如何使用Gmail API检索我的Gmail邮件？

Question

我想要实现的目标:

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我使用的是Gmail的API,基本上我想连接到我的Gmail帐户阅读我的邮件,收件箱类别,并获取每个邮件的基本信息(标题/主题,从,到,日期和发送者).

问题:

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我正在尝试根据自己的需要调整这个用C#编写的Google示例,我正在寻找C#或Vb.Net的解决方案,无论如何.

(请注意,Google会针对不同的用户所示国家/地区显示不同的代码示例,因此该网页的代码可能与每个网站的代码相同,而Google的逻辑确实非常糟糕.)

我在下面的代码中遇到的问题是:

• 我在lblInbox.MessagesTotal财产上得到一个空值.
• msgItem.Raw 财产也总是空的.
• 我还没有发现如何只解析INBOX类别中的消息.
• 我还没有发现如何确定消息是读还是未读.
• 我还没有发现如何确定邮件的基本信息(主题,来自,发送日期,发件人).

这就是我尝试过的,请注意,在调整Google的示例时,我认为该"user"参数应该是Gmail用户帐户名("MyEmail@GMail.com"),但我不确定它应该是那样.

Imports System.Collections.Generic
Imports System.IO
Imports System.Linq
Imports System.Text
Imports System.Threading
Imports System.Threading.Tasks

Imports Google.Apis.Auth.OAuth2
Imports Google.Apis.Services
Imports Google.Apis.Util.Store
Imports Google.Apis.Gmail
Imports Google.Apis.Gmail.v1
Imports Google.Apis.Gmail.v1.Data
Imports Google.Apis.Gmail.v1.UsersResource

Public Class Form1 : Inherits Form

    Private Async Sub Test() Handles MyBase.Shown
        Await GmailTest()
    End Sub

    Public Async Function GmailTest() As Task
        Dim credential As UserCredential
        Using stream As New FileStream("C:\GoogleAPIKey.json", FileMode.Open, FileAccess.Read)
            credential = Await GoogleWebAuthorizationBroker.AuthorizeAsync(GoogleClientSecrets.Load(stream).Secrets,
                                                                           {GmailService.Scope.MailGoogleCom},
                                                                           "MyEmail@GMail.com",
                                                                           CancellationToken.None)
        End Using

        ' Create the service.
        Dim service As New GmailService(New BaseClientService.Initializer() With {
             .HttpClientInitializer = credential,
             .ApplicationName = "What I need to put here?"
        })

        ' Get the "INBOX" label/category.
        Dim lblReq As UsersResource.LabelsResource.ListRequest = service.Users.Labels.List("me")
        Dim lblInbox As Data.Label = lblReq.Execute().Labels.Where(Function(lbl) lbl.Name = "INBOX").Single
        Dim msgCount As Integer? = lblInbox.MessagesTotal

        MsgBox("Messages Count: " & msgCount)

        If (msgCount <> 0) Then

            ' Define message parameters of request.
            Dim msgReq As UsersResource.MessagesResource.ListRequest = service.Users.Messages.List("me")

            ' List messages of INBOX category.
            Dim messages As IList(Of Data.Message) = msgReq.Execute().Messages
            Console.WriteLine("Messages:")
            If (messages IsNot Nothing) AndAlso (messages.Count > 0) Then
                For Each msgItem As Data.Message In messages
                    MsgBox(msgItem.Raw)
                Next
            End If

        End If

    End Function

End Class

题:

---

我会要求最重要的需求(但是,非常欢迎任何帮助解决其他提到的问题):

• 在C#或VB.Net中,如何获取一个集合来迭代INBOX组中的所有电子邮件？

---

更新:

这是我现在使用,其目的是获取所有的集合代码Message指定邮箱第标签,问题是,Payload和Body成员newMsg对象为空,所以我不能阅读电子邮件.

我做错了什么？

Public Async Function GetMessages(ByVal folder As Global.Google.Apis.Gmail.v1.Data.Label) As Task(Of List(Of Global.Google.Apis.Gmail.v1.Data.Message))

    If Not (Me.isAuthorizedB) Then
        Throw New InvalidOperationException(Me.authExceptionMessage)
    Else
        Dim msgsRequest As UsersResource.MessagesResource.ListRequest = Me.client.Users.Messages.List("me")
        With msgsRequest
            .LabelIds = New Repeatable(Of String)({folder.Id})
            .MaxResults = 50
            '.Key = "YOUR API KEY"
        End With

        Dim msgsResponse As ListMessagesResponse = Await msgsRequest.ExecuteAsync()

        Dim messages As New List(Of Global.Google.Apis.Gmail.v1.Data.Message)
        Do While True

