Related
I have a web resource embedded on my CRMform. Its easy to submit the data to CRM but a bit more tricky to populate the web resource (html page) with data from CRM onLoad.
With that being said I have a js file with postMessage as so:
iFrame.contentWindow.postMessage(postObj, 'https://server.xrm.com/crmOrg/WebResources/htmlPageToPostMessageTo');
The following js on another HTML page holds the listener for the postMessage as follows:
$(window).on('message',
function(event) {
// Important. Only accept messages from trusted origins.
if (~event.originalEvent.origin.indexOf('https://server.xrm.com')) {
var messageData = event.originalEvent.data;
//#1
if (messageData.attribute)
{
....do stuff......
}
This behaves very strangely as in sometimes it hits the listener and sometimes it doesn't
In the debugger, it does seem that the following is async:
if `(~event.originalEvent.origin.indexOf('https://server.xrm.com')) {...`
Im fairly certain that there is a timing issue.
Can anybody provide any suggestions?
This is having me and my other dev pull our hair out.
Regards.
It took me sometime to find a workaround, but this seems to fix the issue as you guys have suggested
Promise.resolve(setTimeout(
() => {
iFrame.contentWindow?.postMessage(postObj, 'https://...')
}, 200),
)
The following javascript function works fine for IE, Safari and Firefox. But it fails in Chrome(33.0.) and Opera (16.0.1196). Blank HTML page is displayed on loading.
function readTestXMLFile() {
if (window.ActiveXObject) {
var xmlDoc = new ActiveXObject('Microsoft.XMLDOM');
xmlDoc.async = 'false';
xmlDoc.load('test.xml');
}
else {
var requ = new XMLHttpRequest();
alert("a");
requ.open("GET", "test.xml", false);
alert("b");
requ.send(null); //This line is not working in chrome and opera
alert("c");
var xmlDoc = requ.responseXML;
alert(xmlDoc);
alert("d");
}
return xmlDoc;
}
Only 'a' and 'b' gets printed. It does not continue after that. Same result is observed if I use requ.send() or requ.send("") instead of requ.send(null).
If I remove the statement requ.send(null), then 'null' value is printed for xmlDoc. Still blank HTML loads.
Please let me know what is the right way to get this work on Chrome and Opera.
Thanks
SRB.
Your error message suggest that you are trying to access a local file which is treated as "Cross origin request" if you try and run local server it should work.
Take a look at this previously asked question with the same problem:
Cross origin requests are only supported for HTTP but it's not cross-domain
Then you would access http://localhost/.../test.xml instead of c:/localhost/.../test.xml
You can also set a flag for Chrome to allow local files to request local files: -allow-file-access-from-files
the call to the XMLHttpRequest.send method is Asynchronous so you need to modify the call a little bit. The modified code below will print the response content when the response is returned successfully:
requ.addEventListener("load", function(e) {
alert(req.responseText);
}, false)
requ.send(null);
Update:
I didn't notice that you made the send request call synchronous.
Edit
You need to launch chrome with this parameter to be able to access local files
--allow-file-access-from-files
ex: c:\Browser\chrome.exe --allow-file-access-from-files
I think that the problem is that you're passing null to the send() method. You are making a GET request, so you should call send without parameters. I think chrome throws an exception because of that. Just remove the null
I have created a custom URL protocol handler.
http://
mailto://
custom://
I have registered a WinForms application to respond accordingly. This all works great.
But I would like to be able to gracefully handle the case where the user doesn't have the custom URL protocol handler installed, yet.
In order to be able to do this I need to be able to detect the browser's registered protocol handlers, I would assume from JavaScript. But I have been unable to find a way to poll for the information. I am hoping to find a solution to this problem.
Thanks for any ideas you might be able to share.
This would be a very, very hacky way to do this... but would this work?
Put the link in as normal...
But attach an onclick handler to it, that sets a timer and adds an onblur handler for the window
(in theory) if the browser handles the link (application X) will load stealing the focus from the window...
If the onblur event fires, clear the timer...
Otherwise in 3-5seconds let your timeout fire... and notify the user "Hmm, looks like you don't have the Mega Uber Cool Application installed... would you like to install it now? (Ok) (Cancel)"
Far from bulletproof... but it might help?
There's no great cross-browser way to do this. In IE10+ on Win8+, a new msLaunchUri api enables you to launch a protocol, like so:
navigator.msLaunchUri('skype:123456',
function()
{
alert('success');
},
function()
{
alert('failed');
}
);
If the protocol is not installed, the failure callback will fire. Otherwise, the protocol will launch and the success callback will fire.
