Extracting data from JSON with JavaScript - javascript

Probably a stupid issue, but I am stuck.
I have a node.js server that sends data to a client, like this:
var message_to_client = result;
socket.send(JSON.stringify(message_to_client));
Client succesfully receives the data; if I log it on console, it reads like this:
[{"_id":"55e60d3de4b06ef3ed5f189e","par1":54.2441033, "par2":-10.177503399999999}]
I want to show the par1 value on screen, however I don't seem to be able to 'extract' it from the JSON response.
I tried with the parseJSON function from jQuery and with https://stackoverflow.com/a/22628619/3849735, neither worked.
Anyone can help? Thanks.

Send the response in json format instead in string, like
var message_to_client = result;
socket.send(message_to_client);
client side
data[0].par1
will return the values

Related

POSTMAN - EXPRESS - Modify JSON before writing to file

I have written a POSTMAN call to a server that responds with a list of items in JSON like below:-
{
"count": 6909,
"setIds": [
"1/7842/0889#001",
"2/4259/0166#001",
"ENT0730/0009",
"9D/11181#002",
"1/9676/0001#001",
"2/4718/0001#004",
"2/1783/0044#001",
"1/4501/0001#001",
"1/2028/0002#002",
"2/3120/0079#001",
"2/1672/0024#001",
"2/3398/0064#001"
}
I want to make calls to another server using the value of the setID each time and iterate through all of these so that I end up calling the server thousands of times to verify the response from that server. The problem I have is that the second server expects the set id to be in a form where the forward slashes are converted to underscores and the hashes to dots, so
"1/7842/0889#001"
becomes
"1_7842_0889.001"
I have code that converts one to the other in POSTMAN
var jsonData = pm.response.json()
for (var i=0; i<jsonData.setIds.length; i++)
{
var new_j = jsonData.setIds[i].replace (/#/g, ".");
var new_i = new_j.replace (/\//g, "_");
}
})
This works fine line by line it creates the right thing in the console of POSTMAN but obviously what I really need to do is save the entire JSON in the right form to a file and then read from that file line by line using the corrected data. I don't seem to be able to save the data in a file in the right form using my code and I suspect I am missing something simple. Is there a way to write a file line by line from in side postman or in a script and manipulate the data as I'm creating it?
Alternatively I guess I could read from the JSON I have saved i.e. the full response and iterate through that manipulating the data as a pre-request script?
I have tried to do something like this using environmental variables - so in my first call I do:
var jsonData = JSON.parse(responseBody);
postman.setEnvironmentVariable('setIds', JSON.stringify(jsonData));
and then in my second call to the express server where I want to send my payload I run a pre-request script that I thought would work using the env variable but this fails as it doesn't seem to like the {...
SyntaxError: Unexpected token {
I think there are probably some neat ways of solving this either doing all of this outside of POSTMAN in javascript but I'm a little lost where to start. Any help appreciated
Would tell you are plaing with content, but not setting it back to JSON object ??
jsonData.setIds[i] = new_i;
can help or you can use 2x replace it in a string and convert back to make it easier (in case there are no / or # somewhere else).
var src = {
"count": 6909,
"setIds": [
"1/7842/0889#001",
"2/4259/0166#001",
"ENT0730/0009",
"9D/11181#002",
"1/9676/0001#001",
"2/4718/0001#004",
"2/1783/0044#001",
"1/4501/0001#001",
"1/2028/0002#002",
"2/3120/0079#001",
"2/1672/0024#001",
"2/3398/0064#001"
//...
]
}
var str = JSON.stringify(src, null, 4);
str = str.replace(/\//g,'_').replace(/#/g,'.');
console.log(str);
var res = JSON.parse(str);
console.log(res);

how can I access to a specific json value in my returned data

I send a http GET request which returns JSON data in the following form. I am finding it impossible to access this data despite having no problems with example json that I create. I want to ideally take the array under wifi, and use this data to create a html table, but I think I can work out how to create the table if I could just access the actual elements of the data.
I have tried multiple methods to try and reach the first timestamp. I have tried:
var element = result.undefined.clients.wifi[0].timestamp;
but this returns an error that 'clients' can't be found.
I also tried:
var element = result.clients.wifi[0].timestamp; //and
var element = result.wifi[0].timestamp;
The JSON data returned to a variable is shown below:
result = undefined
{"sourceId":"idid","sourceType":"CLOUD_source","searchMeta":{"maxResults":4,"metricType":["clients"],"family":["wifi"],"Interval":"M1"},
"clients":{"wifi":
[{"timestamp":1424716920,"avg":3,"min":1,"max":4,"Count":8,"sCount":3,"sources":["x1","x2","x3","x4","x5","x6","x7","x8"]},{"timestamp":1424716980,"avg":2,"min":1,"max":3,"Count":4,"sCount":2,"sources":["x3","x4","x8","x4"]},{"timestamp":1424717160,"avg":2,"min":1,"max":3,"Count":9,"sCount":4,"sources":["x3","x4"]}]}}
The JSON data is invalid. If it is returned from a server, you need to go there and correct the data source, (if you have access to that).
Otherwise, perhaps notify the backend guy(s) about it.
If it is from a REST API, and you are "sure" that the server code should be error free, then check that you have supplied all the required parameters in the API request you are making.
I think your JSON is messed up. I ran it through JSONLint, and having the undefined at the beginning causes things to break.

