@devlikeapro/n8n-openapi-node

@devlikeapro/n8n-openapi-node

Turn Your OpenAPI (Swagger) spec into a n8n node!

• Quick Start
  • Installation
  • Usage
• How it works
  • Resource
  • Operation
  • Query Parameters
  • Request Body
  • Headers
• Customization
  • Resource
  • Operation
  • Fields
• Use Cases
• FAQ
  • I have only OpenAPI v2 spec, what can I do?
  • I have openapi.yaml spec, what can I do?
  • How to set up credentials from OpenAPI v3 spec?
  • Why it doesn't work with my OpenAPI spec?

Quick Start

Installation

Add @devlikeapro/n8n-openapi-node as dependency

npm install @devlikeapro/n8n-openapi-node
# OR
pnpm add @devlikeapro/n8n-openapi-node
# OR
yarn add @devlikeapro/n8n-openapi-node

👉 We recommend using one of repo for the template:

• https://github.com/devlikeapro/n8n-nodes-petstore - Petstore example generated from OpenAPI v3 spec
• https://github.com/n8n-io/n8n-nodes-starter - Official n8n nodes starter template

Find more real-world examples in Use Cases section.

Usage

1. Add your openapi.json to src/{NodeName} folder (use OpenAPI v3 and json, see FAQ if you don't have it)

2. Get your Node.properties from OpenAPI v3 spec:

import {INodeType, INodeTypeDescription} from 'n8n-workflow';
import {N8NPropertiesBuilder, N8NPropertiesBuilderConfig} from '@devlikeapro/n8n-openapi-node';
import * as doc from './openapi.json'; // <=== Your OpenAPI v3 spec

const config: N8NPropertiesBuilderConfig = {}
const parser = new N8NPropertiesBuilder(doc, config);
const properties = parser.build()

export class Petstore implements INodeType {
  description: INodeTypeDescription = {
    displayName: 'Petstore',
    name: 'petstore',
    icon: 'file:petstore.svg',
    group: ['transform'],
    version: 1,
    subtitle: '={{$parameter["operation"] + ": " + $parameter["resource"]}}',
    description: 'Interact with Petstore API',
    defaults: {
      name: 'Petstore',
    },
    inputs: ['main'],
    outputs: ['main'],
    credentials: [
      {
        name: 'petstoreApi',
        required: false,
      },
    ],
    requestDefaults: {
      headers: {
        Accept: 'application/json',
        'Content-Type': 'application/json',
      },
      baseURL: '={{$credentials.url}}',
    },
    properties: properties, // <==== HERE
  };
}

How it works

N8NPropertiesBuilder extracts few entities from OpenAPI v3 to your n8n community node:

1. Resource - a list of Tags from OpenAPI spec
2. Operation - a list of Operations from OpenAPI spec (aka Actions in n8n)
3. Query Parameters - a list of operation.parameters from OpenAPI spec
4. Request Body - a list of operation.requestBody.content from OpenAPI spec (only for application/json)
5. Headers - a list of operation.parameters from OpenAPI spec

Resource

By default, it get Tags from OpenAPI spec and converts them to Resource in n8n.

Operation

By default, it gets Operations from OpenAPI spec and converts them to Actions in n8n.

Query Parameters

It gets operation.parameters from OpenAPI spec and converts them to Query Parameters in n8n.

Request Body

It doesn't create the full structure of the request body, only the first level of properties. So if you have request body as

{
  "name": "string",
  "config": {
    "id": 0,
    "name": "string"
  }
}

it creates 2 fields in n8n:

• name - with default value string
• config - with default value {"id": 0, "name": "string"}

Headers

It gets operation.parameters from OpenAPI spec and converts them to Headers in n8n.

Customization

Resource

You can override the way how to extract Resource from OpenAPI Tag defining your custom IResourceParser:

import {IResourceParser} from '@devlikeapro/n8n-openapi-node';

export class CustomResourceParser {
  CUSTOM_DESCRIPTION = {
    "cats": "Cats are cute",
  }

  name(tag: OpenAPIV3.TagObject): string {
    // Your custom logic here
    if (tag['X-Visible-Name']) {
      return tag['X-Visible-Name'];
    }
    return lodash.startCase(tag.name);
  }

  value(tag: Pick<OpenAPIV3.TagObject, "name">): string {
    // Remove all non-alphanumeric characters
    const name = tag.name.replace(/[^a-zA-Z0-9_-]/g, '')
    return lodash.startCase(name)
  }

  description(tag: OpenAPIV3.TagObject): string {
    // Your custom logic here
    return this.CUSTOM_DESCRIPTION[tag.name] || tag.description || '';
  }
}

Alternatively, you can use DefaultResourceParser and override only the methods you need. The default implementation you can find in src/ResourceParser.ts

import {OpenAPIV3} from 'openapi-types';
import * as lodash from 'lodash';
import {DefaultResourceParser} from '@devlikeapro/n8n-openapi-node';

export class CustomResourceParser extends DefaultResourceParser {
  value(tag: OpenAPIV3.TagObject): string {
    return lodash.startCase(tag.name.replace(/[^a-zA-Z0-9_-]/g, ''));
  }
}

Then you use it in N8NPropertiesBuilder in config.resource:

import {N8NPropertiesBuilder, N8NPropertiesBuilderConfig} from '@devlikeapro/n8n-openapi-node';
import * as doc from './openapi.json';

import {CustomResourceParser} from './CustomResourceParser';

const config: N8NPropertiesBuilderConfig = {
  resource: new CustomResourceParser()
}
const parser = new N8NPropertiesBuilder(doc, config);
const properties = parser.build()

Find real example in @devlikeapro/n8n-nodes-waha repository.

