Shiny Developer Series Webinar Discussion - Episode 3 - Mark Edmondson on googleAnalyticsR and linking Shiny to complex APIs

[MarkeD]

First of all thank you very much for having me on the webinar, it was fun

@EconomiCurtis

RB : if i had to inspect where the api call was being made where in the package would i need to look? the idea being that if i had to create a package for another api with oauth i wanted some inspiration

The first place to look would be the httr vignette "Best practices for API packages" which has lots of examples including those using OAuth2. For googleAuthR packages the function factory used by all of them all starts with the gar_api_generator() which adds looking for tokens in Shiny environments, batching and caching. The most modern take is gargle by Jenny Bryan which is under development now.

@EconomiCurtis

CK : Can you advise on best practices for handling api errors? For example, I've deployed a shiny app built upon a google API, but how should I handle api errors that occur in future in production?

Covered in the webinar, but my first reaction is that you want to surface errors as quickly as possible, so would want them to be live even in production. If you want to mask transitory errors though then you can use tryCatch() or the equivalent to return a NULL response upon error, which will invalidate the shiny::reactive() object the API call should be wrapped in, so as you can then use shiny::req() or shiny::validate() to create custom error messages.

@EconomiCurtis

AJ : How do you advice creating user authentication for accessing a plumber API for Excel VBA for example on RStudio Connect

I've never done similar so can't speak from experience, perhaps RStudio Connect has someway you can do this, if not then my first approach would be to use Google Cloud Endpoints which gives you a API proxy to add API keys, caching and authentication, a demo of which I have here that uses Google App Engine Flexible and plumber.

@EconomiCurtis

DH : Can Mark publish a list of his "top" packages like memoise (I think pronounce "memwah")?

I'm so embarrassed at my pronunciation of memoise on the webinar.

If we're talking packages for API packages in particular, my R package stack always includes:

• httr - the godfather of R APIs
• jsonlite - turning R inputs into JSON and back again
• pkgdown - documentation
• memoise - caching responses
• assertthat - defensive programming and checking of inputs

Then depending on how hard it is to parse the response, and how user friendly you want to make the final output you could choose to add some packages to parse the responses such as purrr or dplyr

@EconomiCurtis

MI : Mark please, where did you learn to create packages in such a short period of time? (and thank you very much for the presentation)

For my first package searchConsoleR I read Hadley Wickham's R package book cover to cover, adding the elements to the package as I went.

After that I used the Google Discovery API service integration of googleAuthR via the gar_create_package() function to generate the functions and objects, then added functions to parse those into user-friendly functions, and add lots of documentation. But I don't make any packages at the moment as its enough time maintaining the existing ones.

@EconomiCurtis

RL : What from Mark point of view the best way to grow from a know nothing shiny to a good enough developer - any trick he would have? Thanks

The documentation on the Shiny website I still reference a lot and think are excellent.

I have a post on this forum about my approach to Shiny development that may be helpful.

Other than that I'd say having a good iterative workflow to keep testing each change you do, making sure to not do too much with each reactive object, and get the server side working well first with a basic UI first before making it look pretty.

@EconomiCurtis

IT : I would like to thank Mark for his excellent work! And would like to know about the slack channel and how we could participate? ( context: Mark mentioned that an increasing part of his R-package development time is spent on non-coding tasks, and he relies on a community of package sustainers to help, mostly coordinated on github and slack )

The Slack channel #googleAuthRverse has a signup form here - that and any GitHub issues/pull requests are highly appreciated!