Help Center> API Gateway> Developer Guide (Paris Region)> Calling APIs Through App Authentication> C#
Updated on 2022-02-21 GMT+08:00
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C#

Scenarios

To use C# to call an API through App authentication, obtain the C# SDK, open the project file in the SDK, and then call the API by referring to the API calling example.

Preparing the Environment

  • You have obtained the domain name, request URL, and request method of the API to be called, and the AppKey and AppSecret of the app for calling the API. For more information, see Preparation.
  • You have installed Visual Studio. If not, download it from the official Visual Studio website and install it.

Obtaining the SDK

Log in to the API Gateway console, and download the SDK on the SDKs page by referring to section "SDKs" in the User Guide.

The following table shows the files decompressed from the package.

Name

Description

apigateway-signature\Signer.cs

SDK code

apigateway-signature\HttpEncoder.cs

sdk-request\Program.cs

Sample code for signing requests

backend-signature\

Sample project for backend signing

csharp.sln

Project file

licenses\license-referencesource

Third-party license

Opening a Project

Double-click csharp.sln in the SDK package to open the project. The project contains the following:

  • apigateway-signature: Shared library that implements the signature algorithm. It can be used in the .Net Framework and .Net Core projects.
  • backend-signature: Example of a backend service signature.
  • sdk-request: Example of invoking the signature algorithm. Modify the parameters as required. For details about the sample code, see API Calling Example.

API Calling Example

  1. Import the C# SDK to your project.

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    using APIGATEWAY_SDK;

  2. Generate a new signer and enter the AppKey and AppSecret.

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    Signer signer = new Signer();
signer.Key = "4f5f626b-073f-402f-a1e0-e52171c6100c";
signer.Secret = "******";

  3. Generate an HttpRequest, and specify the method, request URL, and body.

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    HttpRequest r = new HttpRequest("POST",    
                    new Uri("https://c967a237-cd6c-470e-906f-a8655461897e.apigw.exampleRegion.com/app1?query=value"));
r.body = "{\"a\":1}";

  4. Add the x-stage header to the request to specify an environment name. Add other headers to be signed as necessary.

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    r.headers.Add("x-stage", "RELEASE");

  5. Execute the following function to generate HttpWebRequest, and add the X-Sdk-Date and Authorization headers for signing the request:

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    HttpWebRequest req = signer.Sign(r);

  6. Access the API and view the access result.

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    var writer = new StreamWriter(req.GetRequestStream());
writer.Write(r.body);
writer.Flush();
HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
var reader = newStreamReader(resp.GetResponseStream());
Console.WriteLine(reader.ReadToEnd());