Fix: Notification ‘Not enough system resources’ on Foscam NVR

If you try to playback recorded video via a Foscam NVR, you may get the message ‘Not enough system resources’ on screen.

Foscam suggests that this occurs on 4-screen configurations and that you have to double-click one of them to see the respective channel’s recorded video.

https://www.foscam.eu/faq/article/notification-not-enough-system-resources

However, it didn’t work when I tried it (that Foscam NVR hadn’t been recently firmware updated though, so that might have been the cause.

An alternative that did work was to download and use the free Foscam VMS software to do playback. Seems access via web browser can also be enabled on the NVR so that might also be an alternative. All methods of playback (including trying to play from the NVR itself if a screen is already attached) are explained at:

https://www.foscam.com/faqs/view.html?id=78

One can also opt to download videos from the NVR either via a computer, or to a USB storage device connected to the NVR, as shown at:

https://www.foscam.com/Faqs/view/id/79.html

HowTo: make raw_input & input work the same in both Python 2 and 3

Was just trying to make a Python 2 script work in Python 3 and at first it seemed I just needed a small change to add missing parentheses to the argument of a couple of print statements.

But then another issue came up, it wasn’t understanding the command raw_input(somePrompt) that was occuring at various places in that file to input text from the console.

Various solutions were proposed at

https://stackoverflow.com/questions/954834/how-do-i-use-raw-input-in-python-3/62825723

but I think I came up with a cleaner looking solution that works in both Python2 and Python3, that should allow one to use either raw_input or input in both Python2 and Python3 with the semantics of Python2’s raw_input (aka the semantics of Python3’s input).

# raw_input isn't defined in Python3.x, whereas input wasn't behaving 
# like raw_input in Python 2.x. This should make both input and raw_input 
# work in Python 2.x/3.x like the raw_input from Python 2.x 
try: input = raw_input
except NameError: raw_input = input

In practice this came up from ideas at other answers on that SO thread. It tries to define input as raw_input which should fail in Python3.x since raw_input is undefined. In that case it will catch a NameError exception and do the reverse, aka define raw_input as input. However in Python2 the first command should execute fine, overriding the insecure input of Python2.x to work the same as raw_input (not trying to interpret input strings that is). Actually that is what Python 3.x input does.

Wonder why they didn’t declare it like that in the first place though, breaking compilation of Python2 programs. After all semantically only Python2 programs that were using the old insecure input would have an issue, not those that were using raw_input which is the semantics Python3 promotes with its newer input.

Getting resulting SQL string from parametric ADO.net SqlCommand

Microsoft is suggesting to always use Named parameters with SqlCommands for security reasons (to avoid SQL injection exploits), but they haven’t thought of providing a property at SqlCommand to give you back the result SQL so that you can have your app log it without resorting to SQL Server for that logging.

Found a solution at CommandAsSQL project on GitHub and the discussion that brought it to life at https://stackoverflow.com/questions/265192/get-the-generated-sql-statement-from-a-sqlcommand-object/

That solution was only for the case where the type of the SqlCommand was StoredProcedure, but needed to cover non-Stored procedures too (aka type Text of SqlCommand), so I augmented that library with this logic:

    private static void CommandAsSql_Text(this SqlCommand command, 
                                          System.Text.StringBuilder sql)
    {
        string query = command.CommandText;

        foreach (SqlParameter p in command.Parameters)
            query = Regex.Replace(query, 
               "\\B" + p.ParameterName + "\\b", p.ParameterValueForSQL());

        sql.AppendLine(query);
    }

The pull request is at: https://github.com/jphellemons/CommandAsSql/pull/3/commits/527d696dc6055c5bcf858b9700b83dc863f04896

The Regex idea was based on @stambikk’s and EvZ’s comments at that StackOverflow thread and the "Update:" section of https://stackoverflow.com/a/2544661/903783 that mentions "negative look-behind assertion".

The use of \B instead of \b for word boundary detection at the start of the regular expression is because the p.parameterName will always start with a "@" which is not a word character.

Note that ParameterValueForSQL() is an extension method defined at the CommandAsSql library to handle issues like single-quoting string parameter values etc. It may have a bug with its date handling currently though, will submit an issue on that

Btw, other promising piece of code is at https://github.com/jeroenpot/SqlHelper/blob/master/Source/Mirabeau.MsSql.Library/SqlGenerator.cs (mentioned at an answer in this thread). Probably could merge code from CommandAsSql and SqlGenerator if one finds something not working at one or the other.

HowTo: Install Skype desktop on Windows 10 (for older webcams)

On Windows 10, Microsoft (they’ve acquired Skype some years ago) provide a Windows Store app for Skype, however Universal Windows Platform (UWP) apps like that one don’t support older webcams (even the ones embedded in not-that-old laptops).

Unfortunately, Microsoft hasn’t bothered to provide some frame grabber driver to bridge with DirectShow-based etc. older webcams that would allow modern UWP apps to work with such older webcams that do function fine with classic (Win32) applications, provided their classic Windows drivers are installed.

