SoftDev

Coupling ASP.NET Session State With Forms Authentication

Today I was talking with João about a way to couple the lifetime of the ASP.NET session state with the lifetime of Forms Authentication ticket.

My idea was to store the session ID in the UserData property of the forms authentication ticket upon logon and retrieve it with a custom session ID manager.

The login code would be something like this:

protected void Login1_Authenticate(object sender, AuthenticateEventArgs e)
{
    bool isPersistent = this.Login1.RememberMeSet;
    string username = this.Login1.UserName;
    var ticket = new FormsAuthenticationTicket(
        0,
        username,
        DateTime.Now,
        DateTime.Now.AddMinutes(2),
        isPersistent,
        Guid.NewGuid().ToString("N"));

    // Encrypt the ticket.
    var encryptedTicket = FormsAuthentication.Encrypt(ticket);

    // Create the cookie.
    this.Response.Cookies.Add(new HttpCookie(FormsAuthentication.FormsCookieName, encryptedTicket));

    // Redirect back to original URL.
    this.Response.Redirect(FormsAuthentication.GetRedirectUrl(username, isPersistent));
}

For the purpose of this test I am using a Guid as the session ID.

The session ID manager will return this session ID when queried by the session state HTTP module:

public class SessionIdManager : global::System.Web.SessionState.ISessionIDManager
{
    #region ISessionIDManager Members

    public string CreateSessionID(HttpContext context)
    {
        return GetDummySessionIdOrRedirectToLoginPage(context);
    }

    public string GetSessionID(HttpContext context)
    {
        return GetSessionIdFromFormsIdentity(context);
    }

    public void Initialize()
    {
    }

    public bool InitializeRequest(HttpContext context, bool suppressAutoDetectRedirect, out bool supportSessionIDReissue)
    {
        supportSessionIDReissue = false;
        return GetSessionIdFromFormsIdentity(context) == null;
    }

    public void RemoveSessionID(HttpContext context)
    {
    }

    public void SaveSessionID(HttpContext context, string id, out bool redirected, out bool cookieAdded)
    {
        redirected = false;
        cookieAdded = false;
    }

    public bool Validate(string id)
    {
        return true;
    }

    #endregion

    private static string GetSessionIdFromFormsIdentity(HttpContext context)
    {
        var identity = context.User != null ? context.User.Identity as FormsIdentity : null;

        if ((identity == null) || (identity.Ticket == null) || string.IsNullOrEmpty(identity.Ticket.UserData))
        {
            return GetDummySessionIdOrRedirectToLoginPage(context);
        }
        else
        {
            return identity.Ticket.UserData;
        }
    }

    private static string GetDummySessionIdOrRedirectToLoginPage(HttpContext context)
    {
        if (context.Request.CurrentExecutionFilePath.Equals(FormsAuthentication.DefaultUrl, StringComparison.OrdinalIgnoreCase)
                        || context.Request.CurrentExecutionFilePath.Equals(FormsAuthentication.LoginUrl, StringComparison.OrdinalIgnoreCase))
        {
            return Guid.NewGuid().ToString("N");
        }
        else
        {
            FormsAuthentication.RedirectToLoginPage();
            return null;
        }
    }
}

NOTE: Although this might work, it’s just an intellectual exercise and wasn’t fully tested.

Extended WebBrowser Control – Version 0.0.0.0 Uploaded

After a long time, I finally managed to upload a version of the Extended WebBrowser Control to CodePlex.

It's still a work in progress, but it's usable. Feel free to download, comment and file issues. A nice tabbed browser demo is included.

LINQ To SQL Tips & Tricks: String Operations

LINQ With C# (Portuguese)

LINQ brought developers a very user friendly and domain independent style of writing queries.

The fact that the way queries are written is domain independent doesn’t mean that any query will compile the same way or even run the same way. You’ll always need to know how the provider will behave.

LINQ To Objects, for example, will compile queries as a Func<> delegate and the query methods will return IEnumerable(T) implementations.

On the other hand, LINQ To SQL will compile queries as an Expression<Func<>> (which is, in fact, an expression tree) instance and the query methods will return IQueryable(T) implementations.

