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GoBack/GoForward in Win10 UWP WebView

2018 Oct 23, 9:18

The GoBack and GoForward methods on the UWP WebView (x-ms-webview in HTML, Windows.UI.Xaml.Controls.WebView in XAML, and Windows.Web.UI.Interop.WebViewControl in Win32) act the same as the Back and Forward buttons in the Edge browser. They don't necessarily change the top level document of the WebView. If inside the webview an iframe navigates then that navigation will be recorded in the forward/back history and the GoBack / GoForward call may result in navigating that iframe. This makes sense as an end user using the Edge browser since if I click a link to navigate one place and then hit Back I expect to sort of undo that most recent navigation regardless of if that navigation happened in an iframe or the top level document.

If that doesn't make sense for your application and you want to navigate forward or back ignoring iframe navigates, unfortunately there's no perfect workaround.

One workaround could be to try calling GoBack and then checking if a FrameNavigationStarting event fires or a NavigationStarting event fires. If a frame navigates then try calling GoBack again. There could be async races in this case since other navigates could come in and send you the wrong signal and interrupt your multi step GoBack operation.

You could also try keeping track of all top level document navigations and manually navigate back to the URIs you care about. However, GoBack and GoForward also restore some amount of user state (form fills etc) in addition to navigating. Manually calling navigate will not give this same behavior.

PermalinkCommentsuri uwp webview

Tiny browser features: JSBrowser crash resistance

2018 May 13, 4:59

JSBrowser is a basic browser built as a Win10 JavaScript UWP app around the WebView HTML element. Its fun and relatively simple to implement tiny browser features in JavaScript and in this post I'm implementing crash resistance.

The normal DOM mechanisms for creating an HTML WebView create an in-process WebView, in which the WebView runs on a unique UI thread. But we can use the MSWebView constructor instead to create an out-of-process WebView in which the WebView runs in its own distinct WebView process. Unlike an in-process WebView, Web content running in an out-of-process WebView can only crash the WebView process and not the app process.

        this.replaceWebView = () => {
let webview = document.querySelector("#WebView");
// Cannot access webview.src - anything that would need to communicate with the webview process may fail
let oldSrc = browser.currentUrl;
const webviewParent = webview.parentElement;
webviewParent.removeChild(webview);
webview = new MSWebView();
Object.assign(this, {
"webview": webview
});
webview.setAttribute("id", "WebView");

// During startup our currentUrl field is blank. If the WebView has crashed
// and we were on a URI then we may obtain it from this property.
if (browser.currentUrl && browser.currentUrl != "") {
this.trigger("newWebview");
this.navigateTo(browser.currentUrl);
}
webviewParent.appendChild(webview);

I run replaceWebView during startup to replace the in-process WebView created via HTML markup with an out-of-process WebView. I could be doing more to dynamically copy styles, attributes, etc but I know what I need to set on the WebView and just do that.

When a WebView process crashes the corresponding WebView object is no longer useful and a new WebView element must be created. In fact if the old WebView object is used it may throw and will no longer have valid state. Accordingly when the WebView crashes I run replaceWebView again. Additionally, I need to store the last URI we've navigated to (browser.currentUrl in the above) since the crashed WebView object won't know what URI it is on after it crashes.

            webview.addEventListener("MSWebViewProcessExited", () => { 
if (browser.currentUrl === browser.lastCrashUrl) { ++browser.lastCrashUrlCrashCount;
}
else {
browser.lastCrashUrl = browser.currentUrl;
browser.lastCrashUrlCrashCount = 1;
}
// If we crash again and again on the same URI, maybe stop trying to load that URI.
if (browser.lastCrashUrlCrashCount >= 3) {
browser.lastCrashUrl = "";
browser.lastCrashUrlCrashCount = 0;
browser.currentUrl = browser.startPage;
}
this.replaceWebView();
});

I also keep track of the last URI that we recovered and how many times we've recovered that same URI. If the same URI crashes more than 3 times in a row then I assume that it will keep happening and I navigate to the start URI instead.

PermalinkCommentsbrowser javascript jsbrowser uwp webview win10

Application Content URI Rule effects

2017 Jun 30, 3:01

Previously I described Application Content URI Rules (ACUR) parsing and ACUR ordering. This post describes what you get from putting a URI in ACUR.

URIs in the ACUR gain the following which is otherwise unavailable:

  • Geoloc API usage
  • Audio and video capture API usage
  • Pointer lock API usage
  • Web notifications API usage
  • IndexedDB API usage
  • Clipboard API usage
  • window.external.notify access from within webview
  • window.close the primary window
  • Top level navigation in the primary window
  • Cross origin XHR and fetch to ms-appx(-web) scheme URIs
  • Cross origin dirtied canvas read access if dirtied by ms-appx(-web) scheme URIs
  • Cross origin text track for video element for tracks from ms-appx(-web) scheme URIs

URIs in the ACUR that also have full WinRT access additionally gain the following:

  • Cross origin XHR and fetch
  • Cross origin dirtied canvas read access
  • Cross origin text track for video element
  • Local audio and video WinRT plugins work with media elements
PermalinkCommentsapplication-content-uri-rules coding javascript programming windows-store

4 people are living in an isolated habitat for 30 days. Why? Science!

