Develop Reference

How to get ExpandEnvironmentVariables to return custom variables?

I have added a custom environment variable and I'm unable to get it to return in the ExpandEnvironmentVariables.
These 2 calls work fine:
string s = Environment.GetEnvironmentVariable("TEST", EnvironmentVariableTarget.Machine);
// s = "D:\Temp2"
string path = Environment.ExpandEnvironmentVariables(#"%windir%\Temp1");
// path = "C:\Windows\Temp1"
However, this call returns the same input string:
var path = Environment.ExpandEnvironmentVariables(#"%TEST%\Temp1");
// path = "%TEST%\\Temp1"
I expect to get D:\Temp2\Temp1
What am I missing to correctly get the custom EnvironmentVariable in this last call?

Hans and Evk were correct in their comments. Since no one wanted to add an answer I'll close this question out.
For whatever reason ExpandEnvironmentVariables will not get any keys which were added after an application started. I also tested this with a running Windows Service. It was only after I restarted the service that new keys were found and populated.
This behavior is not documented in the Microsoft Documentation.

Fetch TLD from URI via C# [duplicate]

I am using C# and ASP.NET for this.
We receive a lot of "strange" requests on our IIS 6.0 servers and I want to log and catalog these by domain.
Eg. we get some strange requests like these:
http://www.poker.winner4ever.example.com/
http://www.hotgirls.example.com/
http://santaclaus.example.com/
http://m.example.com/
http://wap.example.com/
http://iphone.example.com/
the latter three are kinda obvious, but I would like to sort them all into one as "example.com" IS hosted on our servers. The rest isn't, sorry :-)
So I am looking for some good ideas for how to retrieve example.com from the above. Secondly I would like to match the m., wap., iphone etc into a group, but that's probably just a quick lookup in a list of mobile shortcuts.I could handcode this list for a start.
But is regexp the answer here or is pure string manipulation the easiest way? I was thinking of "splitting" the URL string by "." and the look for item[0] and item[1]...
Any ideas?

You can use the following nuget Nager.PublicSuffix package. It uses the same data source that browser vendors use.
nuget
PM> Install-Package Nager.PublicSuffix
Example
var domainParser = new DomainParser(new WebTldRuleProvider());
var domainInfo = domainParser.Parse("sub.test.co.uk");
//domainInfo.Domain = "test";
//domainInfo.Hostname = "sub.test.co.uk";
//domainInfo.RegistrableDomain = "test.co.uk";
//domainInfo.SubDomain = "sub";
//domainInfo.TLD = "co.uk";

The following code uses the Uri class to obtain the host name, and then obtains the second level host (examplecompany.com) from Uri.Host by splitting the host name on periods.
var uri = new Uri("http://www.poker.winner4ever.examplecompany.com/");
var splitHostName = uri.Host.Split('.');
if (splitHostName.Length >= 2)
{
var secondLevelHostName = splitHostName[splitHostName.Length - 2] + "." +
splitHostName[splitHostName.Length - 1];
}

There may be some examples where this returns something other than what is desired, but country codes are the only ones that are 2 characters, and they may or may not have a short second level (2 or 3 characters) typically used. Therefore, this will give you what you want in most cases:
string GetRootDomain(string host)
{
string[] domains = host.Split('.');
if (domains.Length >= 3)
{
int c = domains.Length;
// handle international country code TLDs
// www.amazon.co.uk => amazon.co.uk
if (domains[c - 1].Length < 3 && domains[c - 2].Length <= 3)
return string.Join(".", domains, c - 3, 3);
else
return string.Join(".", domains, c - 2, 2);
}
else
return host;
}

This is not possible without a up-to-date database of different domain levels.
Consider:
s1.moh.gov.cn
moh.gov.cn
s1.google.com
google.com
Then at which level you want to get the domain? It's completely depends of the TLD, SLD, ccTLD... because ccTLD in under control of countries they may define very special SLD which is unknown to you.

I've written a library for use in .NET 2+ to help pick out the domain components of a URL.
More details are on github but one benefit over previous options is that it can download the latest data from http://publicsuffix.org automatically (once per month) so the output from the library should be more-or-less on a par with the output used by web browsers to establish domain security boundaries (i.e. pretty good).
It's not perfect yet but suits my needs and shouldn't take much work to adapt to other use cases so please fork and send a pull request if you want.