Because LINQ To SQL queries are compiled to an expression tree, that allows the provider to treat the query elements as it sees fit.

In this case, this means that all operations that can be done on the database will be done on the database and the developer must be aware of this when she/he is writing the queries.

Lets take an example using the AdventureWorks database (if you don’t have it, you can download it from here).

I want to build a list of salutation for every employee that has the SalariedFlag set, in the form of:

[Mr.|Mrs.|Miss] <first name> <middle name> <last name>

But there’s also one detail about the data in the database: FirstName, MiddleName and LastName may have trailing spaces and I don’t want them.

This is a simple query like this:

var q1 = from e in context.Employees
         where e.SalariedFlag
         select
            ((e.Gender == 'F') ? ((e.MaritalStatus == 'S') ? "Miss" : "Mrs.") : "Mr.") + " " +
            e.Person.FirstName.Trim() +
            (e.Person.MiddleName == null || e.Person.MiddleName.Trim().Length == 0 ? " " : " " + e.Person.MiddleName.Trim() + " ") +
            e.Person.LastName.Trim();

and it will be executed as:

SELECT ((((
    (CASE
        WHEN UNICODE([t0].[Gender]) = @p0 THEN
            (CASE
                WHEN UNICODE([t0].[MaritalStatus]) = @p1 THEN @p2
                ELSE @p3
             END)
        ELSE CONVERT(NVarChar(4),@p4)
     END)) + @p5) + LTRIM(RTRIM([t1].[FirstName]))) + (
    (CASE
        WHEN ([t1].[MiddleName] IS NULL) OR (LEN(LTRIM(RTRIM([t1].[MiddleName]))) = @p6) THEN CONVERT(NVarChar(MAX),@p7)
        ELSE (@p8 + LTRIM(RTRIM([t1].[MiddleName]))) + @p9
     END))) + LTRIM(RTRIM([t1].[LastName])) AS [value]
FROM [HumanResources].[Employee] AS [t0]
INNER JOIN [Person].[Person] AS [t1] ON [t1].[BusinessEntityID] = [t0].[BusinessEntityID]
WHERE [t0].[SalariedFlag] = 1
-- @p0: Input Int (Size = 0; Prec = 0; Scale = 0) [70]
-- @p1: Input Int (Size = 0; Prec = 0; Scale = 0) [83]
-- @p2: Input NVarChar (Size = 4; Prec = 0; Scale = 0) [Miss]
-- @p3: Input NVarChar (Size = 4; Prec = 0; Scale = 0) [Mrs.]
-- @p4: Input NVarChar (Size = 3; Prec = 0; Scale = 0) [Mr.]
-- @p5: Input NVarChar (Size = 1; Prec = 0; Scale = 0) [ ]
-- @p6: Input Int (Size = 0; Prec = 0; Scale = 0) [0]
-- @p7: Input NVarChar (Size = 1; Prec = 0; Scale = 0) [ ]
-- @p8: Input NVarChar (Size = 1; Prec = 0; Scale = 0) [ ]
-- @p9: Input NVarChar (Size = 1; Prec = 0; Scale = 0) [ ]
-- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 3.5.30729.4926

If you notice the query, there are a lot of text operations going on for each row.

Depending on the number of rows or database load this can prove to be very bad. The result might even be just a timeout.

So, how do we force the string operations to occur on the client instead of the database?

Only IQueryable<T> will be translated to T-SQL. So, all we need to do is change the type of the enumerator being iterated.

One way to do this is using the the AsEnumerable method of the Enumerable class.

