Power Automate：筛选没有分类的邮件

本文将展示如何通过 Power Automate 筛选Outlook 中未分类的邮件.

在当前的 Outlook 365 连接器中，没有可以筛选掉有/无分类的邮件的选项。

当我尝试构建流程时，我以为可以使用Get emails (V3)。尝试之后，我发现到正文中没有类别信息，并且这个还特别消耗API. 下面是来自它的输出信息的body值：一个邮件结构的示例Get emails (V3)。

{
    "id": "value",
    "receivedDateTime": "",
    "hasAttachments": false,
    "internetMessageId": "",
    "subject": "",
    "bodyPreview": "Hi...",
    "importance": "normal",
    "conversationId": "",
    "isRead": false,
    "isHtml": true,
    "body": "html body",
    "from": "",
    "toRecipients": "",
    "attachments": []
},

在我检查每个操作后，发现只能使用Send an HTTP request 

使用Send an HTTP request

此操作构造要调用的 Microsoft Graph REST API 请求。支持以下段：

1. 1st segment: /me, /users/
2. 2nd segment: messages, mailFolders, events, calendar, calendars, outlook, inferenceClassification

/me/messages 可行，但我只想查看收件箱的未读邮件.

/me/mailFolders/Inbox/messages 这个刚刚好

为了演示目的，伪代码如下：

Send an request to query inbox message and apply to unread message.
Filter if any uncategorized message.
For each message found, assign category.

一些无效的方法：

1. 使用 Odata 过滤器

filter=categories eq null //not work
filter=categories in //not work
filter=categories/any(c:c eq '')//not work
filter=categories/any(c:c eq null)//not work
filter=categories/any(c:c eq 'null')//not work
filter=categories/any(c:c eq '')//not work

2. ##### 使用条件过滤

equals(item()?['categories'], null) //not work.
equals(length(item()?['categories']), 0)) //nope

备选的方法

filter=not categories/any() 
//仅当纯筛选未分类的邮件

可行的方法。

empty(item()?['categories'])
//Returns true if the object, array, or string is empty.

因为categories是一个数组，恰好empty函数可以接受数组为参数.

流程概览。

流程分解：

1. 初始化 OData 查询变量

{
    "type": "InitializeVariable",
    "inputs": {
      "variables": [
        {
          "name": "MyQuery",
          "type": "string",
          "value": "filter=isRead eq false&$select=categories&$top=10"
        }
      ]
    },
    "runAfter": {}
  }

2. ##### 发送 HTTP 请求

{
    "type": "OpenApiConnection",
    "inputs": {
      "parameters": {
        "Uri": "https://graph.microsoft.com/v1.0/me/mailFolders/Inbox/messages?$@{variables('MyQuery')}",
        "Method": "GET",
        "ContentType": "application/json"
      },
      "host": {
        "apiId": "/providers/Microsoft.PowerApps/apis/shared_office365",
        "connection": "shared_office365",
        "operationId": "HttpRequest"
      }
    },
    "runAfter": {
      "Initialize_variable_for_OData_query": [
        "Succeeded"
      ]
    }
  }

3. ##### 仅筛选未分类的消息

{
    "type": "Query",
    "inputs": {
      "from": "@body('Send_an_HTTP_request')?['value']",
      "where": "@empty(item()?['categories'])"
    },
    "runAfter": {
      "Send_an_HTTP_request": [
        "Succeeded"
      ]
    }
  }

4. ##### 对于每条未分类的消息

{
    "type": "Foreach",
    "foreach": "@outputs('Filter_array_only_uncategorized_message')['body']",
    "actions": {
      "Assigns_an_Outlook_category": {
        "type": "OpenApiConnection",
        "inputs": {
          "parameters": {
            "messageId": "@items('For_each_uncategorized_message')?['id']",
            "category": "FollowUP" //Your category name.
          },
          "host": {
            "apiId": "/providers/Microsoft.PowerApps/apis/shared_office365",
            "connection": "shared_office365",
            "operationId": "AssignCategory"
          }
        }
      }
    },
    "runAfter": {
      "Filter_array_only_uncategorized_message": [
        "Succeeded"
      ]
    }
  }

5. ##### 分配 Outlook 类别

{
    "type": "OpenApiConnection",
    "inputs": {
      "parameters": {
        "messageId": "@items('For_each_uncategorized_message')?['id']",
        "category": "FollowUP"
      },
      "host": {
        "apiId": "/providers/Microsoft.PowerApps/apis/shared_office365",
        "connection": "shared_office365",
        "operationId": "AssignCategory"
      }
    }
  }

与我之前创建的另一个相比，旧流程消耗了更多的 API。