Scott Hanselman

The Weekly Source Code 33 - Microsoft Open Source inside Google Chrome

September 12, '08 Comments [42] Posted in Microsoft | Programming | Source Code | Windows Client
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First, let me remind you that in my new ongoing quest to read source code to be a better developer, Dear Reader, I present to you thirty-third in a infinite number of posts of "The Weekly Source Code."

That said, what does Microsoft Code have to do with Google Chrome, the new browser from Google? Take a look at the Terms and Conditions for the "Chromium" project up on Google Code. There are 24 different bits of third party software involved in making Chrome work, and one of them is WTL, the Windows Template Library, which was released as Open Source in 2004.

Chrome's use of the Open Source Windows Template Library

WTL is distributed under the MS-PL or Microsoft Public License. This is a VERY relaxed license that basically says "have fun, and don't call if there's trouble." In the Open Source world, licenses like that make people smile.

WTL is a C++ library for Win32 development and is kind of like MFC (Microsoft Foundation Classes), but a lot more lightweight. It was originally worked on by Nenad Stefanovic as an internal thing at Microsoft that was then released as an unsupported sample. Nenad is still listed on the old SourceForge project.

WTL embraces ATL (Active Template Library) which is a series of C++ template classes made to make COM development easier. It was more or less patterned after the STL (Standard Template Library). You may remember that folks like Chris Sells were hard-core ATL wonks. Chris and Chris Tavares (of P&P fame) worked on the ATL Internals book.

WTL was well loved going back to 2002. There's a great post from back then by Simon Steele about The Joys of WTL. Simon says:

The Windows Template Library (WTL) is MFC on template-based steroids - after a successful stretch on the slimfast plan. WTL provides the user-interface frameworks that we need to write proper GUI applications without resorting to the bloated MFC or complicated pure Win32 API programming. A number of the "must-have" classes from MFC are also available as WTL utility classes too, welcome back your old friends CPoint, CSize, CRect and most importantly CString! WTL produces small executables that do not require the MFC run time libraries - in fact if you stay clear of the Visual C++ runtime functions (strcpy and friends) you can dispense with msvcrt.dll as well - leading to really small programs, which run fast too

Windows Template Library was released as Open Source over 4 years ago which is like 28 Internet years. May of 2004 was a long time. I didn't think Microsoft was doing much Open Source that far back, but it appears they were. In fact, back as far as April of 2003 there was talk on the WTL Yahoo Group by Pranish Kumar, then of the Visual C++ team, of trying to figure out how to get the product out into the community in a way that would let it live on.

History: How WTL Became Open Source

I had an IM chat today with Pranish Kumar about how WTL made it out of a 2004 Microsoft as an Open Source project. I'd also encourage you to check out both the Shared Source page at MSFT, the Open Source page, and most importantly, Port 25.

Here's part of my IM with Pranish about how WTL was released:

[WTL] was one of the first if not the first OSS things from Microsoft and it was a tough sell. There was a meeting with some bosses where we were presenting 3 potential OSS items. I guess it was the first "real OSS" with joint MS/Community involvement as opposed to just us posting something externally. WTL was the only one that got approved.

Me: Did it start the Shared Source Initiative?

Yes in the broader sense, I think we took the basis for the license/process from Win CE and a few other components which Microsoft made available (in some form) as shared source. They also looked at BSD and some other licenses.

It was a fascinating experience for many reasons. One of them was seeing the reaction of various Microsoft execs to the whole open source/shared source idea. There was a lot of concern about OSS = Linux, and questions on whether there was business value in us engaging

It's pretty amazing how our stance/attitude has changed, one of the reasons WTL got through is because we convinced management, it had a passionate community base and would really help us foster that base.

I check in on the community now and then (not as regularly as I'd like) and I'm always impressed how it's remained strong.

One of the reasons I wanted to work for ScottGu was because of Microsoft's always improving attitude about releasing source. It's a big company and sometimes moves slow, but more people "get it" now than before.

Digging In

Chrome uses abstraction libraries to draw the GUI on other non-Windows platforms, but for now, what sits underneath part of ChromeViews is good ol' WTL. Makes sense, too. Why not use a native library to get native speeds? They are using WTL 8.0 build 7161 from what I can see.

Chromium is a lot of code. The source tarball is over 400 megs, if you want to try to compile it yourself with VS2005. Let's try to look at a few tiny interesting bits, though. You can check out their "Build Bot" if you like, and watch the development on the Linux and Mac Versions as they progress each day.