The query would now be written as:

var q2 = from e in context.Employees.Where(e => e.SalariedFlag).AsEnumerable()
         select
            ((e.Gender == 'F') ? ((e.MaritalStatus == 'S') ? "Miss" : "Mrs.") : "Mr.") + " " + e.Person.FirstName.Trim() +
            (e.Person.MiddleName == null || e.Person.MiddleName.Trim().Length == 0 ? " " : " " + e.Person.MiddleName.Trim() + " ") +
            e.Person.LastName.Trim();

and it will be executed as:

SELECT
    [t0].[BusinessEntityID],
    [t0].[LoginID],
    [t0].[NationalIDNumber],
    [t0].[JobTitle],
    [t0].[MaritalStatus],
    [t0].[BirthDate],
    [t0].[Gender],
    [t0].[HireDate],
    [t0].[SalariedFlag],
    [t0].[VacationHours],
    [t0].[SickLeaveHours],
    [t0].[CurrentFlag],
    [t0].[rowguid],
    [t0].[ModifiedDate],
    [t1].[BusinessEntityID] AS [BusinessEntityID2],
    [t1].[PersonType],
    [t1].[NameStyle],
    [t1].[Title],
    [t1].[FirstName],
    [t1].[MiddleName],
    [t1].[LastName],
    [t1].[Suffix],
    [t1].[EmailPromotion],
    [t1].[AdditionalContactInfo],
    [t1].[Demographics],
    [t1].[rowguid] AS [rowguid2],
    [t1].[ModifiedDate] AS [ModifiedDate2]
FROM [HumanResources].[Employee] AS [t0]
INNER JOIN [Person].[Person] AS [t1] ON [t1].[BusinessEntityID] = [t0].[BusinessEntityID]
WHERE [t0].[SalariedFlag] = 1
-- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 3.5.30729.4926

As you can notice, text operations are no longer done on the database, but all the columns of both tables are being returned. And this is still a bad thing because we are using network bandwidth with data that won’t be used.

The way to choose the columns that will be retrieved from the database is by selecting only the ones wanted in the select statement. But because we still want string operations the be done on the client, we’ll need to project the desired columns into an intermediary object. Since we won’t need this object outside the query, we’ll use an anonymous type.

The query would now be written as:

var q3 = from n in
             (
                 from e in context.Employees
                 where e.SalariedFlag
                 select new
                 {
                     Gender = e.Gender,
                     MaritalStatus = e.MaritalStatus,
                     FirstName = e.Person.FirstName,
                     MiddleName = e.Person.MiddleName,
                     LastName = e.Person.LastName
                 }
             ).AsEnumerable()
         select ((n.Gender == 'F') ? ((n.MaritalStatus == 'S') ? "Miss" : "Mrs.") : "Mr.") + " " + n.FirstName.Trim()
         + (n.MiddleName == null || n.MiddleName.Trim().Length == 0 ? " " : " " + n.MiddleName.Trim() + " ")
         + n.LastName.Trim();

and it will be executed as:

SELECT
    [t0].[Gender],
    [t0].[MaritalStatus],
    [t1].[FirstName],
    [t1].[MiddleName],
    [t1].[LastName]
FROM [HumanResources].[Employee] AS [t0]
INNER JOIN [Person].[Person] AS [t1] ON [t1].[BusinessEntityID] = [t0].[BusinessEntityID]
WHERE [t0].[SalariedFlag] = 1
-- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 3.5.30729.4926

Notice the call to Enumerable.As Enumerable to translate the LINQ To SQL query into a LINQ To Objects query.

And, to end this long blog post, if you don’t use any string operations on the query, they, obviously, won’t be translated to T-SQL:

var q4 = from e in context.Employees
         where e.SalariedFlag
         select BuildSalutation(e.Gender, e.MaritalStatus, e.Person.FirstName, e.Person.MiddleName, e.Person.LastName);

where BuildSalutation is implemented as:

private static object BuildSalutation(char gender, char maritalStatus, string firstName, string middleName, string lastName)
{
    return ((gender == 'F') ? ((maritalStatus == 'S') ? "Miss" : "Mrs.") : "Mr.") + " "
        + firstName.Trim()
        + (middleName == null || middleName.Trim().Length == 0 ? " " : " " + middleName.Trim() + " ")
        + lastName.Trim();
}

and it will be executed as:

SELECT
    [t0].[Gender] AS [gender],
    [t0].[MaritalStatus] AS [maritalStatus],
    [t1].[FirstName] AS [firstName],
    [t1].[MiddleName] AS [middleName],
    [t1].[LastName] AS [lastName]
FROM [HumanResources].[Employee] AS [t0]
INNER JOIN [Person].[Person] AS [t1] ON [t1].[BusinessEntityID] = [t0].[BusinessEntityID]
WHERE [t0].[SalariedFlag] = 1
-- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 3.5.30729.4926

Have you noticed that this T-SQL query is pretty much the same in the previous example?

