R6 class for constructing GraphQL queries
Public fields
url(character) list of fragments
headerslist of named headers
schemaholds schema
resultholds result from http request
fragments(list) list of fragments
Methods
Method new()
Create a new `GraphqlClient` object
Usage
GraphqlClient$new(url, headers)Method print()
print method for the `GraphqlClient` class
Method load_schema()
load schema, from URL or local file
Method exec()
execute the query
Arguments
query(character) a query, of class `query` or `fragment`
variables(list) named list with query variables values
encoding(character) encoding to use to parse the response. passed on to [crul::HttpResponse] `$parse()` method. default: "UTF-8"
response_headersIf `TRUE`, include the response headers as an attribute of the return object.
...curl options passed on to [crul::verb-POST]
Examples
x <- GraphqlClient$new()
x
#> <ghql client>
#> url:
if (FALSE) {
# make a client
token <- Sys.getenv("GITHUB_TOKEN")
cli <- GraphqlClient$new(
url = "https://api.github.com/graphql",
headers = list(Authorization = paste0("Bearer ", token))
)
# if the GraphQL server has a schema, you can load it
cli$load_schema()
# dump schema to local file
f <- tempfile(fileext = ".json")
cli$dump_schema(file = f)
readLines(f)
jsonlite::fromJSON(readLines(f))
# after dumping to file, you can later read schema from file for faster loading
rm(cli)
cli <- GraphqlClient$new(
url = "https://api.github.com/graphql",
headers = list(Authorization = paste0("Bearer ", token))
)
cli$load_schema(schema_file = f)
# variables
cli$url
cli$schema
cli$schema$data
cli$schema$data$`__schema`
cli$schema$data$`__schema`$queryType
cli$schema$data$`__schema`$mutationType
cli$schema$data$`__schema`$subscriptionType
head(cli$schema$data$`__schema`$types)
cli$schema$data$`__schema`$directives
# methods
## ping - hopefully you get TRUE
cli$ping()
## dump schema
cli$schema2json()
## define query
### creat a query class first
qry <- Query$new()
## another
qry$query('repos', '{
viewer {
repositories(last: 10, isFork: false, privacy: PUBLIC) {
edges {
node {
isPrivate
id
name
}
}
}
}
}')
qry
qry$queries
qry$queries$repos
### execute the query
cli$exec(qry$queries$repos)
# query with a fragment
### define query without fragment, but referring to it
qry <- Query$new()
qry$query('queryfrag', '{
ropensci: repositoryOwner(login:"ropensci") {
repositories(first: 3) {
edges {
node {
...Watchers
}
}
}
}
ropenscilabs: repositoryOwner(login:"ropenscilabs") {
repositories(first: 3) {
edges {
node {
...Watchers
}
}
}
}
}')
### define a fragment
frag <- Fragment$new()
frag$fragment('Watchers', '
fragment on Repository {
watchers(first: 3) {
edges {
node {
name
}
}
}
}')
frag$fragments
frag$fragments$Watchers
### add the fragment to the query 'queryfrag'
qry$add_fragment('queryfrag', frag$fragments$Watchers)
qry
qry$queries$queryfrag
### execute query: we'll hook together the query and your fragment internally
cli$exec(qry$queries$queryfrag)
}