Geeky Bob

I have to admit, I love a good conspiracy theory. But I need to explain what I mean by that - I don't actually believe conspiracy theories, but I love to read articles and blogs from people who do. I typically think that most of the people who believe various conspiracy theories are kind of insane, and therefore they are a never-ending source of amusement for me.

This brings me to one of the biggest conspiracy theories that's circulating the planet right now: Global Warming and Climate Change.

I thoroughly love watching the endless debates that inundate the blogosphere about these two subjects. The bulk of the Internet appears fall into one of two ideological camps: there are "Deniers" who think that nothing is happening, and there are "Chicken Littles" who think that the world is coming to an end. (I personally fall into the group of amused spectators who are constantly laughing at everyone else's reactions. And mark my words people - I am not laughing with you, I am laughing at you.)

With that in mind, let's look at some of the actual science. To begin with, the following new article offers up a dire prediction that the Antarctic ice will melt and the oceans will rise as a result:

• Glaciers Draining Antarctic Basin Destabilized, Big Sea Level Rise All But Certain

This should come as a shock to the NASA scientists who were reporting less than two years ago that the Antarctic ice had reached an all-time high:

• Antarctic Sea Ice Reaches New Maximum Extent

With conflicting articles like these making their way around the Internet, what's a poor armchair scientist supposed to believe? Fear not, for I bring you undisputed truth: ice melts. That's pretty much it. Your scientific takeaway should be this: unless the sun burns out, we're going to have ice in some places of the planet, and no ice in other places. The ice in some places will eventually melt, and some places where there currently is no ice will eventually get ice. If you've studied the history of this planet, then you already know these facts. If you haven't studied the history of the planet, then be quiet until you do. Period. End of story.

That being said, it is an undeniable fact that the earth is getting warmer. Although it needs to be said that the global temperature is rising from one of the lowest temperatures that has occurred in the past several thousand years. 1,000 years ago the earth was considerably warmer than it is now, but 500 years before that it was cooler than it is now, and 500 years before that it was even warmer than it was 1,000 years ago. That's the way that our planet works: the earth heats up, then it cools, then it heats up again. This has been going on for millions upon millions of years. The questions with which we need to be concerned is how fast the temperature is rising, and what is causing the temperature to rise. Here's where I need to intercede once again: unless you are a scientist who is qualified to analyze these two questions based on the staggering volume of information available and years of professional research experience, then you need to be quiet and let someone who is qualified do their job.

As I mentioned earlier, we can easily see that the earth has gone through several demonstrable heating and cooling periods over the past several millennia. But there is one major difference between those periods and the present: we can now take detailed measurements of the process, and unfortunately the scientific world is filled with scientists who cannot agree on the severity of this new data. But what is far worse is that the media world is filled with reporters with nothing better to do than to create ominous predictions in order to drive traffic to their websites and thereby increase their advertising revenue. So we wind up with a situation where people can throw news articles back and forth all day long saying one thing or other without ever proving a valid point. Here's a perfect example:

• Denier Land: How Deniers View Global Warming

As for me, the story gets better, because eventually the conspiracy theorists get involved. There are several theories out there, and they come from all sides. For example, there are some "deniers" who feel that all of this Global Warming stuff is a bunch of malarkey, and their position seemed to be reinforced when it was revealed that a lot of climatologists were faking their data. (It seems that some scientists believed that "The Ends Justify The Means," so they thought that it was acceptable for them to manipulate their data because "The World Will Eventually Thank Them." That may have been a noble cause in their minds, but unfortunately that's bad science.) Then there are the Global Warming proponents who believe that the real impetus behind the deniers is big business and the evil global corporate cabal who would sell their family members if it made a profit. (Unfortunately, there really are some people who are that heinous.) In either case, I love reading the theories from both sides of the argument, because it's not that simple. As a result, their competing theories bring me unending amounts of entertainment.

But at the end of the day, a few categorical facts remain in this debate:

1. The average person is not an actual scientist, and is therefore unqualified to interpret the available data, so he or she is just repeating something they read. As I said earlier, these people need to either go back to school and study the subject in detail, or silence themselves because they're just adding useless noise to the debate. (Although I have pointed out in previous blogs that some people are just parroting whatever their political party of choice is saying, and those people look like idiots.)
2. The actual scientists involved in measuring the data are fractured into opposing groups who think that either the sky is falling or this is a normal process which is nothing out of the ordinary. (And there are a host of other opposing theories, too.) These people are at least qualified to publish their findings in a place where the average person is free to read, (as long as these average people keep their unwelcome and uneducated comments to themselves).
3. The earth is constantly changing as the continents move around, and as a result the global temperatures will be higher or lower than the present, weather zones will shift locations, volcanoes will erupt and spew greenhouse gasses into the atmosphere, tsunamis will devastate coastal regions, the ice caps will shrink and grow, earthquakes will change the landscape, and sea levels will rise and fall.

The only constant in all of this turmoil is change. But unfortunately when change is detected within our current ecosphere and subsequently over-represented by the press, opportunistic knee-jerk reactions from bone-headed idiots are the inevitable result. To quote the great philosopher John Osbourne, "The media sells it, and you live the role."