Use a regular expression:
^https?://([\w./]+[^.])?\.?(\w+\.(com)|(co.uk)|(com.au))$
This will match any URL ending with a TLD in which you are interested. Extend the list for as many as you want. Further, the capturing groups will contain the subdomain, hostname and TLD respectively.

uri.Host.ToLower().Replace("www.","").Substring(uri.Host.ToLower().Replace("www.","").IndexOf('.'))
returns ".com" for
Uri uri = new Uri("http://stackoverflow.com/questions/4643227/top-level-domain-from-url-in-c");
returns ".co.jp" for
Uri uri = new Uri("http://stackoverflow.co.jp");
returns ".s1.moh.gov.cn" for
Uri uri = new Uri("http://stackoverflow.s1.moh.gov.cn");
etc.

HttpRequest.Url.AbsolutePath vs HttpRequest.Path in .NET

I've been using the HttpRequest class in some legacy code, and I've seen that sometimes the path part is obtained using HttpRequest.Path and some other times using HttpRequest.Uri.AbsolutePath.
I personally don't see any difference between both, but maybe I'm missing something.
Are the results of HttpRequest.Path and HttpRequest.Uri.AbsolutePath always 100% equivalent?

Looking at the Reference Source for the Uri, it is built using the Path, so they should be equivalent:
_url = BuildUrl(() => Path);

Yes. They are one and the same. I just run a couple of quick tests and found that the they both are the same. Some research over it showed me that, httprequest.path is an virtual path to the current request which should be exactly the same as absolute path of the URI from that request.

Yes, they should
http://msdn.microsoft.com/en-us/library/system.web.httprequest.path(v=vs.110).aspx
http://msdn.microsoft.com/en-us/library/system.uri.absolutepath(v=vs.110).aspx
The HttpRequest.Path returns an absolute path

Expand environment variable for My Documents

I know I can read environment variables like this:
Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
However, it would be really helpful to me if I could do something like this:
Environment.ExpandEnvironmentVariables(#"%MyDocuments%\Foo");
Is there an environement variable that equals SpecialFolder.MyDocuments?
I also tried to do something like this, but this doesn't lead to the expected result:
Environment.ExpandEnvironmentVariables(#"%USERPROFILE%\My Documents\Foo");
This way I ended up with something like #"C:\Users\<MyUser>\My Documents\Foo" but I what I need is #"\\someservername\users$\<MyUser>\My Documents\Foo".
EDIT: My Goal is NOT to hardcode either environment variable nor the part after that.
Any other suggestions?

No there is no environment variable for the MyDocuments special folder (the same is true for most members of the SpecialFolder enumeration).
Check out this snippet, it might be exactly what you are searching for.
It allows you to do something like that:
string fullPath = SpecialFolder.ExpandVariables(#"%MyDocuments%\Foo");
Note: SpecialFolder.ExpandVariables is a static method of a helper class introduced in the above snippet.

Is there an environment variable that equals SpecialFolder.MyDocuments?
Short answer: No.
Long answer:
Still no. You can type "set" into a Command Prompt to see all you current environment variables. I couldn't find any for my documents folder on my profile (tried on WinXP and Win7).
Also, expanding "%USERPROFILE%\My Documents" would be incorrect since the user's documents folder could be anywhere else (e.g., on my home PC I always change mine to D:\Documents).
If you really need to use environment variables, one solution might be to set the variable yourself:
// this environment variable is created for the current process only
string documents = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
Environment.SetEnvironmentVariable("MYDOCUMENTS", documents);
Another solution might be to use a "fake" environment variable in the path and expand it yourself, something like:
string path = "%MYDOCUMENTS%\\Foo"; // read from config
// expand real env. vars
string expandedPath1 = Environment.ExpandEnvironmentVariables(path);
// expand our "fake" env. var
string documents = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
string expandedPath2 = path.Replace("%MYDOCUMENTS%", documents);

What exactly are you trying to do? Is there any reason why you can't just use Path.Combine?
string docs = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
string foo = Path.Combine(docs, "Foo");

I'm not sure if there is a good way to do this but instead of trying to do environment expansion to get the path why not use the Path.Combine API instead?
Path.Combine(
Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments),
"Foo");