What’s worse though is that although Skype provides a Windows desktop application download at their website (https://www.skype.com/en/get-skype/), when that one is launched on Windows 10 (probably that is the can on Windows 8 too), it just shows a message that one should use the respective Store app and takes one to the respective Windows Store webpage. They haven’t bothered to consider all those users that don’t have a supported webcam on UWP and force them to move to the Skype UWP-based Store app. Note that they could have placed the classic (Win32) Skype application on the Windows Store too (which now supports deployment of such applications via a technology called Desktop Bridge), but I don’t think they’ve considered providing that option to the user either.

So a workarround I had to do on my laptop was to trick their desktop application installer into thinking it was running on Windows 7. To achieve this can right click the .exe file of the installer and select “Properties” (should be the last option at the popup menu shown).

Then, from the “Compatibility” tab select to run in compatibility mode for “Windows 7”. Press OK to close the dialog and just run the installer again, this time it will proceed fine to install the desktop application for Skype which should work with your older webcam, provided you’ve installed the camera drivers at your system. If it still doesn’t work, checkout the webcam diagnostics tool from http://noeld.com/programs.asp?cat=video (and also try webcam with the classic Win32 AMCap application provided there to see if it does show a video feed or not).

Workarround: IE11 changing download file extension to .zip

At ClipFlair Gallery, apart from opening a ClipFlair activity in ClipFlair Studio, downloading of an activity (.clipflair) file is also supported.

However, because the component serialization file format of ClipFlair Studio is XML plus media assets packed in .zip archive (with nesting allowed, where components and whole activities can be placed in other activities), Internet Explorer 11 (and probably other browsers too) was downloading .clipflair files as .zip (changing their file extension).

At first, I thought that occured because I was using MIME type “application/zip” at the IIS web server/site settings for that file extension. So then I tried to change it to “application/octet-stream” hoping that one would be treated as an “opaque” data stream.

However, eventually I ended up setting a custom MIME type “application/clipflair” for the file extension “.clipflair”, because even with “application/octet-stream” (as with the “application/zip” that I had before), IE11 was still saving the .clipflair file as .zip (obviously detecting the zip content in the download stream).

<?xml version=”1.0″?>
<configuration>

<system.webServer>

<directoryBrowse enabled=”true” showFlags=”Size, Extension”/>

<defaultDocument>
<files>
<clear/>
<add value=”index.html”/>
<add value=”Default.aspx”/>
<add value=”Default.html”/>
</files>
</defaultDocument>

<caching>
<profiles>
<add extension=”.log”
policy=”CacheUntilChange”
kernelCachePolicy=”CacheUntilChange”/>
</profiles>
</caching>

<staticContent>
<mimeMap fileExtension=”.log” mimeType=”text/plain”/>
<mimeMap fileExtension=”.clipflair” mimeType=”application/clipflair”/>
<mimeMap fileExtension=”.dzi” mimeType=”text/xml”/>
<mimeMap fileExtension=”.dzc” mimeType=”text/xml”/>
<mimeMap fileExtension=”.cxml” mimeType=”text/xml”/>
</staticContent>

</system.webServer>

<system.web>
<compilation debug=”true” targetFramework=”4.0.3″/>
</system.web>

</configuration>

HowTo: Open page from Internet Explorer (Metro) app into desktop IE

The Windows 8/8.1 app version of Internet Explorer is also known as IE Metro because of the “Metro” codename (inspired by navigation signs in public transport] of the Modern UI design language promoted by Microsoft).

However that version isn’t the full Internet Explorer, in that it is unfortunately not supporting extensibility via plugins in the form of ActiveX controls as the classic (desktop version) of IE. It is only embedding the Flash player engine directly in its codebase, but not Microsoft’s own Rich Internet Application (RIA) rendering engine aka Silverlight, nor Unity or other VRML/X3D, QuickTime/QuickTimeVR etc. plugins.

Browser pages cannot detect the difference between running IE on the desktop or as an app, there is however a workarround for webpage authors or webadmins to force the app version of IE to show a prompt to the user that allows the opening of a page in the desktop version of Internet Explorer. There is also a way for System Administrators to set specific sites to open in the desktop version of IE without the user seeing such prompt.

At https://msdn.microsoft.com/en-us/library/ie/hh968248.aspx, Microsoft mentions:

As a web developer, you can enable the requiresActiveX feature switch either by using this HTTP header:

X-UA-Compatible: requiresActiveX=true

Or by using this meta element on each affected webpage:

<meta http-equiv="X-UA-Compatible" content="requiresActiveX=true"/>

 

I just added the meta tag inside the <head>…</head> block of the Amnesia of Who web version that uses Silverlight and here is how it shows in the IE Metro version (note that Silverlight IS installed in that Windows 8.1 machine, it’s just that it’s not available in that browser, that’s why the Silverlight installation prompt is also shown):

When the user presses the default button “Open on the desktop”, the OS switches to classic desktop mode and shows an Internet Explorer window with the Silverlight application starting fine (or if Silverlight is not installed it will prompt and allow the user to install it – note that Silverlight ActiveX control’s installation doesn’t need administrator permissions since that installation doesn’t affect other users, nor requires any elevated rights in the system to work).