I discuss this topic a bit further here:
https://web.archive.org/web/20180308105244/https://blogs.msdn.microsoft.com/ieinternals/2011/07/13/understanding-protocols/
This topic is of recent (2021) interest; see https://github.com/fingerprintjs/external-protocol-flooding for discussion.
HTML5 defines Custom scheme and content handlers (to my knowledge Firefox is the only implementor so far), but unfortunately there is currently no way to check if a handler already exists—it has been proposed, but there was no follow-up. This seems like a critical feature to use custom handlers effectively and we as developers should bring attention to this issue in order to get it implemented.
There seems to be no straightforward way via javascript to detect the presence of an installed app that has registered a protocol handler.
In the iTunes model, Apple provides urls to their servers, which then provide pages that run some javascript:
http://ax.itunes.apple.com/detection/itmsCheck.js
So the iTunes installer apparently deploys plugins for the major browsers, whose presence can then be detected.
If your plugin is installed, then you can be reasonably sure that redirecting to your app-specific url will succeed.
What seams the most easy solution is to ask the user the first time.
Using a Javascript confirm dialog per example:
You need this software to be able to read this link. Did you install it ?
if yes: create a cookie to not ask next time; return false and the link applies
if false: window.location.href = '/downloadpage/'
If you have control of the program you're trying to run (the code), one way to see if the user was successful in running the application would be to:
Before trying to open the custom protocol, make an AJAX request to a server script that saves the user's intent in a database (for example, save the userid and what he wanted to do).
Try to open the program, and pass on the intent data.
Have the program make a request to the server to remove the database entry (using the intent data to find the correct row).
Make the javascript poll the server for a while to see if the database entry is gone. If the entry is gone, you'll know the user was successful in opening the application, otherwise the entry will remain (you can remove it later with cronjob).
I have not tried this method, just thought it.
I was able to finally get a cross-browser (Chrome 32, Firefox 27, IE 11, Safari 6) solution working with a combination of this and a super-simple Safari extension. Much of this solution has been mentioned in one way or another in this and this other question.
Here's the script:
function launchCustomProtocol(elem, url, callback) {
var iframe, myWindow, success = false;
if (Browser.name === "Internet Explorer") {
myWindow = window.open('', '', 'width=0,height=0');
myWindow.document.write("<iframe src='" + url + "'></iframe>");
setTimeout(function () {
try {
myWindow.location.href;
success = true;
} catch (ex) {
console.log(ex);
}
if (success) {
myWindow.setTimeout('window.close()', 100);
} else {
myWindow.close();
}
callback(success);
}, 100);
} else if (Browser.name === "Firefox") {
try {
iframe = $("<iframe />");
iframe.css({"display": "none"});
iframe.appendTo("body");
iframe[0].contentWindow.location.href = url;
success = true;
} catch (ex) {
success = false;
}
iframe.remove();
callback(success);
} else if (Browser.name === "Chrome") {
elem.css({"outline": 0});
elem.attr("tabindex", "1");
elem.focus();
elem.blur(function () {
success = true;
callback(true); // true
});
location.href = url;
setTimeout(function () {
elem.off('blur');
elem.removeAttr("tabindex");
if (!success) {
callback(false); // false
}
}, 1000);
} else if (Browser.name === "Safari") {
if (myappinstalledflag) {
location.href = url;
success = true;
} else {
success = false;
}
callback(success);
}
}
The Safari extension was easy to implement. It consisted of a single line of injection script:
myinject.js:
window.postMessage("myappinstalled", window.location.origin);
Then in the web page JavaScript, you need to first register the message event and set a flag if the message is received:
window.addEventListener('message', function (msg) {
if (msg.data === "myappinstalled") {
myappinstalledflag = true;
}
}, false);
This assumes the application which is associated with the custom protocol will manage the installation of the Safari extension.
In all cases, if the callback returns false, you know to inform the user that the application (i.e., it's custom protocol) is not installed.
You say you need to detect the browser's protocol handlers - do you really?
What if you did something like what happens when you download a file from sourceforge? Let's say you want to open myapp://something. Instead of simply creating a link to it, create a link to another HTML page accessed via HTTP. Then, on that page, say that you're attempting to open the application for them. If it doesn't work, they need to install your application, which they can do by clicking on the link you'll provide. If it does work, then you're all set.