There is one last thought which I want to leave you with: regardless of your views on Global Warming and Climate Change, we only have one planet - so we only have one chance to get things right. If we destroy the planet, then it's gone. Forever. Period. The Boy Scouts teach that you should leave a place in better condition than you found it. That's a good rule to live by, and it's pretty easy to implement in your daily life through simple actions: recycle as much as you can, turn off lights when you leave a room, pick a car with better gas mileage (or ride a bike when possible), etc. Even if it turned out that humanity had no impact on Global Warming or Climate Change, everyone should still do their part to cut down on pollution and make the world a better place; that's just good stewardship.

UPDATE (October, 2015): The following information is a perfect illustration of why climatology articles cannot be taken out-of-context by their title alone:

• NASA Study: Mass Gains of Antarctic Ice Sheet Greater than Losses

To summarize the article, NASA's monitoring of Antarctica has revealed that snow accumulation exceeds the loss of ice shelves; however, if you walk away with this single talking point without reading the rest of the article, you are ignoring the fact that NASA fully acknowledges that Antarctica is actually losing ice. So even though the frozen regions of Antarctica are increasing in volume, that does not mean that glaciers in Antarctica have ceased melting.

It seems that I have always had a difficult time explaining to people what I do at Microsoft. It's not that I'm unsure about what I do - the details of my job have always been crystal-clear to me and I love what I am doing. It's just that I can't find a way to explain things in a way that doesn't result in blank stares from anyone who isn't a geek. (This problem isn't limited to me, though; my non-technical wife simply responds "I have no idea what he does" when someone asks her what I do for a living.)

Here's a perfect example: when I was a Program Manager on the Internet Information Services (IIS) team, people would often ask me what I did for Microsoft, and I would reply with something like, "I help design and implement the web publishing protocols for Microsoft's web server."

Other Person: [Blank Stare]

I would attempt to remedy the situation by adding, "You know, I design Microsoft's implementation of Internet technologies like the File Transfer Protocol, WebDAV, and the FrontPage Server Extensions."

Other Person: [Blank Stare]

In a sometimes-futile effort to salvage the conversation from complete disaster, I would interject, "You like to use the Internet, right? Well, your computer is on one side of the Internet, and my team helps build the other side of the Internet. That's kind of what I do."

That comment would usually be met with a slight spark of recognition, which was sometimes followed by a half-muttered, "That's nice."

At one time or other during my tenure as a Program Manager on the IIS team I was responsible for a smattering of disparate technologies; things like FTP, WebDAV, FPSE, FastCGI, PHP, URL Rewrite, IIS Express, Log Parser, etc. Most of those technologies garnered little to no interest for the average person, and many of my coworkers found them pretty boring as well. Just the same, I personally found every one of those technologies completely fascinating. (Why else would I spend eight years trying to get just one new command added to FTP?)

A couple of years ago I left the IIS program management team and I joined the writing team which is responsible for documenting Microsoft's ASP.NET framework; and if you have to ask what that means, then you are probably not interested in the answer.

Still, people would ask me what I do for Microsoft, and I would try to explain my job with statements like, "I document the Application Programming Interfaces (or APIs) for Microsoft's ASP.NET."

Other Person: [Blank Stare]

I would try to nudge the conversation along by saying things like, "I help people write web code."

Other Person: [Blank Stare]

Skipping ahead in the conversation, I would usually make a last-ditch attempt by stating, "Let's say you wanted to create a website; if so, you might read something that I wrote in order to help you get started."

Sometimes this remark would illicit a hint of acknowledgment, but usually I just got another blank stare.

This leads me to a few days ago. My wife and I were at dinner, and a waiter asked me what I did for a living. In the back of my mind I started to say something like, "Well, these days I'm documenting a set of APIs that Java programmers will use with Microsoft Azure technologies [blah blah blah]..."

But what actually came out of my mouth was, "I could explain it to you, but I'm pretty sure you wouldn't want me to. Trust me."

I like that answer. I think I'll stick with it in the future. :-)

So here's the deal: I don't use anything from Apple. I have no iPod, no iPhone, no Mac, etc. I buy all of my MP3s through Xbox Music and Amazon. :-] Because of this, I have had no real need to install iTunes or QuickTime in years.

But unfortunately it seemed that I had to install either iTunes or QuickTime at one time or other, mainly because some of my digital cameras recorded video in QuickTime *.MOV format. But over the years I learned to detest both iTunes and QuickTime because of the undesirable ways in which they modified my system; both iTunes and QuickTime would remap all of media settings to open in their @#$% player, which I didn't really want in the first place.

Now that Windows supports the *.MOV format natively, and I can easily convert *.MOV files into something infinitely more useful and universal like *.MP4 format, I really never see the need for installing either iTunes or QuickTime.