Operation

You can override the way how to extract Operation from OpenAPI Operation defining your custom IOperationParser:

import {IOperationParser} from '@devlikeapro/n8n-openapi-node';

export class CustomOperationParser implements IOperationParser {
  shouldSkip(operation: OpenAPIV3.OperationObject, context: OperationContext): boolean {
    // By default it skips operation.deprecated
    // But we can include all operations
    return false
  }

  name(operation: OpenAPIV3.OperationObject, context: OperationContext): string {
    if (operation['X-Visible-Name']) {
      return operation['X-Visible-Name'];
    }
    return lodash.startCase(operation.operationId)
  }

  value(operation: OpenAPIV3.OperationObject, context: OperationContext): string {
    return lodash.startCase(operation.operationId)
  }

  action(operation: OpenAPIV3.OperationObject, context: OperationContext): string {
    // How operation is displayed in n8n when you select your node (right form)
    return operation.summary || this.name(operation, context)
  }

  description(operation: OpenAPIV3.OperationObject, context: OperationContext): string {
    return operation.description || operation.summary || '';
  }
}

Alternatively, you can use DefaultOperationParser and override only the methods you need. The default implementation you can find in src/OperationParser.ts

import {DefaultOperationParser} from '@devlikeapro/n8n-openapi-node';

export class CustomOperationParser extends DefaultOperationParser {
  name(operation: OpenAPIV3.OperationObject, context: OperationContext): string {
    // NestJS add operationId in format CatController_findOne
    let operationId: string = operation.operationId!!.split('_').slice(1).join('_');
    if (!operationId) {
      operationId = operation.operationId as string;
    }
    return lodash.startCase(operationId);
  }
}

Then you use it in N8NPropertiesBuilder in config.operation:

import {N8NPropertiesBuilder, N8NPropertiesBuilderConfig} from '@devlikeapro/n8n-openapi-node';
import * as doc from './openapi.json';
import {CustomOperationParser} from './CustomOperationParser';

const config: N8NPropertiesBuilderConfig = {
  operation: new CustomOperationParser()
}
const parser = new N8NPropertiesBuilder(doc, config);
const properties = parser.build()

Find real example in @devlikeapro/n8n-nodes-waha repository.

Fields

You can override some values for fields at the end, when full properties are ready.

Here's example how you can override session field value (which has 'default' string default value) to more n8n suitable =${$json.session}}:

import {Override} from '@devlikeapro/n8n-openapi-node';

export const customDefaults: Override[] = [
  {
    // Find field by fields matching
    find: {
      name: 'session',
      required: true,
      type: 'string',
    },
    // Replace 'default' field value
    replace: {
      default: '={{ $json.session }}',
    },
  },
];

Then you use it in N8NPropertiesBuilder:

import {N8NPropertiesBuilder, N8NPropertiesBuilderConfig} from '@devlikeapro/n8n-openapi-node';
import * as doc from './openapi.json';
import {customDefaults} from './customDefaults';

const parser = new N8NPropertiesBuilder(doc);
const properties = parser.build(customDefaults);

Find real example in @devlikeapro/n8n-nodes-waha repository.

Use Cases

Here's n8n community nodes generated from OpenAPI specifications you can use for reference:

• @devlikeapro/n8n-nodes-petstore - Petstore example generated from Petstore openapi.json
• @devlikeapro/n8n-nodes-chatwoot - ChatWoot n8n community node from https://www.chatwoot.com/developers/api/. Defines credentials as well ( manually)
• @devlikeapro/n8n-nodes-waha - WAHA - Self-hosted WhatsApp HTTP API you can run in a click!

FAQ

I have only OpenAPI v2 spec, what can I do?

Paste your OpenAPI 2.0 definition into https://editor.swagger.io and select Edit > Convert to OpenAPI 3 from the menu.

https://stackoverflow.com/a/59749691

I have openapi.yaml spec, what can I do?

Paste your yaml spec to https://editor.swagger.io and select File > Save as JSON from the menu.

How to set up credentials from OpenAPI v3 spec?

Right now you need to define it manually. Check ChatWoot node for an example.

Why it doesn't work with my OpenAPI spec?

Open a new issue and please attach your openapi.json file and describe the problem (logs are helpful too).