If you are still reading this, I hope you now aware of how you write your LINQ To SQL queries affect the generated T-SQL.

ReMIX 09 Is Coming To Lisbon, Portugal

ReMIX 09For the first time, ReMIX is coming to Portugal.

The event will have a keynote and 3 tracks (Web Developer, UX and Architect) with 4 sessions each by the best speakers in each field.

Don’t miss it! Register now!

Windows Live Messenger Unable To Connect With Error Code 80040200

Today I came across this issue when trying to sign in to Windows Live Messenger.

Everyone I talked to was able to sign in, though, so I tried another account and was also able to sign in.

Binging around, I found several blog posts pointing to a post in the Messenger Support blog with the solution to this problem. In my case (Windows 7 x64) the solution would be to remove the %LOCALAPPDATA%\Microsoft\Windows Live Contacts (usually C:\Users\<Windows Logon name>\AppData\Local\Microsoft\Windows Live Contacts) folder.

Instead of removing the folder, I thought of renaming it to avoid removing my contacts for all account that were able to sign in. When I tried it, I got an error stating the the folder was already being used by another application.

Since I had Windows Live Mail open and assumed it uses the same contact store, I closed it and was able to sign in to messenger with no problems.

As a developer and architect, I find it disturbing that such errors are presented to the user. The message hinted that there was a problem signing in to the server and, as it turned out, it was a problem with only one account for only one Windows user in only one machine.

So, developers and architects out there (me included), always give the user an error message meaningful to what problem he/she is running into. Adding technical data to help support is nice but should be expressly accessed by the user (Windows Live Messenger got that part right).

Playing With SQL Server CLR Integration – Part IV (Deploying To SQL Server 2005)

With all developed and tested on my laptop using SQL Server 2008, it’s time to deploy to the company’s test machine running SQL Server 2005.

The first thing I ran into when executing:

CREATE ASSEMBLY [MyAssembly]
AUTHORIZATION [dbo]
FROM '...\MyAssembly.dll'
WITH PERMISSION_SET = SAFE
GO

was:

Msg 10327, Level 14, State 1, Line 1
Assembly 'MyAssembly' references assembly 'system.xml.linq, version=3.5.0.0, culture=neutral, publickeytoken=b77a5c561934e089.',
which is not present in the current database.
SQL Server attempted to locate and automatically load the referenced assembly from the same location where referring assembly came from,
but that operation has failed (reason: 2(The system cannot find the file specified.)).
Please load the referenced assembly into the current database and retry your request.

Looks like SQL Server 2005 doesn’t know about .NET Framework 3.5. I’d just load the assemblies being used: System.Core and System.Linq.Xml:

CREATE ASSEMBLY [System.Core]
AUTHORIZATION [dbo]
FROM 'C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Core.dll'
WITH PERMISSION_SET = SAFE
GO

Not so easy:

