Added server-side node compatibility #123

oliverfoster · 2019-02-07T23:50:48Z

#67

Works

Upgraded grunt
Added umd wrapper and grunt code to produce a umd module
Shimmed window.location in node
Fixed a few scope issues
Fixed the way the text-encoding module requires in node
Added url parser to distinguish between node and browser apis
Moved http request abstraction out of ADL.XHR_request and into a new function
Added a node shim for XMLHttpRequest
Changed test readme
Fixed old test for ADL.xapiutil
Added 1 new test for the minified file

Notes

The grunt config can produce source maps for the minified library, just uncomment the respective lines
I've tried to do this with minimal disruption to existing file structures and inferred utilisation patterns.
All files should be able to be used individually in the browser via script tags as before.

xapiwrapper.min.js

Contains the same bundled modules as before.
Should now work in requirejs, commonjs and window.ADL global environments.
Is the main file for the node package and can be included via const adl = require('xapiwrapper'); if published on npm.
Doesn't include a working verson of ADL.launch in node

…le requires, url parsing, node only errors

…added node shim for XMLHttpRequest, fixed a scope issue

vbhayden · 2019-02-08T01:09:09Z

Tracking, but a PR of this scale is going to take a bit to move forward. While I get the interest in having an NPM module with xAPI-everything included, it feels like this would make curation pretty muddy.

Will review this in the next week or so.

oliverfoster · 2019-02-08T07:35:33Z

Let me know once you've reviewed it.

oliverfoster · 2019-02-08T09:41:21Z

src/xapiwrapper.js

@@ -1,3 +1,4 @@
+(function(ADL, root){
 // adds toISOString to date objects if not there
 // from https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toISOString


I've brought all of the functions at the top of this file into the closure defining this module. This is intentional, there doesn't seem to be a good reason to leak these functions into the global scope.

I would add that shimming the native Date object isn't a good idea as this library is clearly intended for use in other, potentially conflicting systems.
Changing it to the following might be more appropriate:

function DateToISOString(date) { }

oliverfoster · 2019-02-08T09:48:34Z

src/xapiwrapper.js

+ * @param {function} [complete ] completion callback function
+ * @return {object} xhr response object
+ */
+ function http(method, url, headers, data, options, complete)


I'm not entirely sure about how I've defined of the http function parameters, but the intent of the code (as a method of performing cross domain http request requests in different environments) seems easier to read when isolated like this. The http function should hopefully exhibit identical behaviour to the original code which was nested inside the XHR_request function, as it's almost a verbatim copy. I have left the LRS specific http request modifications in the XHR_request function to create a distinct line between LRS stuff and the http request stuff. I hope that makes sense? This bit will need the most testing.

oliverfoster · 2019-02-08T09:49:09Z

src/xapiwrapper.js

+
+ // synchronous call in IE, with no asynchronous mode available.
+ if (!async && ieXDomain) {
+ var until = 1000 + new Date();


At some point it might be worth dropping synchronous calls entirely?

oliverfoster · 2019-02-08T09:51:42Z

src/xapiwrapper.js

- body = xhr.responseText;
- }
+ var result;
+ http(


This is where the new http function is used, returning the xhr object as produced.
It greatly simplifies the XHR_request function to abstract away the xhr production but it isn't necessary that this change happen for the node XMLHttpRequest shim to work.

oliverfoster · 2019-02-08T09:53:59Z

test/tests/test.xapiwrapper.js

+ onBrowser = true;
+ }
+ else {
+ ADL = require('../../dist/xapiwrapper.min');


If this test is run in node, this is where the new umd wrapped xapiwrapper is loaded into node for testing.
I have taken the javascript from the example.html, swapped the request from synchronous to asynchronous and added as the first real test of the api in node. Other tests would need to follow.

oliverfoster · 2019-02-08T09:56:28Z

umdwrapper.js

+ // Browser roots
+ factory({}, root, root);
+ }
+}(typeof self !== 'undefined' ? self : this, function (module, window, root) {//<%= output =>


This is a slightly modified umd wrapper to overcome an issue associated with bundling the text-encoding library with the xapiwrapper.min.js. Essentially the text-encoding code tried to performmodule.exports which overrides the export of the xapiwrapper.min.js. In order to stop that I've redefined an empty module variable inside the closure.

In both requirejs and node environments, the ADL api object is now returned as the module export. Otherwise the ADL api is added to the window or global scope as before. It might be worth dropping the requirejs support as I can imagine this library is already used in mixed global scope + requirejs environments and this change to support requirejs would remove the ADL api from the global scope.

oliverfoster · 2019-02-08T10:02:42Z

src/xapiwrapper.js

+
+ if (isNode) {
+ // Import encoding-indexes as required by text-encoding module
+ var eIndexes = require('../node_modules/text-encoding/lib/encoding-indexes');


In node, because the text-encoding/lib/encoding.js file has been bundled into the xapiwrapper.min file encoding.js has lost its original relative path. In node the bundled file requires the encoding-indexes hash, which is not needed in the browser. These lines import the encoding-indexes file into the global scope as they would be if the encoding.js file were in its original location. It isn't great but it does work. An alternative would be to bundle both files but as encoding-indexes is not needed in the browser it would bloat the size of the library for that environment.

