Common HTTP interfaces for API "client side" support
This is a new implementation proposal based in some pre established requisites
- Build with the new .NETCore 3.0
- Has Resilience with Polly
- Has Stream serialization / deserialization for performance
- Support fluent for client configuration
- Minimum dependencies (only one package)
- HttpClient life cycle based on HttpClientFactory (as best practice recommended by Microsoft)
- No dependency on "Newtonsoft", instead rely on "System.Text.Json.JsonSerializer" (netcore3 core) which has better performance
- Minimum effort to setup and run
- Implemented strategy for dependency injection configuration
- Implemented strategy (cleaner and transparent) for identity token injection
- Every operations are async (including serialization/deserialization) to avoid thread locks
- Using "ResponseHeadersRead" (and stream deserialization) for improved performance
- Some code needs refactoring (especially "OAuthTokenProvider" that has some harcoded values)
- Only "GET" and "POST" were implemented, need to do the same for "PUT", "DELETE", "PATCH" and "HEAD" (almost just copy-paste code)
- Identity build on IdentityServer4, needs other strategies
- Identity only supports "client_credentials", need to implement other strategies
- Unit Tests
- Handle exceptions (Coming soon or read my suggestion below)
In your microservice solution, create an ClientSDK project and then follow this simple steps
Install the new package in your "Client.SDK" project
(this is the only dependency you will need)
dotnet add package Netsoft.Core.ApiClient.3.0.0Create a new class for your client
public class DemoClientSDK
{ }Inherit from "HttpClientBase" and create your own interface for DI
The constructor must receive and "HttpClient" which will be injected by DI
public class DemoClientSDK : HttpClientBase, IDemoClientSDK
{
public DemoClientSDK(HttpClient httpClient)
: base(httpClient)
{ }
}Implement your own methods:
public class DemoClientSDK : HttpClientBase, IDemoClientSDK
{
public DemoClientSDK(HttpClient httpClient)
: base(httpClient)
{ }
public async Task<FooResponse> GetFooAsync(int id)
{
var result = await this.GetAsync<FooResponse>($"api/Values/{id}");
return result.Body;
}
}Create a new static class for your DI configuration
public static class ServiceConfigExtensions
{ }Create an extension for "IServiceCollection"
public static class ServiceConfigExtensions
{
public static IServiceCollection AddDemoClient(
this IServiceCollection services,
Uri serviceBaseAddress,
IPolicyConfig policyConfig,
IIdentityConfig identityConfig)
{
return services;
}
}- IServiceCollection is the unity DI services configuration collection
- Uri should be your service url
- IPolicyConfig is supplied by the netsoft package Netsoft.Core.ApiClient.3.0 and it is intended to inject resilience configurations
- IIdentityConfig is supplied by netsoft package Netsoft.Core.ApiClient.3.0 and it is intended to inject indentity configurations
Be aware that all configurations must be supplied by the consumer
Configure your service client
(this configurations may vary according to your own needs)
public static class ServiceConfigExtensions
{
public static IServiceCollection AddDemoClient(
this IServiceCollection services,
Uri serviceBaseAddress,
IPolicyConfig policyConfig,
IIdentityConfig identityConfig)
{
services.AddHttpClient<IDemoClientSDK, DemoClientSDK>(x =>
{
x.BaseAddress = serviceBaseAddress;
x.DefaultRequestHeaders.Add("Accept", "application/json");
x.DefaultRequestHeaders.Add("User-Agent", "HttpClientFactory-Sample");
x.DefaultRequestVersion = new Version(2, 0);
})
.AddResilience(policyConfig)
.AddIdentity(identityConfig, new TokenStrategy());
return services;
}
}Microservices consumers have their life easier
In your Gateway project, create a new static class for your DI configuration
public static class DataGatewayExtensions
{ }Create an extension for "IServiceCollection"
public static class ServiceConfigExtensions
{
public static IServiceCollection AddDataGateways(this IServiceCollection services)
{
return services;
}
}Reference or install the ClientDSK package and use their own extension to configure the client, like this:
public static class ServiceConfigExtensions
{
public static IServiceCollection AddDataGateways(this IServiceCollection services)
{
var serviceProvider = services.BuildServiceProvider();
var policyConfig = serviceProvider.GetRequiredService<IPolicyConfig>();
var identityConfig = serviceProvider.GetRequiredService<IIdentityConfig>();
services.AddDemoClient(
new Uri("https://localhost:44348"),
policyConfig,
identityConfig);
return services;
}
}Then, in your "Presentation" project simply bind your IPolicyConfig and IIdentityConfig with the configuration file and call then ".AddDataGateways" extension
public static class ApiExtensions
{
public static IServiceCollection AddSettings(this IServiceCollection services)
{
services.AddSingleton<IPolicyConfig>(serviceProvider =>
{
var config = serviceProvider.GetRequiredService<IConfiguration>();
var policyConfig = new PolicyConfig();
config.Bind("PolicyConfig", policyConfig);
return policyConfig;
});
services.AddSingleton<IIdentityConfig>(serviceProvider =>
{
var config = serviceProvider.GetRequiredService<IConfiguration>();
var identityConfig = new IdentityConfig();
config.Bind("IdentityConfig", identityConfig);
return identityConfig;
});
return services;
}
}use it
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
services.AddOptions();
services.AddMvc()
//(...Swagger...etc...)
services
.AddSettings() // from Presentation project
.AddDataGateways(); // from Gateway project
}
}As a best practice, Microsoft recommends the use of a middleware in replacement of the old handlers
Add the ExceptionHandler middleware to the pipeline using the Configure method of the startup class
public class Startup
{
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
app.UsePingPong()
.StartSwagger();
app.UseMiddleware<ExceptionsMiddleware>();
app.UseMvc();
return app;
}
}Contributors welcome!
Thanks for taking an interest in the library and the github community!
- Clone this repo
- Make some changes
- Make a pull request