            For Each msg As Global.Google.Apis.Gmail.v1.Data.Message In msgsResponse.Messages
                Dim msgRequest As UsersResource.MessagesResource.GetRequest = Me.client.Users.Messages.Get("me", msg.Id)
                msgRequest.Format = MessagesResource.GetRequest.FormatEnum.Full

                Dim newMsg As Message = Await msgRequest.ExecuteAsync()
                messages.Add(newMsg)
            Next msg

            If Not String.IsNullOrEmpty(msgsResponse.NextPageToken) Then
                msgsRequest.PageToken = msgsResponse.NextPageToken
                msgsResponse = Await msgsRequest.ExecuteAsync()
            Else
                Exit Do
            End If

        Loop

        Return messages

    End If

End Function

Answer 1

目前由于某种原因,许多属性都是null从任何请求中回来的.如果我们有一个电子邮件ID列表,我们仍然可以解决这个问题.然后,我们可以使用这些电子邮件ID发出另一个请求以获取进一步的细节:from,date,subject,和body.@DalmTo也在正确的轨道上,但是关于标题不够近,因为它最近已经改变了,这将需要更多的请求.

private async Task getEmails()
{
    try
    {
        UserCredential credential;
        using (var stream = new FileStream("client_secrets.json", FileMode.Open, FileAccess.Read))
        {
            credential = await GoogleWebAuthorizationBroker.AuthorizeAsync(
                GoogleClientSecrets.Load(stream).Secrets,
                // This OAuth 2.0 access scope allows for read-only access to the authenticated 
                // user's account, but not other types of account access.
                new[] { GmailService.Scope.GmailReadonly, GmailService.Scope.MailGoogleCom, GmailService.Scope.GmailModify },
                "NAME OF ACCOUNT NOT EMAIL ADDRESS",
                CancellationToken.None,
                new FileDataStore(this.GetType().ToString())
            );
        }

        var gmailService = new GmailService(new BaseClientService.Initializer()
        {
            HttpClientInitializer = credential,
            ApplicationName = this.GetType().ToString()
        });

        var emailListRequest = gmailService.Users.Messages.List("EMAILADDRESSHERE");
        emailListRequest.LabelIds = "INBOX";
        emailListRequest.IncludeSpamTrash = false;
        //emailListRequest.Q = "is:unread"; // This was added because I only wanted unread emails...

        // Get our emails
        var emailListResponse = await emailListRequest.ExecuteAsync();

        if (emailListResponse != null && emailListResponse.Messages != null)
        {
            // Loop through each email and get what fields you want...
            foreach (var email in emailListResponse.Messages)
            {
                var emailInfoRequest = gmailService.Users.Messages.Get("EMAIL ADDRESS HERE", email.Id);
                // Make another request for that email id...
                var emailInfoResponse = await emailInfoRequest.ExecuteAsync();

                if (emailInfoResponse != null)
                {
                    String from = "";
                    String date = "";
                    String subject = "";
                    String body = "";
                    // Loop through the headers and get the fields we need...
                    foreach (var mParts in emailInfoResponse.Payload.Headers)
                    {
                        if (mParts.Name == "Date")
                        {
                            date = mParts.Value; 
                        }
                        else if(mParts.Name == "From" )
                        {
                            from = mParts.Value;
                        }
                        else if (mParts.Name == "Subject")
                        {
                            subject = mParts.Value;
                        }

                        if (date != "" && from != "")
                        {
                            if (emailInfoResponse.Payload.Parts == null && emailInfoResponse.Payload.Body != null)
                            {
                                body = emailInfoResponse.Payload.Body.Data;
                            }
                            else
                            {
                                body = getNestedParts(emailInfoResponse.Payload.Parts, "");
                            }
                            // Need to replace some characters as the data for the email's body is base64
                            String codedBody = body.Replace("-", "+");
                            codedBody = codedBody.Replace("_", "/");
                            byte[] data = Convert.FromBase64String(codedBody);
                            body = Encoding.UTF8.GetString(data);                               

                            // Now you have the data you want...                         
                        }
                    }
                }                    
            }
        }           
    }
    catch (Exception)
    {
        MessageBox.Show("Failed to get messages!", "Failed Messages!", MessageBoxButtons.OK); 
    }
}

static String getNestedParts(IList<MessagePart> part, string curr)
{
    string str = curr;
    if (part == null)
    {
        return str;
    }
    else
    {
        foreach (var parts in part)
        {
            if (parts.Parts  == null)
            {
                if (parts.Body != null && parts.Body.Data != null)
                {
                    str += parts.Body.Data;
                }
            }
            else
            {
                return getNestedParts(parts.Parts, str);
            }
        }

        return str;
    }        
}

目前,这种方法会检索所有电子邮件ID,并为每个电子邮件ID得到subject,from,date和body每封电子邮件.整个方法都有评论.如果您有不明白的地方,请告诉我.另一个注意事项:在将此作为答案发布之前,再次对此进行了测试.

