JSON::ParserError: 757: unexpected token at '{ - ruby-on-rails

Question

the current hash is
{\"report_name\"=>\"Study/Control: ABIRATERONE ACETATE - 20151413355\", \"left_mue_start_date\"=>\"02-26-2015\", \"left_mue_end_date\"=>\"03-19-2015\", \"right_mue_start_date\"=>\"02-26-2015\", \"right_mue_end_date\"=>\"03-19-2015\", \"report_formulary_id\"=>\",7581\", \"mue\"=>\"true\", \"mue_type\"=>\"study/control\", \"chain_id\"=>\"1\", \"left_mue_formulary_ids\"=>[\"7581\"], \"action\"=>\"create_report\", \"controller\"=>\"informatics\", \"user_id\"=>339}
now I need to convert it in proper hash like
{"report_name" => "Study/Control: ABIRATERONE ACETATE - 20151413355"}
so I am trying to get it with JSON.parse but I am getting error like:
JSON::ParserError: 757: unexpected token at '{
So if someone know about that so please help me.
and I am using Rails 3.2

Answer 1

What you have is a hash printed as String. To convert it into a Hash use eval.
ch = "{\"report_name\"=>\"Study/Control: ABIRATERONE ACETATE - 20151413355\", \"left_mue_start_date\"=>\"02-26-2015\", \"left_mue_end_date\"=>\"03-19-2015\", \"right_mue_start_date\"=>\"02-26-2015\", \"right_mue_end_date\"=>\"03-19-2015\", \"report_formulary_id\"=>\",7581\", \"mue\"=>\"true\", \"mue_type\"=>\"study/control\", \"chain_id\"=>\"1\", \"left_mue_formulary_ids\"=>[\"7581\"], \"action\"=>\"create_report\", \"controller\"=>\"informatics\", \"user_id\"=>339}"
hash = eval(ch)
# => {"report_name"=>"Study/Control: ABIRATERONE ACETATE - 20151413355", "left_mue_start_date"=>"02-26-2015", "left_mue_end_date"=>"03-19-2015", "right_mue_start_date"=>"02-26-2015", "right_mue_end_date"=>"03-19-2015", "report_formulary_id"=>",7581", "mue"=>"true", "mue_type"=>"study/control", "chain_id"=>"1", "left_mue_formulary_ids"=>["7581"], "action"=>"create_report", "controller"=>"informatics", "user_id"=>339}
PS: A JSON string should look as follows, meaning what you have is not JSON and hence you got JSON::ParserError for using JSON.parse on a non-JSON string :
"{\"report_name\":\"Study/Control: ABIRATERONE ACETATE - 20151413355\",\"left_mue_start_date\":\"02-26-2015\",\"left_mue_end_date\":\"03-19-2015\",\"right_mue_start_date\":\"02-26-2015\",\"right_mue_end_date\":\"03-19-2015\",\"report_formulary_id\":\",7581\",\"mue\":\"true\",\"mue_type\":\"study/control\",\"chain_id\":\"1\",\"left_mue_formulary_ids\":[\"7581\"],\"action\":\"create_report\",\"controller\":\"informatics\",\"user_id\":339}"

Answer 2

To avoid using eval you could use JSON.parse ch.gsub('=>', ':') this way you will get a HASH from your HASH stored as STRING

Answer 3

Last time when I got this issue, since the json file that I got from a API that contains a BOM
UTF-8 BOM is a sequence of bytes (EF BB BF)
What's different between UTF-8 and UTF-8 without BOM?
at the beginning of that string, but you know that part wouldn't display or as readable when we got the string from response. I try to use Ruby JSON to parse it, but I failed, I got the same exception with yours. just a reminder for others, when you get a Json response. By the way, this would be no problem while you are handling that in javascript, but with problems in Python or Ruby languages.

Answer 4

I ran into a similar problem, though it was failing while parsing \"\". This is in regards to using Pact.IO. I mention it here since this is the highest ranked Google result while looking for the error I encountered. The solution in my case was to change the body of a POST in my C# application so that it wasn't using empty string, but a null string. Basically I added this before my HTTP call.
if (request.Method == HttpMethod.Post && request.Content!=null && request.Content.GetType()==typeof(StringContent) && request.Content.ReadAsStringAsync().Result == String.Empty)
request.Content = new StringContent(null);