JObject.Parse(jsonString) is causing issue for boolean data. e.g. The json is :
{
"BoolParam": true
}
I used the following code to parse:
JObject data = JObject.Parse(str1);
foreach (var x in data)
{
string name = x.Key;
Console.Write(name + " (");
JToken value = x.Value;
Console.Write(value.Type + ")\n");
Console.WriteLine(value);
}
This print out the value as :
BoolParam (Boolean) : True
The case sensitivity causes issue as I save this json for later use. The saved json looks like
{
"BoolParam": True
}
However, when i later use it, the JObject.Parse(str) throws error as invalid Json :Unexpected character encountered while parsing value: T. Path 'BoolParam', line 2, position 15.
If I change the case from "True" to "true", it works. I dont want to add this hack to change the case when saving but is there a better way to handle this scenario.
I dont want to add this hack to change the case when saving but is
there a better way to handle this scenario.
No, you have to produce valid JSON when saving if you want to be able to later deserialize it with a JSON serializer such as Newtonsoft JSON. So fixing your saving routing is the right way to go here.
One could use anonymous types and no worry about case sensitivity of boolean type variables
public static void Main()
{
bool a = true;
JObject c = JObject.FromObject(new {BoolParam= a});
Console.WriteLine(c);
}
Output:
{
"BoolParam": true
}
Related
I need to put some numeric value into an JSON array. But every time I use obj.put("key", value) the value is automatically "casted" into Integer.
i.e.
value = 0.0 => {"key": 0}
I want the value in the JSON object to be EXACTLY the same of the value I get from the application.
I thought of using value.getClass in order to get the value of the class and create a match...case method and use value.toString.to*, where * is the corresponding class (i.e the class is Integer, the value will be casted using value.toString.toInt). But this approach is kinda "dirty" in my opinion, and I'm new to Scala so I don't know this language very well and its tricks.
Any suggestion?
EDIT: Here's the code (here I send the JSON to a server):
for ((p, v) <- exportMap){
val obj: JSONObject = new JSONObject()
obj.put("path", parsePathString(p.toString))
if (v.toString.equals("Infinity")) {
obj.put("result", "Inf")
} else {
obj.put("result", v)
}
exportJSONArray.put(obj)
Here I get the JSON from the server, in order to use its data in the app:
var result: Any = jSONObject.get("result")
if (result.equals("Inf")) {
result = Double.PositiveInfinity
}
and then the variable "result" goes in a data structure.
So I need to have the EXACT same type of numeric data.
So I need to have the EXACT same type of numeric data
First of all, you want exact same type, but type is as Any. It's like saying that you don't care about the type. You can use optDouble getter for it:
val result: Double = jSONObject.optDouble("result", Double.PositiveInfinity)
(and it doesn't have to be a var, try not to use vars in Scala)
Next, in the part where you write to the object, you can check whether the value is infinity:
obj.put("result", if(v.isInfinity) "Inf" else v)
I think this solves your problem.
There are very many JSON libraries in Java (and Scala), and you picked one which intentionally does this:
public static String numberToString(Number number) throws JSONException {
if (number == null) {
throw new JSONException("Null pointer");
}
testValidity(number);
// Shave off trailing zeros and decimal point, if possible.
String string = number.toString();
if (string.indexOf('.') > 0 && string.indexOf('e') < 0
&& string.indexOf('E') < 0) {
while (string.endsWith("0")) {
string = string.substring(0, string.length() - 1);
}
if (string.endsWith(".")) {
string = string.substring(0, string.length() - 1);
}
}
return string;
}
You can pick a different one which doesn't.
Please pardon me if this is a repeat question. I have been through some of the questions/answers with a similar requirement but somehow got a bit overwhelmed and confused at the same time. My requirement is:
I get a JSON string/object as a request parameter. ( eg: params.timesheetJSON )
I then have to parse/iterate through it.
Here is the JSON that my grails controller will be receiving:
{
"loginName":"user1",
"timesheetList":
[
{
"periodBegin":"2014/10/12",
"periodEnd":"2014/10/18",
"timesheetRows":[
{
"task":"Cleaning",
"description":"cleaning description",
"paycode":"payCode1"
},
{
"task":"painting",
"activityDescription":"painting description",
"paycode":"payCode2"
}
]
}
],
"overallStatus":"SUCCESS"
}
Questions:
How can I retrieve the whole JSON string from the request? Does request.JSON be fine here? If so, will request.JSON.timesheetJSON yield me the actual JSON that I want as a JSONObject?
What is the best way to parse through the JSON object that I got from the request? Is it grails.converters.JSON? Or is there any other easy way of parsing through? Like some API which will return the JSON as a collection of objects by automatically taking care of parsing. Or is programatically parsing through the JSON object the only way?
