Rvest Problem On Shinyapps.io

[Gordon]

Hello,

My problem is a replica of this one. I have elements of a shiny app embedded in a flexdashboard markdown file along with some webscraping with rvest. Everything works fine locally, but when I published it to shinyapps.io it gives me the following error:

could not find function "xpath_element"

Which points to an rvest issue. Does anyone know how to fix or work around this? My logs.txt file is also attached.

[Tareef Kawaf]

Is it possible to share a small app that can reproduce the issue?  

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[Michael Grosskopf]

If you deploy the template Shiny app in RStudio but add the rvest package and a call to a function from it; for instance adding:

library(rvest)

tmp_html  <- read_html("http://stackoverflow.com/questions/tagged/shiny")

new_links <- tmp_html %>% html_nodes("a") %>% xml_attr("href")

to server.R, it will fail and the error logs show:

2016-07-30T00:23:46.131743+00:00 shinyapps[117519]: shiny version: 0.12.2
2016-07-30T00:23:46.308504+00:00 shinyapps[117519]: Starting R with process ID: '18'
2016-07-30T00:23:46.131747+00:00 shinyapps[117519]: rmarkdown version: NA
2016-07-30T00:23:46.131747+00:00 shinyapps[117519]: knitr version: NA
2016-07-30T00:23:46.131748+00:00 shinyapps[117519]: jsonlite version: 0.9.17
2016-07-30T00:23:46.131748+00:00 shinyapps[117519]: RJSONIO version: NA
2016-07-30T00:23:46.131748+00:00 shinyapps[117519]: htmltools version: 0.2.6
2016-07-30T00:23:46.305438+00:00 shinyapps[117519]: Using jsonlite for JSON processing
2016-07-30T00:23:46.312912+00:00 shinyapps[117519]: Listening on http://0.0.0.0:55910
2016-07-30T00:23:46.413075+00:00 shinyapps[117519]: Loading required package: xml2
2016-07-30T00:23:49.635010+00:00 shinyapps[117519]: Error in do.call(method, list(parsed_selector)) : 
2016-07-30T00:23:49.635015+00:00 shinyapps[117519]:   could not find function "xpath_element"

[Joshua Spiewak]

Perhaps updating to the latest versions of packages will help? I copied those three lines and saw no error:

2016-07-30T03:03:34.180570+00:00 shinyapps[88391]: shiny version: 0.13.2
2016-07-30T03:03:34.180573+00:00 shinyapps[88391]: rmarkdown version: NA
2016-07-30T03:03:34.180573+00:00 shinyapps[88391]: knitr version: NA
2016-07-30T03:03:34.180573+00:00 shinyapps[88391]: jsonlite version: 0.9.20
2016-07-30T03:03:34.180574+00:00 shinyapps[88391]: RJSONIO version: NA
2016-07-30T03:03:34.180574+00:00 shinyapps[88391]: htmltools version: 0.3.5
2016-07-30T03:03:34.331126+00:00 shinyapps[88391]: Using jsonlite for JSON processing
2016-07-30T03:03:34.336425+00:00 shinyapps[88391]:
2016-07-30T03:03:34.336427+00:00 shinyapps[88391]: Starting R with process ID: '17'
2016-07-30T03:03:34.352213+00:00 shinyapps[88391]:
2016-07-30T03:03:34.352216+00:00 shinyapps[88391]: Listening on http://0.0.0.0:52631
2016-07-30T03:03:37.300123+00:00 shinyapps[88391]: Loading required package: xml2

[Michael Grosskopf]

Updating the package and it's dependencies alone didn't work, but updating to R 3.3.1 and having updated all packages did. Thank you very much for the quick reply.

[Gordon]

Hi,

Sorry for the absence of a response. I fixed the problem by updating R and all the packages.