Warning: The Microsoft .Net frameworks assembly 'system.core, version=3.5.0.0, culture=neutral, publickeytoken=b77a5c561934e089, processorarchitecture=msil.' you are registering is not fully tested in SQL Server hosted environment.
Msg 6218, Level 16, State 2, Line 1
CREATE ASSEMBLY for assembly 'System.Core' failed because assembly 'System.Core' failed verification. Check if the referenced assemblies are up-to-date and trusted (for external_access or unsafe) to execute in the database. CLR Verifier error messages if any will follow this message
[ : System.Diagnostics.Eventing.EventProvider::EtwRegister][mdToken=0x600003b][offset 0x0000003D][found Native Int][expected unmanaged pointer] Unexpected type on the stack.
[ : System.Diagnostics.Eventing.EventProvider::EncodeObject][mdToken=0x6000046][offset 0x00000000] Unmanaged pointers are not a verifiable type.
[ : System.Diagnostics.Eventing.EventProvider::WriteMessageEvent][mdToken=0x6000047][offset 0x0000003C][found ref 'System.String'] Expected numeric type on the stack.
[ : System.Diagnostics.Eventing.EventProvider::WriteEvent][mdToken=0x6000049][offset 0x0000012E] Instruction cannot be verified.
[ : System.Diagnostics.Eventing.EventProvider::WriteEvent][mdToken=0x6000049][offset 0x00000030] Instruction cannot be verified.
[ : System.Diagnostics.Eventing.EventProvider::WriteEvent][mdToken=0x600004a][offset 0x0000005F][found ref 'System.String'] Expected numeric type on the stack.
[ : System.Diagnostics.Eventing.EventProvider::WriteEvent][mdToken=0x600004b][offset 0x00000010][found unmanaged pointer][expected unmanaged pointer] Unexpected type on the stack.
[ : System.Diagnostics.Eventing.EventProvider::WriteTransferEvent][mdToken=0x600004c][offset 0x0000007D] Instruction cannot be verified.
[ : System.Diagnostics.Eventing.EventProvider::WriteTransferEvent][mdToken=0x600004c][offset 0x00000309][found Native Int][expected unmanaged pointer] Unexpected type on the stack.
[ : System.Diagnostics.Eventing.EventProvider::WriteTransferEvent][mdToken=0x600004d][offset 0x0000001B][found unmanaged pointer][expected unmanaged pointer] Unexpected type on the stack.
[ : System.Security.Cryptography.CapiNative::ImportSymmetricKey][mdToken=0x60007c2][offset 0x00000071][found address of Byte] Expected numeric type on the stac...

Ok. I’d just load it with PERMISSION_SET = UNSAFE:

CREATE ASSEMBLY [MyAssembly]
AUTHORIZATION [dbo]
FROM '...\MyAssembly.dll'
WITH PERMISSION_SET = UNSAFE
GO

Not yet:

Warning: The Microsoft .Net frameworks assembly 'system.core, version=3.5.0.0, culture=neutral, publickeytoken=b77a5c561934e089, processorarchitecture=msil.' you are registering is not fully tested in SQL Server hosted environment.
Msg 10327, Level 14, State 1, Line 1
CREATE ASSEMBLY for assembly 'System.Core' failed because assembly 'System.Core' is not authorized for PERMISSION_SET = UNSAFE.
The assembly is authorized when either of the following is true: the database owner (DBO) has UNSAFE ASSEMBLY permission and the database has the TRUSTWORTHY database property on; or the assembly is signed with a certificate or an asymmetric key that has a corresponding login with UNSAFE ASSEMBLY permission.
If you have restored or attached this database, make sure the database owner is mapped to the correct login on this server.
If not, use sp_changedbowner to fix the problem.

Solved:

ALTER DATABASE MyDatabase SET TRUSTWORTHY ON
GO

Only than I was able to load the .NET 3.5 assemblies:

CREATE ASSEMBLY [System.Core]
AUTHORIZATION [dbo]
FROM 'C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Core.dll'
WITH PERMISSION_SET = UNSAFE
GO

CREATE ASSEMBLY [System.Xml.Linq]
AUTHORIZATION [dbo]
FROM 'C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Xml.Linq.dll'
WITH PERMISSION_SET = UNSAFE
GO

With all dependencies in place, I tried to load the assembly with PERMISSION_SET = SAFE with no luck:

Msg 6212, Level 16, State 1, Line 1
CREATE ASSEMBLY failed because method 'ShortPropsToXml' on type 'ShortProps'  in safe assembly 'Esi.SA.Encyclopedia' is storing to a static field.
Storing to a static field is not allowed in safe assemblies.

It had to be with PERMISSION_SET = UNSAFE.

After successfully loading the assemblies, I was finally able to create the Transact-SQL definitions for the functions (see Part I and Part II).

Now the DBAs won’t definitely let me use this, but it was fun to build it.

Playing With SQL Server CLR Integration – Part III

You might have noticed that I used LINQ in my last Playing With SQL Server CLR Integration posts (Part I, Part II).