In some places, Chrome uses WTL for little stuff, like macros. For example, in the Chrome AeroTooltipManager, GET_X_LPARAM is a macro:

...snip...
if (u_msg == WM_MOUSEMOVE || u_msg == WM_NCMOUSEMOVE) {
int x = GET_X_LPARAM(l_param);
int y = GET_Y_LPARAM(l_param);
if (last_mouse_x_ != x || last_mouse_y_ != y) {
last_mouse_x_ = x;
last_mouse_y_ = y;
HideKeyboardTooltip();
UpdateTooltip(x, y);
}
...snip...

In other places, they rely on it more, like in text_field.cc that includes atlcrack.h. These are not drugs, mind you, but rather "message crackers" to help get at, and react to, the information inside Window Messages. These are used to create a "message map" of all the events you're interested in. These are macros that expand into an obscene amount of code. They are exceedingly handy.

// CWindowImpl
BEGIN_MSG_MAP(Edit)
MSG_WM_CHAR(OnChar)
MSG_WM_CONTEXTMENU(OnContextMenu)
MSG_WM_COPY(OnCopy)
MSG_WM_CUT(OnCut)
MESSAGE_HANDLER_EX(WM_IME_COMPOSITION, OnImeComposition)
MSG_WM_KEYDOWN(OnKeyDown)
MSG_WM_LBUTTONDBLCLK(OnLButtonDblClk)
MSG_WM_LBUTTONDOWN(OnLButtonDown)
MSG_WM_LBUTTONUP(OnLButtonUp)
MSG_WM_MBUTTONDOWN(OnNonLButtonDown)
MSG_WM_MOUSEMOVE(OnMouseMove)
MSG_WM_MOUSELEAVE(OnMouseLeave)
MSG_WM_NCCALCSIZE(OnNCCalcSize)
MSG_WM_NCPAINT(OnNCPaint)
MSG_WM_RBUTTONDOWN(OnNonLButtonDown)
MSG_WM_PASTE(OnPaste)
MSG_WM_SYSCHAR(OnSysChar) // WM_SYSxxx == WM_xxx with ALT down
MSG_WM_SYSKEYDOWN(OnKeyDown)
END_MSG_MAP()

They also use some handy helpers that are C++ classes around Windows structures. For example, the Windows POINT structure is a class in WTL called CPoint. The class actual derives from the struct. Lots of interesting stuff in there, and WTL is at a pretty low level helping out and keeping things tidy.

Now, moving on to something I found fascinating because it's not documented and may or may not have required some disassembling to accomplish.

Chrome's Odd Use of Data Execution Prevention

This part isn't explicitly about use of open source, but it's darned interesting. This is part of Chrome's WinMain(). It's long, but check out a few interesting bits. First, the big if/else at the beginning. They look at the command line and determine if they (the EXE) are one of three flavors...either a Renderer, a Plugin [host] process, or the Browser process. Notice that they have DEP (Data Execution Prevention) turned on for the Renderer and main Browser, but have to enable ATL7 thinking because there are plugins that weird build in older ways still out there. They are ultimately calling SetProcessDEPPolicy and passing in a flag to enable DEP, as well enabling ATL7 compiled processes. From MSDN help:

"Disables DEP-ATL thunk emulation for the current process, which prevents the system from intercepting NX faults that originate from the Active Template Library (ATL) thunk layer."

These new APIs were added in Vista SP1, Windows XP SP3 and WIndows 2008. Why is ATL special cased? From Michael Howard:

"Older versions of ATL, and by older I mean pre-Visual C++ 2005, used dynamically generated code in small isolated cases. Obviously, without the appropriate APIs this is going to cause problems on a DEP-enabled computer, because you can't execute data. This code is referred to as a "thunk" and versions of ATL in VC++ 2005 and later work correctly with DEP."