This was a recommended approach for IE by Microsoft support
http://msdn.microsoft.com/en-us/library/ms537503%28VS.85%29.aspx#related_topics
"If you have some control over the binaries being installed on a user’s machine, checking the UA in script seems like a relevant approach:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\5.0\User Agent\Post Platform
" -- By M$ support
Every web page has access to the userAgent string and if you drop a custom post platform value, detecting this in javascript using navigator.userAgent is quite simple.
Fortunately, other major browsers like Firefox and Chrome (barring Safari :( ), do not throw "page not found" errors when a link with a custom protocol is clicked and the protocol is not installed on the users machine. IE is very unforgiving here, any trick to click in a invisible frame or trap javascript errors does not work and ends up with ugly "webpage cannot be displayed" error. The trick we use in our case is to inform users with browser specific images that clicking on the custom protocol link will open an application. And if they do not find the app opening up, they can click on an "install" page. In terms of XD this wprks way better than the ActiveX approach for IE.
For FF and Chrome, just go ahead and launch the custom protocol without any detection. Let the user tell you what he sees.
For Safari, :( no answers yet
I'm trying to do something similar and I just discovered a trick that works with Firefox. If you combine it with the trick for IE you can have one that works on both main browsers (I'm not sure if it works in Safari and I know it doesn't work in Chrome)
if (navigator.appName=="Microsoft Internet Explorer" && document.getElementById("testprotocollink").protocolLong=="Unknown Protocol") {
alert("No handler registered");
} else {
try {
window.location = "custom://stuff";
} catch(err) {
if (err.toString().search("NS_ERROR_UNKNOWN_PROTOCOL") != -1) {
alert("No handler registered");
}
}
}
In order for this to work you also need to have a hidden link somewhere on the page, like this:
<a id="testprotocollink" href="custom://testprotocol" style="display: none;">testprotocollink</a>
It's a bit hacky but it works. The Firefox version unfortunately still pops up the default alert that comes up when you try to visit a link with an unknown protocol, but it will run your code after the alert is dismissed.
You can try something like this:
function OpenCustomLink(link) {
var w = window.open(link, 'xyz', 'status=0,toolbar=0,menubar=0,height=0,width=0,top=-10,left=-10');
if(w == null) {
//Work Fine
}
else {
w.close();
if (confirm('You Need a Custom Program. Do you want to install?')) {
window.location = 'SetupCustomProtocol.exe'; //URL for installer
}
}
}
This is not a trivial task; one option might be to use signed code, which you could leverage to access the registry and/or filesystem (please note that this is a very expensive option). There is also no unified API or specification for code signing, so you would be required to generate specific code for each target browser. A support nightmare.
Also, I know that Steam, the gaming content delivery system, doesn't seem to have this problem solved either.
Here's another hacky answer that would require (hopefully light) modification to your application to 'phone home' on launch.
User clicks link, which attempts to launch the application. A unique
identifier is put in the link, so that it's passed to the
application when it launches. Web app shows a spinner or something of that nature.
Web page then starts checking for a
'application phone home' event from an app with this same unique ID.
When launched, your application does an HTTP post to your web app
with the unique identifier, to indicate presence.
Either the web page sees that the application launched, eventually, or moves on with a 'please download' page.
I'm trying to make an AJAX call to CouchDB with Qooxdoo, but as far as I can tell no events seem to be firing on my request object (ie. Nothing is appearing on the console and no alerts are coming up). Can anyone tell me what should be happening/what I'm doing wrong?
(This is all in the 'main' method of my class)
var req = new qx.io.remote.Request('http://localhost:5984/japanese/words', 'GET', 'application/json').set({crossDomain:true,timeout:0});
this.debug("Testing");
req.addListener("created", function(e) {
this.debug("Created");
alert(e.getContent());
}, this);
req.addListener("sending", function(e) {
this.debug("Configured");
alert(e.getContent());
}, this);
...
(This is just a sample - I've added a similar listener for all the events I can think of but nothing is coming up on the console)
My server is running Ubuntu 10.10 with Qooxdoo 1.3.
Edit:
Now trying to request "http://localhost/languages/test.php" (my app is at "http://localhost/languages/index.html") and still no alerts are appearing except for the test one I put outside of any event. My request is now: new qx.io.remote.Request('http://localhost/languages/test.php', 'GET', 'application/json'); The PHP file is returning valid JSON when I access it in my browser. Surely this should work?
