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Posted 21 Sep 2014

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Convert RTF to Plain Text (Revised Again)

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4.91/5 (15 votes)
9 Apr 2016CPOL1 min read
Handling for hex expressions and the trailing '}'

Introduction

Most solutions to convert RTF to plain text with pure T-SQL don't handle special characters like German umlauts and all the other special characters above ASCII(128) because they are not embedded in RTF tags but noted as escaped hex values. Also most of these solutions leave a trailing '}' at the end of the converted text. This revised procedure will solve these problems.

Background

Searching the web for a T-SQL procedure to convert RTF-formatted text to plain text, you'll find a lot of matches. Mainly, there are 2 methods described: the first one uses the RichtextCtrl control with the need to reconfigure SQL server settings to allow access to OLE/COM which might be a problem in environments with high security guidelines (e.g. http://www.experts-exchange.com/Database/MS-SQL-Server/Q_27633014.html). The second one will be found in some slightly different versions which all produce results with restrictions as described above (e.g. http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=90034).

Using the Code

Add the following SQL function to your database:

USE [<YourDatabaseNameHere>]
GO

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

CREATE FUNCTION [dbo].[RTF2Text]
(
    @rtf nvarchar(max)
)
RETURNS nvarchar(max)
AS
BEGIN
    DECLARE @Pos1 int;
    DECLARE @Pos2 int;
    DECLARE @hex varchar(316);
    DECLARE @Stage table
    (
        [Char] char(1),
        [Pos] int
    );

    INSERT @Stage
        (
           [Char]
         , [Pos]
        )
    SELECT SUBSTRING(@rtf, [Number], 1)
         , [Number]
      FROM [master]..[spt_values]
     WHERE ([Type] = 'p')
       AND (SUBSTRING(@rtf, Number, 1) IN ('{', '}'));

    SELECT @Pos1 = MIN([Pos])
         , @Pos2 = MAX([Pos])
      FROM @Stage;

    DELETE
      FROM @Stage
     WHERE ([Pos] IN (@Pos1, @Pos2));

    WHILE (1 = 1)
        BEGIN
            SELECT TOP 1 @Pos1 = s1.[Pos]
                 , @Pos2 = s2.[Pos]
              FROM @Stage s1
                INNER JOIN @Stage s2 ON s2.[Pos] > s1.[Pos]
             WHERE (s1.[Char] = '{')
               AND (s2.[Char] = '}')
            ORDER BY s2.[Pos] - s1.[Pos];

            IF @@ROWCOUNT = 0
                BREAK

            DELETE
              FROM @Stage
             WHERE ([Pos] IN (@Pos1, @Pos2));

            UPDATE @Stage
               SET [Pos] = [Pos] - @Pos2 + @Pos1 - 1
             WHERE ([Pos] > @Pos2);

            SET @rtf = STUFF(@rtf, @Pos1, @Pos2 - @Pos1 + 1, '');
        END

    SET @rtf = REPLACE(@rtf, '\pard', '');
    SET @rtf = REPLACE(@rtf, '\par', '');
    SET @rtf = STUFF(@rtf, 1, CHARINDEX(' ', @rtf), '');

    WHILE (Right(@rtf, 1) IN (' ', CHAR(13), CHAR(10), '}'))
      BEGIN
        SELECT @rtf = SUBSTRING(@rtf, 1, (LEN(@rtf + 'x') - 2));
        IF LEN(@rtf) = 0 BREAK
      END
    
    SET @Pos1 = CHARINDEX('\''', @rtf);

    WHILE @Pos1 > 0
        BEGIN
            IF @Pos1 > 0
                BEGIN
                    SET @hex = '0x' + SUBSTRING(@rtf, @Pos1 + 2, 2);
                    SET @rtf = REPLACE(@rtf, SUBSTRING(@rtf, @Pos1, 4), _
CHAR(CONVERT(int, CONVERT (binary(1), @hex,1))));
                    SET @Pos1 = CHARINDEX('\''', @rtf);
                END
        END

    SET @rtf = @rtf + ' ';

    SET @Pos1 = PATINDEX('%\%[0123456789][\ ]%', @rtf);

    WHILE @Pos1 > 0
        BEGIN
            SET @Pos2 = CHARINDEX(' ', @rtf, @Pos1 + 1);

            IF @Pos2 < @Pos1
                SET @Pos2 = CHARINDEX('\', @rtf, @Pos1 + 1);

            IF @Pos2 < @Pos1
                BEGIN
                    SET @rtf = SUBSTRING(@rtf, 1, @Pos1 - 1);
                    SET @Pos1 = 0;
                END
            ELSE
                BEGIN
                    SET @rtf = STUFF(@rtf, @Pos1, @Pos2 - @Pos1 + 1, '');
                    SET @Pos1 = PATINDEX('%\%[0123456789][\ ]%', @rtf);
                END
        END

    IF RIGHT(@rtf, 1) = ' '
        SET @rtf = SUBSTRING(@rtf, 1, LEN(@rtf) -1);

    RETURN @rtf;
END

When copying the above code to SQL don't forget to remove the underscore (wich is only required in codeproject to break long lines)!

To convert any RTF-formatted content, call the function above passing the RTF content as parameter of type nvarchar(max):

SQL
SELECT [<YourRTFColumnNameHere>]
     , [dbo].[RTF2Text]([<YourRTFColumnNameHere>]) AS [TextFromRTF]
  FROM [dbo].[<YourDatabaseNameHere>]

The function returns the converted text as nvarchar(max) too.

More improvements may be added. If you find any RTF part that isn't covered by the function above, please drop a line here.