Some plugins that might run in a Chrome sandboxed process might be compiled in this way, so that process has a different security DEP setting than the others.

int APIENTRY wWinMain(HINSTANCE instance, HINSTANCE prev_instance,
wchar_t* command_line, int show_command) {
// The exit manager is in charge of calling the dtors of singletons.
base::AtExitManager exit_manager;

// Note that std::wstring and CommandLine got linked anyway because of
// breakpad.
CommandLine parsed_command_line;
std::wstring process_type =
parsed_command_line.GetSwitchValue(switches::kProcessType);

const wchar_t* dll_name = L"chrome.dll";
if (process_type == switches::kPluginProcess) {
// Plugin process.
// For plugins, we enable ATL7 thunking support because we saw old activex
// built with VC2002 in the wild still being used.
sandbox::SetCurrentProcessDEP(sandbox::DEP_ENABLED_ATL7_COMPAT);
} else if (process_type == switches::kRendererProcess) {
// Renderer process.
// For the processes we control, we enforce strong DEP support.
sandbox::SetCurrentProcessDEP(sandbox::DEP_ENABLED);
} else {
// Browser process.
// For the processes we control, we enforce strong DEP support.
sandbox::SetCurrentProcessDEP(sandbox::DEP_ENABLED);
}
...snip...
}

When you dig into their use of DEP, notice this interesting comment, as they try to get DEP working under Windows XP SP2 and Windows Server 2003 SP1. They are using the totally unsupported technique outlined in this article from 2005 to try to turn on DEP. If you try to call this on Vista you'll get back STATUS_NOT_SUPPORTED, of course. ;) There's an official Vista API, and that's SetProcessDEPPolicy.

As an side, and interestingly enough, this undocumented API has been added as a patch just last week to WINE (Windows Emulation) for those who try to emulate Windows under Linux, but outside a VM.

Note the most interesting comment in the method:

"// Completely undocumented from Microsoft. You can find this information by
// disassembling Vista's SP1 kernel32.dll with your favorite disassembler.
enum PROCESS_INFORMATION_CLASS {
ProcessExecuteFlags = 0x22,
}"

Looks like The Chromium authors may have disassembled part of the Windows Kernel in order to achieve this security feature under Windows XP SP2. Probably not cool to do that, but they're clearly doing it for good and not evil, as their intent (from reading their code) is to make their browser safer under XP SP2 and prevent unwanted code execution.

This internal and totally unsupported API is in the Microsoft Windows Internals 4th Edition, Chapter 6, on download.microsoft.com (PDF). It's also mentioned in a Microsoft Research PowerPoint (PPTX). An architect on the Windows Kernel team point out in a forum posting that this was internal:

"I want to stress as a disclaimer that NtSetInformationProcess, class ProcessAccessToken, is an undocumented and unsupported infterface. It is reserved for system component use and is subject to change between operating system releases"

You can see the dance Chrome does below or on their source site. They poke around looking for a method that does what they want, using GetProcAddress:

namespace sandbox {

namespace {

// These values are in the Windows 2008 SDK but not in the previous ones. Define
// the values here until we're sure everyone updated their SDK.
#ifndef PROCESS_DEP_ENABLE
#define PROCESS_DEP_ENABLE 0x00000001
#endif
#ifndef PROCESS_DEP_DISABLE_ATL_THUNK_EMULATION
#define PROCESS_DEP_DISABLE_ATL_THUNK_EMULATION 0x00000002
#endif

// SetProcessDEPPolicy is declared in the Windows 2008 SDK.
typedef BOOL (WINAPI *FnSetProcessDEPPolicy)(DWORD dwFlags);

// Completely undocumented from Microsoft. You can find this information by
// disassembling Vista's SP1 kernel32.dll with your favorite disassembler.
enum PROCESS_INFORMATION_CLASS {
ProcessExecuteFlags = 0x22,
};

// Flags named as per their usage.
const int MEM_EXECUTE_OPTION_ENABLE = 1;
const int MEM_EXECUTE_OPTION_DISABLE = 2;
const int MEM_EXECUTE_OPTION_ATL7_THUNK_EMULATION = 4;
const int MEM_EXECUTE_OPTION_PERMANENT = 8;

// Not exactly the right signature but that will suffice.
typedef HRESULT (WINAPI *FnNtSetInformationProcess)(
HANDLE ProcessHandle,
PROCESS_INFORMATION_CLASS ProcessInformationClass,
PVOID ProcessInformation,
ULONG ProcessInformationLength);

} // namespace

bool SetCurrentProcessDEP(DepEnforcement enforcement) {
#ifdef _WIN64
// DEP is always on in x64.
return enforcement != DEP_DISABLED;
#endif

