running shiny from terminal

[Adrian Duşa]

Hi,

I would like to still be able to use R while running a shiny app.

I thought about running this shiny app from the terminal, using a command like this:

$ Rscript -e 'library(shiny); runApp("shinyapp/")'

Listening on http://127.0.0.1:3002

Error in AppWrapper$new : could not find function "loadMethod"

Calls: runApp -> startApp -> startServer -> $

Execution halted

Does anyone knows what this is?

Can I do something to overcome this?

Thanks,

Adrian

[Joe Cheng]

One of these two will work:

Rscript -e 'library(methods); shiny::runApp("shinyapp/", launch.browser=TRUE)'

or

R --slave --no-restore -e 'shiny::runApp("shinyapp/", launch.browser=TRUE)'

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[Adrian Duşa]

Sweet!
Thanks very much,
Adrian

--
Adrian Dusa
University of Bucharest
Romanian Social Data Archive
Soseaua Panduri nr.90
050663 Bucharest sector 5
Romania

[David Chudzicki]

I just ran into this. Thanks for the answer -- very helpful.

Does the necessity for the user to explicitly load `methods` indicate that there's a dependency on methods which isn't correctly expressed in the `shiny` package?

[Joe Cheng]

No, it's just what Rscript requires you to do. It's a well documented quirk of Rscript, it omits methods from the default package list for performance reasons. 

Sent from Outlook

[David]

Having to explicit load `methods` is a hassle for users (and confusing
to people who haven't encountered this before). I realize it's a quirk
of RScript, but I think it's a quirk that means package authors should
make the dependence on `methods` explicit.

Seems like it would be better to add `methods` to the "Depends: ..."
(e.g. like Hadley did for testthat in response to this issue:
https://github.com/hadley/testthat/issues/122).

According to this (http://r-pkgs.had.co.nz/description.html), adding
it to "Imports: ..." instead of "Depends: ..." should work for users
of R 3.2.0+.

--
David J. Chudzicki
http://davidchudzicki.com
dch...@gmail.com
(518) 366-7303

[Joe Cheng]

Fair enough!

https://github.com/rstudio/shiny/pull/840

[David]

Awesome, thanks!

[Yihui Xie]

The motivation of not loading the methods package was to save some
time when starting up R. Turns out the time saved is about 0.05
seconds, and this 0.05 seconds have wasted so many people countless
hours. Yeah, this thing has been confusing for several years. Depends
won't work for R CMD check because when you load a package (e.g.
shiny::column), the Depends packages will not be attached. It can also
be problematic when another package imports a function from shiny, and
methods in Depends will also be ignored.

According to your reference to Hadley's book, it seems the problem has
been fixed, but I do not see a NEWS item in R 3.2.0. If it has really
been fixed, they should have been shouting from the rooftops in the
NEWS!

Regards,
Yihui

[Ashutosh Singh]

Hey Joe,

I used the latest release of Shiny and created a server and UI in one file (test.R).  This works file in RStudio but I am not able to run this from the command line.

Would you have any thoughts on how to do this?

thanks
Ashu

[Adrian Dușa]

On Mon, Apr 24, 2017 at 10:54 PM, Ashutosh Singh <singh...@gmail.com> wrote:

Hey Joe,

I used the latest release of Shiny and created a server and UI in one file (test.R).  This works file in RStudio but I am not able to run this from the command line.

Hi,

But what exactly did you try and didn't work?

Did you use Rscript or R --slave ?

Adrian

--

Adrian Dusa
University of Bucharest
Romanian Social Data Archive

Soseaua Panduri nr. 90-92

[Ashutosh Singh]

Both 

Best

Ashu

[Ashutosh Singh]

I created a directory "D:\Documents\WQU\Courses\2 - Statistics\Assignments\Unit 1 CS" and in there, I have a file called app.R (attached).

Further, 'created a batch file called test.bat that had the following lines:

Rscript "D:/Documents/WQU/Courses/2 - Statistics/Assignments/run.R"

Would appreciate any help!

Thank you

-A

Ashutosh Singh, CFA
(917) 952 3388

[Adrian Dușa]

There are already two solutions given by Joe Cheng in this thread, if your didn't read it:

Rscript -e 'library(methods); shiny::runApp("shinyapp/", launch.browser=TRUE)'

or

R --slave --no-restore -e 'shiny::runApp("shinyapp/", launch.browser=TRUE)'

Please pay attention to the library(methods) required by Rscript, which you seem to prefer. I went for the second approach, and even got to create executable icons:

https://bookdown.org/dusadrian/QCAbook/QCApackage.html#creating-an-executable-icon

I hope this helps,

Adrian

[Ashutosh Singh]

On Mon, Apr 24, 2017 at 8:46 PM, Adrian Dușa <dusa....@unibuc.ro> wrote:

R --slave --no-restore -e 'shiny::runApp("shinyapp/", launch.browser=TRUE)'

Those are the two methods I tried from a DOS command prompt. The app.R file that contains the server and ui code is a sub-directory called "Unit 1 CS". 

Both commands give me an error:
Error: unexpected end of input

Execution halted

The two commands I tried were:

Rscript -e 'library(methods); shiny::runApp("Unit 1 CS/", launch.browser=TRUE)'

Or

R --slave --no-restore -e 'shiny::runApp("Unit 1 CS/", launch.browser=TRUE)'

[Joe Cheng]

I'd expect that to work (I do something like this every day on my Mac). Can you try it with a trivial app in app.R?

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[Otmane Jai]

Hi ,

I just ran into this. Thanks for the answer -- very helpful.

can we do the same thing but this time for stopping the App (assume we know which server and which port the app is running in) ?

I am using shiny on windows and run my app on my local computer.

My objective is to stop the App to update some data and then re-launch it. and Ia m looking for a way to do this automatically (thought about scheduling a script with rstudio)

thks vm

[Kyle Bachmayer]

I rearranged the syntax and was able to get it to run. Too bad about these small syntax things. Should be better standardized so that people don't get tripped up on things like this.

Rscript -e "library('methods');shiny::runApp('app_folder/', launch.browser=TRUE)"