Like I said, please pardon me if the question is sounding vague. Any good references JSON parsing with grails might also be helpful here.
Edit: There's a change in the way I get the JSON string now. I get the JSON string as a request paramter.
String saveJSON // This holds the above JSON string.
def jsonObject = grails.converters.JSON.parse(saveJSON) // No problem here. Returns a JSONObject. I checked the class type.
def jsonArray = jsonArray.timesheetList // No problem here. Returns a JSONArray. I checked the class type.
println "*** Size of jsonArray1: " + jsonArray1.size() // Returns size 1. It seemed fine as the above JSON string had only one timesheet in timesheetList
def object1 = jsonArray[1] // This throws the JSONException, JSONArray[1] not found. I tried jsonArray.getJSONObject(1) and that throws the same exception.
Basically, I am looking to seamlessly iterate through the JSON string now.
I have wrote some code that explains how this can be done, that you can see below, but to be clear, first the answers to your questions:
Your JSON String as you wrote above will be the contents of your POST payload to the rest controller. Grails will use its data binding mechanism to bind the incomming data to a Command object that your should prepare. It has to have fields corresponding to the parameters in your JSON String (see below). After you bind your command object to your actual domain object, you can get all the data you want, by simply operating on fields and lists
The way to parse thru the JSON object is shown in my example below. The incomming request is esentially a nested map, with can be simply accessed with a dot
Now some code that illustrates how to do it.
In your controller create a method that accepts "YourCommand" object as input parameter:
def yourRestServiceMethod (YourCommand comm){
YourClass yourClass = new YourClass()
comm.bindTo(yourClass)
// do something with yourClass
// println yourClass.timeSheetList
}
The command looks like this:
class YourCommand {
String loginName
List<Map> timesheetList = []
String overallStatus
void bindTo(YourClass yourClass){
yourClass.loginName=loginName
yourClass.overallStatus=overallStatus
timesheetList.each { sheet ->
TimeSheet timeSheet = new TimeSheet()
timeSheet.periodBegin = sheet.periodBegin
timeSheet.periodEnd = sheet.periodEnd
sheet.timesheetRows.each { row ->
TimeSheetRow timeSheetRow = new TimeSheetRow()
timeSheetRow.task = row.task
timeSheetRow.description = row.description
timeSheetRow.paycode = row.paycode
timeSheet.timesheetRows.add(timeSheetRow)
}
yourClass.timeSheetList.add(timeSheet)
}
}
}
Its "bindTo" method is the key piece of logic that understands how to get parameters from the incomming request and map it to a regular object. That object is of type "YourClass" and it looks like this:
class YourClass {
String loginName
Collection<TimeSheet> timeSheetList = []
String overallStatus
}
all other classes that are part of that class:
class TimeSheet {
String periodBegin
String periodEnd
Collection<TimeSheetRow> timesheetRows = []
}
and the last one:
class TimeSheetRow {
String task
String description
String paycode
}
Hope this example is clear enough for you and answers your question
Edit: Extending the answer according to the new requirements
Looking at your new code, I see that you probably did some typos when writting that post
def jsonArray = jsonArray.timesheetList
should be:
def jsonArray = jsonObject.timesheetList
but you obviously have it properly in your code since otherwise it would not work, then the same with that line with "println":
jsonArray1.size()
shuold be:
jsonArray.size()
and the essential fix:
def object1 = jsonArray[1]
shuold be
def object1 = jsonArray[0]
your array is of size==1, the indexing starts with 0. // Can it be that easy? ;)
Then "object1" is again a JSONObject, so you can access the fields with a "." or as a map, for example like this:
object1.get('periodEnd')
I see your example contains errors, which lead you to implement more complex JSON parsing solutions.
I rewrite your sample to the working version. (At least now for Grails 3.x)
String saveJSON // This holds the above JSON string.
def jsonObject = grails.converters.JSON.parse(saveJSON)
println jsonObject.timesheetList // output timesheetList structure
println jsonObject.timesheetList[0].timesheetRows[1] // output second element of timesheetRows array: [paycode:payCode2, task:painting, activityDescription:painting description]
I have a json object that gets passed into a save function as
{
"markings": {
"headMarkings": "Brindle",
"leftForeMarkings": "",
"rightForeMarkings": "sock",
"leftHindMarkings": "sock",
"rightHindMarkings": "",
"otherMarkings": ""
}
** EDIT **
The system parses it and passes it to my function as a mapping. I don't actually have the JSON, although it wouldn't be difficult to build up the JSON myself, it just seems like overkill
* END EDIT **
The toString() function ends up putting the results into the database as
"[rightForeMarkings:, otherMarkings:, leftForeMarkings:sock, leftHindMarkings:sock, rightHindMarkings:, headMarkings:brindle]"
I then want to save that as a string (fairly easy) by calling
params.markings.toString()
From here, I save the info and return the updated information.
