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GraphQL to Postman Collection

Contents

1. Getting Started
2. Command Line Interface
   1. Options
   2. Usage
3. Using the converter as a NodeJS module
   1. Convert Function
   2. Options
   3. ConversionResult
   4. Sample usage
   5. Validate function
4. Conversion Schema

💭 Getting Started

To use the converter as a Node module, you need to have a copy of the NodeJS runtime. The easiest way to do this is through npm. If you have NodeJS installed you have npm installed as well.

$ npm install graphql-to-postman

If you want to use the converter in the CLI, install it globally with NPM:

$ npm i -g graphql-to-postman

📖 Command Line Interface

The converter can be used as a CLI tool as well. The following command line options are available.

gql2postman [options]

Options

• -s <source>, --spec <source> Used to specify the GraphQL specification (file path) which is to be converted

• -o <destination>, --output <destination> Used to specify the destination file in which the collection is to be written

• -p, --pretty Used to pretty print the collection object while writing to a file

• -i, --interface-version Specifies the interface version of the converter to be used. Value can be 'v2' or 'v1'. Default is 'v2'.

• -O, --options Used to supply options to the converter, for complete options details see here

• -c, --options-config Used to supply options to the converter through config file, for complete options details see here

• -t, --test Used to test the collection with an in-built sample specification

• -v, --version Specifies the version of the converter

• -h, --help Specifies all the options along with a few usage examples on the terminal

Usage

• Takes a specification (spec.yaml) as an input and writes to a file (collection.json) with pretty printing and using provided options

$ gql2postman -s spec.yaml -o collection.json -p -O depth=3,includeDeprecatedFields=true

• Takes a specification (spec.yaml) as an input and writes to a file (collection.json) with pretty printing and using provided options via config file

$ gql2postman -s spec.yaml -o collection.json -p  -c ./examples/cli-options-config.json

• Takes a specification (spec.yaml) as an input and writes to a file (collection.json) with pretty printing and using provided options with larger depth limit to make sure more detailed and nested data is generated.

$ gql2postman -s spec.yaml -o collection.json -p -O depth=7,includeDeprecatedFields=true,optimizeConversion=false

• Testing the converter

$ gql2postman --test

🛠 Using the converter as a NodeJS module

In order to use the convert in your node application, you need to import the package using require.

var Converter = require('graphql-to-postman')

The converter provides the following functions:

Convert

The convert function takes in your GraphQL schema or SDL and converts it to a Postman collection.

Signature: convert (data, options, callback);

data:

{ type: 'file', data: 'filepath' }
OR
{ type: 'string', data: '<entire GraphQL string - schema or SDL>' }

options:

{
  depth: 4,
  includeDeprecatedFields: false,
  optimizeConversion: false
}
/*
All three properties are optional. Check the options section below for possible values for each option.
*/

callback:

function (err, result) {
  /*
  result = {
    result: true,
    output: [
      {
        type: 'collection',
        data: {..collection object..}
      }
    ]
  }
  */
}

Options

• depth - The number of levels of information that should be returned. (A depth level of “1” returns that object and its properties. A depth of “2” will return all the nodes connected to the level 1 node, etc.)

• includeDeprecatedFields - Generated queries will include deprecated fields or not.

• optimizeConversion - Optimizes conversion for schemas with complex and nested input objects by reducing the depth to which input objects are resolved in GraphQL variables.

ConversionResult

• result - Flag responsible for providing a status whether the conversion was successful or not.

• reason - Provides the reason for an unsuccessful conversion, defined only if result if false.

• output - Contains an array of Postman objects, each one with a type and data. The only type currently supported is collection.

Sample Usage

const fs = require('fs'),
  Converter = require('graphql-to-postman'),
  gqlData = fs.readFileSync('sample-spec.yaml', {encoding: 'UTF8'});

Converter.convert({ type: 'string', data: gqlData },
  {}, (err, conversionResult) => {
    if (!conversionResult.result) {
      console.log('Could not convert', conversionResult.reason);
    }
    else {
      console.log('The collection object is: ', conversionResult.output[0].data);
    }
  }
);

Validate Function

The validate function is meant to ensure that the data that is being passed to the convert function is a valid JSON object or a valid (YAML/JSON) string.

The validate function is synchronous and returns a status object which conforms to the following schema

Validation object schema

{
  type: 'object',
  properties: {
    result: { type: 'boolean'},
    reason: { type: 'string' }
  },
  required: ['result']
}

Validation object explanation

• result - true if the data is valid GraphQL and can be passed to the convert function

• reason - Provides a reason for an unsuccessful validation of the specification