Thanks

Thanks to all the authors in the web that have posted their solutions until now and therefore deserve the applause. I simply enhanced these solutions to complete the basic conversion.

Thanks also to all users here posting their tips to make the procedure more robust.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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About the Author

NightWizzard
Software Developer (Senior)
Germany Germany
30+ years experience as developer with VB.NET, VB, VBA, VBScript, C#, WPF, WinForms, JavaScript, jQuery, PHP, Delphi, ADO, ADO.NET, ASP.NET, Silverlight, HTML, CSS, XAML, XML, T-SQL, MySQL, MariaDb, MS-ACCESS, dBase, OLE/COM, ActiveX, SEPA/DTAUS, ZUGFeRD, DATEV Format and DATEVconnect, DSGVO, TNT Web-API, MS-Office Addins, etc., including:
- 10+ years experience as developer and freelancer
- 10+ years experience as team leader
- 13+ years experience with CRM solutions

Comments and Discussions

 
QuestionRTF within field Pin
Member 1014725120-Apr-15 10:50
MemberMember 1014725120-Apr-15 10:50 
AnswerRe: RTF within field Pin
NightWizzard20-Apr-15 11:10
MemberNightWizzard20-Apr-15 11:10 
Questionworks like a charm! Pin
Douglas Acosta24-Feb-15 12:13
MemberDouglas Acosta24-Feb-15 12:13 
AnswerRe: works like a charm! Pin
NightWizzard24-Feb-15 13:28
MemberNightWizzard24-Feb-15 13:28 
Questiontags remain in to the output Pin
Member 1139369821-Jan-15 23:26
MemberMember 1139369821-Jan-15 23:26 
AnswerRe: tags remain in to the output Pin
NightWizzard22-Jan-15 1:22
MemberNightWizzard22-Jan-15 1:22 
QuestionError on Invalid object name 'master..sptvalues' Pin
Member 1137165913-Jan-15 1:32
MemberMember 1137165913-Jan-15 1:32 
AnswerRe: Error on Invalid object name 'master..sptvalues' Pin
NightWizzard13-Jan-15 8:36
MemberNightWizzard13-Jan-15 8:36 
spt_values is a stored procedure returning a table of integer values and is part of the system's stored procedures shipped with SQL Server. If it is missing, you can restore it easily - see this article: http://blogs.msdn.com/b/suhde/archive/2009/04/05/invalid-object-name-master-dbo-spt-values-microsoft-sql-server-error-208.aspx[^]

Regards,
Frank
QuestionInvalid length parameter passed to the LEFT or SUBSTRING function. Pin
Batsheva Greenhut2-Dec-14 2:01
MemberBatsheva Greenhut2-Dec-14 2:01 
AnswerRe: Invalid length parameter passed to the LEFT or SUBSTRING function. Pin
NightWizzard2-Dec-14 3:49
MemberNightWizzard2-Dec-14 3:49 
GeneralRe: Invalid length parameter passed to the LEFT or SUBSTRING function. Pin
Batsheva Greenhut2-Dec-14 19:52
MemberBatsheva Greenhut2-Dec-14 19:52 
GeneralRe: Invalid length parameter passed to the LEFT or SUBSTRING function. Pin
NightWizzard3-Dec-14 8:13
MemberNightWizzard3-Dec-14 8:13 
GeneralRe: Invalid length parameter passed to the LEFT or SUBSTRING function. Pin
Batsheva Greenhut3-Dec-14 23:39
MemberBatsheva Greenhut3-Dec-14 23:39 
GeneralRe: Invalid length parameter passed to the LEFT or SUBSTRING function. Pin
NightWizzard3-Dec-14 23:50
MemberNightWizzard3-Dec-14 23:50 
GeneralRe: Invalid length parameter passed to the LEFT or SUBSTRING function. Pin
Batsheva Greenhut3-Dec-14 23:54
MemberBatsheva Greenhut3-Dec-14 23:54 
GeneralRe: Invalid length parameter passed to the LEFT or SUBSTRING function. Pin
hebrahimi14-Dec-14 21:03
Memberhebrahimi14-Dec-14 21:03 
GeneralRe: Invalid length parameter passed to the LEFT or SUBSTRING function. Pin
NightWizzard15-Dec-14 7:37
MemberNightWizzard15-Dec-14 7:37 
AnswerRe: Invalid length parameter passed to the LEFT or SUBSTRING function. Pin
Member 103324005-May-15 3:43
MemberMember 103324005-May-15 3:43 
GeneralRe: Invalid length parameter passed to the LEFT or SUBSTRING function. Pin
NightWizzard5-May-15 9:05
MemberNightWizzard5-May-15 9:05 
GeneralRe: Invalid length parameter passed to the LEFT or SUBSTRING function. Pin
Tomas Granlund9-Nov-15 4:10
MemberTomas Granlund9-Nov-15 4:10 
GeneralRe: Invalid length parameter passed to the LEFT or SUBSTRING function. Pin
NightWizzard9-Nov-15 8:27
MemberNightWizzard9-Nov-15 8:27 
Questionrtf to plain... Pin
Member 1125557822-Nov-14 8:36
MemberMember 1125557822-Nov-14 8:36 
AnswerRe: rtf to plain... Pin
NightWizzard22-Nov-14 9:26
MemberNightWizzard22-Nov-14 9:26 
QuestionRTF to Plain Text Pin
Member 1125557822-Nov-14 7:11
MemberMember 1125557822-Nov-14 7:11 
AnswerRe: RTF to Plain Text Pin
NightWizzard22-Nov-14 7:36
MemberNightWizzard22-Nov-14 7:36 

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