--- title: "Fetching JSON data from REST APIs" date: "2022-01-16" output: html_document vignette: > %\VignetteIndexEntry{Fetching JSON data from REST APIs} %\VignetteEngine{knitr::rmarkdown} \usepackage[utf8]{inputenc} --- This section lists some examples of public HTTP APIs that publish data in JSON format. These are great to get a sense of the complex structures that are encountered in real world JSON data. All services are free, but some require registration/authentication. Each example returns lots of data, therefore not all output is printed in this document. ```r library(jsonlite) ``` ## Github Github is an online code repository and has APIs to get live data on almost all activity. Below some examples from a well known R package and author: ```r hadley_orgs <- fromJSON("https://api.github.com/users/hadley/orgs") hadley_repos <- fromJSON("https://api.github.com/users/hadley/repos") gg_commits <- fromJSON("https://api.github.com/repos/hadley/ggplot2/commits") gg_issues <- fromJSON("https://api.github.com/repos/hadley/ggplot2/issues") #latest issues paste(format(gg_issues$user$login), ":", gg_issues$title) ``` ``` [1] "petres : Inconsistency in `scale_` functions for args `values` and `labels` for `NA` values" [2] "PursuitOfDataScience : Update data.R" [3] "cmaimone : scale_x_datetime limits with histogram/stat_bin: warning message about missing values" [4] "tomsaunders98 : Add options to guide_colourstep" [5] "teunbrand : Duplicated aes warning with multiple modified aesthetics" [6] "krlmlr : Support scale functions in packages not attached via scale_type()" [7] "elong0527 : Shall `NextMethod` be used in `$<-.uneval`" [8] "bkmgit : Update presidential terms dataset" [9] "bkmgit : Presidents terms" [10] "coolbutuseless : Export `datetime_scale`" [11] "davidhodge931 : Create one single legend for a numeric colour variable coloured and filled along a gradient of colours with different alpha values" [12] "yutannihilation : Use pak in R-CMD-check.yaml" [13] "hadley : Option to make default colour schemes accessible?" [14] "davidhodge931 : scale_fill_gradientn and scale_colour_gradientn should support na.translate" [15] "davidhodge931 : should legend styling elements within guide_* instead be within theme?" [16] "markjrieke : `geom_ribbon`: aesthetics can not vary with a ribbon" [17] "bkmgit : Dataset licenses" [18] "jxu : geom_segment example confusing" [19] "twest820 : alpha legend keys darken when geom_ribbons share an alpha value" [20] "WillForan : discarded breaks in scale_x_continuous(trans=\"log10\") w/ min(x)==0" [21] "billdenney : na.rm is ignored with geom_area" [22] "hugesingleton : Is it possible to make the width of geom_boxplot and binwidth in geom_density, and position \"mapable\" in aes()?" [23] "bersbersbers : Fix warning in geom_violin with draw_quantiles" [24] "eliocamp : `geom_contour()` documentation states false precedence of bin and binwidth parameters" [25] "jtlandis : Unexpected results using `guides(x = guide_axis(position = ...))`" [26] "albert-ying : Smarter axis label -- allow string manipulate function in `labs` or `theme`" [27] "Cumol : Width argument to geom_errorbar not passed on when using stat_summary_bin" [28] "twest820 : apparently spurious is.na() warning on use of language in label" [29] "benjaminrich : Add `trans` option in `annotation_logticks()`" [30] "benjaminrich : `annotation_logticks()` with secondary axis" ``` ## CitiBike NYC A single public API that shows location, status and current availability for all stations in the New York City bike sharing imitative. ```r citibike <- fromJSON("https://gbfs.citibikenyc.com/gbfs/en/station_information.json") stations <- citibike$data$stations colnames(stations) ``` ``` [1] "electric_bike_surcharge_waiver" "eightd_station_services" "lat" "external_id" [5] "station_type" "name" "short_name" "station_id" [9] "rental_methods" "rental_uris" "has_kiosk" "region_id" [13] "capacity" "legacy_id" "lon" "eightd_has_key_dispenser" ``` ```r nrow(stations) ``` ``` [1] 1598 ``` ## Ergast The Ergast Developer API is an experimental web service which provides a historical record of motor racing data for non-commercial purposes. ```r res <- fromJSON('http://ergast.com/api/f1/2004/1/results.json') drivers <- res$MRData$RaceTable$Races$Results[[1]]$Driver colnames(drivers) ``` ``` [1] "driverId" "code" "url" "givenName" "familyName" "dateOfBirth" "nationality" [8] "permanentNumber" ``` ```r drivers[1:10, c("givenName", "familyName", "code", "nationality")] ``` ``` givenName familyName code nationality 1 Michael Schumacher MSC German 2 Rubens Barrichello BAR Brazilian 3 Fernando Alonso ALO Spanish 4 Ralf Schumacher SCH German 5 Juan Pablo Montoya MON Colombian 6 Jenson Button BUT British 7 Jarno Trulli TRU Italian 8 David Coulthard COU British 9 Takuma Sato