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GraphQL Template API

Overview

This is API for the GraphQL Template service.

Conventions

  • All calls run over TLS (in production).
  • The API accepts & returns JSON, all POST & PUT payloads are specified in JSON (i.e. not application/x-www-form-urlencoded).
  • All calls accept (for PUT & POST) & return JSON objects, e.g. {"data":{"foo":"bar"}}
  • All requests must conform to GraphQL standards, e.g. contain at least query element. Because of this, requests do not contain a top-level data element.
  • All responses return JSON objects, which will one of, and in some case both:
    • errors - if an error ocurred (contains an array of errors).
    • data - if the response was a success.
  • Additional parameters may be specified in the query string where documented.
  • All time stamps are ISO 8601 strings.
  • Appropriate status codes are used, not limited to:
    • 200 - OK
    • 201 - New resource created
    • 401 - Unauthorized
    • 404 - Not found
  • Where possible, this API attempts to conform to GraphQL convention (which may thus be undocumented).

Authentication

In production, all requests require authentication using Hawk, which is a HMAC style authentication method. Provide an Authorization header containing the authorisation details.

GET /resource/1?b=1&a=2 HTTP/1.1
Host: example.com:8000
Authorization: Hawk id="dh37fgj492je", ts="1353832234", nonce="j4h3g2", ext="some-app-ext-data", mac="6R4rV5iE+NPoym+WwjeHzjAGXUtLNIxmo1vpMofpLAE="

If you don't include correct authentication you will get a 401 with a WWW-Authenticate: Hawk header:

$ curl -i -X POST --data '{}' "https://rb-graphql-template.herokuapp.com/v1/graphql"
HTTP/1.1 401 Unauthorized
Server: Cowboy
Date: Tue, 01 Nov 2016 02:24:54 GMT
Connection: keep-alive
Content-Length: 25
Content-Language: en
Content-Type: text/plain
Via: 1.1 vegur

Request is not authorised

Required Parameters

All API operations expect the following params in their JSON payload (at the root level):

  • query: The GraphQL query, encoded as a JSON string.

You may also supply the following:

  • variables - A JSON object containing the variables referenced in the query.
  • operationName - If supplying multiple operations, the name of the operation to execute, as a JSON string.

Errors

All errors from the API return a top level errors array. Each entry in the array contains information about the error. It will include at least the following (but possibly more) fields:

  • message - A human readable overview of the error (the exception message).

You may also get the following fields:

  • type - The type of the exception.
  • cause - If the exception has an underlying cause, its message.
  • location - The line and column where the error occured.

Note that due to the way GraphQL works, you may sometimes get back both data and an errors top level fields, with a 200 status code. In this case it is up to the client to determine whether this represents failue or not.

For example, a malformed request:

$ curl -i -X POST --data '{ "query" : "{ volumes { number1 } }" }' "http://rb-graphql-template/v1/graphql"
HTTP/1.1 400 Bad Request
Content-Type: application/json
Content-Length: 200

{"errors":[{"message":"Cannot query field 'number1' on type 'VolumeHeader'. Did you mean 'number'? (line 1, column 13):\n{ volumes { number1 } }\n            ^","locations":[{"line":1,"column":13}]}]}```

If the query is malformed, you may get something like:

{
  "errors": [
    {
      "message": "Error processing GraphQL query",
      "type": "GraphQlError",
      "cause": "body cannot be converted to GraphQlQuery: Unable to decode JSON payload: Syntax error while parsing GraphQL query. Invalid input \"{\\n  volumes {\\n    number\\n    title\\n    work {\\n      \\n    }\", expected Comments or SelectionSet (line 1, column 1):\n{\n^."
    }
  ]
}

In the case of multiple errors your response may look like:

{
  "errors": [
    {
      "message": "Cannot query field 'extraConfig' on type 'ArtPrintConfig'. Did you mean 'addnConfig'? (line 14, column 9):\n        extraConfig {\n        ^",
      "locations": [
        {
          "line": 14,
          "column": 9
        }
      ]
    },
    {
      "message": "Cannot query field 'allConfig' on type 'DeviceCaseConfig'. Did you mean 'addnConfig'? (line 44, column 9):\n        allConfig {\n        ^",
      "locations": [
        {
          "line": 44,
          "column": 9
        }
      ]
    }
  ]
}

Environments

Local Development

  • http://localhost:8080

Production

  • https://rb-graphql-template.herokuapp.com

Substitute the domain rb-graphql-template in the examples below with this.

Operations

All operations are performed using GraphQL. The GraphQL endpoint accepts both GET and POST requests, though GETs are limited in the length of the query string and may fail (with 400s). Where possible, prefer POSTs.

  • URL pattern: http://rb-graphql-template/v1/graphql

  • HTTP Verb: POST

Example Request/Response

Success

$ curl -i -X POST --data '{ "query" : "{ volumes { number } }" }' "http://localhost:8080/v1/graphql"
HTTP/1.1 200 OK
Content-Type: application/json
Content-Length: 35

{"data":{"volumes":[{"number":1}]}}

Failure

$ curl -i -X POST --data '{ "query" : "{ volumes { number1 } }" }' "http://localhost:8080/v1/graphql"
HTTP/1.1 400 Bad Request
Content-Type: application/json
Content-Length: 200

{"errors":[{"message":"Cannot query field 'number1' on type 'VolumeHeader'. Did you mean 'number'? (line 1, column 13):\n{ volumes { number1 } }\n            ^","locations":[{"line":1,"column":13}]}]}