Response.md

Azure.Core Response samples

NOTE: Samples in this file apply only to packages that follow Azure SDK Design Guidelines. Names of such packages usually start with Azure.

Most client methods return one of the following types:

• Response - an HTTP response
• Response<T> - a value and HTTP response
• Pageable<T> - a collection of values retrieved in pages
• AsyncPageable<T> - a collection of values asyncrounosly retrieved in pages
• *Operation<T> - a long-running operation see long running operation samples

Accessing HTTP response propreties

// create a client
var client = new SecretClient(new Uri("http://example.com"), new DefaultAzureCredential());

// call a service method, which returns Response<T>
Response<KeyVaultSecret> response = await client.GetSecretAsync("SecretName");

// Response<T> has two main accessors.
// Value property for accessing the deserialized result of the call
KeyVaultSecret secret = response.Value;

// .. and GetRawResponse method for accessing all the details of the HTTP response
Response http = response.GetRawResponse();

// for example, you can access HTTP status
int status = http.Status;

// or the headers
foreach (HttpHeader header in http.Headers)
{
    Console.WriteLine($"{header.Name} {header.Value}");
}

Accessing HTTP response content

// call a service method, which returns Response<T>
Response<KeyVaultSecret> response = await client.GetSecretAsync("SecretName");

Response http = response.GetRawResponse();

Stream contentStream = http.ContentStream;

// Rewind the stream
contentStream.Position = 0;

using (StreamReader reader = new StreamReader(contentStream))
{
    Console.WriteLine(reader.ReadToEnd());
}

Accessing HTTP response well-known headers

You can access well known response headers via properties of ResponseHeaders object:

// call a service method, which returns Response<T>
Response<KeyVaultSecret> response = await client.GetSecretAsync("SecretName");

Response http = response.GetRawResponse();

Console.WriteLine("ETag " + http.Headers.ETag);
Console.WriteLine("Content-Length " + http.Headers.ContentLength);
Console.WriteLine("Content-Type " + http.Headers.ContentType);

Iterating over AsyncPageable using await foreach

This sample requires C# 8 compiler.

// call a service method, which returns AsyncPageable<T>
AsyncPageable<SecretProperties> allSecretProperties = client.GetPropertiesOfSecretsAsync();

await foreach (SecretProperties secretProperties in allSecretProperties)
{
    Console.WriteLine(secretProperties.Name);
}

Iterating over AsyncPageable using while loop

If your project doesn't have C# 8.0 enabled you can still iterate over AsyncPageable using a while loop.

// call a service method, which returns AsyncPageable<T>
AsyncPageable<SecretProperties> allSecretProperties = client.GetPropertiesOfSecretsAsync();

IAsyncEnumerator<SecretProperties> enumerator = allSecretProperties.GetAsyncEnumerator();
try
{
    while (await enumerator.MoveNextAsync())
    {
        SecretProperties secretProperties = enumerator.Current;
        Console.WriteLine(secretProperties.Name);
    }
}
finally
{
    await enumerator.DisposeAsync();
}

Iterating over AsyncPageable pages

If you want to have control over receiving pages of values from the service use AsyncPageable<T>.AsPages method:

// call a service method, which returns AsyncPageable<T>
AsyncPageable<SecretProperties> allSecretProperties = client.GetPropertiesOfSecretsAsync();

await foreach (Page<SecretProperties> page in allSecretProperties.AsPages())
{
    // enumerate through page items
    foreach (SecretProperties secretProperties in page.Values)
    {
        Console.WriteLine(secretProperties.Name);
    }

    // get continuation token that can be used in AsPages call to resume enumeration
    Console.WriteLine(page.ContinuationToken);
}

Iterating over pageable

Pageable<T> is a syncronous version of AsyncPageable<T>, it can be used with a normal foreach loop.

// call a service method, which returns Pageable<T>
Pageable<SecretProperties> allSecretProperties = client.GetPropertiesOfSecrets();

foreach (SecretProperties secretProperties in allSecretProperties)
{
    Console.WriteLine(secretProperties.Name);
}

Handling exceptions

When a service call fails Azure.RequestFailedException would get thrown. The exception type provides a Status property with an HTTP status code an an ErrorCode property with a service-specific error code.

try
{
    KeyVaultSecret secret = client.GetSecret("NonexistentSecret");
}
// handle exception with status code 404
catch (RequestFailedException e) when (e.Status == 404)
{
    // handle not found error
    Console.WriteLine("ErrorCode " + e.ErrorCode);
}