Search code examples
asp.netsqlt-sql

HTML Encoding in T-SQL?

Is there any function to encode HTML strings in T-SQL? I have a legacy database which contains dodgey characters such as '<', '>' etc. I can write a function to replace the characters but is there a better way?

I have an ASP.Net application and when it returns a string it contains characters which cause an error. The ASP.Net application is reading the data from a database table. It does not write to the table itself.

Solution

  • We have a legacy system that uses a trigger and dbmail to send HTML encoded email when a table is entered, so we require encoding within the email generation. I noticed that Leo's version has a slight bug that encodes the & in &lt; and &gt; I use this version:

    CREATE FUNCTION HtmlEncode
(
    @UnEncoded as varchar(500)
)
RETURNS varchar(500)
AS
BEGIN
  DECLARE @Encoded as varchar(500)

  --order is important here. Replace the amp first, then the lt and gt. 
  --otherwise the &lt will become &amp;lt; 
  SELECT @Encoded = 
  Replace(
    Replace(
      Replace(@UnEncoded,'&','&amp;'),
    '<', '&lt;'),
  '>', '&gt;')

  RETURN @Encoded
END
GO