对预检的反应:"尽管启用了CORS,但没有'Access-Control-Allowed-Origin'"

Question

对预检的反应:"尽管启用了CORS,但没有'Access-Control-Allowed-Origin'"

Tro*_*ant 7 cors asp.net-web-api preflight angular2-forms angular2-observables

我无法解决角度4预检请求未通过CORS访问控制检查的问题:"No'Access-Control-Allowed-Origin'".我能够从数据库中成功获取数据,但无法发布/保存数据.我正在使用前端的VS代码访问我的Visual Studio 2015后端.我的Web Api控制器具有以下属性:

[EnableCors(origins: "*", headers: "*", methods: "*")]

    [HttpPost]
    public async Task<IHttpActionResult> Post([FromBody]Employee employee)
    {
        _repo.Create(employee);
        return Ok();
    }

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...但是在提出请求时,我收到的错误是:

XMLHttpRequest无法加载http:// localhost:54429/api/createEmployee /.对预检请求的响应未通过访问控制检查:请求的资源上不存在"Access-Control-Allow-Origin"标头.因此不允许来源' http:// localhost:4200 '访问

在我的vs代码中,我的服务看起来像这样:

postEmployeeForm(employee: Employee): Observable<any>{

    let body = JSON.stringify(employee); 
    let headers = new Headers();
    headers.append('Content-Type', 'application/json');
    let options       = new RequestOptions({ headers: headers });

    console.log('posting employee ' , employee);

    return this.http.post("http://localhost:54429/api/employees/", body, options)
                    .map(this.extractData)
                    .catch(this.handleError)


}

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405从帖子中删除正文和选项后的响应.

不确定我错过了什么.

网络配置

<configuration>
  <configSections>
    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
  </configSections>
  <connectionStrings>
    <add name="DefaultConnection" connectionString="Data Source=(LocalDb)\MSSQLLocalDB;AttachDbFilename=|DataDirectory|\aspnet-TBryant.WebAPI-20170303082842.mdf;Initial Catalog=aspnet-TBryant.WebAPI-20170303082842;Integrated Security=True" providerName="System.Data.SqlClient" />
    <!--<add name="SampleEntities" connectionString="metadata=res://*/MyModels.csdl|res://*/MyModels.ssdl|res://*/MyModels.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=(localdb)\MSSQLLocalDB;initial catalog=Sample;integrated security=True;MultipleActiveResultSets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />-->
    <add name="northwindEntities" connectionString="metadata=res://*/NorthwindModel.csdl|res://*/NorthwindModel.ssdl|res://*/NorthwindModel.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=(localdb)\MSSQLLocalDB;initial catalog=northwind;integrated security=True;MultipleActiveResultSets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />
    <add name="SampleEntities1" connectionString="metadata=res://*/EmployeeDataModel.csdl|res://*/EmployeeDataModel.ssdl|res://*/EmployeeDataModel.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=(localdb)\MSSQLLocalDB;initial catalog=Sample;integrated security=True;MultipleActiveResultSets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />
  </connectionStrings>
  <appSettings></appSettings>
  <system.web>
    <authentication mode="None" />
    <compilation debug="true" targetFramework="4.6.1" />
    <httpRuntime targetFramework="4.6.1" />
  </system.web>
  <system.webServer>
    <!--<httpProtocol>
      <customHeaders>
        <add name="Access-Control-Allow-Origin" value="*"/>
        <add name="Access-Control-Allow-Headers" value="Content-Type"/>
        <add name="Access-Control-Allow-Methods" value="GET,POST,PUT,DELTE,OPTIONS"/>
      </customHeaders>
    </httpProtocol>-->
    <modules>
      <remove name="FormsAuthentication" />
    </modules>
    <handlers>
      <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
      <remove name="OPTIONSVerbHandler" />
      <remove name="TRACEVerbHandler" />
      <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
    </handlers>
  </system.webServer>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="Microsoft.Owin.Security" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-3.0.1.0" newVersion="3.0.1.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Microsoft.Owin.Security.OAuth" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-3.0.1.0" newVersion="3.0.1.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Microsoft.Owin.Security.Cookies" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-3.0.1.0" newVersion="3.0.1.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Microsoft.Owin" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-3.0.1.0" newVersion="3.0.1.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Newtonsoft.Json" culture="neutral" publicKeyToken="30ad4fe6b2a6aeed" />
        <bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Optimization" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-1.1.0.0" newVersion="1.1.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="WebGrease" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-1.5.2.14234" newVersion="1.5.2.14234" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-5.2.3.0" newVersion="5.2.3.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Cors" publicKeyToken="31bf3856ad364e35" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-5.2.3.0" newVersion="5.2.3.0" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
  </entityFramework>
  <system.codedom>
    <compilers>
      <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.CSharpCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:6 /nowarn:1659;1699;1701" />
      <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:14 /nowarn:41008 /define:_MYTYPE=\&quot;Web\&quot; /optionInfer+" />
    </compilers>
  </system.codedom>
</configuration>

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Answer 1

Kir*_*kin 5

我已经成功重现了你的问题。对我有用的解决方案是替换部分Web.config. 在下，使用以下内容system.webServer添加或替换现有块：<handlers>

<handlers>
  <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
  <remove name="OPTIONSVerbHandler" />
  <remove name="TRACEVerbHandler" />
  <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
</handlers>

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如果您已经拥有该确切内容，请尝试将其删除，运行服务器，停止服务器，重新添加内容，然后再次运行服务器。我知道这听起来很奇怪，但我认为这就是最终为我解决问题的原因。祝你好运。

更新#1

现在我们在服务器端发生了一些事情，尝试删除Angular 代码中的Content-Type标头和内容。JSON.stringifyIE：

postEmployeeForm(employee: Employee): Observable<any>{
    console.log('posting employee ' , employee);

    return this.http.post("http://localhost:54429/api/employees/", employee)
        .map(this.extractData)
        .catch(this.handleError)
}

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更新#2

我认为您的 IIS Express 配置可能会覆盖我们所做的一些更改。关闭 Visual Studio，.vs/config在 Windows 资源管理器中删除解决方案根目录下的文件夹，然后尝试重新运行该项目。这应该会重置您的 IIS Express 设置。如果您不太愿意删除该文件夹，只需重命名它并遵循相同的过程即可。

更新#3

我已经设法让你的示例项目运行起来。它演示了 CORS 的问题，但通过使用我最初的添加建议解决了这个问题config.EnableCors：

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        // Web API configuration and services
        config.EnableCors();

        // Web API routes
        config.MapHttpAttributeRoutes();

        config.Routes.MapHttpRoute(
            name: "DefaultApi",
            routeTemplate: "api/{controller}/{id}",
            defaults: new { id = RouteParameter.Optional }
        );
    }
}

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