Cross-domain requests in qooxdoo use a script transport which doesn't fire events. Instead, your server needs to wrap the response data in a call to a static method. See the package documentation of qx.io.remote for details:
http://demo.qooxdoo.org/current/apiviewer/#qx.io.remote
I have created a custom URL protocol handler.
http://
mailto://
custom://
I have registered a WinForms application to respond accordingly. This all works great.
But I would like to be able to gracefully handle the case where the user doesn't have the custom URL protocol handler installed, yet.
In order to be able to do this I need to be able to detect the browser's registered protocol handlers, I would assume from JavaScript. But I have been unable to find a way to poll for the information. I am hoping to find a solution to this problem.
Thanks for any ideas you might be able to share.
This would be a very, very hacky way to do this... but would this work?
Put the link in as normal...
But attach an onclick handler to it, that sets a timer and adds an onblur handler for the window
(in theory) if the browser handles the link (application X) will load stealing the focus from the window...
If the onblur event fires, clear the timer...
Otherwise in 3-5seconds let your timeout fire... and notify the user "Hmm, looks like you don't have the Mega Uber Cool Application installed... would you like to install it now? (Ok) (Cancel)"
Far from bulletproof... but it might help?
There's no great cross-browser way to do this. In IE10+ on Win8+, a new msLaunchUri api enables you to launch a protocol, like so:
navigator.msLaunchUri('skype:123456',
function()
{
alert('success');
},
function()
{
alert('failed');
}
);
If the protocol is not installed, the failure callback will fire. Otherwise, the protocol will launch and the success callback will fire.
I discuss this topic a bit further here:
https://web.archive.org/web/20180308105244/https://blogs.msdn.microsoft.com/ieinternals/2011/07/13/understanding-protocols/
This topic is of recent (2021) interest; see https://github.com/fingerprintjs/external-protocol-flooding for discussion.
HTML5 defines Custom scheme and content handlers (to my knowledge Firefox is the only implementor so far), but unfortunately there is currently no way to check if a handler already exists—it has been proposed, but there was no follow-up. This seems like a critical feature to use custom handlers effectively and we as developers should bring attention to this issue in order to get it implemented.
There seems to be no straightforward way via javascript to detect the presence of an installed app that has registered a protocol handler.
In the iTunes model, Apple provides urls to their servers, which then provide pages that run some javascript:
http://ax.itunes.apple.com/detection/itmsCheck.js
So the iTunes installer apparently deploys plugins for the major browsers, whose presence can then be detected.
If your plugin is installed, then you can be reasonably sure that redirecting to your app-specific url will succeed.
What seams the most easy solution is to ask the user the first time.
Using a Javascript confirm dialog per example:
You need this software to be able to read this link. Did you install it ?
if yes: create a cookie to not ask next time; return false and the link applies
if false: window.location.href = '/downloadpage/'
If you have control of the program you're trying to run (the code), one way to see if the user was successful in running the application would be to:
Before trying to open the custom protocol, make an AJAX request to a server script that saves the user's intent in a database (for example, save the userid and what he wanted to do).
Try to open the program, and pass on the intent data.
Have the program make a request to the server to remove the database entry (using the intent data to find the correct row).
Make the javascript poll the server for a while to see if the database entry is gone. If the entry is gone, you'll know the user was successful in opening the application, otherwise the entry will remain (you can remove it later with cronjob).
I have not tried this method, just thought it.
I was able to finally get a cross-browser (Chrome 32, Firefox 27, IE 11, Safari 6) solution working with a combination of this and a super-simple Safari extension. Much of this solution has been mentioned in one way or another in this and this other question.
Here's the script:
function launchCustomProtocol(elem, url, callback) {
var iframe, myWindow, success = false;
if (Browser.name === "Internet Explorer") {
myWindow = window.open('', '', 'width=0,height=0');
myWindow.document.write("<iframe src='" + url + "'></iframe>");
setTimeout(function () {
try {
myWindow.location.href;
success = true;
} catch (ex) {
console.log(ex);
}
if (success) {
myWindow.setTimeout('window.close()', 100);
} else {
myWindow.close();
}
callback(success);
}, 100);
} else if (Browser.name === "Firefox") {
try {
iframe = $("<iframe />");
iframe.css({"display": "none"});
iframe.appendTo("body");
iframe[0].contentWindow.location.href = url;
success = true;
} catch (ex) {
success = false;
}
iframe.remove();
callback(success);
} else if (Browser.name === "Chrome") {
elem.css({"outline": 0});
elem.attr("tabindex", "1");
elem.focus();
elem.blur(function () {
success = true;
callback(true); // true
});
location.href = url;
setTimeout(function () {
elem.off('blur');
elem.removeAttr("tabindex");
if (!success) {
callback(false); // false
}
}, 1000);
} else if (Browser.name === "Safari") {
if (myappinstalledflag) {
location.href = url;
success = true;
} else {
success = false;
}
callback(success);
}
}
The Safari extension was easy to implement. It consisted of a single line of injection script:
myinject.js:
window.postMessage("myappinstalled", window.location.origin);
Then in the web page JavaScript, you need to first register the message event and set a flag if the message is received:
window.addEventListener('message', function (msg) {
if (msg.data === "myappinstalled") {
myappinstalledflag = true;
}
}, false);
This assumes the application which is associated with the custom protocol will manage the installation of the Safari extension.
