How to start two or more custom URL Protocol from Javascript

Question

I have an old html page that creates a script file and executes it using:

fsoObject = new ActiveXObject("Scripting.FileSystemObject")
wshObject = new ActiveXObject("WScript.Shell")

I am trying to modify it and make it usable also from other browsers. If you know the answer stop reading and please answer. If there is no quick answer, here is the description of my attempts. I was successful in doing the job, but only when the script is shorter than 2000 characters. I need help for scripts longer than 2000 characters.

The webpage is for internal use only, so it is easy for me to create a custom URL protocol on each computer that runs a VBScript file from a network drive.

I created my custom URL Protocol that starts a VBScript file like this:

Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\MyUrlProtocol]
"URL Protocol"=""
@="Url:MyUrlProtocol"
"UseOriginalUrlEncoding"=dword:00000001

[HKEY_CLASSES_ROOT\MyUrlProtocol\DefaultIcon]
@="C:\Windows\System32\WScript.exe"

[HKEY_CLASSES_ROOT\MyUrlProtocol\shell]

[HKEY_CLASSES_ROOT\MyUrlProtocol\shell\open]

[HKEY_CLASSES_ROOT\MyUrlProtocol\shell\open\command]
@="C:\Windows\System32\WScript.exe \"X:\MyUrlProtocol.vbs\" \"%1\""

In MyUrlProtocol.vbs I have this:

MsgBox "The length of the link is " & Len(WScript.Arguments(0)) & " characters"
MsgBox "The content of the link is: " & WScript.Arguments(0)

When I click on <a href="MyUrlProtocol:test" id="test">click me</a> I see two messages, so everything works well (tested with Chrome and IE in Windows 7.)

It works also when I execute document.getElementById("test").click()

I thought this could be the solution: I would pass the text of the script to the VBS static script, which would create the dynamic script and run it, but with this system I can't pass more than ~2000 characters.

So I tried to split the text of the script in chunks smaller than 2000 characters and simulate several clicks on the link, but only the first one works.

So I tried with xmlhttp.open("GET","MyUrlProtocol:test",false);, but Chrome says Cross origin requests are only supported for HTTP.

Is it possible to pass more than 2000 characters to a VBScript script via a custom URL protocol?

If not, is it possible to call several custom URL protocols in sequence?

If not, is there another way to create a script file and run it from Javascript?

EDIT 1

I found a solution, but in Chrome only works when it likes, so I'm back to square one.

The code below in IE executes the script 4 times (correct), but in Chrome only the first execution runs.

If I change it to delay += 2000, then Chrome usually runs the script 2 times, but sometimes 1 and sometimes 3 or even 4 times.

If I change it to delay += 10000, then it usually runs the script 4 times, but sometimes misses one.

The function is always executed 4 times, both in Chrome and IE. What is weird is that the sr.click() sometimes does nothing and the function execution continues.

<HTML>
<HEAD>
  <script>
    var delay;

    function runScript(text) {
      setTimeout(function(){runScript2(text)}, delay);
      delay += 100;
    }

    function runScript2(text) {
      var sr = document.getElementById('scriptRunner');
      sr.href='intelliclad:'+text;
      sr.click();
    }

    function test(){
      delay = 0;
      runScript("uno");
      runScript("due");
      runScript("tre");
      runScript("quattro");
    }
  </script>
</HEAD>
<BODY>
  <input type="button" value="Run test" onclick="test()">
  <a href="nothing yet" id="scriptRunner">scriptRunner</a>
</BODY>
</HMTL>

EDIT 2

I tried with Luke's suggestion of setting the next timeout from inside the call back but nothing changed (IE works always, Chrome whenever it likes).

Here is the new code:

var scripts;
var delay = 2000;

function runScript() {
  var sr = document.getElementById('scriptRunner');
  sr.href = 'intelliclad:' + scripts.shift();
  sr.click();

  if(scripts.length)
    setTimeout(function() {runScript()}, delay);
}

function test(){
  scripts = ["uno", "due", "tre", "quattro"];
  runScript();
}

Some background: The page asks for the shape of a panel, which can be just a few parameters [nfaces=1, shape1='square', width1=100] or hundreds of parameters for panels with many faces, many slots, many fasteners, etc. After asking for all the parameters a script for our internal 3D CAD (which can be larger than 20KB) is generated and the CAD is started and asked to execute the script.