My issue is that since I am storing the object in the DB as a string, I can't seem to get the markings back out as a map (to then be converted to JSON).
I have tried a few different things to no avail, although it is completely possible that I went about something incorrectlywith these...
Eval.me(Item.markings)
evaluate(Item.markings)
Item.markings.toList()
Thanks in advance for the help!
Throwing my tests.
Using JSON converters in Grails, I think this should be the approach: (synonymous to #JamesKleeh and #GrailsGuy)
def json = '''{
"markings": {
"headMarkings": "Brindle",
"leftForeMarkings": "",
"rightForeMarkings": "sock",
"leftHindMarkings": "sock",
"rightHindMarkings": "",
"otherMarkings": ""
}
}'''
def jsonObj = grails.converters.JSON.parse(json)
//This is your JSON object that should be passed in to the method
print jsonObj //[markings:[rightForeMarkings:sock, otherMarkings:, leftForeMarkings:, leftHindMarkings:sock, rightHindMarkings:, headMarkings:Brindle]]
def jsonStr = jsonObj.toString()
//This is the string which should be persisted in db
assert jsonStr == '{"markings":{"rightForeMarkings":"sock","otherMarkings":"","leftForeMarkings":"","leftHindMarkings":"sock","rightHindMarkings":"","headMarkings":"Brindle"}}'
//Get back json obj from json str
def getBackJsobObj = grails.converters.JSON.parse(jsonStr)
assert getBackJsobObj.markings.leftHindMarkings == 'sock'
If I understand correctly, you want to convert a String to a JSON object? You can actually bypass converting it to a map, and parse it directly as a JSON object:
import grails.converters.JSON
def json = JSON.parse(Item.markings)
This will give you your entire JSON object, and then you can just reference the values as you would a map.
Edit #2:
So apparently there is no "safe" way to convert that string back to a map without something custom. I would recommend saving the structure in the database as it originally comes in. If you can do that, then all you would need is JSON.parse()
I am trying to parse some JSON objects which is made just of (string,string) pairs, in order to emulate Resjson behaviour. The file I am parsing contains this.
{
"greeting":"Hello world",
"_greeting.comment":"Hello comment.",
"_greeting.source":"Original Hello",
}
Please note the last comma is incorrect, and I also used http://jsonlint.com/ to test JSON syntax. It tells me it is incorrect, as I expected. My - slightly modified - code is :
string path = #"d:\resjson\example.resjson";
string jsonText = File.ReadAllText(path);
IDictionary<string, string> dict;
try
{
dict = JsonConvert.DeserializeObject<IDictionary<string, string>>(jsonText);
}
catch(Exception ex)
{
// code never reaches here
}
My above code returns the IDictionary with the 3 keys as if the formatting was correct. If I serialize back, the string obtained is without the last comma.
My questions are :
Is Newtonsoft.Json so permissive that it allows users slight errors ?
If so, can I set the permissiveness so that it is more strict ?
Is there a way to check if a string is valid JSON format, using
Newtonsoft.Json with and/or without the permissiveness?
I want every JSON response to post-request to contain a field success. What's the best way to add this field there?
I use code like this to generate JSON responses:
try {
def entity = myService.saveEntity(arg1,arg2)
render entity as JSON //I want to add artificial field 'success = "yes"' here
} catch (ValidationException e) {
render parseErrors(e.errors) as JSON //field 'success = "no"' here
}
I just struggled with this exact issue this week. I wanted to send back a domain class as JSON but at the same time add an 'errorMessage' property that would potentially contain additional information.
Turns out that when using as JSON in grails it sends back a converter object, but its possible to turn that converter instance into a jsonObject using JSON.parse() which we can easily add new values to.
def jsonObject = JSON.parse((entity AS JSON).toString())
jsonObject.put("success", "yes")
render jsonObject as JSON
I think there are a couple of different approaches but this ended up being the easiest for me since I already have custom converters for most of my domain classes and I didn't want to add any other transient properties to my domain object.
Could you return a map containing the success field, and the object wrapped inside a separate variable:
try {
def entity = myService.saveEntity(arg1,arg2)
render [ success:'yes', val:entity ] as JSON
} catch (ValidationException e) {
render [ success:'no', val:parseErrors(e.errors) ] as JSON
}
Not tested it mind...
You can register your own JSON marshaller (at BootStrap.groovy, for example), like:
JSON.registerObjectMarshaller(MyEntity) { MyEntity it ->
return [
someField : it.someField, // you should specify fields for output, or put all '.properties'
success : true // as I understand you always have 'true' for real entity
]
}
where MyEntity is your class you want to use