C# EWS连接出现未经授权(401)错误
我一直在开发一个程序,该程序可以扫描exchange收件箱中来自指定地址的特定电子邮件。目前,该程序读取收件箱,下载附件,并将电子邮件移动到另一个文件夹。然而,在从EWS服务器拉取大约15次后,连接开始出现401未经授权的错误,直到我重新启动程序。该程序设置为通过OAuth登录,因为系统管理员禁用了基本身份验证。下面是我用来获取exchange连接并从收件箱中读取电子邮件的代码 交换连接代码:C# EWS连接出现未经授权(401)错误,c#,.net,exchangewebservices,C#,.net,Exchangewebservices,我一直在开发一个程序,该程序可以扫描exchange收件箱中来自指定地址的特定电子邮件。目前,该程序读取收件箱,下载附件,并将电子邮件移动到另一个文件夹。然而,在从EWS服务器拉取大约15次后,连接开始出现401未经授权的错误,直到我重新启动程序。该程序设置为通过OAuth登录,因为系统管理员禁用了基本身份验证。下面是我用来获取exchange连接并从收件箱中读取电子邮件的代码 交换连接代码: public static async Task<ExchangeService> Get
public static async Task<ExchangeService> GetExchangeConnection()
{
var pcaOptions = new PublicClientApplicationOptions
{
ClientId = AppID,
TenantId = TenantID,
};
var pca = PublicClientApplicationBuilder.CreateWithApplicationOptions(pcaOptions).Build();
var ewsScopes = new string[] { "https://outlook.office365.com/EWS.AccessAsUser.All" };
var securePassword = new SecureString();
foreach (char c in Pasword)
securePassword.AppendChar(c);
try
{
var authResult = await pca.AcquireTokenByUsernamePassword(ewsScopes, Username, securePassword).ExecuteAsync();
ExchangeService exchangeService = new ExchangeService()
{
Credentials = new OAuthCredentials(authResult.AccessToken),
Url = new Uri("https://outlook.office365.com/ews/exchange.asmx"),
};
return exchangeService;
}
catch
{
return null;
}
}
公共静态异步任务GetExchangeConnection()
{
var pcaooptions=新的PublicClientApplicationOptions
{
ClientId=AppID,
TenantId=TenantId,
};
var pca=PublicClientApplicationBuilder.CreateWithApplicationOptions(PCAOOptions).Build();
var ewscopes=新字符串[]{”https://outlook.office365.com/EWS.AccessAsUser.All" };
var securePassword=new SecureString();
foreach(Pasword中的字符c)
securePassword.AppendChar(c);
尝试
{
var authResult=wait pca.AcquireTokenByUsernamePassword(EWSCOpes、Username、securePassword)。ExecuteAsync();
ExchangeService ExchangeService=新的ExchangeService()
{
凭据=新的OAuthCredentials(authResult.AccessToken),
Url=新Uri(“https://outlook.office365.com/ews/exchange.asmx"),
};
返回交换服务;
}
抓住
{
返回null;
}
}
电子邮件检索器
public static List<Email> RetreiveEmails()
{
ExchangeService exchangeConnection = GetExchangeConnection().Result;
try
{
List<Email> Emails = new List<Email>();
TimeSpan ts = new TimeSpan(0, -5, 0, 0);
DateTime date = DateTime.Now.Add(ts);
SearchFilter.IsGreaterThanOrEqualTo EmailTimeFilter = new SearchFilter.IsGreaterThanOrEqualTo(ItemSchema.DateTimeReceived, date);
if (exchangeConnection != null)
{
FindItemsResults<Item> findResults = exchangeConnection.FindItems(WellKnownFolderName.Inbox, EmailTimeFilter, new ItemView(10));
foreach (Item item in findResults)
{
if (item.Subject != null)
{
EmailMessage message = EmailMessage.Bind(exchangeConnection, item.Id);
message.Load(new PropertySet(BasePropertySet.FirstClassProperties, ItemSchema.TextBody));
Emails.Add(new Email(message.DateTimeReceived, message.From.Name.ToString(), message.Subject, message.TextBody.ToString(), (message.HasAttachments) ? "Yes" : "No", message.Id.ToString()));
}
}
}
exchangeConnection = null;
return Emails;
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
return null;
}
}
publicstaticlist RetreiveEmails()
{
ExchangeService exchangeConnection=GetExchangeConnection()。结果;
尝试
{
列表电子邮件=新列表();
TimeSpan ts=新的TimeSpan(0,-5,0,0);
DateTime date=DateTime.Now.Add(ts);
SearchFilter.IsGreaterThanOrEqualTo EmailTimeFilter=newsearchfilter.IsGreaterThanOrEqualTo(ItemSchema.DateTimeReceived,date);
if(exchangeConnection!=null)