I would like to do all on the client side, because the page is served by a Domino web server, which can't even dream of managing such a complex script.

Brian McGinity · Accepted Answer

I didn't read your whole post...have an answer:

I too wish that custom url protocols can handle long urls. They simply do not. IE is even worse as some OSs only accept 800 chars.

So, here's the solution:

For long urls, only pass a single use token.   The vbscript uses the token 
and does a url get to your web server to get all of the data.

This is the only way I've been able to successfully pass lots of data around. If you ever find a clearer solution, please remember to post it here.

Update:

Note that this is the best way I have found to deal with the url protocol limitations. I too wish this was not necessary. This does work and works well.

You mentioned Dominos, so possibly you need something in a POS environment... I create a web based POS system, so we could face a lot of the same issues.

Suppose you want a custom url to print a pdf to the default printer without the annoying popup window. We need to do this thousands of times a day...

When building the web page, add the print button which when pressed calls the custom url: myproto://printpdf?id=12345&tocken=onetimetoken
this will execute your vbscript on the local desktop
in your vbscript, parse the arguments and react. In this case, your command is printpdf and the id is 123456 and you have a onetime tocken key.
have the vb script to an https get to: https://mydomain.com/APIs/printpdf.whatever?id=12345&key=onetimetoken
check the credentials based on the ip address and token, if all aligns, then return the contents of the pdf (you may want to convert the pdf to a byte array string)
now the vbscript has the pdf, assemble it and write it to a temp folder then execute a silent pdf print command (I use Sumatra PDF http://blog.kowalczyk.info/software/sumatrapdf/free-pdf-reader.html)
mission accomplished.

Since I do know what you what to do in your custom url and the general workflow, I can only describe how I've solved the sort url issue.

Using this technique, the possibilities are limitless. You have full control over the local computer running the web browser, you have a onetime use token which grants access to a web API with can return any sort of information you program.

You could write a custom url protocol to turn on the pizza oven if you wanted :)

If you are not able to create the server side code which is listening for vbscript's get request then this would not work.

You might be able to pass the data from the browser to the vbscript using the clipboard.

Update 2:

Since in this case the data is on the client (one single form can define hundreds of parameters), the server API doesn't know what to answer to the vb script request. So the workflow described above must be preceded by these two steps:

The onkeypress event executes a submit to send the current parameters to the server
The server replies with the refreshed form, adding to the body onload a call to a function which uses another submit to call the custom url, as described on point 1 listed above.

Update 3: stenci, what you've added (in Update 2) will work. I would do it like this:

user presses a button saying I'm done editing the form
ajax post the form to the server
the server saves the data and attaches unique key to the datastore
the server returns the key to ajax callback function
now the client has a single use key and invokes the url schema passing the key
vbscript does an https get to the server and passes the key
server returns the data to the vbscript

It is a bit long winded. Once coded it will work like a charm.

The only other alternative I can see is to copy the form data to the clipboard using something like: http://zeroclipboard.org/

and then in vbscript see if you can read the clipboard like: Use clipboard from VBScript

urish · Answer

How about creating an iFrame for each instance? Something like this:

function runScript(text) {
  var iframe = document.createElement('iframe');
  iframe.src = 'intelliclad:'+text;
  document.body.appendChild(iframe);
}

function test(){
  runScript("uno");
  runScript("due");
  runScript("tre");
  runScript("quattro");
}

You can then use css styling to make these iframes transparent / hidden.

How to start two or more custom URL Protocol from Javascript

Tags:

javascript

html

onclick

url-protocol

stenci

2 Answers

Brian McGinity

urish

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How to start two or more custom URL Protocol from Javascript

Tags:

javascript

html

onclick

url-protocol

stenci

2 Answers

Brian McGinity

urish

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Recent Activity

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