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| #https://www.notion.so/n8n/Frontmatter-432c2b8dff1f43d4b1c8d20075510fe4 | |
| contentType: tutorial | |
| # Build a declarative-style node | |
| This tutorial walks through building a declarative-style node. Before you begin, make sure this is the node style you need. Refer to [Choose your node building approach](/integrations/creating-nodes/plan/choose-node-method.md) for more information. | |
| ## Prerequisites | |
| You need the following installed on your development machine: | |
| --8<-- "_snippets/integrations/creating-nodes/prerequisites.md" | |
| You need some understanding of: | |
| - JavaScript/TypeScript | |
| - REST APIs | |
| - git | |
| ## Build your node | |
| In this section, you'll clone n8n's node starter repository, and build a node that integrates the [NASA API](https://api.nasa.gov/){:target=_blank .external-link}. You'll create a node that uses two of NASA's services: APOD (Astronomy Picture of the Day) and Mars Rover Photos. To keep the code examples short, the node won't implement every available option for the Mars Rover Photos endpoint. | |
| /// note | Existing node | |
| n8n has a built-in NASA node. To avoid clashing with the existing node, you'll give your version a different name. | |
| /// | |
| ### Step 1: Set up the project | |
| n8n provides a starter repository for node development. Using the starter ensures you have all necessary dependencies. It also provides a linter. | |
| Clone the repository and navigate into the directory: | |
| 1. [Generate a new repository](https://github.com/n8n-io/n8n-nodes-starter/generate) from the template repository. | |
| 2. Clone your new repository: | |
| ```shell | |
| git clone https://github.com/<your-organization>/<your-repo-name>.git n8n-nodes-nasa-pics | |
| cd n8n-nodes-nasa-pics | |
| ``` | |
| The starter contains example nodes and credentials. Delete the following directories and files: | |
| * `nodes/ExampleNode` | |
| * `nodes/HTTPBin` | |
| * `credentials/ExampleCredentials.credentials.ts` | |
| * `credentials/HttpBinApi.credentials.ts` | |
| Now create the following directories and files: | |
| `nodes/NasaPics` | |
| `nodes/NasaPics/NasaPics.node.json` | |
| `nodes/NasaPics/NasaPics.node.ts` | |
| `credentials/NasaPicsApi.credentials.ts` | |
| These are the key files required for any node. Refer to [Node file structure](/integrations/creating-nodes/build/reference/node-file-structure.md) for more information on required files and recommended organization. | |
| Now install the project dependencies: | |
| ```shell | |
| npm i | |
| ``` | |
| ### Step 2: Add an icon | |
| Save the NASA SVG logo from [here](https://upload.wikimedia.org/wikipedia/commons/e/e5/NASA_logo.svg){:target=_blank .external-link} as `nasapics.svg` in `nodes/NasaPics/`. | |
| --8<-- "_snippets/integrations/creating-nodes/node-icons.md" | |
| ### Step 3: Create the node | |
| Every node must have a base file. Refer to [Node base file](/integrations/creating-nodes/build/reference/node-base-files/index.md) for detailed information about base file parameters. | |
| In this example, the file is `NasaPics.node.ts`. To keep this tutorial short, you'll place all the node functionality in this one file. When building more complex nodes, you should consider splitting out your functionality into modules. Refer to [Node file structure](/integrations/creating-nodes/build/reference/node-file-structure.md) for more information. | |
| #### Step 3.1: Imports | |
| Start by adding the import statements: | |
| ```typescript | |
| import { INodeType, INodeTypeDescription } from 'n8n-workflow'; | |
| ``` | |
| #### Step 3.2: Create the main class | |
