Display the BLOB objects in Coldfusion

Question

I have a query which retrieves the data from Oracle DB. The table which I am retrieving contains one BLOB type column. When I tried to output it as

<cfoutput>#query.blobColumn#</cfoutput>

Its giving me the error "ByteArray objects cannot be converted to strings". I tried using

<cfoutput>#ToString(query.blobColumn)#</cfoutput>

Then it worked, but I am getting the content as "��t�".

Is there any way we can display some text of the blob(XML file) and if user clicks on it, we can display/download the full content of it?

This is the Code i am using

<cfloop query="UpdateResult">  
  <tr id="dataRow">  
     <cfloop index="ColName" `list="#UpdateResult.ColumnList#">  
       <cfif isBinary(UpdateResult[ColName[UpdateResult.CurrentRow])>                  
         <td>#CharsetEncode(UpdateResult[ColName][UpdateResult.CurrentRow], "ISO- 8859-1" ) #</td> 
        <cfelse>
          <td>#UpdateResult[ColName][UpdateResult.CurrentRow]#</td> 
       </cfif> 
      </cfloop>  
    </tr>
 </cfloop>`

Answer 1

You might try using the CharsetEncode() function.

<cfoutput>#CharsetEncode( query.blobCoulmn, "us-ascii" )#</cfoutput>

From the documentation:

Adobe recommends that you use this function, and not the ToString function, to convert binary data to strings in all new applications.

It supports many character sets, us-ascii is only used as an example. Hope this helps!

Answer 2

If the BLOB is binary data, then displaying it as a string won't work. Look into using CFCONTENT to deliver data in binary format. For the end user to receive it properly, you'll probably need to specify an appropriate MIME type.