However, just the other day I installed a new video editor (which shall remain nameless) and it quietly installed QuickTime on my system. I presume that this was to make it easier to import files in *.MOV format into the video editor, but I was pretty upset when I discovered that QuickTime had been installed. What's more, I was angry when I discovered that QuickTime had once again messed up all of my media settings.

In all of this misery is one saving grace: QuickTime has the decency to preserve your original settings. I am assuming that the backups are for when you uninstall QuickTime and attempt to reclaim your system from being hijacked by Apple, but just the same - that little nicety allowed me to fix my system with a little bit of scripting.

So without further introduction - first the script, and then the explanation:

Const HKEY_CLASSES_ROOT = &H80000000
Const strQuickTimeBAK = "QuickTime.bak"

Set objRegistry = GetObject("winmgmts:" & _
  "{impersonationLevel=impersonate}" & _
  "!\\.\root\default:StdRegProv")
 
objRegistry.EnumKey HKEY_CLASSES_ROOT, "", arrSubKeys

For Each objSubkey in arrSubKeys
  If Len(objSubkey)>2 Then
    If Left(objSubkey,1)="." Then
      objRegistry.EnumValues HKEY_CLASSES_ROOT, _
        objSubkey, arrEntryNames, arrValueTypes
      If IsArray(arrEntryNames) Then
        For i = 0 To UBound(arrEntryNames)
          If StrComp(arrEntryNames(i), strQuickTimeBAK, vbTextCompare)=0 Then
            intReturnValue = objRegistry.GetStringValue( _
              HKEY_CLASSES_ROOT, objSubkey, strQuickTimeBAK, strEntryValue)
            If intReturnValue = 0 Then
              intReturnValue = objRegistry.SetStringValue( _
                HKEY_CLASSES_ROOT, objSubkey, "", strEntryValue)
            End If
          End If
        Next
      End If
    End If
  End If
Next

Here's what this script does: first the script enumerates all of the keys under HKEY_CLASSES_ROOT and looks for file extension mappings, then it looks for mappings which have been modified and backed up by QuickTime. When it locates file extensions which have been modified, it copies the value which was backed up into the default location where it belongs.

All-in-all, it's a pretty straight-forward script, but it sucks that I had to write it.

Shortly after I published my FTP ETW Tracing and IIS 8 blog post, I was using the batch file from that blog to troubleshoot an issue that I was having with a custom FTP provider. One of the columns which I display in my results is Clock-Time, which is obviously a sequential timestamp that is used to indicate the time and order in which the events occurred.

(Click the following image to view it full-size.)

At first glance the Clock-Time values might appear to be a range of useless numbers, but I use Clock-Time values quite often when I import the data from my ETW traces into something like Excel and I need to sort the data by the various columns.

That being said, apart from keeping the trace events in order, Clock-Time isn't a very user-friendly value. However, LogParser has some great built-in functions for crunching date/time values, so I decided to update the script to take advantage of some LogParser coolness and reformat the Clock-Time value into a human-readable Date/Time value.

My first order of business was to figure out how to decode the Clock-Time value; since Clock-Time increases for each event, it is obviously an offset from some constant, and after a bit of searching I found that the Clock-Time value is the offset in 100-nanosecond intervals since midnight on January 1, 1601. (Windows uses that value in a lot of places, not just ETW.) Once I had that information, it was pretty easy to come up with a LogParser formula to convert the Clock-Time value into the local time for my system, which is much easier to read.

With that in mind, here is the modified batch file:

@echo off

rem ======================================================================

rem Clean up old log files
for %%a in (ETL CSV) do if exist "%~n0.%%a" del "%~n0.%%a"

echo Starting the ETW session for full FTP tracing...
LogMan.exe start "%~n0" -p "IIS: Ftp Server" 255 5 -ets
echo.
echo Now reproduce your problem.
echo.
echo After you have reproduced your issue, hit any key to close the FTP
echo tracing session. Your trace events will be displayed automatically.
echo.
pause>nul

rem ======================================================================

echo.
echo Closing the ETW session for full FTP tracing...
LogMan.exe stop "%~n0" -ets

rem ======================================================================

echo.
echo Parsing the results - this may take a long time depending on the size of the trace...
if exist "%~n0.etl" (
   TraceRpt.exe "%~n0.etl" -o "%~n0.csv" -of CSV
   LogParser.exe "SELECT [Clock-Time], TO_LOCALTIME(ADD(TO_TIMESTAMP('1601-01-01 00:00:00', 'yyyy-MM-dd hh:mm:ss'), TO_TIMESTAMP(DIV([Clock-Time],10000000)))) AS [Date/Time], [Event Name], Type, [User Data] FROM '%~n0.csv'" -i:csv -e 2 -o:DATAGRID -rtp 20
)

When you run this new batch file, it will display an additional "Date/Time" column with a more-informative value in local time for the sever where you captured the trace.

(Click the following image to view it full-size.)

The new Date/Time column is considerably more practical, so I'll probably keep it in the batch file that I use when I am troubleshooting. You will also notice that I kept the original Clock-Time column; I chose to do so because I will undoubtedly continue to use that column for sorting when I import the data into something else, but you can safely remove that column if you would prefer to use only the new Date/Time value.