SAT Japanese 10 Giancarlo Fisichella FIS Italian ``` ## ProPublica Below an example from the [ProPublica Nonprofit Explorer API](https://projects.propublica.org/nonprofits/api) where we retrieve the first 10 pages of tax-exempt organizations in the USA, ordered by revenue. The `rbind_pages` function is used to combine the pages into a single data frame. ```r #store all pages in a list first baseurl <- "https://projects.propublica.org/nonprofits/api/v2/search.json?order=revenue&sort_order=desc" pages <- list() for(i in 0:10){ mydata <- fromJSON(paste0(baseurl, "&page=", i), flatten=TRUE) message("Retrieving page ", i) pages[[i+1]] <- mydata$organizations } #combine all into one organizations <- rbind_pages(pages) #check output nrow(organizations) ``` ``` [1] 1100 ``` ```r organizations[1:10, c("name", "city", "strein")] ``` ``` name city strein 1 0 DEBT EDUCATION INC SANTA ROSA 46-4744976 2 0 TOLERANCE INC SUWANEE 27-2620044 3 00 MOVEMENT INC PENSACOLA 82-4704419 4 00006 LOCAL MEDIA 22-6062777 5 0003 POSTAL FAMILY CINCINNATI 31-0240910 6 0005 GA HEPHZIBAH 58-1514574 7 0005 WRIGHT-PATT CREDIT UNION BEAVERCREEK 31-0278870 8 0009 DE GREENWOOD 26-4507405 9 0011 CALIFORNIA REDWAY 36-4654777 10 00141 LOCAL MEDIA 94-0507697 ``` ## New York Times The New York Times has several APIs as part of the NYT developer network. These interface to data from various departments, such as news articles, book reviews, real estate, etc. Registration is required (but free) and a key can be obtained at [here](http://developer.nytimes.com/signup). The code below includes some example keys for illustration purposes. ```r #search for articles article_key <- "&api-key=b75da00e12d54774a2d362adddcc9bef" url <- "http://api.nytimes.com/svc/search/v2/articlesearch.json?q=obamacare+socialism" req <- fromJSON(paste0(url, article_key)) articles <- req$response$docs colnames(articles) ``` ``` [1] "abstract" "web_url" "snippet" "lead_paragraph" "print_section" "print_page" "source" [8] "multimedia" "headline" "keywords" "pub_date" "document_type" "news_desk" "section_name" [15] "byline" "type_of_material" "_id" "word_count" "uri" "subsection_name" ``` ```r #search for best sellers books_key <- "&api-key=76363c9e70bc401bac1e6ad88b13bd1d" url <- "http://api.nytimes.com/svc/books/v2/lists/overview.json?published_date=2013-01-01" req <- fromJSON(paste0(url, books_key)) bestsellers <- req$results$list category1 <- bestsellers[[1, "books"]] subset(category1, select = c("author", "title", "publisher")) ``` ``` author title publisher 1 Gillian Flynn GONE GIRL Crown Publishing 2 John Grisham THE RACKETEER Knopf Doubleday Publishing 3 E L James FIFTY SHADES OF GREY Knopf Doubleday Publishing 4 Nicholas Sparks SAFE HAVEN Grand Central Publishing 5 David Baldacci THE FORGOTTEN Grand Central Publishing ``` ## Twitter The twitter API requires OAuth2 authentication. Some example code: ```r #Create your own appication key at https://dev.twitter.com/apps consumer_key = "EZRy5JzOH2QQmVAe9B4j2w"; consumer_secret = "OIDC4MdfZJ82nbwpZfoUO4WOLTYjoRhpHRAWj6JMec"; #Use basic auth secret <- jsonlite::base64_enc(paste(consumer_key, consumer_secret, sep = ":")) req <- httr::POST("https://api.twitter.com/oauth2/token", httr::add_headers( "Authorization" = paste("Basic", gsub("\n", "", secret)), "Content-Type" = "application/x-www-form-urlencoded;charset=UTF-8" ), body = "grant_type=client_credentials" ); #Extract the access token httr::stop_for_status(req, "authenticate with twitter") token <- paste("Bearer", httr::content(req)$access_token) #Actual API call url <- "https://api.twitter.com/1.1/statuses/user_timeline.json?count=10&screen_name=Rbloggers" req <- httr::GET(url, httr::add_headers(Authorization = token)) json <- httr::content(req, as = "text") tweets <- fromJSON(json) substring(tweets$text, 1, 100) ``` ``` [1] "Surface reconstruction with R(CGAL) {https://t.co/Kou9gFUmod} #rstats #DataScience" [2] "A dashboard illustrating bivariate time series forecasting with `ahead` {https://t.co/HYS6UIKMgl} #" [3] "Handling Categorical Data in R – Part 4 {https://t.co/aZa7O7Ppxd} #rstats #DataScience" [4] "Solving the ‘preserving the sum after rounding’ problem for a soccer waffle viz {https://t.co/uNtOL" [5] "Community Management Transition for rOpenSci. A Message from Stefanie Butland {https://t.co/r7YuZjV" [6] "New R job: Data Services Specialist https://t.co/sy2goVMxbq #rstats #DataScience #jobs" [7] "RTutor: Gasoline Taxes and Consumer Behavior {https://t.co/nIxUNfihoK} #rstats #DataScience" [8] "Shinywordle: A shiny app to solve the game Worldle and the power of regular expressions {https://t." [9] "10 New books added to Big Book of R {https://t.co/jD0IYutHTN} #rstats #DataScience" [10] "Clipping an isosurface to a ball, and more {https://t.co/Yz0qbSB3IB} #rstats #DataScience" ```