| The node must export an interface that implements INodeType. This interface must include a `description` interface, which in turn contains the `properties` array. | |
| /// note | Class names and file names | |
| Make sure the class name and the file name match. For example, given a class `NasaPics`, the filename must be `NasaPics.node.ts`. | |
| /// | |
| ```typescript | |
| export class NasaPics implements INodeType { | |
| description: INodeTypeDescription = { | |
| // Basic node details will go here | |
| properties: [ | |
| // Resources and operations will go here | |
| ] | |
| }; | |
| } | |
| ``` | |
| #### Step 3.3: Add node details | |
| All nodes need some basic parameters, such as their display name, icon, and the basic information for making a request using the node. Add the following to the `description`: | |
| ```typescript | |
| displayName: 'NASA Pics', | |
| name: 'NasaPics', | |
| icon: 'file:nasapics.svg', | |
| group: ['transform'], | |
| version: 1, | |
| subtitle: '={{$parameter["operation"] + ": " + $parameter["resource"]}}', | |
| description: 'Get data from NASAs API', | |
| defaults: { | |
| name: 'NASA Pics', | |
| }, | |
| inputs: ['main'], | |
| outputs: ['main'], | |
| credentials: [ | |
| { | |
| name: 'NasaPicsApi', | |
| required: true, | |
| }, | |
| ], | |
| requestDefaults: { | |
| baseURL: 'https://api.nasa.gov', | |
| headers: { | |
| Accept: 'application/json', | |
| 'Content-Type': 'application/json', | |
| }, | |
| }, | |
| ``` | |
| n8n uses some of the properties set in `description` to render the node in the Editor UI. These properties are `displayName`, `icon`, `description`, and `subtitle`. | |
| #### Step 3.4: Add resources | |
| The resource object defines the API resource that the node uses. In this tutorial, you're creating a node to access two of NASA's API endpoints: `planetary/apod` and `mars-photos`. This means you need to define two resource options in `NasaPics.node.ts`. Update the `properties` array with the resource object: | |
| ```typescript | |
| properties: [ | |
| { | |
| displayName: 'Resource', | |
| name: 'resource', | |
| type: 'options', | |
| noDataExpression: true, | |
| options: [ | |
| { | |
| name: 'Astronomy Picture of the Day', | |
| value: 'astronomyPictureOfTheDay', | |
| }, | |
| { | |
| name: 'Mars Rover Photos', | |
| value: 'marsRoverPhotos', | |
| }, | |
| ], | |
| default: 'astronomyPictureOfTheDay', | |
| }, | |
| // Operations will go here | |
| ] | |
| ``` | |
| `type` controls which UI element n8n displays for the resource, and tells n8n what type of data to expect from the user. `options` results in n8n adding a dropdown that allows users to choose one option. Refer to [Node UI elements](/integrations/creating-nodes/build/reference/ui-elements.md) for more information. | |
| #### Step 3.5: Add operations | |
| The operations object defines the available operations on a resource. | |
| In a declarative-style node, the operations object includes `routing` (within the `options` array). This sets up the details of the API call. | |
| Add the following to the `properties` array, after the `resource` object: | |
| ```typescript | |
| { | |
| displayName: 'Operation', | |
| name: 'operation', | |
| type: 'options', | |
| noDataExpression: true, | |
| displayOptions: { | |
| show: { | |
| resource: [ | |
| 'astronomyPictureOfTheDay', | |
| ], | |
| }, | |
| }, | |
| options: [ | |
| { | |
| name: 'Get', | |
| value: 'get', | |
| action: 'Get the APOD', | |
| description: 'Get the Astronomy Picture of the day', | |
| routing: { | |
| request: { | |
| method: 'GET', | |
| url: '/planetary/apod', | |
| }, | |
| }, | |
| }, | |
| ], | |
| default: 'get', | |
| }, | |
