`curl` package not installed, falling back to using `url()`

[Kevin_Sturm]

I want to deploy my shiny app on shinyapps.io. However, I get warnings, when I get to the following step while deploying my app:

Uploading bundle for application: 2485509...Warning in FUN(X[[i]], ...) :
  Unable to find repository URL for package nlme

The deployment keeps going anyways. But when completed shinyapps prompts the following message, when loading the app in a new tab:
ERROR: An error has occurred. Check your logs or contact the app author for clarification.

When I check the logs, the only obvious issue is the following package warning: "curl package not installed, falling back to using url()"

2020-06-21T19:00:26.233382+00:00 shinyapps[2485472]: 
2020-06-21T19:00:26.402608+00:00 shinyapps[2485472]:     col_factor
2020-06-21T19:00:26.461294+00:00 shinyapps[2485472]: 
2020-06-21T19:00:26.233382+00:00 shinyapps[2485472]:     intersect, setdiff, setequal, union
2020-06-21T19:00:26.402608+00:00 shinyapps[2485472]: 
2020-06-21T19:00:26.461296+00:00 shinyapps[2485472]: Attaching package: ‘zoo’
2020-06-21T19:00:26.462576+00:00 shinyapps[2485472]: `curl` package not installed, falling back to using `url()`
2020-06-21T19:00:26.461297+00:00 shinyapps[2485472]: 
2020-06-21T19:00:26.461626+00:00 shinyapps[2485472]: The following objects are masked from ‘package:base’:
2020-06-21T19:00:26.461627+00:00 shinyapps[2485472]: 
2020-06-21T19:00:26.461628+00:00 shinyapps[2485472]:     as.Date, as.Date.numeric
2020-06-21T19:00:26.461628+00:00 shinyapps[2485472]: 
2020-06-21T19:00:26.684613+00:00 shinyapps[2485472]: )
2020-06-21T19:00:26.684819+00:00 shinyapps[2485472]: See spec(...) for full column specifications.
2020-06-21T19:00:26.688904+00:00 shinyapps[2485472]: `curl` package not installed, falling back to using `url()`
2020-06-21T19:00:26.684608+00:00 shinyapps[2485472]: Parsed with column specification:
2020-06-21T19:00:26.684611+00:00 shinyapps[2485472]: cols(
2020-06-21T19:00:26.684612+00:00 shinyapps[2485472]:   .default = col_double(),
2020-06-21T19:00:26.684612+00:00 shinyapps[2485472]:   `Province/State` = col_character(),
2020-06-21T19:00:26.684612+00:00 shinyapps[2485472]:   `Country/Region` = col_character()
2020-06-21T19:00:26.852165+00:00 shinyapps[2485472]: Parsed with column specification:
2020-06-21T19:00:26.852168+00:00 shinyapps[2485472]:   .default = col_double(),
2020-06-21T19:00:26.852168+00:00 shinyapps[2485472]:   `Province/State` = col_character(),
2020-06-21T19:00:26.852169+00:00 shinyapps[2485472]:   `Country/Region` = col_character()
2020-06-21T19:00:26.852169+00:00 shinyapps[2485472]: )
2020-06-21T19:00:26.852167+00:00 shinyapps[2485472]: cols(
2020-06-21T19:00:26.852325+00:00 shinyapps[2485472]: See spec(...) for full column specifications.
2020-06-21T19:00:26.858643+00:00 shinyapps[2485472]: `curl` package not installed, falling back to using `url()`
2020-06-21T19:00:27.026641+00:00 shinyapps[2485472]: Parsed with column specification:
2020-06-21T19:00:27.026642+00:00 shinyapps[2485472]: cols(
2020-06-21T19:00:27.026644+00:00 shinyapps[2485472]:   .default = col_double(),
2020-06-21T19:00:27.026644+00:00 shinyapps[2485472]:   `Province/State` = col_character(),
2020-06-21T19:00:27.026644+00:00 shinyapps[2485472]:   `Country/Region` = col_character()
2020-06-21T19:00:27.026645+00:00 shinyapps[2485472]: )
2020-06-21T19:00:27.026851+00:00 shinyapps[2485472]: See spec(...) for full column specifications.
2020-06-21T19:00:27.096637+00:00 shinyapps[2485472]: Warning: Error in ..stacktraceon..: object 'df_country_t' not found
2020-06-21T19:00:27.099948+00:00 shinyapps[2485472]: Stack trace (innermost first):
2020-06-21T19:00:27.099949+00:00 shinyapps[2485472]:     13: runApp
2020-06-21T19:00:27.099950+00:00 shinyapps[2485472]:     12: fn
2020-06-21T19:00:27.099951+00:00 shinyapps[2485472]:     10: tryCatchOne
2020-06-21T19:00:27.099951+00:00 shinyapps[2485472]:      9: tryCatchList
2020-06-21T19:00:27.099950+00:00 shinyapps[2485472]:     11: doTryCatch
2020-06-21T19:00:27.099951+00:00 shinyapps[2485472]:      8: tryCatch
2020-06-21T19:00:27.099952+00:00 shinyapps[2485472]:      7: connect$retry
2020-06-21T19:00:27.099952+00:00 shinyapps[2485472]:      6: eval
2020-06-21T19:00:27.099952+00:00 shinyapps[2485472]:      5: eval
2020-06-21T19:00:27.099953+00:00 shinyapps[2485472]:      2: eval.parent
2020-06-21T19:00:27.099953+00:00 shinyapps[2485472]:      4: eval
2020-06-21T19:00:27.099953+00:00 shinyapps[2485472]:      3: eval
2020-06-21T19:00:27.099954+00:00 shinyapps[2485472]:      1: local
2020-06-21T19:00:27.100201+00:00 shinyapps[2485472]: Error : An error has occurred. Check your logs or contact the app author for clarification.

You shall find the app here: https://sabaidee.shinyapps.io/covid-19_shinyapp/

I would be glad, if anybody can give me a hint to solve that issue.

[HanOostdijk]

The curl message is a warning, but there is a complaint (error):
object 'df_country_t' not found.

Disclaimer: I have still to start with my first Shiny project.

[Kevin_Sturm]

Thank you HanOostdijk for reacting on my topic. I also thought that a warning shouldn't stop the app from beeing functional on shinyapps.io. I also recognized that the object df_country_t is, for whatever reason, not found. I don't get this error when I run the app locally. Is there anything what runs differently on the server than on my local pc?

[andresrcs]

We don't have enough information to help you out, Could you check what your app's logs say?

Can you show the code for your app? or even better can you provide a reproducible example (reprex) illustrating your issue? Please have a look at this resources, to see how to create one for a shiny app

Chapter 5 Workflow | Mastering Shiny

Shiny debugging and reprex guide

Shiny issues can be challenging to resolve relative to other problems with your code or statistical methods. Shiny apps are often large, complex projects with interacting files. When seeking help from others it is considered polite to: First, do your best to work through RStudio's debugging tools to diagnose your issue on your own. Often those shiny logs and tracebacks are useful to others trying to help out. Second, strive to minimize the effort required to replicate your issue. You can do this with a reproducible example ("reprex"). Shiny Debugging Errors in Shiny code can be difficult to track down. If you don't know where your problem is coming from, you can track it down with some o…

[Kevin_Sturm]

Thank you @andresrcs. As I went through my code, I found the cause for this issue. The reason was a simple misplacement of code sections, causing a variable to be missing. I am thankful for all of you trying to help, even if it's one of the simpler error causes.
The shiny app is now operational. However, one table produces other numbers than my local initialization. I'm surprised where this comes from - will dig deeper into my code.