Check string content of response before retrying with Polly

Check string content of response before retrying with Polly

To check the content of a response before retrying with Polly, you can use the HttpResponseMessage.Content.ReadAsStringAsync() method to read the content of the response as a string. Then you can examine the content and decide whether or not to retry.

Here's an example of how to use Polly to retry an HTTP request and check the response content before retrying:

int retryCount = 3;
var httpClient = new HttpClient();
var retryPolicy = Policy
    .Handle<HttpRequestException>()
    .OrResult<HttpResponseMessage>(r => {
        var responseContent = r.Content.ReadAsStringAsync().GetAwaiter().GetResult();
        // Check response content and return true to retry, false to stop retrying
        return responseContent.Contains("error");
    })
    .WaitAndRetryAsync(retryCount, retryAttempt => TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)));

var response = await retryPolicy.ExecuteAsync(async () => {
    var request = new HttpRequestMessage(HttpMethod.Get, "https://example.com/api/some-resource");
    return await httpClient.SendAsync(request);
});

In this example, the retryPolicy will retry the request up to retryCount times if an HttpRequestException is thrown or if the response content contains the string "error". The WaitAndRetryAsync method specifies a backoff strategy that doubles the wait time between each retry attempt.

Note that in this example, we are using the GetAwaiter().GetResult() method to block the execution and get the result synchronously. This is because retryPolicy is an asynchronous method, but responseContent is a string and cannot be retrieved asynchronously.

Examples

  1. "C# Polly retry based on specific string content in response"

    var policy = Policy
    .HandleResult<string>(content => content.Contains("RetryCondition"))
    .Retry(3, (exception, retryCount, context) =>
    {
        // Log or handle retry
    });

var result = policy.Execute(() =>
{
    // Make HTTP request or perform operation returning a string response
    return GetApiResponse();
});

    Code Description: Use Polly to handle retries based on a specific string content condition in the response.

  2. "C# Polly retry on multiple string content conditions in response"

    var policy = Policy
    .HandleResult<string>(content => content.Contains("RetryCondition1") || content.Contains("RetryCondition2"))
    .Retry(3, (exception, retryCount, context) =>
    {
        // Log or handle retry
    });

var result = policy.Execute(() =>
{
    // Make HTTP request or perform operation returning a string response
    return GetApiResponse();
});

    Code Description: Extend the Polly policy to handle retries based on multiple string content conditions in the response.

  3. "C# Polly retry if response string content matches regex pattern"

    var policy = Policy
    .HandleResult<string>(content => Regex.IsMatch(content, "RetryPattern"))
    .Retry(3, (exception, retryCount, context) =>
    {
        // Log or handle retry
    });

var result = policy.Execute(() =>
{
    // Make HTTP request or perform operation returning a string response
    return GetApiResponse();
});

    Code Description: Utilize a regex pattern to match string content in the response for determining retry conditions.

  4. "C# Polly wait and retry based on specific string content in response"

    var policy = Policy
    .HandleResult<string>(content => content.Contains("RetryCondition"))
    .WaitAndRetry(3, retryAttempt => TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)), (exception, timespan, retryCount, context) =>
    {
        // Log or handle retry
    });

var result = policy.Execute(() =>
{
    // Make HTTP request or perform operation returning a string response
    return GetApiResponse();
});

    Code Description: Use Polly's WaitAndRetry to introduce exponential backoff while retrying based on specific string content conditions.

  5. "C# Polly retry with circuit breaker and string content condition"

    var policy = Policy
    .HandleResult<string>(content => content.Contains("RetryCondition"))
    .CircuitBreaker(3, TimeSpan.FromSeconds(30), (exception, duration) =>
    {
        // Log or handle circuit breaker open
    })
    .Retry(3, (exception, retryCount, context) =>
    {
        // Log or handle retry
    });

var result = policy.Execute(() =>
{
    // Make HTTP request or perform operation returning a string response
    return GetApiResponse();
});

    Code Description: Combine Polly's retry and circuit breaker policies to handle retries and circuit breaker conditions based on string content.

  6. "C# Polly fallback with retry based on response string content"

    var policy = Policy
    .HandleResult<string>(content => content.Contains("RetryCondition"))
    .Retry(3, (exception, retryCount, context) =>
    {
        // Log or handle retry
    })
    .Fallback((result, context) =>
    {
        // Fallback logic
        return "FallbackResponse";
    });

var result = policy.Execute(() =>
{
    // Make HTTP request or perform operation returning a string response
    return GetApiResponse();
});

    Code Description: Implement a Polly policy with a fallback mechanism in case retry conditions are not met.

  7. "C# Polly retry with custom exception based on response string content"

    var policy = Policy
    .HandleResult<string>(content => content.Contains("RetryCondition"))
    .Retry(3, (exception, retryCount, context) =>
    {
        // Log or handle retry
        throw new CustomRetryException("Custom retry exception message");
    });

var result = policy.Execute(() =>
{
    // Make HTTP request or perform operation returning a string response
    return GetApiResponse();
});

    Code Description: Throw a custom exception during retry based on specific string content conditions in the response.

  8. "C# Polly retry with different policies for different string content conditions"

    var policy = Policy
    .HandleResult<string>(content => content.Contains("RetryCondition1"))
    .Retry(3, (exception, retryCount, context) =>
    {
        // Log or handle retry
    })
    .OrResult(content => content.Contains("RetryCondition2"))
    .WaitAndRetry(3, retryAttempt => TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)), (exception, timespan, retryCount, context) =>
    {
        // Log or handle retry
    });

var result = policy.Execute(() =>
{
    // Make HTTP request or perform operation returning a string response
    return GetApiResponse();
});

    Code Description: Use different Polly policies for different string content conditions in the response.

  9. "C# Polly retry with context-based string content condition"

    var policy = Policy
    .HandleResult<string>((content, context) => content.Contains(context["RetryCondition"].ToString()))
    .Retry(3, (exception, retryCount, context) =>
    {
        // Log or handle retry
    });

var result = policy.Execute(() =>
{
    // Make HTTP request or perform operation returning a string response
    return GetApiResponse();
}, new { RetryCondition = "SpecificCondition" });

    Code Description: Use context-based string content conditions for retries in Polly, allowing dynamic conditions.

  10. "C# Polly retry with asynchronous string content condition check"

    var policy = Policy
    .HandleResultAsync<string>(async content => await CheckStringContentAsync(content))
    .Retry(3, (exception, retryCount, context) =>
    {
        // Log or handle retry
    });

var result = policy.ExecuteAsync(async () =>
{
    // Make asynchronous HTTP request or perform operation returning a string response
    return await GetApiResponseAsync();
});

    Code Description: Perform an asynchronous string content condition check during Polly retries.

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