That wraps it up for today's post. :-)

Note: This blog was originally posted at http://blogs.msdn.com/robert_mcmurray/

In the past I have written a couple of blogs about using the FTP service's Event Tracing for Windows (ETW) features to troubleshoot issues; see FTP and ETW Tracing and Troubleshooting Custom FTP Providers with ETW for details. Those blog posts contain batch files which use the built-in Windows LogMan utility to capture an ETW trace, and they use downloadable LogParser utility to parse the results into human-readable form. I use the batch files from those blogs quite often, and I tend to use them a lot when I am developing custom FTP providers which add new functionality to my FTP servers.

Unfortunately, sometime around the release of Windows 8 and Windows Server 2012 I discovered that the ETW format had changed, and the current version of LogParser (version 2.2) cannot read the new ETW files. When you try to use the batch files from my blog with IIS 8, you see the following errors:

Verifying that LogParser.exe is in the path...
Done.

Starting the ETW session for full FTP tracing...
The command completed successfully.

Now reproduce your problem.

After you have reproduced your issue, hit any key to close the FTP tracing session. Your trace events will be displayed automatically.

Closing the ETW session for full FTP tracing...
The command completed successfully.

Parsing the results - this may take a long time depending on the size of the trace...
Task aborted.
Cannot open <from-entity>: Trace file "C:\temp\ftp.etl" has been created on a OS version (6.3) that is not compatible with the current OS version

Statistics:
-----------
Elements processed: 0
Elements output: 0
Execution time: 0.06 seconds

I meant to research a workaround at the time, but one thing led to another and I simply forgot about doing so. But I needed to use ETW the other day when I was developing something, so that seemed like a good time to quit slacking and come up with an answer. :-)

With that in mind, I came up with a very easy workaround, which I will present here. Once again, this batch file has a requirement on LogParser being installed on your system, but for the sake of brevity I have removed the lines from this version of the batch file which check for LogParser. (You can copy those lines from my previous blog posts if you want that functionality restored.)

Here's the way that this workaround is implemented: instead of creating an ETW log and then parsing it directly with LogParser, this new batch file invokes the built-in Windows TraceRpt command to parse the ETW file and save the results as a CSV file, which is then read by LogParser to view the results in a datagrid like the batch files in my previous blogs:

@echo off

rem ======================================================================

rem Clean up old log files
for %%a in (ETL CSV) do if exist "%~n0.%%a" del "%~n0.%%a"

echo Starting the ETW session for full FTP tracing...
LogMan.exe start "%~n0" -p "IIS: Ftp Server" 255 5 -ets
echo.
echo Now reproduce your problem.
echo.
echo After you have reproduced your issue, hit any key to close the FTP
echo tracing session. Your trace events will be displayed automatically.
echo.
pause>nul

rem ======================================================================

echo.
echo Closing the ETW session for full FTP tracing...
LogMan.exe stop "%~n0" -ets

rem ======================================================================

echo.
echo Parsing the results - this may take a long time depending on the size of the trace...
if exist "%~n0.etl" (
   TraceRpt.exe "%~n0.etl" -o "%~n0.csv" -of CSV
   LogParser.exe "SELECT [Clock-Time], [Event Name], Type, [User Data] FROM '%~n0.csv'" -i:csv -e 2 -o:DATAGRID -rtp 20
)

Here's another great thing about this new batch file - it will also work down-level on Windows 7 and Windows Server 2008; so if you have been using my previous batch files with IIS 7 - you can simply replace your old batch file with this new version. You will see a few differences between the results from my old batch files and this new version, namely that I included a couple of extra columns that I like to use for troubleshooting.

(Click the following image to view it full-size.)

There is one last thing which I would like to mention in closing: I realize that it would be much easier on everyone if Microsoft simply released a new version of LogParser which works with the new ETW format, but unfortunately there are no plans at the moment to release a new version of LogParser. And trust me - I'm just as depressed about that fact as anyone else. :-(

Note: This blog was originally posted at http://blogs.msdn.com/robert_mcmurray/

I keep seeing people repost this annoying little image to their Facebook pages with a question that asks "How many squares do you see?":

First of all, I find these kinds of brain teasers annoying, and the fact that this image shows up every few months or so is only adding to my pre-existing dislike for this particular distraction. What's more annoying, however, is watching the debate that inevitably unfolds with regard to how many squares are displayed.

With that in mind, I will ruin this for future generations by stating that it contains 40 squares, and I created the following animation which shows where that number comes from:

With that in mind, please make the madness stop and just say "no" to posting useless brain teasers.

