Additional details on HttpClientFactory #2823

5 Answer(s)

• 

  0

  gterdem created 2 years ago

  Senior .NET Developer

  You may want to check these framework modules:

  • Volo.Abp.Http.Client.IdentityModel
  • Volo.Abp.Http.Client.IdentityModel.Web

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• 

  0

  viswajwalith created 2 years ago

  You may want to check these framework modules:

  • Volo.Abp.Http.Client.IdentityModel
  • Volo.Abp.Http.Client.IdentityModel.Web

  Can you please validate our understanding which I mentioned in my Question Posting.

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• 

  0

  gterdem created 2 years ago

  Senior .NET Developer

  We would like to understand the http request flow between Web(MVC UI) Layer and WebGateway.

  From the microservice solution perspective, WebUI (I am assuming you mean public-web application) is not a layer but an application.

  Can you please provide more details on communication between WebUI & WebGateway (for http requests) and relevant code which passes Barer token etc...

  I think you want to learn generally how the proxying works; how an HTTP request is done, headers are set and forwarded; not just microservice specific. So I will try to explain better.

  Your request is created by ClientProxyBase (or DynamicHttpProxyInterceptor if you are using dynamic proxying):

  protected IRemoteServiceHttpClientAuthenticator ClientAuthenticator => LazyServiceProvider.LazyGetRequiredService<IRemoteServiceHttpClientAuthenticator>();
  
  protected virtual async Task<HttpContent> RequestAsync(ClientProxyRequestContext requestContext)
  {
      ...
      // Gets the remote service configuration
      RemoteServiceConfigurationProvider.GetConfigurationOrDefaultAsync(clientConfig.RemoteServiceName);
      
      // Creates the HttpClient service configuration
      var client = HttpClientFactory.Create(clientConfig.RemoteServiceName);
      
      ...    
      
      // Authentication headers are forwarded or set in here based on remoteServiceConfig
      if (requestContext.Action.AllowAnonymous != true)
      {
          await ClientAuthenticator.Authenticate(
              new RemoteServiceHttpClientAuthenticateContext(
                  client,
                  requestMessage,
                  remoteServiceConfig,
                  clientConfig.RemoteServiceName
              )
          );
      }
  
      ...
  }
  

  IRemoteServiceHttpClientAuthenticator is implemented by:

  • IdentityModelRemoteServiceHttpClientAuthenticator under Volo.Abp.Http.Client.IdentityModel module:

  await IdentityModelAuthenticationService.TryAuthenticateAsync(
              context.Client,
              context.RemoteService.GetIdentityClient() ?? context.RemoteServiceName
          );
  

  Uses IdentityModelAuthenticationService to authenticate the service as below:

  public async Task<bool> TryAuthenticateAsync(
          [NotNull] HttpClient client,
          string identityClientName = null)
  {
      var accessToken = await GetAccessTokenOrNullAsync(identityClientName);
      if (accessToken == null)
      {
          return false;
      }
  
      SetAccessToken(client, accessToken);
      return true;
  }
  protected virtual void SetAccessToken(HttpClient client, string accessToken)
  {
      //TODO: "Bearer" should be configurable
      client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
  }
  

  • HttpContextIdentityModelRemoteServiceHttpClientAuthenticator under Volo.Abp.Http.Client.IdentityModel.Web module that extends IdentityModelRemoteServiceHttpClientAuthenticator and handles authentication when HTTP context is available (For UI based applications like Razor/MVC):

  public override async Task Authenticate(RemoteServiceHttpClientAuthenticateContext context)
  {
      if (context.RemoteService.GetUseCurrentAccessToken() != false)
      {
          var accessToken = await GetAccessTokenFromHttpContextOrNullAsync();
          if (accessToken != null)
          {
              context.Request.SetBearerToken(accessToken);
              return;
          }
      }
  
      await base.Authenticate(context);
  }
  
  protected virtual async Task<string> GetAccessTokenFromHttpContextOrNullAsync()
  {
      var httpContext = HttpContextAccessor?.HttpContext;
      if (httpContext == null)
      {
          return null;
      }
  
      return await httpContext.GetTokenAsync("access_token");
  }
  

  • There is also AccessTokenProviderIdentityModelRemoteServiceHttpClientAuthenticator under Volo.Abp.Http.Client.IdentityModel.WebAssembly module that extends IdentityModelRemoteServiceHttpClientAuthenticator and uses IAccessTokenProvider for getting/setting authorization headers for blazor applications.

