选择节点构建方式#

n8n提供两种节点构建风格：声明式与编程式。

多数节点建议采用声明式风格，该风格具有以下特点：

• 采用基于JSON的语法，编写更简便且能降低代码缺陷风险
• 具备更好的未来兼容性
• 支持REST API集成

编程式风格更为冗长，以下场景必须使用该风格：

• 触发器节点
• 非REST架构节点（包括需调用GraphQL接口的节点及使用外部依赖的节点）
• 需对输入数据进行转换处理的节点
• 完整版本控制需求（详见节点版本控制了解版本控制类型）

数据处理差异#

两种风格的核心差异在于数据处理与API请求构建方式：编程式需通过execute()方法读取输入数据及参数后构建请求，而声明式通过operations对象中的routing键实现该功能。关于节点参数与execute()方法的详细信息，请参阅节点基础文件。

语法差异#

通过以下代码片段对比可直观理解两种风格的差异。本例创建了SendGrid集成的简化版"FriendGrid"，注意这些片段仅为突出构建风格差异的非完整示例：

编程式风格：

import {
	IExecuteFunctions,
	INodeExecutionData,
	INodeType,
	INodeTypeDescription,
	IRequestOptions,
} from 'n8n-workflow';

// Create the FriendGrid class
export class FriendGrid implements INodeType {
  description: INodeTypeDescription = {
    displayName: 'FriendGrid',
    name: 'friendGrid',
    . . .
    properties: [
      {
        displayName: 'Resource',
        . . .
      },
      {
        displayName: 'Operation',
        name: 'operation',
        type: 'options',
        displayOptions: {
          show: {
              resource: [
              'contact',
              ],
          },
        },
        options: [
          {
            name: 'Create',
            value: 'create',
            description: 'Create a contact',
          },
        ],
        default: 'create',
        description: 'The operation to perform.',
      },
      {
        displayName: 'Email',
        name: 'email',
        . . .
      },
      {
        displayName: 'Additional Fields',
        // Sets up optional fields
      },
    ],
};

  async execute(this: IExecuteFunctions): Promise<INodeExecutionData[][]> {
    let responseData;
    const resource = this.getNodeParameter('resource', 0) as string;
    const operation = this.getNodeParameter('operation', 0) as string;
    //Get credentials the user provided for this node
    const credentials = await this.getCredentials('friendGridApi') as IDataObject;

    if (resource === 'contact') {
      if (operation === 'create') {
      // Get email input
      const email = this.getNodeParameter('email', 0) as string;
      // Get additional fields input
      const additionalFields = this.getNodeParameter('additionalFields', 0) as IDataObject;
      const data: IDataObject = {
          email,
      };

      Object.assign(data, additionalFields);

      // Make HTTP request as defined in https://sendgrid.com/docs/api-reference/
      const options: IRequestOptions = {
        headers: {
            'Accept': 'application/json',
            'Authorization': `Bearer ${credentials.apiKey}`,
        },
        method: 'PUT',
        body: {
            contacts: [
            data,
            ],
        },
        url: `https://api.sendgrid.com/v3/marketing/contacts`,
        json: true,
      };
      responseData = await this.helpers.httpRequest(options);
      }
    }
    // Map data to n8n data
    return [this.helpers.returnJsonArray(responseData)];
  }
}

在声明式风格中：

import { INodeType, INodeTypeDescription } from 'n8n-workflow';

// Create the FriendGrid class
export class FriendGrid implements INodeType {
  description: INodeTypeDescription = {
    displayName: 'FriendGrid',
    name: 'friendGrid',
    . . .
    // Set up the basic request configuration
    requestDefaults: {
      baseURL: 'https://api.sendgrid.com/v3/marketing'
    },
    properties: [
      {
        displayName: 'Resource',
        . . .
      },
      {
        displayName: 'Operation',
        name: 'operation',
        type: 'options',
        displayOptions: {
          show: {
            resource: [
              'contact',
            ],
          },
        },
        options: [
          {
            name: 'Create',
            value: 'create',
            description: 'Create a contact',
            // Add the routing object
            routing: {
              request: {
                method: 'POST',
                url: '=/contacts',
                send: {
                  type: 'body',
                  properties: {
                    email: {{$parameter["email"]}}
                  }
                }
              }
            },
            // Handle the response to contact creation
            output: {
              postReceive: [
                {
                  type: 'set',
                  properties: {
                    value: '={{ { "success": $response } }}'
                  }
                }
              ]
            }
          },
        ],
        default: 'create',
        description: 'The operation to perform.',
      },
      {
        displayName: 'Email',
        . . .
      },
      {
        displayName: 'Additional Fields',
        // Sets up optional fields
      },
    ],
  }
  // No execute method needed
}