to set the dropdown to '7' I will get an error, which I want to avoid. The data does not appear on a regular schedule, so I cannot simply assume that the data for month X will appear on date Y.

I believe that with Selenium itself there is a helper class available, but I'm not sure whether I can access that through RSelenium.

Example code follows - may be a bit ropey as I'm still far from familiar with the package.

library(RSelenium)
RSelenium::checkForServer()
RSelenium::startServer()

remDr <- remoteDriver(remoteServerAddr = "localhost",
                      port = 4444,
                      browserName = "firefox"
                      )
remDr <- remoteDriver()
Sys.sleep(5)
remDr$open()
remDr$getStatus()

remDr$navigate("http://jamaserv.jama.or.jp/newdb/eng/index.html")

## Switch to left frame
frameElems <- remDr$findElements(using = "tag name", "frame")
sapply(frameElems, function(x){x$getElementAttribute("src")})
remDr$switchToFrame(frameElems[[1]])

webElem <- remDr$findElement(using = 'xpath', "//select[@name='txtTargetToMm']")

## Use javascript to set values
script <- paste0("arguments[0].value = '", 2, "'; arguments[0].onchange();") # set to February
remDr$executeScript(script, list(webElem))
webElem$getElementAttribute('value')    # check to see if it worked

Sometimes I like to pull the curl request directly from the development console and just wrap it in system. It's not pretty, but it almost always works. Open the console, switch to the network tab, perform your action, right click on element with your data, Copy as curl. — Brandon Bertelsen
– Brandon Bertelsen, Commented Jul 24, 2015 at 17:56

jdharrison · Accepted Answer · 2017-02-23 13:32:11Z

6

You can use the selectTag method to interact with HTML select elements:

library(RSelenium)

rD <- rsDriver(verbose = F)
remDr <- rD$client
remDr$navigate("http://jamaserv.jama.or.jp/newdb/eng/index.html")

## Switch to left frame
frameElems <- remDr$findElements(using = "tag name", "frame")
sapply(frameElems, function(x){x$getElementAttribute("src")})
remDr$switchToFrame(frameElems[[1]])

webElem <- remDr$findElement(using = 'xpath', "//select[@name='txtTargetToMm']")
opts <- webElem$selectTag()

> opts$text
[1] "JANUARY"   "FEBRUARY"  "MARCH"     "APRIL"     "MAY"       "JUNE"      "JULY"      "AUGUST"   
[9] "SEPTEMBER" "OCTOBER"   "NOVEMBER"  "DECEMBER" 
> opts$value
[1] "1"  "2"  "3"  "4"  "5"  "6"  "7"  "8"  "9"  "10" "11" "12"
> opts$selected
[1] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE  TRUE

# select the third month (march)
opts$elements[[3]]$clickElement()

# check whether it is selected
opts <- webElem$selectTag()
opts$selected

> opts$selected
[1] FALSE FALSE  TRUE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE

rm(rD)
gc()

answered Feb 23, 2017 at 13:32

jdharrison

30.5k4 gold badges83 silver badges91 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Til Hund Over a year ago

If I try to run your code, but I get an error Error: attempt to apply non-function when trying to execute opts$elements[[3]]$clickElement().

Collectives™ on Stack Overflow

Read values in dropdown menu element with RSelenium

1 Answer 1

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related