Develop Reference

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/

Transforming JSON in a node stream with a map or template

I'm relatively new to Javascript and Node and I like to learn by doing, but my lack of awareness of Javascript design patterns makes me wary of trying to reinvent the wheel, I'd like to know from the community if what I want to do is already present in some form or another, I'm not looking for specific code for the example below, just a nudge in the right direction and what I should be searching for.
I basically want to create my own private IFTTT/Zapier for plugging data from one API to another.
I'm using the node module request to GET data from one API and then POST to another.
request supports streaming to do neat things like this:
request.get('http://example.com/api')
.pipe(request.put('http://example.com/api2'));
In between those two requests, I'd like to pipe the JSON through a transform, cherry picking the key/value pairs that I need and changing the keys to what the destination API is expecting.
request.get('http://example.com/api')
.pipe(apiToApi2Map)
.pipe(request.put('http://example.com/api2'));
Here's a JSON sample from the source API: http://pastebin.com/iKYTJCYk
And this is what I'd like to send forward: http://pastebin.com/133RhSJT
The transformed JSON in this case takes the keys from the value of each objects "attribute" key and the value from each objects "value" key.
So my questions:
Is there a framework, library or module that will make the transform step easier?
Is streaming the way I should be approaching this? It seems like an elegant way to do it, as I've created some Javascript wrapper functions with request to easily access API methods, I just need to figure out the middle step.
Would it be possible to create "templates" or "maps" for these transforms? Say I want to change the source or destination API, it would be nice to create a new file that maps the source to destination key/values required.
Hope the community can help and I'm open to any and all suggestions! :)
This is an Open Source project I'm working on, so if anyone would like to get involved, just get in touch.

Yes you're definitely on the right track. There are two stream libs I would point you towards, through which makes it easier to define your own streams, and JSONStream which helps to convert a binary stream (like what you get from request.get) into a stream of parsed JSON documents. Here's an example using both of those to get you started:
var through = require('through');
var request = require('request');
var JSONStream = require('JSONStream');
var _ = require('underscore');
// Our function(doc) here will get called to handle each
// incoming document int he attributes array of the JSON stream
var transformer = through(function(doc) {
var steps = _.findWhere(doc.items, {
label: "Steps"
});
var activeMinutes = _.findWhere(doc.items, {
label: "Active minutes"
});
var stepsGoal = _.findWhere(doc.items, {
label: "Steps goal"
});
// Push the transformed document into the outgoing stream
this.queue({
steps: steps.value,
activeMinutes: activeMinutes.value,
stepsGoal: stepsGoal.value
});
});
request
.get('http://example.com/api')
// The attributes.* here will split the JSON stream into chunks
// where each chunk is an element of the array
.pipe(JSONStream.parse('attributes.*'))
.pipe(transformer)
.pipe(request.put('http://example.com/api2'));

As Andrew pointed out there's through or event-stream, however I made something even easier to use, scramjet. It works the same way as through, but it's API is nearly identical to Arrays, so you can use map and filter methods easily.
The code for your example would be:
DataStream
.pipeline(
request.get('http://example.com/api'),
JSONStream.parse('attributes.items.*')
)
.filter((item) => item.attibute) // filter out ones without attribute
.reduce((acc, item) => {
acc[item.attribute] = item.value;
return acc;
.then((result) => request.put('http://example.com/api2', result))
;
I guess this is a little easier to use - however in this example you do accumulate the data into an object - so if the JSON's are actually much longer than this, you may want to turn it back into a JSONStream again.

Serve dynamic javascript file with nodejs

Questions
How to serve javascript file dynamically? Specifically, the scripts maintain most of its body but with some variables changable (imagine HTML Jade template, but this is for pure javascript).
Scenario
When user or browser (http GET in general) visits /file.js passing parameter api, e.g. /file.js?api=123456, I would like to output pure javascript where I can take that 123456 and put in inside of my code, dynamically. Content-Type is application/javascript.
Sample:
var api = #{req.query.api}; //Pseudo
//The rest of my javascripts template
...
From my main .js file, I have set up the route:
app.get( '/file.js', function( req, res ) {
//Pseudo code that I would like to achieve
var name = req.query.name;
res.render( 'out_put_javascript_file_from_jade_file.jade', { name: name } );
});
So when a person visits /file.js, the script file will be rendered differently based on the parameter api passed in the URL. The only possible dynamic way I can think of is using Jade, but it doesn't allow pure javascript template. I believe there must be other solutions.
Please excuse my explanation. The problem is somewhat like this: How to generate a pure JavaScript file with Jade

