JSON.parse fails to create an object from a string - javascript

I am using ruby on rails to create a cookie that returns an array containing the params of the request back to the view as a string. However, I get the following error when I JSON.parse that string:
JSON.parse('%7B%22specialty%22%3A%5B%22Anesthesiology%22%5D%7D')
Uncaught SyntaxError: Unexpected token % in JSON at position 0
how do I fix this?

The string is not valid json.
It is uri encoded so decode it using decodeURIComponent()
JSON.parse(decodeURIComponent('%7B%22specialty%22%3A%5B%22Anesthesiology%22%5D%7D'))

Other answers are correct in saying that the payload is URI encoded, but decodeURIComponent is only a javascript method. To decode it ruby-side, use URI.unescape.
JSON.parse(URI.unescape('%7B%22specialty%22%3A%5B%22Anesthesiology%22%5D%7D'))
You say you're using rails, so the URI object should already be available, but if you weren't using rails you would need to require 'uri' first.

You need to use decodeURIComponent to first decode the string.
JSON.parse(decodeURIComponent(
'%7B%22specialty%22%3A%5B%22Anesthesiology%22%5D%7D'
));
As the string is encoded. Once you decode it, you get the key value pair, i.e. the object in the form of a string. Now you can use JSON.parse to form the Javascript object.

Related

How can I resolve JSON parsing error 'JSON.parse: bad control character in string literal'?

In NodeJS Backend, I send my data to client as:-
res.end(filex.replace("<userdata>", JSON.stringify({name:user.name, uid:user._id, profile:user.profile}) ))
//No error here and Object is stringified perfectly
//user is object returned in mongoDB's result
The JSON string looks like this:
{"name":"Rishavolva","uid":"5f3ce234fd83024334050872","profile":{"pic":{"small_link":"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJyZXBsaWNhcyI6MiwidXJpcyI6W3siZGJfbmFtZSI6ImlmcmRiMDAxIiwidGFibGUiOiJGSUxFIiwiaWQiOjQ4fSx7ImRiX25hbWUiOiJpZnJkYjAwMiIsInRhYmxlIjoiRklMRSIsImlkIjo0OH1dLCJ1aWRfd2hpdGVsaXN0IjoiKiIsImlhdCI6MTU5ODE2MzMzNX0.9NkGnEumn4JW8IN0KFgxgN_6_4wN8qOgezNTyzz9osY","big_link":"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJyZXBsaWNhcyI6MiwidXJpcyI6W3siZGJfbmFtZSI6ImlmcmRiMDAxIiwidGFibGUiOiJGSUxFIiwiaWQiOjQ3fSx7ImRiX25hbWUiOiJpZnJkYjAwMiIsInRhYmxlIjoiRklMRSIsImlkIjo0N31dLCJ1aWRfd2hpdGVsaXN0IjoiKiIsImlhdCI6MTU5ODE2MzMzNX0.yxQ1GrhLsWPn8Qwu42EfTDXqaYwFtrM6f_7cAH2eLRY"},"aboutme":"I am Rishav Bhowmik\r\nand this is navratna pulaow"}}
and that UID is just a mongodb's primary key as string, and other two base 64 strings are just JWT tokens.
Now, when this JSON string reaches the Browser, I parse it with simple:
JSON.parse(`<userdata>`)
//remember I used filex.replace("<userdata>", JSON.stringify...) in the server
For reference, my MongoDB Document here is:
Now when JSON.parse is executed on the JSON string it will look like this on final JS code.
JSON.parse(`{"name":"Rishavolva","uid":"5f3ce234fd83024334050872","profile":{"pic":{"small_link":"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJyZXBsaWNhcyI6MiwidXJpcyI6W3siZGJfbmFtZSI6ImlmcmRiMDAxIiwidGFibGUiOiJGSUxFIiwiaWQiOjQ4fSx7ImRiX25hbWUiOiJpZnJkYjAwMiIsInRhYmxlIjoiRklMRSIsImlkIjo0OH1dLCJ1aWRfd2hpdGVsaXN0IjoiKiIsImlhdCI6MTU5ODE2MzMzNX0.9NkGnEumn4JW8IN0KFgxgN_6_4wN8qOgezNTyzz9osY","big_link":"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJyZXBsaWNhcyI6MiwidXJpcyI6W3siZGJfbmFtZSI6ImlmcmRiMDAxIiwidGFibGUiOiJGSUxFIiwiaWQiOjQ3fSx7ImRiX25hbWUiOiJpZnJkYjAwMiIsInRhYmxlIjoiRklMRSIsImlkIjo0N31dLCJ1aWRfd2hpdGVsaXN0IjoiKiIsImlhdCI6MTU5ODE2MzMzNX0.yxQ1GrhLsWPn8Qwu42EfTDXqaYwFtrM6f_7cAH2eLRY"},"aboutme":"I am Rishav Bhowmik\r\nand this is navratna pulaow"}}`)
I get this error:
Uncaught SyntaxError: JSON.parse: bad control character in string literal at line 1 column 702 of the JSON data
the string at position 702 of the JSON string is \n
First of all, how can \n be a control character?
What should I do to resolve this?
Has this problem arrised due to MONGODB result?
\n is a control character signifying a new line. In JSON, those control characters (more specifically the \) must be escaped inside strings.
This will raise the error:
JSON.parse(`{"hello":"world\n"}`)
This wont:
JSON.parse(`{"hello":"world\\n"}`)
So one way would be to use something like replace to ensure your aboutme is properly escaped before JSON serialization. See: How to escape a JSON string containing newline characters using JavaScript?
Ok have done some experimentation and have a solution.
The Trick is to do JSON.stringify() twice,
Like,
html_text.replace('/*<whatever>*/', JSON.stringify( JSON.stringify(the_object) ) )
If suppose html_text has a line which is
<script>
const object_inbrowser = JSON.parse(/*<whatever>*/)
// no need to add qotes, `JSON.stringify` in the server will do that for you
</script>