In all cases, if the callback returns false, you know to inform the user that the application (i.e., it's custom protocol) is not installed.
You say you need to detect the browser's protocol handlers - do you really?
What if you did something like what happens when you download a file from sourceforge? Let's say you want to open myapp://something. Instead of simply creating a link to it, create a link to another HTML page accessed via HTTP. Then, on that page, say that you're attempting to open the application for them. If it doesn't work, they need to install your application, which they can do by clicking on the link you'll provide. If it does work, then you're all set.
This was a recommended approach for IE by Microsoft support
http://msdn.microsoft.com/en-us/library/ms537503%28VS.85%29.aspx#related_topics
"If you have some control over the binaries being installed on a user’s machine, checking the UA in script seems like a relevant approach:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\5.0\User Agent\Post Platform
" -- By M$ support
Every web page has access to the userAgent string and if you drop a custom post platform value, detecting this in javascript using navigator.userAgent is quite simple.
Fortunately, other major browsers like Firefox and Chrome (barring Safari :( ), do not throw "page not found" errors when a link with a custom protocol is clicked and the protocol is not installed on the users machine. IE is very unforgiving here, any trick to click in a invisible frame or trap javascript errors does not work and ends up with ugly "webpage cannot be displayed" error. The trick we use in our case is to inform users with browser specific images that clicking on the custom protocol link will open an application. And if they do not find the app opening up, they can click on an "install" page. In terms of XD this wprks way better than the ActiveX approach for IE.
For FF and Chrome, just go ahead and launch the custom protocol without any detection. Let the user tell you what he sees.
For Safari, :( no answers yet
I'm trying to do something similar and I just discovered a trick that works with Firefox. If you combine it with the trick for IE you can have one that works on both main browsers (I'm not sure if it works in Safari and I know it doesn't work in Chrome)
if (navigator.appName=="Microsoft Internet Explorer" && document.getElementById("testprotocollink").protocolLong=="Unknown Protocol") {
alert("No handler registered");
} else {
try {
window.location = "custom://stuff";
} catch(err) {
if (err.toString().search("NS_ERROR_UNKNOWN_PROTOCOL") != -1) {
alert("No handler registered");
}
}
}
In order for this to work you also need to have a hidden link somewhere on the page, like this:
<a id="testprotocollink" href="custom://testprotocol" style="display: none;">testprotocollink</a>
It's a bit hacky but it works. The Firefox version unfortunately still pops up the default alert that comes up when you try to visit a link with an unknown protocol, but it will run your code after the alert is dismissed.
You can try something like this:
function OpenCustomLink(link) {
var w = window.open(link, 'xyz', 'status=0,toolbar=0,menubar=0,height=0,width=0,top=-10,left=-10');
if(w == null) {
//Work Fine
}
else {
w.close();
if (confirm('You Need a Custom Program. Do you want to install?')) {
window.location = 'SetupCustomProtocol.exe'; //URL for installer
}
}
}
This is not a trivial task; one option might be to use signed code, which you could leverage to access the registry and/or filesystem (please note that this is a very expensive option). There is also no unified API or specification for code signing, so you would be required to generate specific code for each target browser. A support nightmare.
Also, I know that Steam, the gaming content delivery system, doesn't seem to have this problem solved either.
Here's another hacky answer that would require (hopefully light) modification to your application to 'phone home' on launch.
User clicks link, which attempts to launch the application. A unique
identifier is put in the link, so that it's passed to the
application when it launches. Web app shows a spinner or something of that nature.
Web page then starts checking for a
'application phone home' event from an app with this same unique ID.
When launched, your application does an HTTP post to your web app
with the unique identifier, to indicate presence.
Either the web page sees that the application launched, eventually, or moves on with a 'please download' page.