Have XML with another embedded XML encoded in base64 - how to extract?

Question

Hi guys,
I have a XML-RPC web service that returns a response like this:
<methodResponse>
<params>
<param>
<value>
<base64>
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
</base64>
</value>
</param>
</params>
</methodResponse>The base64 value is another XML embedded document that I have to extract.
I have the following code (don't know if it's the best approach), where l_val is a CLOB and l_xml is XMLTYPE:
l_val := DBMS_XMLGEN.convert( l_xml.extract('/methodResponse/params/param/value/base64/text()').getclobval(), 1 );How can I decode the base64-encoded contents of the l_val CLOB and store the result into another CLOB that I can then process with xmlsequence() and extract()?
Thanks in advance. Regards,
Georger

Answer 1

Hi mdrake,
I saw your answer on the other thread :)
I know about the 32K limitation; that's why I need to store the decoded CLOB in another CLOB, as bigger documents will often be the case. I've been reading about this for a while, to no avail.
Do you believe BASE64_DECODE_CLOB could be changed to return CLOB rather than VARCHAR2? Regards,
Georger
mdrake wrote:
You'll need to do some work in this if the Encoded XML is bigger than 32K
SQL> set long 10000 pages 0
SQL> CREATE OR REPLACE FUNCTION BASE64_DECODE_CLOB (INPUT CLOB)
2  return VARCHAR2
3  as
4    V_RAW_BUFFER RAW(32767);
5    V_VARCHAR2_BUFFER VARCHAR2(32767);
6  begin
7    V_VARCHAR2_BUFFER := DBMS_LOB.SUBSTR(INPUT,32767,1);
8    V_RAW_BUFFER := UTL_RAW.CAST_TO_RAW(V_VARCHAR2_BUFFER);
9    V_RAW_BUFFER :=  UTL_ENCODE.BASE64_DECODE(V_RAW_BUFFER);
10    V_VARCHAR2_BUFFER := UTL_RAW.CAST_TO_VARCHAR2(V_RAW_BUFFER);
11    return V_VARCHAR2_BUFFER;
12  end;
13  /
Function created.
SQL> set serveroutput on
SQL> --
SQL> with XML as
2  (
3  select XMLType(
4  '<methodResponse>
5  <params>
6  <param>
7  <value>
8  <base64>
9  PD94bWwgdmVyc2lvbj0iMS4wIiBlbmNvZGluZz0iVVRGLTgiPz4KPHNlYXJjaFJlc3VsdD48bnVtcm93cz4xPC9udW1yb3dzPjxmb3VuZD4xPC9mb3VuZD48d29yZGl
uZm8+IGJvdMOjbyA6IDU8L3dvcmRpbmZvPjxzZWFyY2h0aW1lPjAuMDA2PC9zZWFyY2h0aW1lPjxmaXJzdGRvYz4xPC9maXJzdGRvYz48bGFzdGRvYz4xPC9sYXN0ZG9jPjx
3b3JkaW5mb2FsbD5ib3TDo28gOiA1IC8gNTwvd29yZGluZm9hbGw+PGl0ZW0+PHVybGlkPjE5PC91cmxpZD48dXJsPmh0dHA6Ly9jZW50cmFsL2dhcnJhcy9RdWVtX21hdG9
1X0pGSy9hcnRlZmF0b3MvaHRtLzc1MDUuaHRtPC91cmw+PGNvbnRlbnQ+dGV4dC9odG1sPC9jb250ZW50Pjx0aXRsZT5Tb3VuZE1BWDwvdGl0bGU+PGtleXdvcmRzPjwva2V
5d29yZHM+PGRlc2M+PC9kZXNjPjx0ZXh0Pi4uLiBlIGNvbXVuaWNhw6fDo28gdmlhIEludGVybmV0LiBDbGlxdWUgbm8gJmx0O2ZvbnQgY29sb3I9JnF1b3Q7MDAwMDg4JnF
