Accessing a key's value from json body - json

Question

I have sent a post request to node express server
app.post('/addUsers', function (req, res) {
var newuser = req.body;
console.log(newuser);
fs.readFile( __dirname + "/" + "users.json", 'utf8', function (err, data) {
data = JSON.parse( data );
data["user4"] = newuser // how can i create a user4 here currently i get an error as newsier is whole req body or something .
console.log( data );
// res.end(data);
res.end( JSON.stringify(data));
});
})
and i have got the value of newuser to console as
{ '{"user4":{"password":"killer","id":4,"profession":"kuchbhi","name":"mukesh"}}': '' }
The question is how can i get the value of user4 so that i can add it to the list of users .
I was using this dictionary in swift
["user4":["name" : "mukesh",
"password" : "killer",
"profession" : "kuchbhi",
"id": 4]]
which i changed to this once knowing its not valid json
["name" : "mukesh",
"password" : "killer",
"profession" : "kuchbhi",
"id": 4]
and know i don't get the error but the data from server response (i have printed it in Xcode console)after adding the fourth user is quite not in the format i think it should be , it looks like this
["user2": {
id = 2;
name = suresh;
password = password2;
profession = librarian;
}, "user4": {
"{\"password\":\"killer\",\"profession\":\"kuchbhi\",\"id\":4,\"name\":\"mukesh\"}" = "";
}, "user1": {
id = 1;
name = mahesh;
password = password1;
profession = teacher;
}, "user3": {
id = 3;
name = ramesh;
password = password3;
profession = clerk;
}]
all other entries are added by me manually in users.son.
This is what is logged into terminal console
user4: { '{"password":"killer","profession":"kuchbhi","id":4,"name":"mukesh"}': '' } }
which i still think is not good json or is it ?
Thank you quite a novice with format conversions and servers get/post thingy .

Answer 1

At the moment, the json that you receive/present is not valid.
Once you actually manage to receive valid JSON from the client, this will look like the following.
var u = {"user4":{"password":"killer","id":4,"profession":"kuchbhi","name":"mukesh"}};
For any json you can get its keys by using the command
var theKeys = Object.keys(u);
In the example above, there is only one key for the entire JSON, so the variable theKeys has contents [ 'user4' ]. Hence, you will be able to access the username that you want by looking at theKeys[0].
Similarly, you can get the properties for the inner json document using the command
Object.keys(u[theKeys[0]]);
which will return [ 'password', 'id', 'profession', 'name' ].
EDIT
Based on the comment below, perhaps the following code can help you send the json object correctly from the client side.
NSDictionary *aDictionary = #{
#"user4": #{#"password": #"killer",
#"id": #4,
#"profession": #"kuchbhi"
}};
NSError * error;
NSData * theData = [NSJSONSerialization dataWithJSONObject:aDictionary options:0 error:&error];
NSString * newStr = [[NSString alloc] initWithData:theData encoding:NSUTF8StringEncoding];
NSLog(#"body: %#", newStr);
[newStr release];
And here is a solution to send json correctly using swift: https://stackoverflow.com/a/31938246/1355058