  Basically, how to set the authorization header is based on application type;

  • Server-to-server communication without HTTP context uses Volo.Abp.Http.Client.IdentityModel module
  • MVC/Razor application uses Volo.Abp.Http.Client.IdentityModel.Web module
  • Blazor application uses Volo.Abp.Http.Client.IdentityModel.WebAssembly module

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• 

  0

  viswajwalith created 2 years ago

  Volo.Abp.Http.Client.IdentityModel

  Thanks for the detailed explanation, Yes this is what we expected. I am going through the details will let you know in case of any queries

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• 

  0

  viswajwalith created 2 years ago

  We would like to understand the http request flow between Web(MVC UI) Layer and WebGateway.

  From the microservice solution perspective, WebUI (I am assuming you mean public-web application) is not a layer but an application.

  Can you please provide more details on communication between WebUI & WebGateway (for http requests) and relevant code which passes Barer token etc...

  I think you want to learn generally how the proxying works; how an HTTP request is done, headers are set and forwarded; not just microservice specific. So I will try to explain better.

  Your request is created by ClientProxyBase (or DynamicHttpProxyInterceptor if you are using dynamic proxying):

  protected IRemoteServiceHttpClientAuthenticator ClientAuthenticator => LazyServiceProvider.LazyGetRequiredService<IRemoteServiceHttpClientAuthenticator>(); 
   
  protected virtual async Task<HttpContent> RequestAsync(ClientProxyRequestContext requestContext) 
  { 
      ... 
      // Gets the remote service configuration 
      RemoteServiceConfigurationProvider.GetConfigurationOrDefaultAsync(clientConfig.RemoteServiceName); 
       
      // Creates the HttpClient service configuration 
      var client = HttpClientFactory.Create(clientConfig.RemoteServiceName); 
       
      ...     
       
      // Authentication headers are forwarded or set in here based on remoteServiceConfig 
      if (requestContext.Action.AllowAnonymous != true) 
      { 
          await ClientAuthenticator.Authenticate( 
              new RemoteServiceHttpClientAuthenticateContext( 
                  client, 
                  requestMessage, 
                  remoteServiceConfig, 
                  clientConfig.RemoteServiceName 
              ) 
          ); 
      } 
   
      ... 
  } 
  

  IRemoteServiceHttpClientAuthenticator is implemented by:

  • IdentityModelRemoteServiceHttpClientAuthenticator under Volo.Abp.Http.Client.IdentityModel module:

  await IdentityModelAuthenticationService.TryAuthenticateAsync( 
              context.Client, 
              context.RemoteService.GetIdentityClient() ?? context.RemoteServiceName 
          ); 
  

  Uses IdentityModelAuthenticationService to authenticate the service as below:

  public async Task<bool> TryAuthenticateAsync( 
          [NotNull] HttpClient client, 
          string identityClientName = null) 
  { 
      var accessToken = await GetAccessTokenOrNullAsync(identityClientName); 
      if (accessToken == null) 
      { 
          return false; 
      } 
   
      SetAccessToken(client, accessToken); 
      return true; 
  } 
  protected virtual void SetAccessToken(HttpClient client, string accessToken) 
  { 
      //TODO: "Bearer" should be configurable 
      client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken); 
  } 
  

  • HttpContextIdentityModelRemoteServiceHttpClientAuthenticator under Volo.Abp.Http.Client.IdentityModel.Web module that extends IdentityModelRemoteServiceHttpClientAuthenticator and handles authentication when HTTP context is available (For UI based applications like Razor/MVC):

  public override async Task Authenticate(RemoteServiceHttpClientAuthenticateContext context) 
  { 
      if (context.RemoteService.GetUseCurrentAccessToken() != false) 
      { 
          var accessToken = await GetAccessTokenFromHttpContextOrNullAsync(); 
          if (accessToken != null) 
          { 
              context.Request.SetBearerToken(accessToken); 
              return; 
          } 
      } 
   
      await base.Authenticate(context); 
  } 
   
  protected virtual async Task<string> GetAccessTokenFromHttpContextOrNullAsync() 
  { 
      var httpContext = HttpContextAccessor?.HttpContext; 
      if (httpContext == null) 
      { 
          return null; 
      } 
   
      return await httpContext.GetTokenAsync("access_token"); 
  } 
  

  • There is also AccessTokenProviderIdentityModelRemoteServiceHttpClientAuthenticator under Volo.Abp.Http.Client.IdentityModel.WebAssembly module that extends IdentityModelRemoteServiceHttpClientAuthenticator and uses IAccessTokenProvider for getting/setting authorization headers for blazor applications.

  Basically, how to set the authorization header is based on application type;

  • Server-to-server communication without HTTP context uses Volo.Abp.Http.Client.IdentityModel module
  • MVC/Razor application uses Volo.Abp.Http.Client.IdentityModel.Web module
  • Blazor application uses Volo.Abp.Http.Client.IdentityModel.WebAssembly module

  Thanks for the details, now we are able to over ride the specific method to add additional headers (in our sample solution) . Thanks for the support

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