2016 Feb 1, 3:27

nasa:

This 30 day mission will help our researchers learn how isolation and close quarters affect individual and group behavior. This study at our Johnson Space Center prepares us for long duration space missions, like a trip to an asteroid or even to Mars.

image

The Human Research Exploration Analog (HERA) that the crew members will be living in is one compact, science-making house. But unlike in a normal house, these inhabitants won’t go outside for 30 days. Their communication with the rest of planet Earth will also be very limited, and they won’t have any access to internet. So no checking social media kids!

The only people they will talk with regularly are mission control and each other.

image

The crew member selection process is based on a number of criteria, including the same criteria for astronaut selection.

What will they be doing?

Because this mission simulates a 715-day journey to a Near-Earth asteroid, the four crew members will complete activities similar to what would happen during an outbound transit, on location at the asteroid, and the return transit phases of a mission (just in a bit of an accelerated timeframe). This simulation means that even when communicating with mission control, there will be a delay on all communications ranging from 1 to 10 minutes each way. The crew will also perform virtual spacewalk missions once they reach their destination, where they will inspect the asteroid and collect samples from it. 

A few other details:

  • The crew follows a timeline that is similar to one used for the ISS crew.
  • They work 16 hours a day, Monday through Friday. This includes time for daily planning, conferences, meals and exercises.  
  • They will be growing and taking care of plants and brine shrimp, which they will analyze and document.

But beware! While we do all we can to avoid crises during missions, crews need to be able to respond in the event of an emergency. The HERA crew will conduct a couple of emergency scenario simulations, including one that will require them to maneuver through a debris field during the Earth-bound phase of the mission. 

image

Throughout the mission, researchers will gather information about cohabitation, teamwork, team cohesion, mood, performance and overall well-being. The crew members will be tracked by numerous devices that each capture different types of data.

image

Past HERA crew members wore a sensor that recorded heart rate, distance, motion and sound intensity. When crew members were working together, the sensor would also record their proximity as well, helping investigators learn about team cohesion.

Researchers also learned about how crew members react to stress by recording and analyzing verbal interactions and by analyzing “markers” in blood and saliva samples.

image

In total, this mission will include 19 individual investigations across key human research elements. From psychological to physiological experiments, the crew members will help prepare us for future missions.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

PermalinkComments

4 people are living in an isolated habitat for 30 days. Why? Science!

2016 Feb 1, 3:27

nasa:

This 30 day mission will help our researchers learn how isolation and close quarters affect individual and group behavior. This study at our Johnson Space Center prepares us for long duration space missions, like a trip to an asteroid or even to Mars.

image

The Human Research Exploration Analog (HERA) that the crew members will be living in is one compact, science-making house. But unlike in a normal house, these inhabitants won’t go outside for 30 days. Their communication with the rest of planet Earth will also be very limited, and they won’t have any access to internet. So no checking social media kids!

The only people they will talk with regularly are mission control and each other.

image

The crew member selection process is based on a number of criteria, including the same criteria for astronaut selection.

What will they be doing?

Because this mission simulates a 715-day journey to a Near-Earth asteroid, the four crew members will complete activities similar to what would happen during an outbound transit, on location at the asteroid, and the return transit phases of a mission (just in a bit of an accelerated timeframe). This simulation means that even when communicating with mission control, there will be a delay on all communications ranging from 1 to 10 minutes each way. The crew will also perform virtual spacewalk missions once they reach their destination, where they will inspect the asteroid and collect samples from it. 

A few other details:

  • The crew follows a timeline that is similar to one used for the ISS crew.
  • They work 16 hours a day, Monday through Friday. This includes time for daily planning, conferences, meals and exercises.  
  • They will be growing and taking care of plants and brine shrimp, which they will analyze and document.

But beware! While we do all we can to avoid crises during missions, crews need to be able to respond in the event of an emergency. The HERA crew will conduct a couple of emergency scenario simulations, including one that will require them to maneuver through a debris field during the Earth-bound phase of the mission. 

image

Throughout the mission, researchers will gather information about cohabitation, teamwork, team cohesion, mood, performance and overall well-being. The crew members will be tracked by numerous devices that each capture different types of data.

image

Past HERA crew members wore a sensor that recorded heart rate, distance, motion and sound intensity. When crew members were working together, the sensor would also record their proximity as well, helping investigators learn about team cohesion.