You can expand environment variables using then Environment.GetEnvironmentVariable method. Given your comment, I would suggest breaking your path up into 2 separate config settings to make expanding it easier:
string variablePath = "%appdata%".Trim('%'); //read from some config setting
string appdataPath = Environment.GetEnvironmentVariable(variablePath);
string subdir = "foo"; //some other config setting
string myDir = Path.Combine(appdataPath, subdir);

No it does not exist. The easiest way to check is to run "set" from command line and see yourself.
Start-> run -> cmd
set
set |findstr /i documents

Does C# have an equivalent to JavaScript's encodeURIComponent()?

In JavaScript:
encodeURIComponent("©√") == "%C2%A9%E2%88%9A"
Is there an equivalent for C# applications? For escaping HTML characters I used:
txtOut.Text = Regex.Replace(txtIn.Text, #"[\u0080-\uFFFF]",
m => #"&#" + ((int)m.Value[0]).ToString() + ";");
But I'm not sure how to convert the match to the correct hexadecimal format that JS uses. For example this code:
txtOut.Text = Regex.Replace(txtIn.Text, #"[\u0080-\uFFFF]",
m => #"%" + String.Format("{0:x}", ((int)m.Value[0])));
Returns "%a9%221a" for "©√" instead of "%C2%A9%E2%88%9A". It looks like I need to split the string up into bytes or something.
Edit: This is for a windows app, the only items available in System.Web are: AspNetHostingPermission, AspNetHostingPermissionAttribute, and AspNetHostingPermissionLevel.

Uri.EscapeDataString or HttpUtility.UrlEncode is the correct way to escape a string meant to be part of a URL.
Take for example the string "Stack Overflow":
HttpUtility.UrlEncode("Stack Overflow") --> "Stack+Overflow"
Uri.EscapeUriString("Stack Overflow") --> "Stack%20Overflow"
Uri.EscapeDataString("Stack + Overflow") --> Also encodes "+" to "%2b" ---->Stack%20%2B%20%20Overflow
Only the last is correct when used as an actual part of the URL (as opposed to the value of one of the query string parameters)

HttpUtility.HtmlEncode / Decode
HttpUtility.UrlEncode / Decode
You can add a reference to the System.Web assembly if it's not available in your project

I tried to do full compatible analog of javascript's encodeURIComponent for c# and after my 4 hour experiments I found this
c# CODE:
string a = "!##$%^&*()_+ some text here али мамедов баку";
a = System.Web.HttpUtility.UrlEncode(a);
a = a.Replace("+", "%20");
the result is:
!%40%23%24%25%5e%26*()_%2b%20some%20text%20here%20%d0%b0%d0%bb%d0%b8%20%d0%bc%d0%b0%d0%bc%d0%b5%d0%b4%d0%be%d0%b2%20%d0%b1%d0%b0%d0%ba%d1%83
After you decode It with Javascript's decodeURLComponent();
you will get this:
!##$%^&*()_+ some text here али мамедов баку
Thank You for attention

System.Uri.EscapeUriString() didn't seem to do anything, but System.Uri.EscapeDataString() worked for me.

Try Server.UrlEncode(), or System.Web.HttpUtility.UrlEncode() for instances when you don't have access to the Server object. You can also use System.Uri.EscapeUriString() to avoid adding a reference to the System.Web assembly.

For a Windows Store App, you won't have HttpUtility. Instead, you have:
For an URI, before the '?':
System.Uri.EscapeUriString("example.com/Stack Overflow++?")
-> "example.com/Stack%20Overflow++?"
For an URI query name or value, after the '?':
System.Uri.EscapeDataString("Stack Overflow++")
-> "Stack%20Overflow%2B%2B"
For a x-www-form-urlencoded query name or value, in a POST content:
System.Net.WebUtility.UrlEncode("Stack Overflow++")
-> "Stack+Overflow%2B%2B"

You can use the Server object in the System.Web namespace
Server.UrlEncode, Server.UrlDecode, Server.HtmlEncode, and Server.HtmlDecode.
Edit: poster added that this was a windows application and not a web one as one would believe. The items listed above would be available from the HttpUtility class inside System.Web which must be added as a reference to the project.