How to simplify return's statement from try-catch

Question

How can I simplify the following code:

try
{
    var metadata = GetMetadata();
    return metadata ?? _provider.GetLatestMetadata(guid);
}
catch (AuthenticationException)
{
    return _provider.GetLatestMetadata(guid);
}
catch (HttpUnauthorizedRequestException)
{
    return _provider.GetLatestMetadata(guid);
}
catch (WebException)
{
    return _provider.GetLatestMetadata(guid);
}
catch (VcenterException)
{
    return _provider.GetLatestMetadata(guid);
}

I would like to avoid code duplication.

Is it possible?

Why don't you catch universal base `catch (Exception)` if you want to avoid code duplication? — Yeldar Kurmangaliyev, Dec 03 '15 at 10:00

score 7 · Accepted Answer · answered Dec 03 '15 at 10:02

7

If you don't want to do a catch-all and really need to avoid duplicate code, you can catch the specific exceptions with an exception filter:

try
{
    var metadata = GetMetadata();
    return metadata ?? _provider.GetLatestMetadata(guid);
}
catch (Exception ex) when ( ex is AuthenticationException
                            || ex is HttpUnauthorizedRequestException
                            || ex is WebException
                            || ex is VcenterException
                          )
{
    return _provider.GetLatestMetadata(guid);
}

answered Dec 03 '15 at 10:02

Patrick Hofman

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Oh. `when`...So many years of programming and actually I just have learned this...Even never heard this before. Just wow. – Yeldar Kurmangaliyev Dec 03 '15 at 10:09
It is just a C# 6 operator, so it is still new :) – Patrick Hofman Dec 03 '15 at 10:09
Ah, I see. Looks like I was too happy seeing null-conditional operator, string interpolation and default values for auto-properties and didn't notice this. Thanks for explanation! :) – Yeldar Kurmangaliyev Dec 03 '15 at 10:11
Without the C# 6 operator `when` do I need to `throw` exception inside `catch`? – Anatoly Dec 03 '15 at 10:37
You can rewrite this as a regular `if` of course. In your else branch, just `throw;`. – Patrick Hofman Dec 03 '15 at 10:38
`if (ex is AuthenticationException || ..) { return .. } else { throw; }` like this? or I can throw without `else`? – Anatoly Dec 03 '15 at 10:42
1

You can do both. No problem. – Patrick Hofman Dec 03 '15 at 10:42
I asked because I didn't any `throw` in my code question – Anatoly Dec 03 '15 at 10:45

How to simplify return's statement from try-catch

1 Answers1