// Try documented ways first.
// Only available on Vista SP1 and Windows 2008.
// http://msdn.microsoft.com/en-us/library/bb736299.aspx
FnSetProcessDEPPolicy SetProcDEP =
reinterpret_cast<FnSetProcessDEPPolicy>(
GetProcAddress(GetModuleHandle(L"kernel32.dll"),
"SetProcessDEPPolicy"));

if (SetProcDEP) {
ULONG dep_flags;
switch (enforcement) {
case DEP_DISABLED:
dep_flags = 0;
break;
case DEP_ENABLED:
dep_flags = PROCESS_DEP_ENABLE |
PROCESS_DEP_DISABLE_ATL_THUNK_EMULATION;
break;
case DEP_ENABLED_ATL7_COMPAT:
dep_flags = PROCESS_DEP_ENABLE;
break;
default:
NOTREACHED();
return false;
}
return 0 != SetProcDEP(dep_flags);
}

// Go in darker areas.
// Only available on Windows XP SP2 and Windows Server 2003 SP1.
// http://www.uninformed.org/?v=2&a=4
FnNtSetInformationProcess NtSetInformationProc =
reinterpret_cast<FnNtSetInformationProcess>(
GetProcAddress(GetModuleHandle(L"ntdll.dll"),
"NtSetInformationProcess"));

if (!NtSetInformationProc)
return false;

// Flags being used as per SetProcessDEPPolicy on Vista SP1.
ULONG dep_flags;
switch (enforcement) {
case DEP_DISABLED:
// 2
dep_flags = MEM_EXECUTE_OPTION_DISABLE;
break;
case DEP_ENABLED:
// 9
dep_flags = MEM_EXECUTE_OPTION_PERMANENT | MEM_EXECUTE_OPTION_ENABLE;
break;
case DEP_ENABLED_ATL7_COMPAT:
// 0xD
dep_flags = MEM_EXECUTE_OPTION_PERMANENT | MEM_EXECUTE_OPTION_ENABLE |
MEM_EXECUTE_OPTION_ATL7_THUNK_EMULATION;
break;
default:
NOTREACHED();
return false;
}

HRESULT status = NtSetInformationProc(GetCurrentProcess(),
ProcessExecuteFlags,
&dep_flags,
sizeof(dep_flags));
return SUCCEEDED(status);
}

} // namespace sandbox

It's a really interesting read and there's a lot of stuff going on in the comments, like TODOs, HACKs, and the like. All the stuff you'd expect to see any application of significant size. Funny, it's been at least 5 years since I've thought about C++ deeply. And to think I used to do all this -> stuff full time for money!

There's lots more to see. Check out the About Box version checks where they were blocking on Vista SP1 with UAC disabled. Also, the Threading stuff is interesting as they have a Thread Class that was ported to Mac and Linux. Finally check out Pickle.cc, as they serialize objects by "pickling them." Pickle is serialization for Python, and this looks like they're serializing between C++ and Python, and this is a C++ implementation of Pickle.

Back on WTL, you can download the final MS release of WTL 7.1 at Microsoft Downloads if you're interested. However, the more interesting release is the 8.0 release from June of 2007. This was the most recent release from the community! WTL 8 includes full support for Vista!

I think it's great that Microsoft is releasing more and more code in either Shared Source, Reference Source, or my favorite, Open Source as MS-PL. The fact that Google was able to use it, even this small part, really speaks to the spirit of Open Source.

Related Links

About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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The .NET Framework and the Browser's UserAgent String

September 11, '08 Comments [42] Posted in ASP.NET | Programming
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Vote Now! One of the things I'd said I'd do, Dear Reader, when I went to work for the Big Blue Monster, was to get your feedback into The Company whenever possible. Here's another opportunity for us to effect change, however small.

A while back I made a little site called http://www.smallestdotnet.com that would look at your Browser's UserAgent

and let you know the size that the latest .NET Framework would be for you (ballpark size). In the process I've gotten to see a LOT of interesting Browser UserAgents in the IIS logs.

If you visit the site and scroll down, you'll see YOUR Browser UserAgent at the bottom. Here's mine:

Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; WOW64; Trident/4.0; SLCC1; .NET CLR 2.0.50727; .NET CLR 3.5.21022; Media Center PC 5.0; Zune 2.5; MS-RTC LM 8; .NET CLR 3.0.30618)

Notice that I've got IE8 on 64-bit Windows. However, there's other stuff in there, like I have the Zune software, I have Media Center enabled, and I've got three versions of the .NET Framework. In this example, 2.0, 3.0, and 3.5.