Like most people these days, I tend to swap a lot of removable storage devices between my ever-growing assortment of computing devices. The trouble is, I also have an ever-growing collection of removable storage devices, so it gets difficult keeping track of which device is which when I view them in Windows Explorer. The default images are pretty generic, and even though I try to use meaningful names, most of the drives look the same:

By using a simple and under-used Windows feature, I have been personalizing my drives so that they have meaningful icons in Windows Explorer that will be displayed when I plug them into any of my computing devices:

Here's how this works - you just need to store two files in the root folder of each removable drive, both of which will be discussed in more detail later:

• autorun.inf - which defines the icon to use
• icon.ico - which is the icon/image to use for the drive

Creating the Autorun.inf File

The autorun.inf file defines the icon that will be used in Windows Explorer, and its syntax very simple:

[autorun]
icon=icon.ico

Paste the above code into Windows Notepad and save it as autorun.inf in the root folder of your removable drive.

Creating the Icon.ico File

This part is a little trickier because you have to find an image and convert it to an icon. I find all of my images by using http://images.bing.com/ to search for a particular removable drive - see http://tinyurl.com/mztbald for an example. What I am looking for is a specific image for the removable drive that I am using, and if I can't find a specific image then I will look for a generic image that works. The following image illustrates that idea:

Once I have an image, I need to convert it to an Icon file. To do my conversions, I use AveIconifier 2.1 by Andreas Verhoeven, which you can download through the Internet Archive at the following URL:

http://web.archive.org/web/20060613232414/http://mpj.tomaatnet.nl/Aveicon.zip

When you open the application, it will prompt you to drag and drop a PNG file into it.

If you were only able to find a JPG or GIF file, don't worry - you can open the image in Windows Paint and click File -> Save As -> PNG Picture to save it as a PNG image:

Once you drag a PNG image into AveIconifier, you can drag out the ICO file that you will need to rename to Icon.ico and save that the root folder of your removable drive.

Click the following image to see what a completed icon that was created with AveIconifier to show looks like.

Hiding the Autorun.inf and Icon.ico Files

One last thing that I do is optional, which is to hide and protect the autorun.inf and icon.ico files. To do so, open a command prompt and change directory to the root of your removable drive, then enter the following commans:

• attrib +r +h +s autorun.inf
• attrib +r +h +s icon.ico

These two commands will make the files as read-only, hidden, system files, which should normally prevent you from seeing them when you open your drive in Windows Explorer, and it should prevent them from being accidentally deleted.

Viewing the Changes

After you have saved both the autorun.inf and icon.ico files to the root of your removable drive, you will need to eject the drive and re-attach it to your system in order to see the effects. But as you can see in my earlier illustration, personalization of the drives makes them much easier to identify.

Note: This blog was originally posted at http://blogs.msdn.com/robert_mcmurray/

I received an email yesterday from the RFC Editor that a new Request for Comments (RFC) document has just been published, RFC 7151, which adds support for a new "HOST" command to FTP. This new command allows hosting multiple FTP sites on a single IP address, much like what Host Headers provide for HTTP.

Here's the URL to the new RFC on the RFC Editor website:

File Transfer Protocol HOST Command for Virtual Hosts
http://www.ietf.org/rfc/rfc7151.txt

Or you can see the HTML-based version at the following URL:

http://tools.ietf.org/html/rfc7151

One minor point which I would like to clarify is that this adds a new command for FTP to specify which virtual host to connect to. I periodically hear people referring to this as "FTP Host Headers", but that is technically incorrect since FTP does not have request headers like HTTP. Here's a simple example of what the communications flow looks like when the HOST command is used:

I need to make sure that I thank my co-author for this RFC, Paul Hethmon, who has authored other FTP-related RFCs over the years. For example, Paul wrote RFC 3659, and he co-wrote RFC 2389 with Robert Elz. As a result, the Internet community has Paul and Robert to thank for several great FTP command extensions in the past. (e.g. FEAT, OPTS, MDTM, SIZE, REST, MLST, MLSD, etc.) Paul and I co-wrote RFC 7151 over the past several years, and it was great working with him.

Support for the HOST command has been built-in to Microsoft's FTP service since IIS 7.0, but now that the RFC has been officially published I hope that this feature will be adopted by other FTP servers and clients. That being said, IIS is not the only implementation of the FTP HOST command; at the time of this blog post, these are the server and client implementations that I am aware of which already provide support for this new command. (Note: there may be more than I have listed here; these are just the implementations that I currently know about.)

• FTP Servers:
  • FTP Daemon (see http://www.pro-bono-publico.de/projects/ftpd.html)
  • Ipswitch (in the WS_FTP service; see http://www.ipswitchft.com/)
  • Microsoft (in the IIS FTP service; see http://www.iis.net/)
  • RhinoSoft (in the Serv-U File server; see http://www.serv-u.com/)
• FTP Clients:
  • Microsoft (in the Visual Studio 2010/2012/2013 and Expression Web 4 products)
  • Rebex (in the Rebex FTP/SSL for .NET library; see http://www.rebex.net/)
  • RhinoSoft (in the FTP Voyager client; see http://www.rhinosoft.com/)
  • Scooter Software (in the Beyond Compare client; see http://scootersoftware.com/)
  • SmartFTP (in the SmartFTP client; see http://smartftp.com/)

In addition to the clients listed above, if you have been reading my series on FTP clients over the past few years, I have posted details on how to use the FTP HOST command with some other FTP clients which do not provide built-in support. For example, the Core FTP Client allows you to specific pre-login commands as part of an FTP site's connection properties, so you can manually type in the HOST command and save it along the site's settings.