parse json string with forward slashes - javascript

Looks pretty simple but I am unable to figure it out
var str="[{name:\"House\",id:\"1\"},{name:\"House and Land\",id:\"5\"},{name:\"Land\",id:\"6\"},{name:\"Terrace\",id:\"11\"}]";
JSON.parse(str.replace(/\s/g, "").replace(/\//g, ''));
I am unable to the convert above string(which comes from 3rd party website) to valid json so that I can iterate it on my side
error
VM5304:1 Uncaught SyntaxError: Unexpected token n in JSON at position 2
at JSON.parse (<anonymous>)
JSON requires the keys to be quoted. It appears that your keys are coming in unquoted. So add another .replace statement to insert the quote back in:
.replace(/(\w+):/g, '"$1":');
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON
Property names must be double-quoted strings; trailing commas are forbidden.
COMPLETE SOLUTION:
.replace(/(,|{)\s*(\w+)\s*:/g, '$1"$2":');

How to deserialize Json object which contain control character using Dojo.fromJson

I am using Dojo.fromJson to convert json string to javascript object, but throw exception. Because, there are control characters such as ',\n,\r in the json string.
How can I solve this problem in dojo? convert json string to javascript object, even if there are control characters.
I use Newtonsoft.JsonConvert.SerializeObject to convert C# oject to json data. Json Object: {"name":"'\"abc\n123\r"} then, I use Dojo.fromJson(' {"name":"'\"abc\n123\r"}') to convert json data to javascript object.
Thank you very much!
Problem, i believe is the double-quote which should be escaped by triple backslashes. You can use "native browser JSON decode" as searchterm for "dojo fromJson" synonym.
Without knowing my way around C# - I havent tested but i believe following should work:
string c_sharp_name = "'\"abc\n123\r";
// C#Object.name
c_sharp_name = c_sharp_name.
replace('"', '\\"'). // maybe add a slash on serverside
replace('\n', '\\\n').
replace('\r', '\\\r');
since
while this fails:
{"name":"'\"abc\n123\r"} // your single backslash
this would work:
{"name":"'\\\"abc\\\n123\\\r"} // working triple backslash escape

JSON parsing syntax error with manually entered string

When I try to stringyfy
ABC
<a href="abc.co.dds">
dfsdsf
</a>
JSON gives me
"ABC\n\n dfsdsf\n"
but when I try
s=('"ABC\n\n dfsdsf\n"');
JSON.parse(s)
I get a SyntaxError: Unexpected token on my console
How can I parse a manually entered string with JSON?
From the JSON specification (second 2):
A JSON text is a serialized object or array.
Since you are starting with a string (and not an object or an array), a JSON serializer should (IMO) throw an exception instead of giving you an escaped string.
You can work around your problem by wrapping your string in { "data": your_string } before converting to JSON (using whatever syntax that language you are using supports for objects/hash maps/associative arrays/etc). Obviously, you'll need to access foo.data after parsing the JSON to a native object at the other end).

javascript eval json with base64 encoded field

I am using sun.misc.BASE64Encoder to encode an encrypted value, which is then added to a JSON field and subsequently sent to the client. I use Javascript's eval() function on the client to create an object from the JSON code. When eval() runs, it gives the error:
unterminated string literal
There are other fields in the JSON code, but I've narrowed the error specifically to the base64 encoded field. Here's the offending line of javascript code:
var result = eval( '(' + xhr.responseText + ')' );
Here's the JSON object from the Servlet:
{
'resource':'resource?Signature=j79r/2Hly+HqhS/6fdd+prfsR+kUNijUvDN0QJ14ZR43gzYScOMDypt/crks/CEphTUXVptJvSol
1ZOOvScCUhNOCb7dZk/3MKnI5tOewSACXK32/OJNd8hYpZtSTn+WhA6+f9BUIUZWA83U8Cud/Tb8V
R1yQWbDGG/mM/NiUSiY=',
'url':'http://somesite.com/pr'
}
I'm not sure why eval is dying, but it seems the value of the 'resource' JSON field contains something it doesn't care for.
Thanks in advance.
Tim
I think it may be because your JSON appears to have line breaks in it. If you remove them, does it work?

Categories