Researchers also learned about how crew members react to stress by recording and analyzing verbal interactions and by analyzing “markers” in blood and saliva samples.

image

In total, this mission will include 19 individual investigations across key human research elements. From psychological to physiological experiments, the crew members will help prepare us for future missions.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

PermalinkComments

Retweet of FTC

2015 Nov 15, 4:40
Cross-Device Tracking workshop introductory remarks by FTC Chairwoman @EdithRamirezFTC. Watch live: https://kvgo.com/ftc/11-16-2015-Cross-Device-Tracking … #FTCXDT
PermalinkComments

Tweet from David_Risney

2015 Sep 21, 2:58
Enjoying Pixies Indie Cindy. Greens and Blues sounds like it's missing from the FLCL soundtrack or maybe Polaris.
PermalinkComments

Retweet of phirm

2015 Sep 3, 7:03
Hey guys, tonight is this song's first night out. Can you help it find a few million ears to hang out in? http://music.mikephirman.com/track/i-c-a-n-t-s-p-e-l-l …
PermalinkComments

Tweet from David_Risney

2015 Aug 16, 11:08
HO scale trains totally cover impressive spiral looped track https://youtu.be/qUZVv0nr2rc 
PermalinkComments

laughingsquid: Live Band Performs ‘Mario Kart’ Song as Man...

2015 May 27, 3:11


laughingsquid:

Live Band Performs ‘Mario Kart’ Song as Man Races Down the Video Game Track

PermalinkComments

laughingsquid: Live Band Performs ‘Mario Kart’ Song as Man...

2015 May 27, 3:11


laughingsquid:

Live Band Performs ‘Mario Kart’ Song as Man Races Down the Video Game Track

PermalinkComments

Retweet of thegrugq

2015 Apr 12, 9:47
War in the Web 2.0 era: how Air Forces deal (or don’t) with Internet-based flight tracking tools. Interesting http://theaviationist.com/2014/10/13/war-2-adsb-opsec/ …
PermalinkComments

Tweet from David_Risney

2015 Feb 8, 11:17
Analysis of 2011 DARPA Challenge tracks down the trolls who destroyed their competitors crowd sourced solution. https://medium.com/backchannel/how-a-lone-hacker-shredded-the-myth-of-crowdsourcing-d9d0534f1731 …
PermalinkComments

Serializing JavaScript Promise Execution

2013 Aug 10, 3:07
Occasionally I have need to run a set of unrelated promises in series, for instance an object dealing with a WinRT camera API that can only execute one async operation at a time, or an object handling postMessage message events and must resolve associated async operations in the same order it received the requests. The solution is very simply to keep track of the last promise and when adding a new promise in serial add a continuation of the last promise to execute the new promise and point the last promise at the result. I encapsulate the simple solution in a simple constructor:

    function PromiseExecutionSerializer() {
var lastPromise = WinJS.Promise.wrap(); // Start with an empty fulfilled promise.

this.addPromiseForSerializedExecution = function(promiseFunction) {
lastPromise = lastPromise.then(function () {
// Don't call directly so next promise doesn't get previous result parameter.
return promiseFunction();
});
}
}

The only thing to watch out for is to ensure you don't pass the result of a previous promise onto a subsequent promise that is unrelated.
PermalinkCommentsasync javascript promise technical

This might be the strangest release of classic Chicago label...

2013 May 17, 5:43


This might be the strangest release of classic Chicago label Trax yet! The clue’s in the title - it’s Daft Punk brassified. We get four classics by the world’s most famous Gallic robot duo: “Harder, Better, Faster, Stronger” gets turned into a 1940s Dick Tracy-style riff-off with every form of trumpet imaginable, “Around The World” mixes wind instruments with that famous vocal mantra, “Da Funk” features plenty of sassy brass and “One More Time” wraps things up on a swingin’, jazzy high.

PermalinkCommentsSoundCloud Iamjasonalexander Brass Music music cover daft-punk

laughingsquid: Stick-N-Find, Tiny Bluetooth Stickers Help You...

2013 Jan 4, 5:35


laughingsquid:

Stick-N-Find, Tiny Bluetooth Stickers Help You Keep Track of Things

PermalinkComments

Visitor Tracking Without Cookies (or How To Abuse HTTP 301s) (scatmania.org)

2012 Nov 11, 1:26

Moral: laws should cover behavior not specific technologies. The implementation can change, laws shouldn’t take such dependencies.

PermalinkCommentshttp law legal technical 301 cookie privacy

Its a suitcase 3D printer. Nice soundtrack too.

2012 Jul 28, 1:54PermalinkCommentsmake 3d-printer video suitcase

Jet Set Radio HD coming soon with awesome soundtrack...

2012 Jun 1, 2:55


Jet Set Radio HD coming soon with awesome soundtrack promised. Exciting!

PermalinkCommentsjet-set-radio video-game game video music xbox

Play Fez

2012 May 7, 3:30

I'm done playing Fez. The style is atmospheric retro nastalgia and on the surface the gameplay is standard 2D platformer with one interesting Flatland style game mechanic but dig deeper to find Myst style puzzles. Despite the following I thoroughly enjoyed the game and would recommend it to anyone intrigued by the previous. Five eighths through the game I ran into one of the game's infamous Fez save game breaking issues, but I enjoyed the game enough that I started over before any patches were released and had no further issues.

While playing the game I created some tools to help keep track of my Fez notes (spoilers) including a Pixelated Image Creator that makes it easy to generate data URIs for large, black and white pixelated images, and (spoilers) a Fez Transliteration Tool to help me translate the in-game writing system.

PermalinkCommentsvideo-game fez game xbox
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