Here's a UserAgent that showed up today on http://www.smallestdotnet.com:

Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1) ; .NET CLR 1.0.3705; InfoPath.1; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 1.1.4322; .NET CLR 3.0.04506.590; .NET CLR 3.5.20706; .NET CLR 3.0.04506.648; .NET CLR 3.5.21022; Zune 2.5; WWTClient2; MS-RTC LM 8; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)

Now, this guy is clearly a developer who has installed beta versions of things, but he's also got InfoPath and a bunch of other stuff. Still, that's a pretty crazy UserAgent and it's being transmitted all the time.

Registry Editor

UserAgents are added for IE in the Registry, as seen in the screenshot above.

Why Should You Care?

In the case of a system with IE and a lot of .NET Framework versions, ASP.NET currently truncates the UserAgent at 256 characters so my own case, the site was only getting part of the story. They might change that truncation number, but ultimately, I think we all want tidy UserAgents, right?

UserAgent length matters. Early versions of FireFox had a UserAgent Limit of 127 characters and used to return null before the bug was fixed last month and now it truncates. The FireFox plugin added when you installed .NET by default only shows the most recent .NET Framework. Do you want that functionality in .NET?

Truncated UserAgents can also mean you might get "Unknown" Back from Request.Browser.Browser. In my case, I was getting an exception from Request.Browser.ClrVersion because the truncated CLR Version was something like ".NET CLR 3.".

There's some people looking at this internally, and there's three groups involved. There's Internet Explorer, involved peripherally, there's the CLR Team and the installer that adds the values, and there's the ASP.NET team who cares because of the server-side sniffing.

Poll/Questions

Vote Now!The questions I have for you are these:

  • Do you use these .NET Framework-specific values? What for? How do they improve your site or make your user experience different?
  • If the .NET Framework-specific values were removed completely what would that mean to you or your business?
  • What if the values were conflated to show just the most recent .NET Framework?
    • Could you get the information you needed using just the value of the latest version?
  • What if the values were conflated to show just the major side-by-side CLR releases?
    • For example, 1.x, 3.5SP1 and 4.0. In that example, 3.5SP1 implies 2.x and 3.0. If you just had 2.0, you'd see 1.x, 2.0, and that'd be it.
    • Could you get the information you needed using just the value of the those major CLR/Framework versions?

Please take a moment and do this micropoll. It's ONE question with ONE vote button. Literally two seconds of your time. You can also add the poll to your blog. Also, leave comments and I'll make sure the right people seem them.

About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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Microsoft IE8 and Google Chrome - Processes are the New Threads

September 9, '08 Comments [52] Posted in Tools
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I happened to install Google Chrome (Alpha) the same day I installed Internet Explorer 8 (Beta). I noticed immediately, as I'm sure many of you have, that both browsers isolate tabs in different processes.

Unix folks have known about the flexibility of forking a process forever. In Unix, fork() is just about the easiest thing you can do. Also, fork()ing in Unix will copy the whole process and all variables into a new space. Everything after the fork happens twice. Multitasking made easy.

In Windows, you call CreateProcess() and you don't get a copy or clone. You just start up a whole new universe, starting from the very beginning - NOT from the call to CreateProcess().

What processes in Windows and Unix do have in common is that they each get their own protected virtual memory space. They are all alone and isolated. If a process crashes it's less of a crisis than if a thread within a process crashes.

(In .NET, AppDomains are like mini-processes, but they just aren't as completely isolated as a process is, so you can still bork an AppDomain enough that the whole process dies.)

Why does all this matter? Well, back in the day, most folks on Windows would recommend that developers interested in multi-tasking use threads. There's even been talk about fibers (really tiny threads within threads...like superstrings ;) ) However, darnnit, processes are easy.

Ah! But they're slow! They're slow to start up, and they are slow to communicate between, right? Well, kind of, not really anymore. There's this thing called Moore's Law that keeps marching on. Making a new process and talking to it in any of the myriad IPC (Inter-process Communication) methods available just isn't that much of a problem these days. Just open up Process Explore and enter "Tree View" sometime to see how many programs you use every day are actually multiple .exe's working together.

You can learn more about IE8 and how their multiple-process model works in both IE7 and IE8. (IE7 had this process isolation feature also...except one tab per security zone.)