{
FindItemsResults findResults=exchangeConnection.FindItems(WellKnownFolderName.Inbox、EmailTimeFilter、new ItemView(10));
foreach(findResults中的项目)
{
if(item.Subject!=null)
{
EmailMessage=EmailMessage.Bind(exchangeConnection,item.Id);
Load(新属性集(BasePropertySet.FirstClassProperties,ItemSchema.TextBody));
Emails.Add(新电子邮件(message.DateTimeReceived,message.From.Name.ToString(),message.Subject,message.TextBody.ToString(),(message.HasAttachments)?“是”:“否”,message.Id.ToString());
}
}
}
exchangeConnection=null;
回复邮件;
}
捕获(例外e)
{
Console.WriteLine(如ToString());
返回null;
}
}
当电子邮件检索器尝试创建exchange连接或从文件夹请求电子邮件时,会发生此错误。在这两种情况下,代码都会出错,并在使用前十几次有效的凭据时给我401个未经授权的凭据,然后在多次尝试后失败。我已尝试使用多个不同的帐户,但所有帐户都存在此问题,我已确保该应用程序已获得访问exchange收件箱的授权。非常感谢您提供的任何建议或帮助。在对401错误进行进一步跟踪后,该错误导致令牌在其1小时寿命结束时出现问题。这是由于原始OAuth令牌的初始寿命为1小时。但是,这可以通过设置代码在需要时自动刷新令牌来解决。下面是为遇到此问题的任何其他人解决此问题的代码 身份验证管理器:
class AuthenticationManager
{
protected IPublicClientApplication App { get; set; }
public AuthenticationManager(IPublicClientApplication app)
{
App = app;
}
public async Task<AuthenticationResult> AcquireATokenFromCacheOrUsernamePasswordAsync(IEnumerable<String> scopes, string username, SecureString password)
{
AuthenticationResult result = null;
var accounts = await App.GetAccountsAsync();
if (accounts.Any())
{
try
{
result = await (App as PublicClientApplication).AcquireTokenSilent(scopes, accounts.FirstOrDefault()).ExecuteAsync();
}
catch (MsalUiRequiredException)
{ }
}
if (result == null)
{
result = await (App as PublicClientApplication).AcquireTokenByUsernamePassword(scopes, username, password).ExecuteAsync();
}
return result;
}
}
类身份验证管理器
{
受保护的IPublicClient应用程序应用程序{get;set;}
公共身份验证管理器(IPublicClient应用程序)
{
App=App;
}
公共异步任务AcquireATokenFromCacheOrUsernamePasswordAsync(IEnumerable作用域、字符串用户名、SecureString密码)
{
AuthenticationResult=null;
var accounts=wait App.GetAccountsAsync();
if(accounts.Any())
{
尝试
{
结果=等待(应用程序作为PublicClientApplication)。AcquireTokenSilent(作用域、帐户。FirstOrDefault())。ExecuteAsync();
}
捕获(MsalUiRequiredException)
{ }
}
如果(结果==null)
{
结果=等待(应用程序作为PublicClientApplication)。AcquireTokenByUsernamePassword(作用域、用户名、密码)。ExecuteAsync();
}
返回结果;
}
}
我使用直接用户名和密码身份验证,但代码行也可以切换到通过交互方法获得用户身份验证。该代码实质上创建了一个新的身份验证管理器实例,其中包含一个PublicClientApplication,用于初始化它,其中包含appID和tenantID。初始化后,您可以调用AquireTokenFromCacheOrUsernamePasswordAsync,它将尝试查看是否存在用于获取令牌的帐户。接下来,它将尝试检索以前缓存的令牌,如果令牌在5分钟内过期,则刷新该令牌。如果有可用的令牌,它会将其返回给主应用程序。如果没有可用的令牌,它将使用提供的用户名和密码获取新令牌。这段代码的实现如下所示
class ExchangeServices
{
AuthenticationManager Manager = null;
public ExchangeServices(String AppId, String TenantID)
{
var pcaOptions = new PublicClientApplicationOptions
{
ClientId = AppID,
TenantId = TenantID,
};
var pca = PublicClientApplicationBuilder.CreateWithApplicationOptions(pcaOptions).Build();
Manager = new AuthenticationManager(pca);
}
public static async Task<ExchangeService> GetExchangeService()
{
var ewsScopes = new string[] { "https://outlook.office365.com/EWS.AccessAsUser.All" }
var securePassword = new SecureString();
foreach(char c in Password)
securePassword.AppendChar(c);
var authResult = await Manager.AquireATokenFromCacheOrUsernamePasswordAsync(ewsScopes, Username, securePassword);
ExchangeService exchangeService = new ExchangeService()
{
Credentials = new OAuthCredentials(authResult.AccessToken),
Url = new Uri("https://outlook.office365.com/ews/exchange.asmx");
};
return exchangeService;
}
}
类交换服务
{
AuthenticationManager=null;
公共Exchange服务(字符串AppId,