I couldn’t make it work with the standard Visual Studio 2008 SQL CLR project template. Changing the Target Framework to .NET Framework 3.5 wasn’t enough. I had to edit the .csproj file by hand:

<?xml version="1.0" encoding="utf-8"?> <Project ToolsVersion="3.5" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003"> <!— ... -->

<ItemGroup> <!— ... --> <Reference Include="System.Core"> <RequiredTargetFramework>3.5</RequiredTargetFramework> </Reference> <Reference Include="System.Xml.Linq"> <RequiredTargetFramework>3.5</RequiredTargetFramework> </Reference> </ItemGroup> <!— ... --> </Project>

Playing With SQL Server CLR Integration – Part II

On my last post, I showed how to convert a property bag stored in text to a CLR Table-Valued Function.

I started thinking that I could retrieve the property values, but I couldn’t change them or add new properties.

Passing a table as a parameter is still not possible in SQL Server 2005. And that would force me to load the table into a variable, change it and load it back into the property bag.

Or I could create functions to Create, Update and Delete properties from the property bag.

Or I could just use XML. All it takes is creating a CLR Scalar-Valued Function to convert the property bag to an XML representation and another to convert the XML back to the property bag format.

It still makes me load the property bag into a variable if I want to change it, but it’s usable in SQL Server 2005, which was the targeted platform.

Converting the property bag to an XML document is easy using the previously created enumerator:

[Microsoft.SqlServer.Server.SqlFunction(
    Name = "ShortPropsToXml",
    IsDeterministic = true,
    IsPrecise = false,
    DataAccess = DataAccessKind.None,
    SystemDataAccess = SystemDataAccessKind.None)]
public static SqlXml ShortPropsToXml(string shortPropsText)
{
    var xml = new XElement("ShortProps",
        from shortProp in ShortPropsEnumerable(shortPropsText)
        select new XElement("p",
            new XAttribute("n", shortProp.Key),
            new XCData(shortProp.Value)));

    using (var buffer = new MemoryStream())
    {
        using (var xmlWriter = XmlWriter.Create(buffer, new XmlWriterSettings { CheckCharacters = false }))
        {
            xml.WriteTo(xmlWriter);
        }

        buffer.Position = 0;

        using (XmlReader xmlReader = XmlReader.Create(buffer, new XmlReaderSettings { CheckCharacters = false }))
        {
            return new SqlXml(xmlReader);
        }
    }
}

Converting the an XML document back into the property bag format is also easy:

[Microsoft.SqlServer.Server.SqlFunction(
    Name = "XmlToShortProps",
    IsDeterministic = true,
    IsPrecise = false,
    DataAccess = DataAccessKind.None,
    SystemDataAccess = SystemDataAccessKind.None)]
public static SqlChars XmlToShortProps(SqlXml shortPropsXml)
{
    var xml = XDocument.Parse(shortPropsXml.Value);

    var textBuilder = new StringBuilder();
    foreach (var item in xml.Document.Element("ShortProps").Elements("p"))
    {
        textBuilder.AppendFormat("[[[{1}]]]{0}{2}{0}", Environment.NewLine, item.Attribute("n").Value, item.Value);
    }

    return new SqlChars(textBuilder.ToString().ToCharArray());
}

Now it’s just uploading the new version of the assembly to the database:

ALTER ASSEMBLY [MyAssembly]
FROM '...\MyAssembly.dll'
GO

And defining the Scalar-Valued Functions in Transact-SQL:

CREATE FUNCTION [dbo].[ShortPropsToXml](@shortPropsText [nvarchar](4000))
RETURNS [xml] WITH EXECUTE AS CALLER
AS 
EXTERNAL NAME [Esi.SA.Encyclopedia].[ShortProps].[ShortPropsToXml]
GO

CREATE FUNCTION [dbo].[XmlToShortProps](@shortPropsXml [xml])
RETURNS [nvarchar](max) WITH EXECUTE AS CALLER
AS 
EXTERNAL NAME [Esi.SA.Encyclopedia].[ShortProps].[XmlToShortProps]
GO

And it’s all set to go.

