问题
I am very new to the Erlang and I am getting badarg error when I try to convert binary to string as shown below.
Prefix = binary:bin_to_list(wh_json:get_ne_value(<<"prefix">>, Patterns)),
where Patterns
are:
Pattern1--> {[{<<"prefix">>,<<>>},{<<"callerId">>,<<"1001">>},{<<"cid_regex">>,<<"^\\+?1001">>}]}
Pattern2--> {[{<<"prefix">>,<<"12">>},{<<"callerId">>,<<"1001">>},{<<"cid_regex">>,<<"^\\+?1001">>}]}
for Pattern2
it works fine but for Pattern1
I am getting this error because prefix does not have any value in Pattern1
.
So, can any one tell me how I can handle this situation where prefix value can be null
or any value, it should work for both the conditions.
回答1:
Check whether wh_json:get_ne_value
returns undefined
before calling binary:bin_to_list
:
Prefix =
case wh_json:get_ne_value(<<"prefix">>, Patterns) of
undefined ->
prefix_not_found;
BinaryPrefix when is_binary(BinaryPrefix) ->
binary:bin_to_list(BinaryPrefix)
end
来源:https://stackoverflow.com/questions/25199963/handle-badarg-in-erlang