Type: Package
Title: General Purpose 'GraphQL' Client
Description: A 'GraphQL' client, with an R6 interface for initializing a connection to a 'GraphQL' instance, and methods for constructing queries, including fragments and parameterized queries. Queries are checked with the 'libgraphqlparser' C++ parser via the 'gaphql' package.
Version: 0.1.0
License: MIT + file LICENSE
URL: https://github.com/ropensci/ghql (devel) https://docs.ropensci.org/ghql (docs)
BugReports: https://github.com/ropensci/ghql/issues
Encoding: UTF-8
Language: en-US
Imports: crul, jsonlite, R6, graphql
Suggests: testthat
RoxygenNote: 7.0.2
X-schema.org-applicationCategory: Web
X-schema.org-keywords: http, API, web-services, curl, data, GraphQL
X-schema.org-isPartOf: https://ropensci.org
NeedsCompilation: no
Packaged: 2020-02-24 18:13:41 UTC; sckott
Author: Scott Chamberlain ORCID iD [aut, cre]
Maintainer: Scott Chamberlain <myrmecocystus@gmail.com>
Repository: CRAN
Date/Publication: 2020-03-04 14:30:06 UTC

ghql

Description

General purpose GraphQL client

ghql API

The main interface in this package is [GraphqlClient], which produces a client (R6 class) with various methods for interacting with a GraphQL server. [GraphqlClient] also accepts various input parameters to set a base URL, and any headers required, which is usually the required set of things needed to connect to a GraphQL service.

[Query] is an interface to creating GraphQL queries, which works together with [GraphqlClient]

[Fragment] is an interface to creating GraphQL fragments, which works together with [GraphqlClient]

Author(s)

Scott Chamberlain myrmecocystus@gmail.com

Fragment

Description

ghql fragment class

Value

a 'Fragment' class (R6 class)

Public fields

fragments

(list) list of fragments

Methods

Public methods

Method print()

print method for the 'Fragment' class

Usage
Fragment$print(x, ...)
Arguments
x

self

...

ignored

Method fragment()

create a fragment by name

Usage
Fragment$fragment(name, x)
Arguments
name

(character) fragment name

x

(character) the fragment

Returns

nothing returned; sets fragments internally

Examples

# make a fragment class
frag <- Fragment$new()

# define a fragment
frag$fragment('Watchers', '
  fragment on Repository {
    watchers(first: 3) {
      edges {
        node {
          name
       }
    }
  }
}')

# define another fragment
frag$fragment('Stargazers', '
  fragment on Repository {
    stargazers(first: 3) {
      edges {
        node {
          name
       }
    }
  }
}')
frag
frag$fragments
frag$fragments$Watchers
frag$fragments$Stargazers

GraphqlClient

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

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)

Query

Description

ghql query class

Value

a 'Query' class (R6 class)

Public fields

queries

(list) list of queries

Methods

Public methods

Method print()

print method for the 'Query' class

Usage
Query$print(x, ...)
Arguments
x

self

...

ignored

Method query()

define query in a character string

Usage
Query$query(name, x)
Arguments
name

(character) name of the query

x

(character) the query

Returns

nothing returned; sets query with 'name' internally

Method add_fragment()

add a fragment to a query

Usage
Query$add_fragment(query_name, fragment)
Arguments
query_name

(character) the query name to add the fragment to

fragment

(character) the fragment itself

Returns

nothing returned; sets the fragment with the query

Method parse2json()

parse query string with libgraphqlparser and get back JSON

Usage
Query$parse2json(query, parse_schema = FALSE)
Arguments
query

(character) a query to parse

parse_schema

(logical) enable schema definition parsing? default: 'FAlSE'

Returns

adf

Note

we run an internal method 'check_query()' that runs the public method ‘parse2json()' - if the query doesn’t pass the libgraphqlparser parser, we return the error message

Examples

# make a client
qry <- Query$new()

## define query
qry$query('query2', '{
  viewer {
    repositories(last: 10, isFork: false, privacy: PUBLIC) {
      edges {
        node {
          isPrivate
          id
          name
        }
      }
    }
  }
}')
qry
qry$queries
qry$queries$query2

# fragments
## by hand
qry$query('querywithfrag', '{
  ropensci: repositoryOwner(login:"ropensci") {
    repositories(first: 3) {
      edges {
        node {
          ...Watchers
        }
      }
    }
  }
  ropenscilabs: repositoryOwner(login:"ropenscilabs") {
    repositories(first: 3) {
      edges {
        node {
          ...Watchers
        }
      }
    }
  }
}
fragment Watchers on Repository {
  watchers(first: 3) {
    edges {
      node {
        name
      }
    }
  }
}')
qry
qry$queries
qry$queries$querywithfrag


## Not run: 
token <- Sys.getenv("GITHUB_GRAPHQL_TOKEN")
con <- GraphqlClient$new(
  url = "https://api.github.com/graphql",
  headers = list(Authorization = paste0("Bearer ", token))
)
jsonlite::fromJSON(con$exec(qry$queries$querywithfrag))

## use Fragment class fragments generator
### define query without fragment, but referring to it
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, and use it later
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
qry$queries$queryfrag

## End(Not run)