Now, given this property bag definition:

declare @text nvarchar(max)='[[[name1]]]
value1
[[[name2]]]
value2
[[[name3]]]
value3
'

I can change it into XML:

DECLARE @xml [xml] = dbo.ShortPropsToXml(@text)
  • Update:
    set @xml.modify('replace value of (/ShortProps/p[@n="name2"]/text())[1] with "new value2"')
    
  • Insert:
    set @xml.modify('insert <p n="name4">Value4.1
    Value4.2</p> after (/ShortProps/p[@n="name2"])[1]')
  • Delete
    set @xml.modify('delete (/ShortProps/p[@n="name3"])[1]')
  • Convert back to the property bag format:

    print dbo.XmlToShortProps(@xml)

    [[[name1]]]
    value1
    [[[name2]]]
    new value2
    [[[name4]]]
    Value4.1
    Value4.2

  • Query as a table:

    select T.C.value('./@n', 'nvarchar(max)') as Name, T.C.value('.', 'nvarchar(max)') as Value from @xml.nodes('/ShortProps/p') T(C)
    Name Value
    name1 value1
    name2 new value2
    name4 Value4.1

    Value4.2

Unfortunately, the application uses characters that are invalid to SQL Server as XML characters and I can’t use it on that application. I’ll have to understand those values better and add other fields to the table and XML.

Playing With SQL Server CLR Integration – Part I

I’m currently working with an application that stores a property bag in a SQL Server column like this:

[[[name1]]]
value1
[[[name2]]]
value2.1
value2.2
[[[name3]]]
value3

Don’t ask me why it’s done like this. It just is.

The application decodes this property bag into its inner structures and all works fine.

Sometimes I would like to query the database directly or do some reporting on those properties and just can’t.

So, I thought this was a good use case for SQL Server CLR Integration. I decided to build a CLR Table-Valued Function that would return the property bag as a two column table.

Parsing the property bag text can easily be achieved with a simple regular expression:

new Regex(
        string.Format(@"(?<Name>(?<=\[\[\[).*(?=\]\]\]{0}))\]\]\]{0}(?<Value>(([\s\S]*?(?={0}\[\[\[))|([\s\S]*?(?={0}$))))", Environment.NewLine),
        RegexOptions.Multiline | RegexOptions.ExplicitCapture | RegexOptions.CultureInvariant | RegexOptions.Compiled);

Ultrapico’s Expresso was a big help when developing this regular expression.

In case you don’t know, the way CLR Table-Valued Function are built is using an initial method to take the input and return an IEnumerable and row filler method the receives the enumerator item and outputs the column values.

Since these are really key-value pairs of strings, I decided to use )>) Structure" href="http://msdn.microsoft.com/library/5tbh8a42.aspx" target=_blank>KeyValuePair<string, string> instances to store each item and the enumerator became simply this:

private static IEnumerable<KeyValuePair<string, string>> ShortPropsEnumerable(string shortPropsText)
{
    return from Match m in shortPropsRegex.Matches(shortPropsText)
           select new KeyValuePair<string, string>(m.Groups["Name"].Value, m.Groups["Value"].Value);
}

And the implementation of the CLR Table-Valued Function is as simple as this:

[Microsoft.SqlServer.Server.SqlFunction(
    Name = "ShortPropsToTable",
    FillRowMethodName = "ShortPropsToTableFillRow",
    TableDefinition = "Name NVARCHAR(4000), Value NVARCHAR(4000)",
    IsDeterministic = true,
    IsPrecise = false,
    DataAccess = DataAccessKind.None,
    SystemDataAccess = SystemDataAccessKind.None)]
public static IEnumerable ShortPropsToTable(string shortPropsText)
{
    return ShortPropsEnumerable(shortPropsText);
}

public static void ShortPropsToTableFillRow(object item, out SqlChars name, out SqlChars value)
{
    KeyValuePair<string, string> shortProp = (KeyValuePair<string, string>)item;

    name = new SqlChars(shortProp.Key);
    value = new SqlChars(shortProp.Value);
}

To use this in SQL Server a few simple steps are need:

  1. Load the assembly into the database:
    CREATE ASSEMBLY [MyAssembly]
    AUTHORIZATION [dbo]
    FROM '...\MyAssembly.dll'
    WITH PERMISSION_SET = SAFE
    GO

