In Ruby, is there a way to check if a string is valid json before trying to parse it?
For example getting some information from some other urls, sometimes it returns json, sometimes it could return a garbage which is not a valid response.
My code:
def get_parsed_response(response)
parsed_response = JSON.parse(response)
end
You can create a method to do the checking:
def valid_json?(json)
JSON.parse(json)
true
rescue JSON::ParserError, TypeError => e
false
end
You can parse it this way
begin
JSON.parse(string)
rescue JSON::ParserError => e
# do smth
end
# or for method get_parsed_response
def get_parsed_response(response)
parsed_response = JSON.parse(response)
rescue JSON::ParserError => e
# do smth
end
I think parse_json should return nil if it's invalid and shouldn't error out.
def parse_json string
JSON.parse(string) rescue nil
end
unless json = parse_json string
parse_a_different_way
end
null and false are valid JSON, too. JSON.parse returns nil and false which would be treated as a parse error in the code above.Let me suggest a shorter variant
def valid_json?(string)
!!(JSON.parse(string) || true) rescue false
end
> valid_json?("test")
=> false
> valid_json?("{\"mail_id\": \"999129237\", \"public_id\": \"166118134802\"}")
=> true
> valid_json?("false")
=> true
def valid_json?(json)
begin
JSON.parse(json)
return true
rescue Exception => e
return false
end
end
answer here: https://gist.github.com/ascendbruce/7070951
JSON.parse(string) rescue nil