You can learn more about Chrome and how they talk between their multiple "Render" processes in this architectural overview. They are using named pipes if you were wondering how Chrome talks to itself.

Tab/Process Isolation

I'll open up an instance of IE8 and open one tab with cnn.com and other with hanselman.com. I'll do the same with Google Chrome. Here's what Process Explorer shows.

Picture of the Process Tree in Process Explorer 

Why are some of the processes brown? Those are jobs, a new kind of process added in Windows 2000. Jobs are made with CreateJobObject and AssignProcessToJobObject. You can also get a Job using CreateProcess as unless you specify the CREATE_BREAKAWAY_FROM_JOB flag. Jobs in Windows can be controlled as a group and resource limits can be set on them. You can learn more about Jobs and why they can be more secure up on MSDN.

Crash Protection

The whole point of having more than one process for a browser is for crash protection. I've had every browser I've ever used crash in one tab while I was hoping to keep my other 49 tabs open.

Let's blow away some processes manually and see what the browsers do. I'll blow away the non-job process for Chrome.exe.

Chrome with a Sad Plugin face

Looks like that process hosted Flash. See how the Flash object has been replaced on the cnn.com home page with a sad puzzle piece? Cool. Chrome hosts plugins in their own process also.

Lets blow away another Chrome.exe process. Ah, looks like that particular process was rendering hanselman.com. It's been replaced by a sad-page icon.

Scott Hanselmans Computer Zen - Google Chrome (2)

OK, let's blow away an IE8 process....

Balloon Help in IE8 telling me that a tab has been recovered

Ah, looks like the FIRST time a page crashes in IE8, it dumps the process, the tab disappears, then the tab comes back automatically to try to put the user where they were before. I'll kill the new process...

Website restore error - Windows Internet Explorer

Looks like IE8b2 will only try a few times to automatically restore the bad tab then it gives up and gives its equivalent sad-tab and says "the website continues to have a problem." Also cool. This beta includes an option to turn "automatic crash recovery" off or on.

If the parent process dies (or, in this case, I kill it myself!) then I'll get a dialog from IE8 offering to restore the last session.

Windows Internet Explorer

I'll get this similar message in Google Chrome.

image

Very cool. Now I have two browsers that I can open up a buttload of tabs in and not worry about maxing-out process limits or having one bad tab messing up the whole bunch.

PS: If you are poking around in Chrome, try visiting pages like: "about:network", "about:stats", "about:dns" and "about:memory"

About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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Firefox, ClickOnce, XBAPs and .NET 3.5 SP1

September 5, '08 Comments [3] Posted in ASP.NET | BabySmash | Musings | Tools | Windows Client | WPF
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One of the things that I noticed immediately when I made the SmallestDotNet was that Firefox was reporting the version of the .NET Framework installed. There's a Firefox extension that is installed with .NET 3.5SP1. I was stoked about this because I'd like users of BabySmash to be able to use ClickOnce from Firefox to launch it.

ClickOnce and Firefox

When you install .NET Framework 3.5SP1, there's a key written to the registry whether Firefox is installed or not. If Firefox is installed later, it will notice the key and use the plugin. If it's already installed, it'll just work. The registry key points to a Firefox Extension (XPI) that acts like the 3rd party FFClickOnce extension that a lot of us installed before.

The registry key is at HKLM:\Software\Mozilla\Firefox\Extensions This Firefox Addin helps ClickOnce applications work from inside of Firefox 2 or Firefox 3. It'll be installed with any installation of .NET 3.5 SP1, including the smaller Client Profile.

The add-in looks like this...

Picture of the Firefox Addins dialog

And its options dialog looks like this:

image

On my system the Firefox UserAgent now looks like this:

Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.0.1) Gecko/2008070208 Firefox/3.0.1 (.NET CLR 3.5.30729)

By default, as you can see in the dialog, the browser will report just the most recent version of the .NET Framework unless you say otherwise.

What happens if the FFClickOnce extension is already installed?

In Firefox 3 the FFClickOnce add on will automatically get disabled as it has not been updated.

In Firefox 2 the FFClickOnce extension does not alter the user agent string due to a safeguard against creating a user agent greater than 128 characters.  What happens when the user clicks on a .application link is dependent on the user’s configuration.

For Firefox 2.0 this is the table of possible prompting/launching configurations.  The default for each add-on is marked in bold. 