The text-encoding library provides a shim for the TextDecoder and TextEncoder apis.

oliverfoster · 2019-02-08T10:05:31Z

src/xapiwrapper.js

+ }
+
+ // Node shim for browser location
+ var location = isNode ?


The location object is used in the browser to determine a few things about how the http request should be made. It doesn't exist in node so this is just the minimal necessary replacement to get the code working.
It would be better just to skip the location checks in node altogether.

oliverfoster · 2019-02-08T10:08:50Z

src/xapiwrapper.js

@@ -184,7 +182,7 @@ function isDate(date) {

 if (verifyxapiversion && testConfig.call(this))
 {
- window.ADL.XHR_request(this.lrs, this.lrs.endpoint+"about", "GET", null, null,
+ ADL.XHR_request(this.lrs, this.lrs.endpoint+"about", "GET", null, null,


I have removed all module internal references to the global scope window as it's different in different environments. The umd wrapper normalises all of this and it's unnecessary anyway as we already have a reference to the ADL object.

oliverfoster · 2019-02-08T10:09:22Z

src/xapiwrapper.js

@@ -165,8 +164,7 @@ function isDate(date) {

 function getbase(url)
 {
- var l = document.createElement("a");
- l.href = url;
+ var l = parseUrl(url);


The document object doesn't exist in node so I've added a cross platform parseUrl function to appropriately differentiate. The parseUrl function returns a subtly different parsing object in both environments, but the differences don't matter much here.

Node url parsing
Browser url parsing

oliverfoster · 2019-02-13T13:22:52Z

Just checking in. Any thoughts on this?

vbhayden · 2019-02-13T14:21:52Z

Ok, going to look at this today. Do you have a sample app.js file or something to show it working that I could use as a starting place?

oliverfoster · 2019-02-13T14:40:03Z

I was using the tests to do that.

This file can be run using $ mocha test/tests/test.xapiwrapper.js https://github.com/adlnet/xAPIWrapper/blob/29154f51be1c0df8753923116100f66fdecf1a4e/test/tests/test.xapiwrapper.js

This one to get the above text running in the browser:
https://github.com/adlnet/xAPIWrapper/blob/29154f51be1c0df8753923116100f66fdecf1a4e/test/textXAPIWrapper.html

It demonstrates the xapiwrapper.min.js statement, verbs, activity etc api working in both node and the browser. Launch doesn't work in node. It'll give an error.
ADL.launch()

vbhayden · 2019-02-13T15:27:14Z

Simple examples seem to run, will look more at it later. 👍

In the meantime, it doesn't produce intellisense and we'll probably need to have more rigorous tests with more complex statement varieties.

oliverfoster · 2019-02-14T09:51:48Z

Yup, totally agree.

Do you have any suggestions for statement varieties?

For the intellisense I reckon it'd be easiest to produce a non-minified but compiled version with comments intact. I will have a look to see if we can just import the uncompiled source files instead though. Irritatingly the ADL object transcends multiple files but hopefully the code is segregated enough to allow that to happen without one file needing references to code in another. I don't know if it's preferable to use the uncompiled source directly? Any thoughts?

oliverfoster · 2019-02-18T16:06:14Z

Closed in favour of #126 : with intellisense and a few of the more complex bits removed.

oliverfoster added 6 commits February 7, 2019 22:16

Upgraded grunt, added umdwrapper, fixed readme

4787e24

node fixes: shimmed window.location, scope issues, text-encoding modu…

ff47b51

…le requires, url parsing, node only errors

Moved http request abstraction from ADL.XHR_request to new function, …

429bd10

…added node shim for XMLHttpRequest, fixed a scope issue

Fixed and added tests

a393480

Fixed return vs continue bug

0906a42

Fixed comment typos and readded missing comment

29154f5

vbhayden added the enhancement label Feb 8, 2019

vbhayden self-requested a review February 8, 2019 01:09

vbhayden assigned FlorianTolk Feb 8, 2019

oliverfoster commented Feb 8, 2019

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oliverfoster closed this Feb 18, 2019

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Added server-side node compatibility #123

Added server-side node compatibility #123

oliverfoster commented Feb 7, 2019

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oliverfoster commented Feb 18, 2019

Added server-side node compatibility #123

Added server-side node compatibility #123

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oliverfoster commented Feb 7, 2019

Works

Notes

xapiwrapper.min.js

vbhayden commented Feb 8, 2019

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