A Little Bit of History

When I joined the feature team which was creating the FTP service for Windows Server 2008, one of the things that bothered us was that there was no way at the protocol level to host multiple FTP sites on the same IP address. There were several ways that FTP server implementations were approximating that sort of functionality, for example the User Isolation features that we ship with FTP for IIS, but each FTP server seemed to be implementing its own workaround and there was no standardization.

Because of this limitation, our team received a lot of requests to add "FTP Host Headers," although as I explained earlier FTP has no concept of request headers. To help address some of the questions which I was often seeing, I explained the lack of hostname support for FTP in detail in the comments section of my FTP User Isolation with Multiple User Accounts blog that I posted back in 2006, which was shortly before we began work on implementing the HOST command. I will paraphrase some of my comments here:

While I realize that the ability host multiple FTP sites on the same IP address and port like HTTP is a desired configuration, the simple answer is that FTP does not currently support this at the protocol level. To put things in perspective, RFC 959 is the governing document for FTP, and that was published in October of 1985. FTP was simply not designed for the Internet as we use and understand it today, even though it is a generally reliable protocol that many people will continue to use for some time. HTTP/1.1 was designed much later and resolved this problem, but only for HTTP requests.

There are three ways that you can create unique bindings for a web or HTTP site: IP address, port, or host header. FTP can create unique bindings by IP address or port, but the FTP protocol does not currently provide support for hostnames.

Here's why: HTTP packets consist of a set of request headers and possibly a block of data. Here's an example of a simple GET request:

GET /default.aspx HTTP/1.0 [CrLf]
Accept: */* [CrLf]
[CrLf]

When HTTP 1.1 was published in RFC 2068 and RFC 2616, it defined a header for specifying a "host" name in a separate name/value pair:

GET /default.aspx HTTP/1.1 [CrLf]
Host: example.com [CrLf]
Accept: */* [CrLf]
[CrLf]

The "Host" header allows multiple HTTP virtual servers ("hosts") on the same IP address and port that are differentiated by host name. While this works great for the HTTP protocol, FTP currently has no comparable functionality. As such, the FTP protocol would have to be updated to allow multiple hosts on the same IP address and port, then FTP servers and clients would need to be updated to accommodate the changes to FTP.

While my explanation may have clarified root cause of the FTP limitation for anyone who was asking about it, I personally thought the situation was unacceptable. This inspired me to research the addition of a new command for FTP which would allow FTP clients to specify hostnames. As I was researching how to propose a new RFC document to the IETF, I discovered that Paul Hethmon had been researching the same problem a few years earlier. I contacted Paul and offered to combine our work, and he agreed. After several years of work and a great deal of supportive assistance from dozens of great people whom I met through the IETF, RFC 7151 has finally been published.

There are a lot of people besides Paul whom I should thank, and we mention them in the acknowledgments section of our RFC, which you can read at the following URL:

http://tools.ietf.org/html/rfc7151#appendix-B

One final note - two of my coworkers, Jaroslav Dunajsky and Wade Hilmo, are mentioned in the acknowledgments section of the RFC. Jaroslav is the developer who implemented the FTP HOST command for IIS, and Wade is a senior developer on the IIS team who graciously allowed me to bounce ideas off him while I was doing my research over the past few years. (I probably I owe him a lunch or two.)

Note: This blog was originally posted at http://blogs.msdn.com/robert_mcmurray/

For this next installment in my series about FTP clients, I want to take a look at WinSCP, which is an open source FTP/SFTP client that is available from the following URL:

http://www.winscp.net/

For this blog post I used WinSCP 5.5.1, and it was available for free when I wrote this blog post. That being said, WinSCP's author (Martin Prikryl) takes donations. (And I think that it's a worthy cause; I like to support independent development work.)

WinSCP 5.5 Overview

When you open WinSCP 5.5, you will first see the Login dialog box, which will be empty until you add some sites to the list. The Login dialog allows you to create folders so you can categorize your sites, and the user interface is comparable to what you would expect in a Site Manager for other FTP clients.

Fig. 1 - The opening Login dialog in WinSCP 5.5.

When you are adding FTP sites, you have three choices for the protocol: FTP, SCP, and SFTP; you also have four choices for encryption: No encryption, TLS/SSL Implicit encryption, TLS Explicit encryption, and SSL Explicit encryption. (I'll discuss those later.)

When you open a site for which you did not save the password, (which I highly recommend), you will be prompted for your password.

Fig. 2 - The WinSCP 5.5 Password dialog.

Once your FTP site is opened, the main application window is displayed, and it resembles a two-column file explorer interface with local and remote folders, which you might expect from a GUI-based FTP client. (Note: WinSCP refers to this as it's "Commander" interface.)

Fig. 3 - Local and Remote Folders.

That being said, if you change your application preferences, you can change the user interface so that it uses a single-column file explorer interface with a folder tree, which might be useful if you would rather use the FTP client as a drag-and-drop repository. (Note: WinSCP refers to this as it's "Explorer" interface.)

