Develop Reference

Save/Load Variables in js

I'm trying to create a save/load function for my game in js, but I have basically no idea with how to go through with doing this. I can save variables to a JSON file or LocalStorage, but I don't know how to load them back into the program. I'm also pretty sure I'm exporting variables the wrong way as well. Any help?

Normally, I use JSON format to store and read data (of any type).
To save data (using key gamedata as example):
var myData = {
name: 'David',
score: 10
}
localStorage.setItem('gamedata', JSON.stringify(myData));
** without JSON.stringify, you data will be saved as string [Object object]
To retrieve the data back:
var savedData = localStorage.getItem('gamedata'); // savedData is string
var myData = JSON.parse(savedData); // parse JSON string to java object

setup a bin on www.myJSON.com. p5 has built in functionality for ajax requests such as loadJSON. that way it's not in local storage and you can access your data if you have it on github. I know your struggle, I used to deal with this sort of issue myself before I found myJSON

API Connect - 500 error when including basic Javascript

I'm trying some basic API Connect tutorials on IBM's platform (running locally using loopback) and have got completely stuck at an early point.
I've built a basic API service with some in-memory data and setter / getter functions. I've then built a separate API which takes two GET parameters and uses one of my getter functions to perform a search based on two criteria. When I run it, I successfully get a response with the following JSON object:
[{"itemId":1,"charge":9,"itemSize":2,"id":2}]
I've then tried to add a piece of server logic that modifies the response data - at this point, I'm just trying to add an extra field. I've added a Javascript component in the Assemble view and included the following code (taken from a tutorial), which I thought should modify the message body returned by the API while still passing it through:
//APIC: get the payload
var json = apim.getvariable('message.body');
//console.error("json %s", JSON.stringify(json));
//same: code to inject new attribute
json.platform = 'Powered by IBM API Connect';
//APIC: set the payload
//message.body = json;
apim.setvariable('message.body', json);
Instead of getting an extra JSON parameter ("platform"), all I get is a 500 error when I call the service. I'm guessing that I'm doing something fundamentally wrong, but all the docs suggest these are the right variable names to use.

You can't access json.platform but at that point json variable is json type. Are you sure that you can add a property to a json type variable if your json object lacks of that property? I mean: What if you first parse the json variable of json type to a normal object, then add new property, and finally stringify to json type again for body assigning purposes?
var json = JSON.parse(apim.getvariable('message.body')); //convert to normal object
json.platform = 'Powered by IBM API Connect'; //add new property
apim.setvariable('message.body', JSON.stringify(json)); //convert to json again before setting as body value

You need to get the context in some determined format, and in this function do your logic. For example if your message is in json you need to do:
apim.readInputAsJSON(function (error, json) {
if (error)
{
// handle error
apim.error('MyError', 500, 'Internal Error', 'Some error message');
}
else
{
//APIC: get the payload
var json = apim.getvariable('message.body');
//console.error("json %s", JSON.stringify(json));
if(json){
//same: code to inject new attribute
json.platform = 'Powered by IBM API Connect';
//APIC: set the payload
//message.body = json;
apim.setvariable('message.body', json);
}
}
});
Reference:
IBM Reference

You have the message.body empty, put a invoke/proxy policy before your gateway/javascript policy for example.

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 });

how to pass complicated data between mvc and javascript

I'm trying to build a UI with two dropdowns. The first one is "category", the second one is "sub-category". I can build a static list of "category" in my razor view. I want the "sub-category" item list to be dynamically updated when "category" is changed. I'm trying to pass all category information from server side to client side since the list is not big and there is no security issue. But I cannot find a good way to format my data and transfer it to client side. I can generate a json object with all of my category trees using the following code:
ExpandoObject catToSubcatMap = new ExpandoObject();
foreach (var cat in repository.Categories)
{
var subcats = repository.SubCategories.Where(s => s.ParentID == cat.CategoryID);
List<Object> subcatNameList = new List<object>();
foreach(var subcat in subcats)
{
subcatNameList.Add(new { Name = subcat.Name });
}
AddProperty(catToSubcatMap, cat.Name, subcatNameList);
}
Session["CatToSubcatMap"] = JsonConvert.SerializeObject(catToSubcatMap, Newtonsoft.Json.Formatting.Indented, new JsonSerializerSettings { NullValueHandling = NullValueHandling.Ignore });
The json itself looks perfect. But when I tried to read the value from my jQuery function, it failed:
var sss = '#Session["CatToSubcatMap"]';
It seems like there are too many special characters in the json string. My generic question is: how should I format and pass complicated data between server and client. Using Viewbag or Session, which one is preferred?
Thanks
Chris

You can do what you are trying to do; what you have should be formatted correctly, but you just have to include Html.Raw.
var sss = #(
Html.Raw(Session["CatToSubcatMap"].ToString())
);
Raw will essentially write out directly to the response without encoding the contents, which is what likely was happening.

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)