| { | |
| displayName: 'Operation', | |
| name: 'operation', | |
| type: 'options', | |
| noDataExpression: true, | |
| displayOptions: { | |
| show: { | |
| resource: [ | |
| 'marsRoverPhotos', | |
| ], | |
| }, | |
| }, | |
| options: [ | |
| { | |
| name: 'Get', | |
| value: 'get', | |
| action: 'Get Mars Rover photos', | |
| description: 'Get photos from the Mars Rover', | |
| routing: { | |
| request: { | |
| method: 'GET', | |
| }, | |
| }, | |
| }, | |
| ], | |
| default: 'get', | |
| }, | |
| { | |
| displayName: 'Rover name', | |
| description: 'Choose which Mars Rover to get a photo from', | |
| required: true, | |
| name: 'roverName', | |
| type: 'options', | |
| options: [ | |
| {name: 'Curiosity', value: 'curiosity'}, | |
| {name: 'Opportunity', value: 'opportunity'}, | |
| {name: 'Perseverance', value: 'perseverance'}, | |
| {name: 'Spirit', value: 'spirit'}, | |
| ], | |
| routing: { | |
| request: { | |
| url: '=/mars-photos/api/v1/rovers/{{$value}}/photos', | |
| }, | |
| }, | |
| default: 'curiosity', | |
| displayOptions: { | |
| show: { | |
| resource: [ | |
| 'marsRoverPhotos', | |
| ], | |
| }, | |
| }, | |
| }, | |
| { | |
| displayName: 'Date', | |
| description: 'Earth date', | |
| required: true, | |
| name: 'marsRoverDate', | |
| type: 'dateTime', | |
| default:'', | |
| displayOptions: { | |
| show: { | |
| resource: [ | |
| 'marsRoverPhotos', | |
| ], | |
| }, | |
| }, | |
| routing: { | |
| request: { | |
| // You've already set up the URL. qs appends the value of the field as a query string | |
| qs: { | |
| earth_date: '={{ new Date($value).toISOString().substr(0,10) }}', | |
| }, | |
| }, | |
| }, | |
| }, | |
| // Optional/additional fields will go here | |
| ``` | |
| This code creates two operations: one to get today's APOD image, and another to send a get request for photos from one of the Mars Rovers. The object named `roverName` requires the user to choose which Rover they want photos from. The `routing` object in the Mars Rover operation references this to create the URL for the API call. | |
| #### Step 3.6: Optional fields | |
| Most APIs, including the NASA API that you're using in this example, have optional fields you can use to refine your query. | |
| To avoid overwhelming users, n8n displays these under **Additional Fields** in the UI. | |
| For this tutorial, you'll add one additional field, to allow users to pick a date to use with the APOD endpoint. Add the following to the properties array: | |
| ```typescript | |
| { | |
| displayName: 'Additional Fields', | |
| name: 'additionalFields', | |
| type: 'collection', | |
| default: {}, | |
| placeholder: 'Add Field', | |
| displayOptions: { | |
| show: { | |
| resource: [ | |
| 'astronomyPictureOfTheDay', | |
| ], | |
| operation: [ | |
| 'get', | |
| ], | |
| }, | |
| }, | |
| options: [ | |
| { | |
| displayName: 'Date', | |
| name: 'apodDate', | |
| type: 'dateTime', | |
| default: '', | |
| routing: { | |
| request: { | |
| // You've already set up the URL. qs appends the value of the field as a query string | |
| qs: { | |
| date: '={{ new Date($value).toISOString().substr(0,10) }}', | |
| }, | |
| }, | |
| }, | |
| }, | |
| ], | |
| } | |
| ``` | |
| ### Step 4: Set up authentication | |
| The NASA API requires users to authenticate with an API key. | |
| Add the following to `nasaPicsApi.credentials.ts`: | |
| ```typescript | |
| import { | |
| IAuthenticateGeneric, | |
| ICredentialType, | |
| INodeProperties, | |
| } from 'n8n-workflow'; | |
| export class NasaPicsApi implements ICredentialType { | |
| name = 'NasaPicsApi'; | |
| displayName = 'NASA Pics API'; | |
| // Uses the link to this tutorial as an example | |