Answer 2

对不起这不是答案,我不能对Zaggler的答案添加评论(刚加入),所以只是发布作为一个新答案,Zaggler的答案非常好,但是有一个小问题.当电子邮件正文有多个部分时.Convert.FromBase64 .....对两个连接的base64字符串不起作用.所以会发生异常.更好的转换然后加入身体部位.

有人问代码,这是完成的测试代码.他们中的大多数是从Zaggler复制的,但我最终有一些例外.所以我追溯到上述问题.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.IO;
using Google.Apis.Auth.OAuth2;
using Google.Apis.Gmail.v1;
using Google.Apis.Gmail.v1.Data;
using Google.Apis.Services;
using Google.Apis.Util.Store;

namespace GmailTests
{
    class Program
    {
        // If modifying these scopes, delete your previously saved credentials
        // at ~/.credentials/gmail-dotnet-quickstart.json
        static string[] Scopes = { GmailService.Scope.GmailModify };
        static string ApplicationName = "Gmail API .NET Quickstart";

        static void Main(string[] args)
        {
            UserCredential credential;

            using (var stream =
                new FileStream("client_secret.json", FileMode.Open, FileAccess.Read))
            {
                string credPath = System.Environment.GetFolderPath(
                    System.Environment.SpecialFolder.Personal);
                credPath = Path.Combine(credPath, ".credentials/gmail-dotnet-quickstart2.json");

                credential = GoogleWebAuthorizationBroker.AuthorizeAsync(
                    GoogleClientSecrets.Load(stream).Secrets,
                    Scopes,
                    "user",
                    CancellationToken.None,
                    new FileDataStore(credPath, true)).Result;
                Console.WriteLine("Credential file saved to: " + credPath);
            }

            // Create Gmail API service.
            var service = new GmailService(new BaseClientService.Initializer()
            {
                HttpClientInitializer = credential,
                ApplicationName = ApplicationName,
            });


            var re = service.Users.Messages.List("me");
            re.LabelIds = "INBOX";
            re.Q = "is:unread"; //only get unread;

            var res = re.Execute();

            if (res != null && res.Messages != null)
            {
                Console.WriteLine("there are {0} emails. press any key to continue!", res.Messages.Count);
                Console.ReadKey();

                foreach (var email in res.Messages)
                {
                    var emailInfoReq = service.Users.Messages.Get("me", email.Id);
                    var emailInfoResponse = emailInfoReq.Execute();

                    if (emailInfoResponse != null)
                    {
                        String from = "";
                        String date = "";
                        String subject = "";
                        String body = "";
                        //loop through the headers and get the fields we need...
                        foreach (var mParts in emailInfoResponse.Payload.Headers)
                        {
                            if (mParts.Name == "Date")
                            {
                                date = mParts.Value;
                            }
                            else if (mParts.Name == "From")
                            {
                                from = mParts.Value;
                            }
                            else if (mParts.Name == "Subject")
                            {
                                subject = mParts.Value;
                            }

                            if (date != "" && from != "")
                            {
                                if (emailInfoResponse.Payload.Parts == null && emailInfoResponse.Payload.Body != null)
                                    body = DecodeBase64String(emailInfoResponse.Payload.Body.Data);
                                else
                                    body = GetNestedBodyParts(emailInfoResponse.Payload.Parts, "");

                                //now you have the data you want....

                            }

                        }

                        //Console.Write(body);
                        Console.WriteLine("{0}  --  {1}  -- {2}", subject, date, email.Id);
                        Console.ReadKey();
                    }
                }
            }
        }

        static String DecodeBase64String(string s)
        {
            var ts = s.Replace("-", "+");
            ts = ts.Replace("_", "/");
            var bc = Convert.FromBase64String(ts);
            var tts = Encoding.UTF8.GetString(bc);

            return tts;
        }

        static String GetNestedBodyParts(IList<MessagePart> part, string curr)
        {
            string str = curr;
            if (part == null)
            {
                return str;
            }
            else
            {
                foreach (var parts in part)
                {
                    if (parts.Parts == null)
                    {
                        if (parts.Body != null && parts.Body.Data != null)
                        {
                            var ts = DecodeBase64String(parts.Body.Data);
                            str += ts;
                        }
                    }
                    else
                    {
                        return GetNestedBodyParts(parts.Parts, str);
                    }
                }

                return str;
            }
        }
    }
}