I have the following C# method:
[HttpPost]
public JsonResult GetDateBasedRegex(string date)
{
string[] arr = CommonMethods.GetDateBasedRegex(date);
JsonResult retVal = Json(JsonConvert.SerializeObject(retVal));
return retVal;
}
arr contains the following:
And retVal.Data contains this value:
That C# method is invoked by this JS:
var date = $('#myDateField').val();
AjaxRequest(date, 'html', 'post', '/Common/GetDateBasedRegex', 'application/json;', function (response)
{
var result = JSON.parse(response);
}
);
I've set a breakpoint and added a watch for both response and result:
response is slightly longer because it escapes the quotes but otherwise they're the same value.
Both variables are a single string. How can I parse this value into an array? I looked at a variety of "suggested questions" by SO when typing this question,
the most relevant one seems to be this: Javascript how to parse JSON array but I'm already doing what the selected answer suggests.
I tried making a JS fiddle: http://jsfiddle.net/zc2o6v52/ but due to the quotes added by the debugger I had to tweak the values slightly in order to get it to work. If I use the variable csharpJsonSerializedString or result the loop works but when I use response I get an "Uncaught SyntaxError: Unexpected string" error in my console.
What am I doing wrong? How do you parse an array from a JSON string?
EDIT
C# retval's value:
"[\"^[0-9]{9}[A-Z0-9]{0,3}$\",\"^[A-Z]{1,3}([0-9]{6}|[0-9]{9})$\"]"
JS response's value:
""[\"^[0-9]{9}[A-Z0-9]{0,3}$\",\"^[A-Z]{1,3}([0-9]{6}|[0-9]{9})$\"]""
JS result's value:
"["^[0-9]{9}[A-Z0-9]{0,3}$","^[A-Z]{1,3}([0-9]{6}|[0-9]{9})$"]"
Grabbed all of these by right click -> Copy value, so they include the 'wrapping' set of quotes to make it a string.
The C# looks like it's formed right for how one would define a JS array. It seems like response is wrapped with an extra set of quotes though?
I also tried changing my JS to define var result = ['','']; outside of the ajax call, then to update its value with JSON.parse() but it still remains a single string afterwards.
Assuming this is the exact value your API returns on the POST request
"[\"^[0-9]{9}[A-Z0-9]{0,3}$\",\"^[A-Z]{1,3}([0-9]{6}|[0-9]{9})$\"]"
This is no json, so JSON.parse can't work. Your JSON should look like this:
[
"^[0-9]{9}[A-Z0-9]{0,3}$",
"^[A-Z]{1,3}([0-9]{6}|[0-9]{9})$"
]
The best way would be to fix the backend to return the right value (this might point you in the right direction). Otherwise, you need to get rid of the quotation marks at the beginning and end which are added to your result variable:
var result = "\"[\"^[0-9]{9}[A-Z0-9]{0,3}$\",\"^[A-Z]{1,3}([0-9]{6}|[0-9]{9})$\"]\"";
result = result.substring(1, result.length-1);
var jsonData = JSON.parse(result);
for (var i = 0; i < jsonData.length; i++) {
console.log(jsonData[i]);
}
If that doesn't work, check how your response data in the ajax function differs from the valid json mentioned above.
Related
I've been trying to load certain Json with Ajax GET request and then parsing it.
However when trying to access the Json key from HTML script tag it was undefined.
In order to debug this issue, I logged all the keys of Json in console as well as the Json itself. Therefore i utilized this function:
function getInv() {
$.get( "/inventory/", function( data ) {
var invList = data.split(",, "); // Explanation is below
console.log(invList[0]) // Just testing with first object
console.log(Object.keys(invList[0]));
});
}
getInv();
Purpose of data.split(",, "):
Since my backend script uses different programming language, I had to interpret it to the one suitable for Javascript.
There also were multiple Json objects, So i separated them with ",, " and then split them in Javascript in order to create a list of Json objects.
After calling the function, Following output was present:
Although the interesting part is that after pasting Json object in console like this:
This was the output:
So basically, in script tag, i was unable to access object's keys, although once i used it manually in console, all keys could be accessed.
