Styjun

How should I handle this exception for API data requester?
The Dostuff1,2,3 is 3 different functions that retrieves data from an API. This function is ran every minute. What I want to do is to catch the exception, but not stop the program, and rather let it retry on the next iteration. How should I solve this? I guess I shouldn't be using throw, but the code want me to return something.

public async Task<string> Dostuff1,2,3()

 try
 
 using (HttpResponseMessage result = await _httpClient.GetAsync(Adrdess))
 using (HttpContent content = result.Content)
 
 result.EnsureSuccessStatusCode();
 string data = await content.ReadAsStringAsync();
 

 return data;
 
 catch (Exception ex)
 
 Console.WriteLine("Error");
 throw;
 

If the return value is what concerns you, then you can return null or new Task<string>(() => string.Empty) since they basically mean that you have no data to return.

Now it depends if you have a project with clear requirements where you should always have a default value to return or some other data source if this one is not available, but if you just want the code to compile, you can have a simple return null; there.

Your code looks duplicated to me. Instead of making 3 different functions, you should rather have one with arguments:

public async Task<string> GetStringFromAPIAsync( string resource )

 // check input
 if( string.IsNullOrWhitespace(resource) ) throw new ArgumentException(nameof(resource));

 using (HttpResponseMessage result = await _httpClient.GetAsync(resource))
 using (HttpContent content = result.Content)
 
 result.EnsureSuccessStatusCode();
 return await content.ReadAsStringAsync(); 
 // Issue in your code: 'data' was out of scope for the return.
 // string data = await content.ReadAsStringAsync();
 
 // return data; <- "data" is not visible here!

Mind that I got rid of all the exception handling here, since from my POV, it should be done by the caller, which also gives you more flexibility.

For example: you could write another function for retry like so:

public async Task<string> GetStringFromAPIWithRetryAsync(string resource, int maxRetry)

 // limit retry to 1 .. 100
 for( int retry = Math.Min(Math.Max(1,maxRetry),100); retry > 0 ; retry--)
 try
 return await GetStringFromAPIAsync( resource );
 
 catch(Exception ex) // Actually, you'd only catch exceptions where a retry makes sense.
 if( retry > 0 )
 Log.Warn("Attempt to get string from 0 failed! Reason: 1", resource, ex.Message);
 else
 throw;
 
 
 

If you just need a default in case of error, you could do this:

public async Task<string> GetStringFromAPIOrDefaultAsync(string resource, string defaultValue)

 string returnValue = defaultValue;
 try
 returnValue = await GetStringFromAPIAsync( resource );
 
 catch(Exception) 
 Log.Warn("Attempt to get string from 0 failed! Reason: 1", resource, ex.Message);
 
 return returnValue;
 
}