Fig. 4 - Remote Folder Tree and Files.

WinSCP 5.5 has support for automation through .NET and COM, and documentation about automating WinSCP 5.5 programmatically is available on the WinSCP website at the following URL:

WinSCP .NET Assembly and COM Library

There are several detailed automation examples on the WinSCP website that are written in C#, VB.NET, PowerShell, JavaScript, VBScript, etc., and the documentation is quite good. If you need to do a lot of FTP scripting and you are looking for a good way to automate your FTP sessions, you might want to consider this FTP client.

If you don't want to write a bunch of code, you can also automate WinSCP from a command line, and the documentation about that is available on the WinSCP website at the following URL:

WinSCP Command-line Options

Another great feature about WinSCP is that it can be downloaded as portable executables, which makes it easy to copy between systems. This is a great feature for me since I like to keep a collection of handy utilities in my SkyDrive/OneDrive folders.

Using WinSCP 5.5 with FTP over SSL (FTPS)

WinSCP 5.5 has built-in support for FTP over SSL (FTPS), and it supports both Explicit and Implicit FTPS. To specify which type of encryption to use for FTPS, you need to choose the appropriate option from the Encryption drop-down menu for an FTP site.

Fig. 5 - Specifying the FTPS encryption.

Once you have established an FTPS connection through WinSCP 5.5, the user experience is the same as it is for a standard FTP connection. That being said, I could not find a way to drop out of FTPS once a connection is established, so FTPS is an all or nothing option for your sessions.

Using Using WinSCP 5.5 with True FTP Hosts

True FTP hosts are not supported natively, and even though WinSCP 5.5 allows you to send post-login commands after an FTP site has been opened, I could not find a way to send a custom command before sending user credentials, so true FTP hosts cannot be used.

Using Using WinSCP 5.5 with Virtual FTP Hosts

WinSCP 5.5's login settings allow you to specify the virtual host name as part of the user credentials by using syntax like "ftp.example.com|username" or "ftp.example.com\username", so you can use virtual FTP hosts with WinSCP 5.5.

Fig. 6 - Specifying an FTP virtual host.

Scorecard for WinSCP 5.5

This concludes my quick look at a few of the FTP features that are available with WinSCP 5.5, and here are the scorecard results:

That wraps things up for today's blog. Your key take-aways should be: WinSCP 5.5 is good FTP client with a lot of options, and it has a very powerful automation story. As I mentioned earlier, if you have to do a lot of FTP automation, you should really take a look at this FTP client.

Note: This blog was originally posted at http://blogs.msdn.com/robert_mcmurray/

In December of 2012 I wrote a blog titled "Using Classic ASP and URL Rewrite for Dynamic SEO Functionality", in which I described how to use Classic ASP and URL Rewrite to dynamically-generate Robots.txt and Sitemap.xml or Sitemap.txt files. I received a bunch of requests for additional information, so I wrote a follow-up blog this past November titled "Revisiting My Classic ASP and URL Rewrite for Dynamic SEO Functionality Examples" which illustrated how to limit the output for the Robots.asp and Sitemap.asp files to specific sections of your website.

That being said, I continue to receive requests for additional ways to stretch those samples, so I thought that I would write at least a couple of blogs on the subject. With that in mind, for today I wanted to show how you can add additional content types to the samples.

Overview

Here is a common question that I have been asked by several people:

"The example only works with *.html files; how do I include my other files?"

That's a great question, and additional content types are really easy to implement, and the majority of the code from my original blog will remain unchanged. Here's the file by file breakdown for the changes that need made:

If you are already using the files from my original blog, no changes need to be made to your Robots.asp file or the URL Rewrite rules in your Web.config file because the updates in this blog will only impact the output from the Sitemap.asp file.

Updating the Sitemap.asp File

My original sample contained a line of code which read "If StrComp(strExt,"html",vbTextCompare)=0 Then" and this line was used to restrict the sitemap output to static *.html files. For this new sample I need to make two changes:

1. I am adding a string constant which contains a list of file extensions from several content types to use for the output.
2. I replace the line of code which performs the comparison.

Note: I define the constant near the beginning of the file so it's easier for other people to find; I would normally define that constant elsewhere in the code.

