Develop Reference

Multi element JSON object from JavaScript

I have a Javascript JSON object
const student = { name: "bob", age: 7, grade: 6 }
and I can pass it to my Web API using axios POST command by
JSON.stringify(student)
and I can build my student object by looping an array and passing in a value such as
let studentArr= []
const student = { name: studentArr[i]["name"], age: studentArr[i]["age"], grade: studentArr[i]["grade"}
I'm using i in the example as the index because it could have 100 students. As long as I pass in only one value for i, everything works fine. My question is how can I make it into a multi-element JSON object from my array. I've been spoiled by Newtonsoft.Json where I can pull data from a SQL database and create a JSON object. If I just JSON.stringify(studentARR) is shows empty. I want to pass to the Web API all of the students on one post so the Web API can make a document and download it back.
I seen many different ways of trying to accomplish this and the methods seem to change over time. Thanks for the help

Why do you have to JSON.stringify if you are using axios. The declaration of axios.post accepts URL as first parameter and the data which is formdata or the JSON object as second parameter
I'm pretty sure that you might not need to use JSON.stringify if you are using axios to post to a Web API
Example of using Axios post method https://axios-http.com/docs/post_example

Need Help to implement Tincan Javascript API

I'm working on tincan JavaScript API. The issue my data format is total change and TinCan have specified a why to pass data along with call. Help me to adjust my data in TinCan Api format. Here is sample data one of my call.
var data = {
"groupId": "groupId",
"groupName": "gNameEncrypt",
"tutorNames": "tutorNames",
"actorNames": "actorNames",
"otherNames": "otherNames"
};
Current what i do i simply decode this data and send it like this.
var actionList = new TinCan(
{
recordStores: [{
endpoint: "http://example.com",
username: username,
password: password,
allowFail: false
}]
});
var action = new TinCan.Agent({
"name": "insert"
});
actionList.getStatements({
'params': {
'agent': action,
'verb': {
'id': $.base64.encode(data)
}
},
'callback': function (err, data) {
console.info(data.more);
var urlref = "http://<?php echo $_SERVER['SERVER_NAME'] . ":" . $_SERVER['SERVER_PORT'] . $uriParts[0] . "?" ?>t=" + data.more.TutorToken;
window.location.href = urlref;
}
});
crypt.finish();
});

There are really two parts here:
need to get data into an xAPI (formerly Tin Can) format, and
the code itself.
In depth,
I think you need to take another look at how xAPI is used in general. Data is stored a JSON "Statement" object that has 3 required properties and various other optional ones. These properties often contain complex objects that are very extensible. It is hard to tell from what you've shown what you are really trying to capture and what the best approach would be. I suggest reading some material about the xAPI statement format. http://experienceapi.com/statements-101/ is a good starting point, and to get at least some coverage of all the possibilities continue with http://experienceapi.com/statements/ .
The code you've listed is attempting to get already stored statements based on two parameters rather than trying to store a statement. The two parameters being "agent" and "verb". In this case We can't tell what the verb is supposed to be since we don't know what data contains, I suspect this isn't going to make sense as a verb which is intended to be the action of a statement. Having said that the fact that the "actor" has a value of action is questionable, as that really sounds more like what a "verb" should contain. Getting the statements right as part of #1 should make obvious how you would retrieve those statements. As far as storing those statements, if you're using the TinCan interface object you would need to use the sendStatement method of that object. But this interface is no longer recommended, the recommended practice is to construct a TinCan.LRS object and interact directly with it, in which case you'd be using the saveStatement method.
I would recommend looking at the "Basic Usage" section of the project home page here: http://rusticisoftware.github.io/TinCanJS/ for more specifics look at the API doc: http://rusticisoftware.github.io/TinCanJS/doc/api/latest/

How to correctly parse the JSON?

