Querying a GraphQL client for linked data using R

Querying a GraphQL client for linked data using R

The following script relies on the ghql R package (Chamberlain 2017) to query multidimensional QB datasets using GraphQL. The example uses the graphql-qb service at graphql-qb.publishmydata.com which stores data from statistics.gov.scot.

---

Install the ghql package from GitHub (and devtools if not already installed)

devtools::install_github("hadley/devtools")
devtools::install_github("ropensci/ghql")

Load the necessary R packages

library(ghql) # for querying 
library(jsonlite) # for parsing the json response
library(httr) # for working with URLs
library(tidyverse) # for tidying data

Initialize the GraphQL client by pointing it to the appropriate endpoint e.g. http://graphql-qb.publishmydata.com/graphql

client <- GraphqlClient$new(url = "http://graphql-qb.publishmydata.com/graphql")

No OAuth token is required for this endpoint but the headers argument can be used for this purpose.

Make a Query class object

qry <- Query$new()

Add your GraphQL query, e.g. Filter datasets about gender and return the title and description

qry$query('query', '
  {
    datasets(dimensions: {and: ["http://statistics.gov.scot/def/dimension/gender"]}) {
      title
      description
    }
  }
')

Return the responses

responses <- client$exec(qry$queries$query)

Convert to a dataframe and return column names

df <- as.data.frame(responses)
glimpse(df)

## Observations: 55
## Variables: 2
## $ data.datasets.title       <chr> "Mid-Year Population Estimates (hist...
## $ data.datasets.description <chr> "Mid-year estimates by age and gende...

Change the column names

df <- rename(df, Dataset = data.datasets.title,
             Description = data.datasets.description)

The table below shows the first 6 responses.

Dataset	Description
Mid-Year Population Estimates (historical geographical boundaries)	Mid-year estimates by age and gender. Higher level geographies are aggregated using 2001 data zones.
Pupil Attainment	Number of pupils who attained a given number of qualifications by level and stage.
Earnings	Median gross weekly earnings (£s) by gender and workplace/residence measure.
Income Support Claimants	Number of income support claimants by age and gender (age split not available for gender).
Healthy Life Expectancy	Years of Healthy Life Expectancy (including confidence intervals) by gender
Disability Living Allowance	Number of Disability Living Allowance claimants by age group and gender.

References

• Chamberlain, Scott (2017). ghql: General Purpose GraphQL Client. R package version 0.0.3.9110. https://github.com/ropensci/ghql
• Ooms, Jeroen (2014). The jsonlite Package: A Practical and Consistent Mapping Between JSON Data and R Objects. arXiv:1403.2805 [stat.CO] URL https://arxiv.org/abs/1403.2805.
• Wickham, Hadley (2017). httr: Tools for Working with URLs and HTTP. R package version 1.3.1. https://CRAN.R-project.org/package=httr
• Wickham, Hadley (2017). tidyverse: Easily Install and Load 'Tidyverse' Packages. R package version 1.1.1. https://CRAN.R-project.org/package=tidyverse