If you want to do something quick and dirty, then you can do something like this (based on your example in the comments).
App init - read the .js template file and cache it:
// this should be async, but hey, not teaching you that part here yet
var fileJs = fs.readFileSync('file.js.template');
File.js:
(function() {
$(window).on('load', function() {
alert('Your api key is API_KEY_CONST');
});
})();
Request:
GET /api/file.js?key=123
Router:
app.get('/api/file.js', function(req, res) {
var key = req.query.key;
var key = fetchKeyFromDBSync(); // just to make it easier here, no async.
var out = fileJs.replace(API_KEY_CONST, key);
res.setHeader('content-type', 'text/javascript');
res.write(out);
res.end();
});
Now, this is really dumb and you should not try it at home, but it simply demonstrates how to do what you wanted.
Edit:
Depending on the file length, you might perform a bit better if you put the chunks of the file into an array, like:
var fileChunks = ['(function(){ blablabla;', 'var myAPIKey=', 'KEY_PLACEHOLDER', '; alert (myAPIKey);', '})()']
So later when you're resolving it with the real API key, you join the file.
fileChunks[2] = '12345';
var responseData = fileChunks.join('');
res.write(responseData);
But your last-accessed api key is then held in an array. Not quite future proof, but it shouls work if you need something quick.

Databinding to Windows 8 ListView

I'm having massive problems with databinding to a ListView in a Windows 8 app using Javascript.
Inside the "activated" event on default.js I have written some code to get some data from a web service and push it into an array. This bit works OK and the array is populated.
The problem I have is that the app won't recognise the data. I have this code in a page called inspections.html:
data-win-options="{itemTemplate: select('#imageTextListCollectionTemplate'),
itemDataSource: dataList.dataSource,
layout: {type: WinJS.UI.ListLayout}}
and then in the "activated" event I declare:
var dataList = new Array();
and push the data from the web service into this array. But at runtime I get an error that says something along the lines of "can't find dataSource on undefined dataList".
I've done some of the examples on the MS website and in one of them it creates a dummy dataset and references it from a namespace. I kinda think that what I'm missing here is a namespace too but I don't know what the namespace for default.js is. Or maybe I'm wrong and it's something totally different.
Please help - this is so fundamental (and should be easy) but I can't get my head around it.

Do you want to create datalist in HTML or javascript?
It seems you want to create it from JavaScript. Assuming that you have already pushed your data into array from your webservice, you only need to call:
var dataList = new WinJS.Binding.List(array);
now accessing dataList.dataSource is perfectly valid.
Also, to create the datalist you don't always need an array. You could probably start with an empty list and then keep inserting data directly into the data list from web services, like:
var dataList = new WinJS.Binding.List([]);
dataList.push(value1);
dataList.push(value2);
...
Hope it helps. Let me know if you have any more questions.

If you are getting troubled by assigning datasource in HTML side
Prefer js side like
var list = new WinJS.Binding.List(array here);
listView.itemDataSource = list.dataSource;
by using this you can easily go through the data which you are binding to ListView.

How to pass a "new" object in JavaScript in Socket.IO

I'm trying to pass objects from one client to another client, e.g. pieces in a multiplayer board game. I have a working solution using JSON.parser and __proto__, but I'm curious to know if there is a better way.
Client sends:
var my_piece = new BoardPiece();
// ... my_piece is assigned data, like x-y coordinates
socket.send(JSON.stringify(my_piece));
Server forwards the piece to others:
client.broadcast(piece);
Another client receives:
var your_piece = JSON.parse(json);
your_piece.__proto__ = BoardPiece.prototype; // provide access to BoardPiece's functions
It's the last step where I use __proto__ that I'm concerned I may be shooting myself in the foot. Is there a better suggestion?

// clientone.js
var piece = new BoardPiece();
// ...
socket.send(JSON.stringify(piece));
// clienttwo.js
var piece = BoardPiece.Create(JSON.parse(json));
...
// BoardPiece.js
function BoardPiece() {
}
BoardPiece.prototype.toJSON = function() {
var data = {};
data.foo = this.foo;
...
return data;
};
BoardPiece.Create = function(data) {
var piece = new BoardPiece();
piece.foo = data.foo;
...
return piece;
}
Firstly using the toJSON method on your objects allows JSON.stringify to immediatly convert your object to JSON. This is part of the JSON API. The JSON API will call the toJSON method if it exists and converts that object to JSON.
This basically allows you to serialize your object as and how you want.
The second part is adding a factory method as a property of your constructor which takes your serialized JSON data and creates a new boardpiece. It will then inject your serialized data into that boardpiece object.
So your serializing only the data you care about and then passing that data through a factory method. This is the best way to send custom objects from one client to another.

There are a bunch of object syncing projects for node that might make life easier. For starters, check out:
NowJS
node-object-sync
Re-using Backbone.js Models on the server with Node.js and Socket.io to build real-time apps

Have tou tried jQuery's $.extend() method? http://api.jquery.com/jQuery.extend/