What could be the purpose behind this? It seems quite strange that different outputs are given. Perhaps invList[0] is not Json object at all in the script tag? Thanks!
data.split() returns an array of strings, not objects. You need to use JSON.parse() to parse the JSON string to the corresponding objects.
function getInv() {
$.get( "/inventory/", function( data ) {
var invList = data.split(",, ");
console.log(invList[0]) // Just testing with first object
var obj = JSON.parse(invList[0]);
console.log(Object.keys(obj));
});
}
You can use .map() to parse all of them, then you'll get an array of objects like you were expecting:
var invList = data.split(",, ").map(JSON.parse);
I am creating and sending a JSON Object with jQuery, but I cannot figure out how to parse it properly in my Ajax servlet using the org.json.simple library.
My jQuery code is as follows :
var JSONRooms = {"rooms":[]};
$('div#rooms span.group-item').each(function(index) {
var $substr = $(this).text().split('(');
var $name = $substr[0];
var $capacity = $substr[1].split(')')[0];
JSONRooms.rooms.push({"name":$name,"capacity":$capacity});
});
$.ajax({
type: "POST",
url: "ParseSecondWizardAsync",
data: JSONRooms,
success: function() {
alert("entered success function");
window.location = "ctt-wizard-3.jsp";
}
});
In the servlet, when I use request.getParameterNames() and print it out to my console I get as parameter names rooms[0][key] etcetera, but I cannot parse the JSON Array rooms in any way. I have tried parsing the object returned by request.getParameter("rooms") or the .getParameterValues("rooms") variant, but they both return a null value.
Is there something wrong with the way I'm formatting the JSON data in jQuery or is there a way to parse the JSON in the servlet that I'm missing?
Ask for more code, even though the servlet is still pretty much empty since I cannot figure out how to parse the data.
The data argument of $.ajax() takes a JS object representing the request parameter map. So any JS object which you feed to it will be converted to request parameters. Since you're passing the JS object plain vanilla to it, it's treated as a request parameter map. You need to access the individual parameters by exactly their request parameter name representation instead.
String name1 = request.getParameter("rooms[0][name]");
String capacity1 = request.getParameter("rooms[0][capacity]");
String name2 = request.getParameter("rooms[1][name]");
String capacity2 = request.getParameter("rooms[1][capacity]");
// ...
You can find them all by HttpServletRequest#getParameterMap() method:
Map<String, String[]> params = request.getParameterMap();
// ...
You can even dynamically collect all params as follows:
for (int i = 0; i < Integer.MAX_VALUE; i++) {
String name = request.getParameter("rooms[" + i + "][name]");
if (name == null) break;
String capacity = request.getParameter("rooms[" + i + "][capacity]");
// ...
}
If your intent is to pass it as a real JSON object so that you can use a JSON parser to break it further down into properties, then you have to convert it to a String before sending using JS/jQuery and specify the data argument as follows:
data: { "rooms": roomsAsString }
This way it's available as a JSON string by request.getParameter("rooms") which you can in turn parse using an arbitrary JSON API.
Unrelated to the concrete problem, don't use $ variable prefix in jQuery for non-jQuery objects. This makes your code more confusing to JS/jQuery experts. Use it only for real jQuery objects, not for plain vanilla strings or primitives.
var $foo = "foo"; // Don't do that. Use var foo instead.
var $foo = $("someselector"); // Okay.
How can i retrieve the values from such JSON response with javascript, I tried normal JSON parsing seem doesn't work
[["102",true,{"username":"someone"}]]
Tried such codes below:
url: "http://somewebsite.com/api.php?v=json&i=[[102]]",
onComplete: function (response) {
var data = response.json[0];
console.log("User: " + data.username); // doesnt work
var str = '[["102",true,{"username":"someone"}]]';
var data = JSON.parse(str);
console.log("User: " + data[0][2].username);
Surround someone with double quotes
Traverse the array-of-array before attempting to acces the username property
If you are using AJAX to obtain the data, #Alex Puchkov's answer says it best.
