gargle

The goal of gargle is to take some of the agonizing pain out of working with Google APIs. This includes functions and classes for handling common credential types and for preparing, executing, and processing HTTP requests.

The target user of gargle is an R package author who is wrapping one of the ~250 Google APIs listed in the APIs Explorer. gargle aims to play roughly the same role as Google’s official client libraries, but for R. gargle may also be useful to useRs making direct calls to Google APIs, who are prepared to navigate the details of low-level API access.

gargle’s functionality falls into two main domains:

• Auth. The token_fetch() function calls a series of concrete credential-fetching functions to obtain a valid access token (or it quietly dies trying).
  • This covers explicit service accounts, application default credentials, Google Compute Engine, and the standard OAuth2 browser flow.
  • gargle offers the Gargle2.0 class, which extends httr::Token2.0. It is the default class for user OAuth 2.0 credentials. There are two main differences from httr::Token2.0: greater emphasis on the user’s email (e.g. Google identity) and default token caching is at the user level.
• Requests and responses. A family of functions helps to prepare HTTP requests, (possibly with reference to an API spec derived from a Discovery Document), make requests, and process the response.

See the articles for holistic advice on how to use gargle.

Installation

You can install the released version of gargle from CRAN with:

install.packages("gargle")

And the development version from GitHub with:

# install.packages("devtools")
devtools::install_github("r-lib/gargle")

Basic usage

gargle is a low-level package and does not do anything visibly exciting on its own. But here’s a bit of usage in an interactive scenario where a user confirms they want to use a specific Google identity and loads an OAuth2 token.

library(gargle)

token <- token_fetch()
#> The gargle package is requesting access to your Google account. Select a
#> pre-authorised account or enter '0' to obtain a new token. Press
#> Esc/Ctrl + C to abort.

#> 1: [email protected]
#> 2: [email protected]

#> Selection: 1

token
#> <Token (via gargle)>
#>   <oauth_endpoint> google
#>              <app> gargle-demo
#>            <email> [email protected]
#>           <scopes> ...userinfo.email
#>      <credentials> access_token, expires_in, refresh_token, scope, ...

Here’s an example of using request and response helpers to make a one-off request to the Web Fonts Developer API. We show the most popular web font families served by Google Fonts.

library(gargle)

req <- request_build(
  method = "GET",
  path = "webfonts/v1/webfonts",
  params = list(
    sort = "popularity"
  ),
  key = gargle_api_key(),
  base_url = "https://www.googleapis.com"
)
resp <- request_make(req)
out <- response_process(resp)

out <- out[["items"]][1:8]
vapply(out, function(x) x[["family"]], character(1))
#> [1] "Roboto"           "Open Sans"        "Lato"             "Montserrat"      
#> [5] "Noto Sans JP"     "Source Sans Pro"  "Roboto Condensed" "Oswald"

Please note that the ‘gargle’ project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.

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