Develop Reference

Need browser equivalent of this specific implementation of crypto.createHmac method

So, I have this piece of code that's written in Node.js
crypto.createHmac('sha256', secret).update(orderedParams).digest('hex')
I wish to bring this piece of code in the browser but that doesn't work since the 'crypto' library is not supported on the browser. Can somebody just help me re-create the same method in the browser?

An HMAC can be determined by most crypto libraries, e.g. CryptoJS or WebCrypto API.
The following example uses CryptoJS:
var secret = 'my secret';
var orderedParams = 'the ordered params';
// Short
var hmac3 = CryptoJS.HmacSHA256(orderedParams, secret).toString();
console.log(hmac3.replace(/(.{48})/g,'$1\n'));
// Progressive
var hmac2 = CryptoJS.algo.HMAC.create(CryptoJS.algo.SHA256, secret).update(orderedParams).finalize().toString();
console.log(hmac2.replace(/(.{48})/g,'$1\n'));
<script src="https://cdnjs.cloudflare.com/ajax/libs/crypto-js/4.0.0/crypto-js.min.js"></script>

You can try to use crypto-browserify.
It's a reimplementation of crypto, made it so that it can run on the Browser.

Unable to download large data using javascript

I have a large data in form of JSON object in the javascript. I have converted it into the string using JSON.stringify(). Now my use case is to provide this large string in a text file to the user. So for this i have written below code.
HTML code
<button id='text_feed' type="submit">Generate ION Feed</button>
Javascript code
var text = //huge string
$("#text_feed").click(function() {
_generateFeed(text);
});
var _generateFeed = function(text) {
//some code here
$("#textLink").attr("href",
"data:attachment/txt," + encodeURIComponent(text)) [0].click();
});
};
Problem: When the string length is small , i am able to download the data .
But when the string length goes higher (> 10^5) , my page crashes.
This occurred because "encodeUriComponet(text)" is not able to encode large
data.
I also tried window.open("data:attachment/txt," + encodeURIComponent(text));
But again my page got crashed because of the same reason that encodeURIComponet was unable to encode such a large string.
Another approach: I was also thinking of writing the data into a file using HTML5 File write API , but it has support only in Chrome web browser , but i need to make this work for atleast firefox and chrome both.
Use Case
I don't want to do multiple downloads by breaking the data, as i need to have data in a single file in the end.
And my target is to support string of aprroximately 10^6 length. Can anyone help me how to download/write this amount of data into a single file.

From the OP:
I solved it as below.
var _generateFeed = function(text) {
/*some code here*/
var url = URL.createObjectURL( new Blob( [text], {type:'text/plain'} ) );
$("#textLink").attr("href",url)[0].click();
};
Notes:
URL.createObjectURL() is compatible with modern browsers and IE10+, but it is an unstable, experimental technology.
Objects created using URL.createObjectURL() "must be released by calling URL.revokeObjectURL() when you no longer need them." - MDN

C# Faster way to get javascript DOM than EO.WebBrowser

I have code in place where I'm using EO.WebBrowser to get the html from a page using the EO.WebView Request:
var cookie = new EO.WebBrowser.Cookie("cookie", "value");
cookie.Path = path;
cookie.Domain = domain;
var options = new BrowserOptions();
options.EnableWebSecurity = false;
Runtime.SetDefaultOptions(options);
var request = new Request(url);
request.Cookies.Add(cookie);
webView.LoadRequestAndWait(request);
Finally I use the following to get the HTML I need:
webView.GetDOMWindow().document.body.outerHTML
My issue is that this is very slow and although I can get it to run it locally, I can not get it to run on Azure server code. Is there a way to do the same thing using HttpWebRequest?

You can use JavaScript:
var data = (string)webView.EvalScript("document.body.outerHTML");

No, HttpWebRequest (and other similar "get me HTML response") methods will only give you HTML itself and will not run JavaScript on the page.
For server side processing of dynamic HTML consider using proper headless internet browser? instead of trying to convince regular IE to work correctly without UI.

the eo.webbrowser runs multi-process like chrome and unsupported by many cloud service environment.
just use WebClient or HttpWebRequest or RestSharp or something like that can do http requests to get the response html.

how to refer SQLite SIMPLE way in Javascript-App just use 'DB_open, execute SQL..' VS2012

I want to write an App (JS) with SQLite (VS2012). So I can't find a easy beginnerguide for this. When I install the SQLite for Windows Runtime. There is a C++ code (GitHub) to insert in the Projekt.
So, what happens with the JS - Projekt?
How can JS refer to properties and methodes of the DB-Objekt (dll, ocx, whatever from the SQLite-Runtime) just to open DB, execute SQL etc. in a simple way?
In Android-Browser following simple JS code (no more) is korrekt:
var shortName = 'testDb';
var version = '1.0';
var displayName = 'test db';
var maxSize = 1048576; // in bytes
mydb = window.openDatabase(shortName, version, displayName, maxSize);
function(transaction) {
transaction.executeSql('CREATE TABLE IF NOT EXISTS person(id INTEGER ..);', [], NullDataHandler, errorHandler);
}
Is somebody here - can show me the same SIMPLE in VS2012 without an Overhead, advanced settings and error-mangement - I can't follow the code?
1. DB_open : ..
2. Execute SQL : ..
Many Greetings from Bavaria
ralphi
PS: Why isn't it allowed to insert links?