So the problem with this is that it looks like an array in an array. So to access an element you would do something like this.
console.log(obj[0][0]);
should print 102
Lets say you created the object like so:
var obj = [["102",true,{"username":someone}]];
this is how you would access each element:
obj[0][0] is 102
obj[0][1] is true
and obj[0][2]["username"] is whatever someone is defined as
From other peoples answers it seems like some of the problem you may be having is parsing a JSON string. The standard way to do that is use JSON.parse, keep in mind this is only needed if the data is a string. This is how it should be done.
var obj = JSON.parse(" [ [ "102", true, { "username" : someone } ] ] ")
It depends on where you are getting JSON from:
If you use jQuery
then jQuery will parse JSON itself and send you a JavaScript variable to callback function. Make sure you provide correct dataType in $.ajax call or use helper method like $.getJSON()
If you getting JSON data via plain AJAX
then you can do:
var jsonVar = JSON.parse(xhReq.responseText);
I'm confused as to how I should be using JSON objects within MVC and how they should passed from Controller, to View, to Jscript.
I'm also not sure if I'm correctly parsing the JSON objects at the right points...
My controller is returning a PartialView with a json object ("Variables" is a list of data e.g. Id=2012, Name=BillyJoel, Value="£2,000"):
public ActionResult JavascriptConstants() {
var variables = Service.Obtain<VariableService>().All().ToList();
var json = new JavaScriptSerializer().Serialize(variables);
return PartialView("JavascriptConstants", json);
}
My View then makes this data available to my scripts by creating this variable:
#model string
...
var mvcListOfVariablesInDB = '#Html.Raw(Json.Encode(Model))';
My Jscript file then accesses the data and attempts to pull out the information and key value pairs, but seems to be interpreting the JSON as a string:
var variableList = $.parseJSON(mvcListOfVariablesInDB);
for (var variable in variableList) {
alert(variableList[variable]);
}
This just returns alerts of ", [, {, etc. as each character of the string is displayed. How do I access the key values of the JSON object?
I've tried changing my JS to use:
var variableList = $.parseJSON(mvcListOfVariablesInDB);
But this just gives me an Uncaught SyntaxError: Unexpected token I error in my browser (I'm assuming when it hits the "I" of "Id).
Any help much appreciated, thanks.
I found the issue:
The issue was the use of JavaScriptSerializer().Serialize(foo) as this was creating a JSON object that contained newlines and tabs instead of replacing them with \n and \t.
$.parseJSON() cannot handle newlines and so throws up unexpected token error.
This was corrected by importing the JSON.NET package and using :
var json = JsonConvert.SerializeObject(variables);
This passed a JSON object with newlines and tabs replaced with \n's and \t's. Which can then be made accessible to the View using:
#model string
...
var mvcListOfVariablesInDB = '#Html.Raw(Json.Encode(Model))';
and finally in the script using:
var variableList = $.parseJSON(mvcListOfVariablesInDB)
Hope this helps someone else one day...
Hi I am using a Java script variable
var parameter = $(this).find('#[id$=hfUrl]').val();
This value return to parameter now
"{'objType':'100','objID':'226','prevVoting':'" // THIS VALUE RETURN BY
$(this).find('[$id=hfurl]').val();
I want to store objType value in new:
var OBJECTTYPE = //WHAT SHOULD I WRITE so OBJECTTYPE contain 400
I am trying
OBJECTTYPE = parameter.objType; // but it's not working...
What should I do?
Try using parameter['objType'].
Just a note: your code snippet doesn't look right, but I guess you just posted it wrong.
Ok, not sure if I am correct but lets see:
You say you are storing {'objType':'100','objID':'226','prevVoting':' as string in a hidden field. The string is not a correct JSON string. It should look like this:
{"objType":100,"objID":226,"prevVoting":""}
You have to use double-quotes for strings inside a JSON object. For more information, see http://json.org/
Now, I think with $(this).find('[$id=hfurl]'); you want to retrieve that value. It looks like you are trying to find an element with ID hfurl,but $id is not a valid HTML attribute. This seems like very wrong jQuery to me. Try this instead:
var parameter = $('#hfurl').val();
parameter will contain a JSON string, so you have to parse it before you can access the values:
parameter = $.parseJSON(parameter);
Then you should be able to access the data with parameter.objType.
Update:
I would not store "broken" JSON in the field. Store the string similar to the one I shoed above and if you want to add values you can do it after parsing like so:
parameter.vote = vote;
parameter.myvote = vote;
It is less error prone.