.NET Assistant FFClickOnce Result
No Prompt Prompt FFClickOnce prompts and handles the click
No Prompt No Prompt FFClickOnce handles the click
Prompt Prompt

.NET Assistant prompts and handles the click

Prompt No Prompt

FFClickOnce handles the click

When both add-ons are in the default configuration the user will get the FFClickOnce prompt and click once activation will follow the FFClickOnce path which may bypass IE download policy.  In all cases the normal ClickOnce UI will be shown.

What this all means is that ClickOnce will work in FireFox 2 and 3, whether FFClickOnce is installed or not.

How's it done?

The plugin is written with standard XUL (pronounced zoo-el) via XML and JS.

As an aside, I think it's cool that the XML namespace for XUL is:
http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul

You can go find the plugin yourself in:

C:\Windows\Microsoft.NET\Framework\v3.5\Windows Presentation Foundation\DotNetAssistantExtension

It's a .jar file, and you can copy it out and rename it .zip and open it up. The basic gist is that the plugin watches for a particular MIMEType and application, and if it matches, it launches the ClickOnce application using the the .NET Framework's PresentationHost.exe.

isClickOnce: function()
{
var mimeInfo = dialog.mLauncher.MIMEInfo;

// Checking the file extension may be second guessing the webserver
// but when 'prompt' is set the user will still have a save button.
if (mimeInfo.MIMEType == "application/x-ms-application" ||
mimeInfo.primaryExtension == "application")
{
return true;
}

return false;
},


launch_application: function()
{
this.execute(this.getSystem32Dir() + \\PresentationHost.exe,
"-LaunchApplication " + dialog.mLauncher.source.spec);

dialog.mDialog.close();
}

It's not too complex, and it's sure nice that BabySmash users can use ClickOnce to launch the smash.

XBAP

XBAPs, or XAML Browser Applications are also enabled in Firefox in .NET 3.5 using the standard NPAPI browser plugin API. The NPWPF.dll enables XBAPs under Firefox.

Image of the NPWPF.dll that enables XBAPs

XBAPs are WPF applications that run inside the Browser's Chrome. They're good for Intranet applications where you want really easy deployment, the complete .NET Framework (as opposed to Silverlight) and a browser's navigational model.

If you type in about:plugins in Firefox, you can get a list, including this one:

The about:plugins page in Firefox 

Notice the MIME Types that this plugin has registered for and the extensions (suffixes) it handles. Each of these plugins are automatically installed and enabled when you install the .NET Framework 3.5SP1, so you can count on them.

Thanks to Eric Harding, Troy Martez and Jennifer Lee for helping me pull this information together. They're going to be adding more content to the Windows Client website very soon with more details how for developers to package and use the .NET Client Profile. They'll also be releasing lots of documentation and details on ClickOnce and deployment improvements in the framework. I'll point you to everything I can dig up, Dear Reader, as soon as I can.

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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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Family Calendar Management - Sharing Life between Outlook and Web Calendars and the Magic of iCalendar

September 5, '08 Comments [7] Posted in Musings | Tools
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Recently while talking to a friend I said something like "Oh, yes, my wife send me a meeting request for that." My friend was shocked. "How did you get your wife to send you Outlook Invites?" they said.

I was surprised they thought it was a big deal that we might manage our lives and appointments the same way a business runs their meetings. Why manage one's calendar with attention and detail at work, the use a Post-It Note or a Dry Erase board at home? Each to his or her own, to be sure, but ultimately find a system that works for you.

Don't give me the standard "Wow, that's a lot of work to set this up" comments. This took all of 10 minutes to do, I'm just being extra detailed for those who like their instructions along with pictures, clear steps and a little philosophy and history.

Here's what works for us and how we set it up. I talked about it in Podcast 58 on Synchronizing Your Internet Calendars.

Basics in a Nutshell

This is the setup my wife and I have. I sync portions* of my calendar with a web calendar. Each of us can see each other's calendars as she subscribes to that calendar. My Outlook is my work email address, and I also have my personal email. She can send me Meeting Invites to either account. When I accept them, they'll show up in both places.

Diagram showing how my calendars sync

On Calendar Sharing

I'm using Outlook and The Wife is using Google Calendar, so this post uses those two products as an example. That's useful because they are both very common, and the combination is common. Also, it's nice to see Microsoft Products working with non-Microsoft Products using Open Standards.