I have developed a Cordova android plugin for my library. The library is used for sending events across different connected devices.
JS interface receives a JSON from the java side. What I want to do is to parse this before reaching the application so that the developer can directly use it as a JS object. When I tried to parse the JSON in my plugin's JS interface, I am running into issues. Below is an example:
Received by JS interface:
{"key":"name","data":"{\"name\":\"neil\",\"age\":2,\"address\":\"2 Hill St\"}"}
After parsing in JS interface:
Object {key: "name", data: "{"name":"neil","age":2,"address":"2 Hill St"}"}
data:"{"name":"neil","age":2,"address":"2 Hill St"}"
key:"name"
__proto__:Object
As you can see, if this data reaches the app and the developer accesses the data:
eventData.key = name;
eventData.data = {"name":"neil","age":2,"address":"2 Hill St"};
eventData.data.name = undefined
How can I parse the inner data as well in my JS interface so that the developer can access directly. In the above case, he has to parse eventData.data to access the properties. I don't want this to happen and I want to do this in JS interface itself.
Please note that eventData can have many properties and hence they should be properly parsed before passing into the app.
I am new to Javascript and hence finding it difficult to understand the problem.

It seems that your returned JSON contains a string for the data property.
var response = {"key":"name","data":"{\"name\":\"neil\",\"age\":2,\"address\":\"2 Hill St\"}"};
//Parse the data
var jsonData = JSON.parse(response.data);
console.log(jsonData.name); //neil
console.log(jsonData.age); //2
console.log(jsonData.address);//"2 Hill St"

As others pointed out, you have to do JSON.parse(eventData.data) as the data comes as a string.
You have to look why that happens. The inner data might be stored in this way, in some cases its valid to store it in db as flat object or it is stringified twice by mistake:
var innerdata = JSON.stringify({ name: "neil" });
var eventData = JSON.stringify({ key: "name", data: innerdata });
would correspond to your received string.
Correct way to stringify in first place would be:
var innerdata = { name: "neil" };
var eventData = JSON.stringify({ key: "name", data: innerdata });

SAPUI5 Create OData entity with dates - generates incorrect request payload that ends in CX_SXML_PARSE_ERROR

We are trying to create an entity that has date attributes via an odata service. Backend is an sap system. This entity has only 3 key attributes plus a bunch of other attributes. We have identified that dates in the keys are the root cause of the problem.
Keys:
Pernr type string,
begda type datetime
endda type datetime.
The code below, (which does not work), has been severely simplified when trying to troubleshoot the issue. At the moment, it reads an entity from an entity set and immediately tries to create one with exactly the same data.
Code:
var oODataModel = new sap.ui.model.odata.ODataModel("/sap/opu/odata/sap/Z_PERSONAL_DATA_SRV/");
//Test entity to be saved
var entity = null;
//Handler for read error
var handleReadE = function (oEvent){
alert("error");
};
//Handler for read success
var handleRead = function (oEvent){
//Get the data read from backend
entity = oEvent.results[0];
//Try to create a new entity with same data
oODataModel.create('/PersDataSet', entity, null, function(){
alert("Create successful");
},function(oError){
alert("Create failed", oError);
});
};
oODataModel.read("/PersDataSet", null, [], true, handleRead, handleReadE);
In the gateway error log, an xml parsing error appears. In this log, we can see the request data and it can be seen that the dates are transported with String types. These dates are defined in the service as DateTimes so the request is rejected.
Example:
<m:properties>
<d:Pernr m:type="Edm.String">00000001</d:Pernr>
<d:Endda m:type="Edm.String">9999-12-31T00:00:00</d:Endda>
<d:Begda m:type="Edm.String">1979-05-23T00:00:00</d:Begda>
When the entity is read, the backend does not send any type information. It sends like the following example:
<m:properties>
<d:Pernr>72010459</d:Pernr>
<d:Endda>9999-12-31T00:00:00</d:Endda>
<d:Begda>1876-07-21T00:00:00</d:Begda>
And, indeed, if we try to save the same info without the type=".." it works. So the problem are the incorrect types ODataModel.create adds to the xml.
My question is:
Can I tell ODataModel.create to not add this type info? It is not doing a good job inferring the types.
Can anyone share an example reading and writing dates through odata?
Thank you very much in advance.

the data returned from oODataModel.read is raw, before you post you need to parse it
var handleRead = function (oEvent){
//Get the data read from backend
entity = oEvent.results[0];
var newEntity = jQuery.extend({},entity);
delete newEntity.__metadata;
newEntity.Begda = new Date(entity.Begda);
newEntity.Endda = new Date(entity.Endda);
//Try to create a new entity with same data
oODataModel.create('/PersDataSet', newEntity, null, function(){
why not use json instead of xml?