<%
    Option Explicit
    On Error Resume Next
    
    Const strContentTypes = "htm|html|asp|aspx|txt"
    
    Response.Clear
    Response.Buffer = True
    Response.AddHeader "Connection", "Keep-Alive"
    Response.CacheControl = "public"
    
    Dim strFolderArray, lngFolderArray
    Dim strUrlRoot, strPhysicalRoot, strFormat
    Dim strUrlRelative, strExt

    Dim objFSO, objFolder, objFile

    strPhysicalRoot = Server.MapPath("/")
    Set objFSO = Server.CreateObject("Scripting.Filesystemobject")
    
    strUrlRoot = "http://" & Request.ServerVariables("HTTP_HOST")
    
    ' Check for XML or TXT format.
    If UCase(Trim(Request("format")))="XML" Then
        strFormat = "XML"
        Response.ContentType = "text/xml"
    Else
        strFormat = "TXT"
        Response.ContentType = "text/plain"
    End If

    ' Add the UTF-8 Byte Order Mark.
    Response.Write Chr(CByte("&hEF"))
    Response.Write Chr(CByte("&hBB"))
    Response.Write Chr(CByte("&hBF"))
    
    If strFormat = "XML" Then
        Response.Write "<?xml version=""1.0"" encoding=""UTF-8""?>" & vbCrLf
        Response.Write "<urlset xmlns=""http://www.sitemaps.org/schemas/sitemap/0.9"">" & vbCrLf
    End if
    
    ' Always output the root of the website.
    Call WriteUrl(strUrlRoot,Now,"weekly",strFormat)

    ' --------------------------------------------------
    ' This following section contains the logic to parse
    ' the directory tree and return URLs based on the
    ' files that it locates.
    ' -------------------------------------------------- 
    strFolderArray = GetFolderTree(strPhysicalRoot)

    For lngFolderArray = 1 to UBound(strFolderArray)
        strUrlRelative = Replace(Mid(strFolderArray(lngFolderArray),Len(strPhysicalRoot)+1),"\","/")
        Set objFolder = objFSO.GetFolder(Server.MapPath("." & strUrlRelative))
        For Each objFile in objFolder.Files
            strExt = objFSO.GetExtensionName(objFile.Name)
            If InStr(1,strContentTypes,strExt,vbTextCompare) Then
                If StrComp(Left(objFile.Name,6),"google",vbTextCompare)<>0 Then
                    Call WriteUrl(strUrlRoot & strUrlRelative & "/" & objFile.Name, objFile.DateLastModified, "weekly", strFormat)
                End If
            End If
        Next
    Next

    ' --------------------------------------------------
    ' End of file system loop.
    ' -------------------------------------------------- 
    If strFormat = "XML" Then
        Response.Write "</urlset>"
    End If
    
    Response.End

    ' ======================================================================
    '
    ' Outputs a sitemap URL to the client in XML or TXT format.
    ' 
    ' tmpStrFreq = always|hourly|daily|weekly|monthly|yearly|never 
    ' tmpStrFormat = TXT|XML
    '
    ' ======================================================================

    Sub WriteUrl(tmpStrUrl,tmpLastModified,tmpStrFreq,tmpStrFormat)
        On Error Resume Next
        Dim tmpDate : tmpDate = CDate(tmpLastModified)
        ' Check if the request is for XML or TXT and return the appropriate syntax.
        If tmpStrFormat = "XML" Then
            Response.Write " <url>" & vbCrLf
            Response.Write " <loc>" & Server.HtmlEncode(tmpStrUrl) & "</loc>" & vbCrLf
            Response.Write " <lastmod>" & Year(tmpLastModified) & "-" & Right("0" & Month(tmpLastModified),2) & "-" & Right("0" & Day(tmpLastModified),2) & "</lastmod>" & vbCrLf
            Response.Write " <changefreq>" & tmpStrFreq & "</changefreq>" & vbCrLf
            Response.Write " </url>" & vbCrLf
        Else
            Response.Write tmpStrUrl & vbCrLf
        End If
    End Sub

    ' ======================================================================
    '
    ' Returns a string array of folders under a root path
    '
    ' ======================================================================

    Function GetFolderTree(strBaseFolder)
        Dim tmpFolderCount,tmpBaseCount
        Dim tmpFolders()
        Dim tmpFSO,tmpFolder,tmpSubFolder
        ' Define the initial values for the folder counters.
        tmpFolderCount = 1
        tmpBaseCount = 0
        ' Dimension an array to hold the folder names.
        ReDim tmpFolders(1)
        ' Store the root folder in the array.
        tmpFolders(tmpFolderCount) = strBaseFolder
        ' Create file system object.
        Set tmpFSO = Server.CreateObject("Scripting.Filesystemobject")
        ' Loop while we still have folders to process.
        While tmpFolderCount <> tmpBaseCount
            ' Set up a folder object to a base folder.
            Set tmpFolder = tmpFSO.GetFolder(tmpFolders(tmpBaseCount+1))
              ' Loop through the collection of subfolders for the base folder.
            For Each tmpSubFolder In tmpFolder.SubFolders
                ' Increment the folder count.
                tmpFolderCount = tmpFolderCount + 1
                ' Increase the array size
                ReDim Preserve tmpFolders(tmpFolderCount)
                ' Store the folder name in the array.
                tmpFolders(tmpFolderCount) = tmpSubFolder.Path
            Next
            ' Increment the base folder counter.
            tmpBaseCount = tmpBaseCount + 1
        Wend
        GetFolderTree = tmpFolders
    End Function
%>

That's it. Pretty easy, eh?

I have also received several requests about creating a sitemap which contains URLs with query strings, but I'll cover that scenario in a later blog.

Note: This blog was originally posted at http://blogs.msdn.com/robert_mcmurray/