  2. CREATE FUNCTION [dbo].[ShortPropsToTable](@shortPropsText [nvarchar](4000))
    RETURNS  TABLE (
        [Name] [nvarchar](4000) NULL,
        [Value] [nvarchar](4000) NULL
    ) WITH EXECUTE AS CALLER
    AS 
    EXTERNAL NAME [MyAssembly].[ShortProps].[ShortPropsToTable]
    GO
    

  3. Enable CLR Integration:
    EXEC sp_configure 'clr enabled', 1
    GO
    RECONFIGURE
    GO
    

And all is set to go.

Now I can just query the property bag as a table:

SELECT
    e.[ID],
    e.[Name],
    e.[Class],
    e.[Type],
    p.[Name],
    p.[Value]
FROM
    dbo.Entity as e
    CROSS APPLY dbo.ShortPropsToTable(e.[ShortProps]) as p

Just for curiosity, for a little over 50000 entities (that can be retrieved on about 1 second on my laptop), I got a little under 630000 properties in les then 40 seconds.

40 seconds might seem a lot compared to the 1 second, but I would like to see better times using T-SQL. And develop and test the TVF in just a couple of hours.

Now, if only he DBAs would allow me to use it. It doesn’t fit into the company’s “security policy”, you know.

Typemock Is Launching The ASP.NET Bundle – Get Free Licenses


Typemock is launching a new product for ASP.NET developers – the ASP.NET Bundle - and for the launch they are giving out FREE licenses to bloggers and their readers.


The ASP.NET Bundle is the ultimate ASP.NET unit testing solution, and offers both Typemock Isolator and Ivonna, the ASP.NET Isolator add-on, for a discounted price.


ASP.NET Bundle launch giveaway:
For the ASP.NET Bundle launch Typemock are giving away free licenses to bloggers and their readers.


How do I get the free license?


Are you a blogger, webmaster, or internet columnist? Get your free license by helping Typemock launch their new ASP.NET Bundle, the ultimate ASP.NET unit testing solution.


Post the text below on your blog (as is, with links) and tell them about it . If you are in the first 60 to mail us after posting, your license will be on its way!


If you have an ASP.NET dedicated blog, you'll get a license automatically (even if more than 60 submit) during the first week of this announcement.


8 bloggers will also get an additional 2 licenses (each) to give away / raffle to their readers or friends.


A few simple requirements:




  1. You must own a website, blog space or internet column, older than 2 months, or get permission from the owner of such a site.


  2. Your post must include the text below (including the links) between *Begin* and *End*.

*Begin*


Unit Testing ASP.NET? ASP.NET unit testing has never been this easy.


Typemock is launching a new product for ASP.NET developers – the ASP.NET Bundle - and for the launch will be giving out FREE licenses to bloggers and their readers.


The ASP.NET Bundle is the ultimate ASP.NET unit testing solution, and offers both Typemock Isolator, a unit test tool and Ivonna, the Isolator add-on for ASP.NET unit testing, for a bargain price.


Typemock Isolator is a leading .NET unit testing tool (C# and VB.NET) for many ‘hard to test’ technologies such as SharePoint, ASP.NET, MVC, WCF, WPF, Silverlight and more. Note that for unit testing Silverlight there is an open source Isolator add-on called SilverUnit.


The first 60 bloggers who will blog this text in their blog and tell us about it, will get a Free Isolator ASP.NET Bundle license (Typemock Isolator + Ivonna). If you post this in an ASP.NET dedicated blog, you'll get a license automatically (even if more than 60 submit) during the first week of this announcement.


Also 8 bloggers will get an additional 2 licenses (each) to give away to their readers / friends.


Go ahead, click the following link for more information on how to get your free license.


*End*


Once you post this in your site, just drop them a line at asp@typemock.com with your name and the post URL to get your free license.


Hurry up – this offer is limited to the first 60 bloggers, or to ASP.NET dedicated bloggers who will post this in the first week.


Make sure to follow their Blog, Site or Twitter for updates on this event.


Unit Test Today! Get Typemock Isolator!