| // Replace with your own docs links when building your own nodes | |
| documentationUrl = 'https://docs.n8n.io/integrations/creating-nodes/build/declarative-style-node/'; | |
| properties: INodeProperties[] = [ | |
| { | |
| displayName: 'API Key', | |
| name: 'apiKey', | |
| type: 'string', | |
| default: '', | |
| }, | |
| ]; | |
| authenticate = { | |
| type: 'generic', | |
| properties: { | |
| qs: { | |
| 'api_key': '={{$credentials.apiKey}}' | |
| } | |
| }, | |
| } as IAuthenticateGeneric; | |
| } | |
| ``` | |
| For more information about credentials files and options, refer to [Credentials file](/integrations/creating-nodes/build/reference/credentials-files.md). | |
| ### Step 5: Add node metadata | |
| Metadata about your node goes in the JSON file at the root of your node. n8n refers to this as the codex file. In this example, the file is `NasaPics.node.json`. | |
| Add the following code to the JSON file: | |
| ```json | |
| { | |
| "node": "n8n-nodes-base.NasaPics", | |
| "nodeVersion": "1.0", | |
| "codexVersion": "1.0", | |
| "categories": [ | |
| "Miscellaneous" | |
| ], | |
| "resources": { | |
| "credentialDocumentation": [ | |
| { | |
| "url": "" | |
| } | |
| ], | |
| "primaryDocumentation": [ | |
| { | |
| "url": "" | |
| } | |
| ] | |
| } | |
| } | |
| ``` | |
| For more information on these parameters, refer to [Node codex files](/integrations/creating-nodes/build/reference/node-codex-files.md). | |
| ### Step 6: Update the npm package details | |
| Your npm package details are in the `package.json` at the root of the project. It's essential to include the `n8n` object with links to the credentials and base node file. Update this file to include the following information: | |
| ```json | |
| { | |
| // All node names must start with "n8n-nodes-" | |
| "name": "n8n-nodes-nasapics", | |
| "version": "0.1.0", | |
| "description": "n8n node to call NASA's APOD and Mars Rover Photo services.", | |
| "keywords": [ | |
| // This keyword is required for community nodes | |
| "n8n-community-node-package" | |
| ], | |
| "license": "MIT", | |
| "homepage": "https://n8n.io", | |
| "author": { | |
| "name": "Test", | |
| "email": "test@example.com" | |
| }, | |
| "repository": { | |
| "type": "git", | |
| // Change the git remote to your own repository | |
| // Add the new URL here | |
| "url": "git+<your-repo-url>" | |
| }, | |
| "main": "index.js", | |
| "scripts": { | |
| // don't change | |
| }, | |
| "files": [ | |
| "dist" | |
| ], | |
| // Link the credentials and node | |
| "n8n": { | |
| "n8nNodesApiVersion": 1, | |
| "credentials": [ | |
| "dist/credentials/NasaPicsApi.credentials.js" | |
| ], | |
| "nodes": [ | |
| "dist/nodes/NasaPics/NasaPics.node.js" | |
| ] | |
| }, | |
| "devDependencies": { | |
| // don't change | |
| }, | |
| "peerDependencies": { | |
| // don't change | |
| } | |
| } | |
| ``` | |
| You need to update the `package.json` to include your own information, such as your name and repository URL. For more information on npm `package.json` files, refer to [npm's package.json documentation](https://docs.npmjs.com/cli/v8/configuring-npm/package-json){:target=_blank .external-link}. | |
| ## Test your node | |
| --8<-- "_snippets/integrations/creating-nodes/testing.md" | |
| ## Next steps | |
| * [Deploy your node](/integrations/creating-nodes/deploy/index.md). | |
| * View an example of a declarative node: n8n's [Brevo node](https://github.com/n8n-io/n8n/tree/master/packages/nodes-base/nodes/Brevo){:target=_blank .external-link}. Note that the main node is declarative, while the trigger node is in programmatic style. | |
| * Learn about [node versioning](/integrations/creating-nodes/build/reference/node-versioning.md). | |