 

I hope that Microsoft, apart from keeping on supporting this workarround, will do a clever move this time and embed Silverlight too (apart from the Flash engine that was in IE Metro) in the Spartan browser that it prepares as the Windows 10 default touch browser. And why not, provide some extensibility method for it, since HTML5 cannot become a huge, impossible to implement beast, that covers every future conceived functionality for the web.

Fix: Hypelinks not clickable in RichTextBox under Silverlight

Just fixed a nasty bug in ClipFlair Studio (http://studio.clipflair.net), where one couldn’t click hyperlinks in the Text component when set at ReadOnly mode. In that mode hyperlinks should open up new web pages (in Edit mode you can edit/remove them only of course), but instead when clicked they would show something like a focus rectangle (which they normally never show).

The situation was hard to debug since it wasn’t obvious what had caused the issue (it was working some time ago). I eventually found out that when the RichTextBox in Silverlight (may occur in WPF and WinRT too, haven’t tried) has a Transparent background, then Hyperlinks in it let MouseLeftButtonDown events pass through, so OnMouseLeftButtonDown will fire at their visual parent (or other visual ancestor) if no component in the visual chain marks the event as handled (such events bubble up towards the top of the visual hierarchy/containment chain).

This shouldn’t be much of a problem, if there wasn’t another issue, where if the ancestor called CaptureMouse in their OnMouseLeftButtonDown overriden method (from Control class), which is usual in mouse dragging code (in my case it was a FloatingWindow [TextWindow] that was the visual ancestor of RichTextBox), the hyperlink fails to fire when clicked and shows that weird solid-line border arround it instead.

The fix was easy once I knew what was happening, I attached a MouseLeftButtonDown event handler to the RichTextBox (if one was subclassing it [assuming it allows to do so] they could also have opted to add an overriden OnMouseLeftButtonDown method) that sets Handled property of the event parameter to true to consume it. The fix is available at CodePlex.

One can verify that the fix works now by downloading a sample ClipFlair Activity from https://www.dropbox.com/s/1zr36190xb0m6vk/Test_Text_URLs.clipflair and opening it in ClipFlair Studio. Can also download and build/run the source code of the previous broken version 1faaa8b35749 and test with that save activity file to see that the URLs didn’t open before when clicked but showed a rectangle arround them intead.

HowTo: Tell IE to use compatibility mode without editing your web pages

at http://www.mono-software.com/Mono/Pages/Discussion/dtopic/_YyUBIlx5kiqHaNqAQeltg/br-brake-bug-in-IE11-and-clipflair-text-editor/

one reads:

We are using Telerik’s rich text editor (RadEditor), and it seems that RadEditor has specific behaviour regarding insertion of break tags.

To circumvent this issue please try to add host header in ISS 7 (website level):

Name = "X-UA-Compatible"
Value = "IE=EmulateIE10"

Or, you can insert Html Meta tag on a PreRender event (of Page that uses RadEditor):

HtmlMeta meta = new HtmlMeta();

meta.Attributes.Add("http-equiv", "X-UA-Compatible");

meta.Attributes.Add("content", "IE=EmulateIE10");

Page.Header.Controls.Add(meta);

 

This is a very handy trick, one can open up a website at IIS console and open HTTP Response Headers node and then add the Name / Value pair X-UA-Compatible / IE=EmulateIE10 to force say Internet Explorer 11 to behave like Internet Explorer 10

To confirm it works, press F12 to show developer tools in IE11 and see at the right that it says “IE10” instead of “Edge” at the HTML engine selection dropdown list (compatibility mode).

 

Gotcha: Silverlight’s Uri class constructor eats up part after last slash

Via trial and error, I recently found out that when creating a Uri combining another Uri and a suffix part (tried at Silverlight, but I guess it’s a .NET issue in general), it eats up the last part of the (first) Uri if it doesn’t end with "/".

That is, if you combine http://test.com/a with b.doc you get http://test.com/b.doc instead of http://test.com/a/b.doc that one might expect having used the Path.Combine of .NET on the local filesystem before (if hope I do remember well how that one behaves). So you have to make sure the first part of the path you combine has / at the end (e.g. http://test.com/a/ in the case above).

Personally I feel this is a bug at Uri class (since it breaks the least surprise principle [for developers with desktop experience at least]), but it may have been made so to follow some W3C suggestions or Javascript standard behaviour or whatever.

Example:

The following code will eat up part after last / (that is Uploads) instead of appending / (as Path would do on Windows).

const string STORAGE_URL = "http://test.com/Uploads"; //error: need "/" at end
Uri fileUri = new Uri(new Uri(STORAGE_URL), fileName + ".wav");

So, one can use instead:

const string STORAGE_URL = "http://test.com/Uploads";
Uri fileUri = new Uri(STORAGE_URL + "/" + fileName + ".wav");

Else fix the STORAGE_URL at the first sample to have "/" at the end (but this can break easily by changing the URL in the future and forgetting to add the trailing / or reading it from some configuration file and having the user enter a URL without a trailing / which can easily occur)