GraphqlClient: GraphqlClient

In ghql: General Purpose 'GraphQL' Client

Description

R6 class for constructing GraphQL queries

Value

a 'GraphqlClient' class (R6 class)

Public fields

url

(character) list of fragments

headers

list of named headers

schema

holds schema

result

holds result from http request

fragments

(list) list of fragments

Methods

Public methods

• GraphqlClient$new()

• GraphqlClient$print()

• GraphqlClient$ping()

• GraphqlClient$load_schema()

• GraphqlClient$dump_schema()

• GraphqlClient$schema2json()

• GraphqlClient$fragment()

• GraphqlClient$exec()

• GraphqlClient$prep_query()

---

Method new()

Create a new 'GraphqlClient' object

Usage

GraphqlClient$new(url, headers)

Arguments

url

(character) URL for the GraphQL schema

headers

Any acceptable headers, a named list. See examples

Returns

A new 'GraphqlClient' object

---

Method print()

print method for the 'GraphqlClient' class

Usage

GraphqlClient$print(x, ...)

Arguments

x

self

...

ignored

---

Method ping()

ping the GraphQL server

Usage

GraphqlClient$ping(...)

Arguments

...

curl options passed on to [crul::verb-HEAD]

Returns

'TRUE' if successful response, 'FALSE' otherwise

---

Method load_schema()

load schema, from URL or local file

Usage

GraphqlClient$load_schema(schema_url = NULL, schema_file = NULL, ...)

Arguments

schema_url

(character) url for a schema file

schema_file

(character) path to a schema file

...

curl options passed on to [crul::verb-GET]

Returns

nothing, loads schema into '$schema' slot

---

Method dump_schema()

dump schema to a local file

Usage

GraphqlClient$dump_schema(file)

Arguments

file

(character) path to a file

Returns

nothing, writes schema to 'file'

---

Method schema2json()

convert schema to JSON

Usage

GraphqlClient$schema2json(...)

Arguments

...

options passed on to [jsonlite::toJSON()]

Returns

json

---

Method fragment()

load schema, from URL or local file

Usage

GraphqlClient$fragment(name, x)

Arguments

name

(character) fragment name

x

(character) the fragment

Returns

nothing returned; sets fragments internally

---

Method exec()

execute the query

Usage

GraphqlClient$exec(query, variables, encoding = "UTF-8", ...)

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"

...

curl options passed on to [crul::verb-POST]

Returns

character string of response, if successful

---

Method prep_query()

not used right now

Usage

GraphqlClient$prep_query(query)

Arguments

query

(character) a query, of class 'query' or 'fragment'

Examples

x <- GraphqlClient$new()
x

## Not run: 
# make a client
token <- Sys.getenv("GITHUB_GRAPHQL_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)

## End(Not run)

ghql documentation built on March 26, 2020, 6:26 p.m.