However, the most important philosophical point to get from this section is that whatever service you are using, make sure you pick one that allows you to have control over your data and how it's published. Data Portability is important. You want to make sure you can get your data in and out of your chosen store. Preferably that'll be using a format like iCalendar (RFC 2445). Just knowing that the standard exists is empowering, because now you know what to look for.

Sharing (Publishing) in Outlook 2007

In Outlook, there's two kinds of Calendar "sharing." There's Sharing and Publishing, in fact. Sharing in Outlook language means to Share your Calendar internally to your company's Exchange Server, while Publishing means to send your Calendar out to the Internet. By default this means to calendars.office.microsoft.com, but it can mean elsewhere.

TIP: I put my Free Busy info at http://www.hanselman.com/freebusy which just redirects to the Office site. This makes it easy for others to schedule meetings with me without giving away personal information or calendar details. I just publish free/busy time.

image

You CAN, if you like, publish your calendar out to the Internet as an ICS file, also called a "webcal" and then have other calendars pull from that. However, I prefer to have more control over what I publish, as I've got work meetings and things I may not want out of my Outlook.

SyncMyCal or Google Calendar Sync

I want to part (or all) of my calendar into my wife's calendar. She uses Google Calendar, and I've got a Google Calendar using my personal email address.

In order to get my appointments into Google Calendar, I prefer to use SyncMyCal software (I paid $25 for it). There is another free tool from Google called Google Calendar Sync but it's VERY basic. I prefer SyncMyCal (enough to pay for it). It's an addin that runs inside of Outlook and it supports multiple calendars, can sync a specific Outlook category (like just Personal events), does date-range-filters, and will sync Contacts if you like.

Public Calendars and Subscribing to Calendars in Outlook

There's lots of sites that have lists of events and calendars. The best of them, like Upcoming.org include webcal/iCal/xCal feeds for all the events. Most personal web-based calendaring systems like Google Calendar (and my wife's calendar) have URLs that you can subscribe to.

image

For example, the Subscribe button on the Upcoming site includes an iCal option. These URLs look like:

webcal://upcoming.yahoo.com/calendar/v2/search_all/?search_placeid=RlEYPWubBZtlFXkb&rt=1

Even though they have webcal:// at the beginning, they are still serving the calendars over HTTP. However, the webcal:// "psuedo-protocol" is a hacky way to get something to happen when you click on it. Because I have Outlook installed, clicking that iCal link gets me this dialog:

Microsoft Office Outlook

Clicking yes adds a new calendar to Outlook in "Other Calendars."

image

This is how I add all sorts of calendars into Outlook. I've got Team Calendars from Sharepoint, Calendars from our Intranet, as well as the wife's.Any calendar can be viewed side-by-side with the main.

Picture of my Outlook Calendar side-by-side with another

Or, I can overlay them. This is really useful for viewing The Wife's calendar and finding time where we can both free. The secondary calendar appears "ghosted" and overlaid over the primary. You can even show multiple (6, 7, etc) calendars and easily find time for meetings amongst your teammates.

Picture of my Outlook Calendar overlaid with another

Consuming Web Calendars from inside Google Calendar

If you've got a calendar "in the cloud" with a URL to an ICS, it's easy to add them to Google Calendar. In Calendar click "Add" under Other Calendars and click "Add By Url":

image

This is where you'd paste in the iCal URL for the calendar you're trying to consume. The wife does this with public calendars. For family there's a faster way. Just click on your calendar and click "share this calendar" and Google takes care of the rest.

IMPORTANT NOTE and CYA DISCLAIMER: It's ironic that while I've been using various plugins for Outlook Calendar synchronization for the last four+ years and never lost a thing, this week while on a trip (and while writing this post) I lost (almost) all my future appointments. Because I'm using SyncMyCal along with three different other experimental plugins, not to mention syncing with Mobile Devices, my gut says it's not SyncMyCal. However, this near-data loss is an important reminder that there's always a chance you can lose something important when you're using any synchronization software that syncs deletes. 

I got my data back by going to another machine I had with Outlook on it, launched Outlook and immediately put it into Offline mode so the deletes from the server wouldn't come down. I exported that range of missing appointments from that machine and imported them to another. The final calendar was then updated in Exchange. Crisis averted, but it was a scary time. If you lose your data, I can't help you. Be careful.

* filtering out private/sensitive/NDA work meetings via categories

About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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Disclaimer: The opinions expressed herein are my own personal opinions and do not represent my employer's view in any way.