I assume your Javascript is running on a web page. Actually, There is no way to manipulate the Sqlite database from a web page. For security reason, the ability to access local files from a web page is strictly limited. Despite new HTML5-supported browsers allow you to access local files in a limited and safe way, directly using local database is not possible in HTML world.

Mozilla (Firefox, Thunderbird) Extension: How to get extension id (from install.rdf)?

If you are developing an extension for one of the mozilla applications (e.g. Firefox, Thunderbird, etc.) you define a extension id in the install.rdf.
If for some reason you need to know the extension id e.g. to retrieve the extension dir in local file system (1) or if you want to send it to a webservice (useage statistic) etc. it would be nice to get it from the install.rdf in favour to have it hardcoded in your javascript code.
But how to access the extension id from within my extension?
1) example code:
var extId = "myspecialthunderbirdextid#mydomain.com";
var filename = "install.rdf";
var file = extManager.getInstallLocation(extId).getItemFile(extId, filename);
var fullPathToFile = file.path;

I'm fairly sure the 'hard-coded ID' should never change throughout the lifetime of an extension. That's the entire purpose of the ID: it's unique to that extension, permanently. Just store it as a constant and use that constant in your libraries. There's nothing wrong with that.
What IS bad practice is using the install.rdf, which exists for the sole purpose of... well, installing. Once the extension is developed, the install.rdf file's state is irrelevant and could well be inconsistent.
"An Install Manifest is the file an Add-on Manager-enabled XUL application uses to determine information about an add-on as it is being installed" [1]
To give it an analogy, it's like accessing the memory of a deleted object from an overflow. That object still exists in memory but it's not logically longer relevant and using its data is a really, really bad idea.
[1] https://developer.mozilla.org/en/install_manifests

Like lwburk, I don't think its available through Mozilla's API's, but I have an idea which works, but it seems like a complex hack. The basic steps are:
Set up a custom resource url to point to your extension's base directory
Read the file and parse it into XML
Pull the id out using XPath
Add the following line to your chrome.manifest file
resource packagename-base-dir chrome/../
Then we can grab and parse the file with the following code:
function myId(){
var req = new XMLHttpRequest();
// synchronous request
req.open('GET', "resource://packagename-base-dir/install.rdf", false);
req.send(null);
if( req.status !== 0){
throw("file not found");
}
var data = req.responseText;
// this is so that we can query xpath with namespaces
var nsResolver = function(prefix){
var ns = {
"rdf" : "http://www.w3.org/1999/02/22-rdf-syntax-ns#",
"em" : "http://www.mozilla.org/2004/em-rdf#"
};
return ns[prefix] || null;
};
var parser = CCIN("#mozilla.org/xmlextras/domparser;1", Ci.nsIDOMParser);
var doc = parser.parseFromString(data, "text/xml");
// you might have to change this xpath expression a bit to fit your setup
var myExtId = doc.evaluate("//em:targetApplication//em:id", doc, nsResolver,
Ci.nsIDOMXPathResult.FIRST_ORDERED_NODE_TYPE, null);
return myExtId.singleNodeValue.textContent;
}
I chose to use a XMLHttpRequest(as opposed to simply reading from a file) to retrieve the contents since in Firefox 4, extensions aren't necessarily unzipped. However, XMLHttpRequest will still work if the extension remains packed (haven't tested this, but have read about it).
Please note that resource URL's are shared by all installed extensions, so if packagename-base-dir isn't unique, you'll run into problems. You might be able to leverage Programmatically adding aliases to solve this problem.
This question prompted me to join StackOverflow tonight, and I'm looking forward participating more... I'll be seeing you guys around!

As Firefox now just uses Chrome's WebExtension API, you can use #serg's answer at How to get my extension's id from JavaScript?:
You can get it like this (no extra permissions required) in two
different ways:
Using runtime api: var myid = chrome.runtime.id;
Using i18n api: var myid = chrome.i18n.getMessage("##extension_id");

I can't prove a negative, but I've done some research and I don't think this is possible. Evidence:
This question, which shows that
the nsIExtensionManager interface
expects you to retrieve extension
information by ID
The full nsIExtensionManager interface
description, which shows no
method that helps
The interface does allow you to retrieve a full list of installed extensions, so it's possible to retrieve information about your extension using something other than the ID. See this code, for example:
var em = Cc['#mozilla.org/extensions/manager;1']
.getService(Ci.nsIExtensionManager);
const nsIUpdateItem = Ci.nsIUpdateItem;
var extension_type = nsIUpdateItem.TYPE_EXTENSION;
items = em.getItemList(extension_type, {});
items.forEach(function(item, index, array) {
alert(item.name + " / " + item.id + " version: " + item.version);
});
But you'd still be relying on hardcoded properties, of which the ID is the only one guaranteed to be unique.

Take a look on this add-on, maybe its author could help you, or yourself can figure out:
[Extension Manager] Extended is very
simple to use. After installing, just
open the extension manager by going to
Tools and the clicking Extensions. You
will now see next to each extension
the id of that extension.
(Not compatible yet with Firefox 4.0)
https://addons.mozilla.org/firefox/addon/2195