选择你的节点构建方法(Choose your node building approach)

n8n 提供两种节点构建方式：声明式和编程式。

🌐 n8n has two node-building styles, declarative and programmatic.

对于大多数节点，你应该使用声明式风格。这种风格：

🌐 You should use the declarative style for most nodes. This style:

• 使用基于 JSON 的语法，编写更简单，引入错误的风险更低。
• 更具前瞻性。
• 支持与 REST API 集成。

编程风格更为冗长。你必须在以下情况下使用编程风格：

🌐 The programmatic style is more verbose. You must use the programmatic style for:

• 触发器节点
• 任何非基于 REST 的节点。这包括需要调用 GraphQL API 的节点以及使用外部依赖的节点。
• 任何需要转换传入数据的节点。
• 完整版本控制。有关版本类型的更多信息，请参阅 Node 版本控制。

数据处理差异(Data handling differences)

声明式和编程式风格的主要区别在于它们如何处理传入的数据并构建 API 请求。编程式风格需要一个 execute() 方法，该方法读取传入的数据和参数，然后构建请求。声明式风格则通过 operations 对象中的 routing 键来处理此问题。有关节点参数和 execute() 方法的更多信息，请参阅 Node 基础文件。

🌐 The main difference between the declarative and programmatic styles is how they handle incoming data and build API requests. The programmatic style requires an execute() method, which reads incoming data and parameters, then builds a request. The declarative style handles this using the routing key in the operations object. Refer to Node base file for more information on node parameters and the execute() method.

语法差异(Syntax differences)

要理解声明式和程序化风格的区别，请比较下面的两个代码片段。这个示例创建了 SendGrid 集成的简化版本，称为“FriendGrid”。以下代码片段并不完整：它们强调的是节点构建风格的差异。

🌐 To understand the difference between the declarative and programmatic styles, compare the two code snippets below. This example creates a simplified version of the SendGrid integration, called "FriendGrid." The following code snippets aren't complete: they emphasize the differences in the node building styles.

程序化风格：

🌐 In programmatic style:

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)];
  }
}

声明式风格：

🌐 In declarative style:

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
}