Thanks all for the help.
We got this working accounting for the following:
The problem of the wrong types appended to the attributes comes from the read itself. The object returned by read has a __metadata attribute which describes the values. In this object the dates are set with type=edm.string, even when the service says they are DateTime. To me this is a bug of the .read function.
When trying to use the same object to save, create sees the __metatada on the entry and uses those values, producing type edm.string type for the dates. This caused the request to be rejected. Manually changing these __metadata.properties...type to Edm.DateTime makes it work.
In the end, we did the following:
Dates are parsed manually from the Odata response, creating a js Date
object from the strings in format "yyyy-mm-ddT00:00:00", to make it work with control bindings. When we want to save, the reverse is done.
The object to be created is a new object with
only the attributes we care (no __metadata)

Angular.js accessing and displaying nested models efficiently

I'm building a site at the moment where there are many relational links between data. As an example, users can make bookings, which will have booker and bookee, along with an array of messages which can be attached to a booking.
An example json would be...
booking = {
id: 1,
location: 'POST CDE',
desc: "Awesome stackoverflow description."
booker: {
id: 1, fname: 'Lawrence', lname: 'Jones',
},
bookee: {
id: 2, fname: 'Stack', lname: 'Overflow',
},
messages: [
{ id: 1, mssg: 'For illustration only' }
]
}
Now my question is, how would you model this data in your angular app? And, while very much related, how would you pull it from the server?
As I can see it I have a few options.
Pull everything from the server at once
Here I would rely on the server to serialize the nested data and just use the given json object. Downsides are that I don't know what users will be involved when requesting a booking or similar object, so I can't cache them and I'll therefore be pulling a large chunk of data every time I request.
Pull the booking with booker/bookee as user ids
For this I would use promises for my data models, and have the server return an object such as...
booking = {
id: 1,
location: 'POST CDE',
desc: "Awesome stackoverflow description."
booker: 1, bookee: 2,
messages: [1]
}
Which I would then pass to a Booking constructor, which would resolve the relevant (booker,bookee and message) ids into data objects via their respective factories.
The disadvantages here are that many ajax requests are used for a single booking request, though it gives me the ability to cache user/message information.
In summary, is it better practise to rely on a single ajax request to collect all the nested information at once, or rely on various requests to 'flesh out' the initial response after the fact.
I'm using Rails 4 if that helps (maybe Rails would be more suited to a single request?)

I'm going to use a system where I can hopefully have the best of both worlds, by creating a base class for all my resources that will be given a custom resolve function, that will know what fields in that particular class may require resolving. A sample resource function would look like this...
class Booking
# other methods...
resolve: ->
booking = this
User
.query(booking.booker, booking.bookee)
.then (users) ->
[booking.booker, booking.bookee] = users
Where it will pass the value of the booker and bookee fields to the User factory, which will have a constructor like so...
class User
# other methods
constructor: (data) ->
user = this
if not isNaN(id = parseInt data, 10)
User.get(data).then (data) ->
angular.extend user, data
else angular.extend this, data
If I have passed the User constructor a value that cannot be parsed into a number (so this will happily take string ids as well as numerical) then it will use the User factorys get function to retrieve the data from the server (or through a caching system, implementation is obviously inside the get function itself). If however the value is detected to be non-NaN, then I'll assume that the User has already been serialized and just extend this with the value.
So it's invisible in how it caches and is independent of how the server returns the nested objects. Allows for modular ajax requests and avoids having to redownload unnecessary data via its caching system.
Once everything is up and running I'll write some tests to see whether the application would be better served with larger, chunked ajax requests or smaller modular ones like above. Either way this lets you pass all model data through your angular factories, so you can rely on every record having inherited any prototype methods you may want to use.