Read JSON String Shown In URL Using Javascript

i am trying to create a simple web app that gets the latitude and longitude stored in a JSON string and uses them to place markers on a google map. Currently, I have a program on a server which retrieves a JSON string with data when a URL is entered into a web browser. The JSON string produced is as follows:-
{"employees":[{"email":"bones93#hotmail.co.uk","lat":"53","lon":"-3","alt":"0","date":"unknown","time":"unknown"},{"email":"unknown","lat":"0","lon":"0","alt":"0","date":"unknown","time":"unknown"},{"email":"unknown","lat":"0","lon":"0","alt":"0","date":"unknown","time":"unknown"}]}
What method could i use in JavaScript that would allow me to get the JSON string that is produced?
P.S I know I will need to parse the text afterwards to make a JSON Object, this is something that can be done afterwards.
Use the Jquery library's get method to request the data from the server. Here is a link to a simple W3 tutorial : http://www.w3schools.com/jquery/ajax_get.asp
Your code will look something like this:
$("button").click(function(){
$.get("/your/server/url",function(data){
var result = JSON.parse(data);
// Process result.employees
});
});
You could use
var x = JSON.parse('{"employees":[{"email":"bones93#hotmail.co.uk","lat":"53","lon":"-3","alt":"0","date":"unknown","time":"unknown"},{"email":"unknown","lat":"0","lon":"0","alt":"0","date":"unknown","time":"unknown"},{"email":"unknown","lat":"0","lon":"0","alt":"0","date":"unknown","time":"unknown"}]}');
and then access it with:
x["employees"][0]["lat"];
try this for normal strings:
JSON.parse(str)
or if you're using AJAX to get that Json you can use as following:
$.get(..,'json')
OR
$.post(..,'json')

Problems with displaying JSON data I got from a server

I'm new to JSON/AJAX and
I've some problems with displaying data out of a JSON-object I've got from a server..
The url "http://localhost:8387/rest/resourcestatus.json" represents this object, which I would like to display via HTML/Javascript.. This object stores some monitoring information:
{"groupStatus":[
{"id":"AL Process","time":1332755316976,"level":0,"warningIds":[],"errorIds":[]},
{"id":"AL:instance1","time":1332919465317,"level":0,"warningIds":[],"errorIds":[]},
{"id":"AL:instance2","time":1332919465317,"level":1,"warningIds":["documentarea.locked"],"errorIds":[]},
{"id":"SL","time":1331208543687,"level":0,"warningIds":[],"errorIds":[]}
]}
Since the requested url is different from my domain I can't create a typical XMLHttpRequest.. So I found out that there's an AJAX cross-domain request which can be realised via jQuerys "getJSON()" method.
I want to display the ids and their level in a table.
Any solution to achieve this?
i think you are referring to JSONP. see jQuery.ajax Ex:
var url = 'http://localhost:8387/rest/resourcestatus.json';
$.getJSON(url+'?callback=?', function(data)
{
//data is
/*{
"groupStatus":
[
{"id":"AL Process","time":1332755316976,"level":0,"warningIds":[],"errorIds":[]},
{"id":"AL:instance1","time":1332919465317,"level":0,"warningIds":[],"errorIds":[]},
{"id":"AL:instance2","time":1332919465317,"level":1,"warningIds":["documentarea.locked"],"errorIds":[]},
{"id":"SL","time":1331208543687,"level":0,"warningIds":[],"errorIds":[]}
]
}*/
});
on the server side you will need to wrap the response into a JavaScript function: response = Request["callback"] +"("+ response+")";
the result will look like this:
?({"groupStatus":[{"id":"AL ....})
So the browser will actually load a valid java script code.
The callback function of $.getJSON contains the result of the AJAX call in it's argument.
$.getJSON('http://localhost:8387/rest/resourcestatus.json', function(data) {
$(data.groupStatus).each(function() {
// do something with $(this).id
});
});

Send JSON Object to Rails

Hi I'm new to rails so please bear with me :) I want to send JSON object to rails and save it to database. basically I have a data entered by the user then I have a javascript function thats retrieves the data and convert it into JSON object. What i want is to sent the JSON object maybe through ajax to rails and save it to the database.Can anyone give me any idea how to do it. thnx
function save(){
----(some codes)
notesArray.push({ Index: i, Title: title.val(), Content: content.val()});
// json encode it
var jsonStr = JSON.stringify(notesArray);
//want to add code here to send to rails
}
If you're using jQuery, it's very easy to do this using $.post():
$.post('/some/page/here', {notes: jsonStr});
As to "handle the JSON object in the controllers" you can use parsed_params = CGI.parse(params[:_json]) ,then you can get what you what througt parsed_params[key1][key2]

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