1b3Q7Jmd0OyZsdDtiJmd0O2JvdMOjbyZsdDsvYiZndDsmbHQ7L2ZvbnQmZ3Q7IGNvbSBvIGxvZ290aXBvIEFuZHJlYSBlbSAuLi4gYWRxdWlyaXIgdW1hIGF0dWFsaXphw6f
Do28sIGNsaWNhbmRvIG5vICZsdDtmb250IGNvbG9yPSZxdW90OzAwMDA4OCZxdW90OyZndDsmbHQ7YiZndDtib3TDo28mbHQ7L2ImZ3Q7Jmx0Oy9mb250Jmd0OyBjb20gbyD
DrWNvbmUgRm9uZSBkZSBvdXZpZG8uIERlcG9pcyBkZSAuLi4gJyBWaXJ0dWFsIEVhcicnICwgYmFzdGFuZG8gY2xpY2FyIG5vICZsdDtmb250IGNvbG9yPSZxdW90OzAwMDA
4OCZxdW90OyZndDsmbHQ7YiZndDtib3TDo28mbHQ7L2ImZ3Q7Jmx0Oy9mb250Jmd0OyBjb20gw61jb25lIE91dmlkby4gQXDDs3MgYWRxdWlyaXIgZSA8L3RleHQ+PHNpemU
+MTg1MDM8L3NpemU+PHJhdGluZz41LjUwNSU8L3JhdGluZz48bW9kaWZpZWQ+MTAvMDgvMjAwMiAxNjo1ODoxMCAtMDQwMDwvbW9kaWZpZWQ+PG9yZGVyPjE8L29yZGVyPjx
jcmM+LTE5NjM3MDA5MzQ8L2NyYz48Y2F0ZWdvcnk+PC9jYXRlZ29yeT48bGFuZz5lbi11czwvbGFuZz48Y2hhcnNldD53aW5kb3dzLTEyNTI8L2NoYXJzZXQ+PHNpdGVpZD4
0NjE1ODk0NjE8L3NpdGVpZD48cG9wX3Jhbms+MC4wMDAwMDwvcG9wX3Jhbms+PG9yaWdpbmlkPjA8L29yaWdpbmlkPjwvaXRlbT48L3NlYXJjaFJlc3VsdD4K
10  </base64>
11  </value>
12  </param>
13  </params>
14  </methodResponse>') OBJECT_VALUE
15  from dual
16  )
17  select XMLSERIALIZE(DOCUMENT XMLTYPE(BASE64_DECODE_CLOB(extract(OBJECT_VALUE,'/methodResponse/params/param/value/base64/text()'
).getClobVal())) as CLOB INDENT SIZE=2)
18    from XML
19  /
<?xml version="1.0" encoding="UTF-8"?>
<searchResult>
<numrows>1</numrows>
<found>1</found>
<wordinfo> botπo : 5</wordinfo>
<searchtime>0.006</searchtime>
<firstdoc>1</firstdoc>
<lastdoc>1</lastdoc>
<wordinfoall>botπo : 5 / 5</wordinfoall>
<item>
<urlid>19</urlid>
<url>http://central/garras/Quem_matou_JFK/artefatos/htm/7505.htm</url>
<content>text/html</content>
<title>SoundMAX</title>
<keywords/>
<desc/>
<text>... e comunicaτπo via Internet. Clique no &lt;font color="000088&
quot;&gt;&lt;b&gt;botπo&lt;/b&gt;&lt;/font&gt; com o logotipo Andrea em ... adqu
irir uma atualizaτπo, clicando no &lt;font color="000088"&gt;&lt;b&gt;
botπo&lt;/b&gt;&lt;/font&gt; com o φcone Fone de ouvido. Depois de ... &apos; Vi
rtual Ear&apos;&apos; , bastando clicar no &lt;font color="000088"&gt;
&lt;b&gt;botπo&lt;/b&gt;&lt;/font&gt; com φcone Ouvido. Ap≤s adquirir e </text>
<size>18503</size>
<rating>5.505%</rating>
<modified>10/08/2002 16:58:10 -0400</modified>
<order>1</order>
<crc>-1963700934</crc>
<category/>
<lang>en-us</lang>
<charset>windows-1252</charset>
<siteid>461589461</siteid>
<pop_rank>0.00000</pop_rank>
<originid>0</originid>
</item>
</searchResult>
SQL>And don't expect it to be the fastest soln in history.