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Re: Advice on how to process xsd:base64Binary XML element retrieved from a web service.
- From: Scott Klement <sk@xxxxxxxxxxxxxxxx>
- To: HTTPAPI and FTPAPI Projects <ftpapi@xxxxxxxxxxxxxxxxxxxxxx>
- Subject: Re: Advice on how to process xsd:base64Binary XML element retrieved from a web service.
- Date: Thu, 12 Dec 2013 23:30:07 -0600
hi Paul,
HTTPAPI was originally written for OS/400 V4R2, and therefore does not
"directly" support variables longer than 65535 characters long.
However, in many cases HTTPAPI does have pointer-based interfaces that
allow data as large as 16 MB to be returned -- so in order to handle
data "up to approx 1 MB" you will want to use the pointer-based
interfaces. You can use them in conjunction with V7R1's support for
large variables.
Steps:
1) Before calling http_url_post_xml(), you should call
http_XmlReturnPtr(*ON). What this does is change the way the XML
parser returns data. Instead of returning as a 65535 character string,
it will now return it as a data structure, that has subfield for a
pointer, and a subfield with a 10i 0 integer containing the length of
the string in bytes.
D XmlString_t ds qualified Template
D Data *
D Len 10i 0
2) Change your 'Incoming' procedure (NOTE: you can call this procedure
whatever you like, it does not have to be 'Incoming', that was just a
name I used as an example) to receive this data structure in place of
the 'value' string.
D Incoming PR
D rate 8F
D depth 10I 0 value
D name 1024A varying const
D path 24576A varying const
D value likeds(XmlString_t)
D attrs * dim(32767)
D const options(*varsize)
3) Now that 'value' is coming in as a pointer, it can be as large as
you want. You can now pass the 'value' parameter to tbe base64_decode
procedure to eliminate the base64 encoding. Personally I like to use a
VARYING variable for this sort of thing, and there's a trick to working
with VARYING as a pointer... you need to set it's length to the
maximum length first, then pass the address of only the data portion,
then set it's length back to the returned length.
D resultVar s len(2000000) varying
%len(resultVar) = %len(resultVar: *MAX);
decodedlen = base64_decode( value.data
: value.len
: %addr(resultVar: *data)
: %len(ResultVar: *MAX) );
%len(resultVar) = decodedlen;
4) Now you have the decoded data in 'resultVar'. However, you should
know that this data will have the exact same binary value that it had
when it was encoded. If your data is text and the sender had it
encoded in ASCII (or Unicode), then your data in resultVar will in
ASCII, so you'll probably want to translate it to EBCDIC next.
If the data in resultVar is not text, like an image, PDF, Word
Document, sound file, etc... then you won't want to translate it to
EBCDIC, as that would corrupt the data. (That is what is meant by
'binary')
5) Not sure what you want to do next, it'll depend on the purpose of
this data. Should it be written to the IFS? Stored in a BLOB? So
I'll leave that part as an exercise for you.
Good luck....
On 12/12/2013 9:48 AM, [1]PReid@xxxxxxxxxxxx wrote:
Hello everyone. I am not very experienced with Web Services so bear
with me. I did a fair bit of research on the various forums before
posting, but I failed to find a good example of what I am looking for.
I'm hoping that someone can help, possibly with an example.
I am predominately an RPG programmer. We are running an IBM Power 7 at
V7R1, and I have Scott's HTTPAPI V1.24 downloaded and installed. I am
using HTTPAPI to consume another Web Service and it works beautifully.
My latest challenge it that I have consume a Web Service that includes
an element in the XML response that is data type xsd:base64Binary and
I'm not really sure how to do it. The WSDL for this web service is:
[1][2]https://www.myshawtracking.ca/otsWebWS/services/OTSWebSvcs/wsdl/OTSW
ebSvcs.wsdl
The WIKI for this Web Service is:
[2][3]https://intinfo.myqualcomm.com/display/iWebInt/ESS+High-Volume+Deque
ue
The method that I must consume is named DEQUEUE2.
I have created an RPG program that POSTS a request to the Web Service
using the following HTTPAPI subprocedure:
rc = http_url_post_xml(
'[4]https://www.myshawtracking.ca:443/otsWebWS/services/OTSWebSvcs'
: %addr(SOAP) + 2
: %len(SOAP)
: *NULL
: %paddr(Incoming)
: %addr(rate)
: HTTP_TIMEOUT
: HTTP_USERAGENT
: 'text/xml'
: '[5]http://www.qualcomm.com/dequeue2');
I am receiving rc = 1 which I believe means that I am successfully
receiving an XML response. FYI - The procedure "Incoming" was copied
from Scott's EXAMPLE11.
The response XML is as follows.
<soapenv:Body>
<dequeue2Response>
<dequeue2Return>
<count>6</count>
<transactionIdOut>58744654</transactionIdOut>
(transactions>
PD94bWwgdmVyc2lvbj0iMS4wIiBlbmNvZGluZz0iVVRGLTgiPz48dHJjaz4=
</transactions>
</dequeue2Return>
</dequeue2Response>
</soapenv:Body>
The "transactions" element is xsd:base64Binary and I don't know how to
decode it. I have downloaded Scott's BASE64R4 service program and I
suspect I'd use procedure BASE64_DECODE, but I'm not sure how I would
employ it in this situation. Also...according to the wiki the
"transactions" element could be as large as "Approximately 1mb"
although I'm not really sure what they mean by approximately??
The "count" and "transactionIdOut" and not encoded and I need the data
in them in addition to the encoded data.
I understand that I may not even be using the correct post procedure
(remember I'm not that experienced) and in the interim I am going to
try some of Scott's other procedures.
Any help or examples on how to get this data would be much appreciated.
Thanks!
___________________________________________________________
Paul Reid
Application Developer III
Erb Group of Companies | 290 Hamilton Road | New Hamburg, Ontario | N3A
1A2
Phone: 519.662.6133 ext. 2363
Web: [3][6]http://www.erbgroup.com/
References
1. [7]https://www.myshawtracking.ca/otsWebWS/services/OTSWebSvcs/wsdl/OTSWebS
vcs.wsdl
2. [8]https://intinfo.myqualcomm.com/display/iWebInt/ESS+High-Volume+Dequeue
3. [9]http://www.erbgroup.com/
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References
1. mailto:PReid@xxxxxxxxxxxx
2. https://www.myshawtracking.ca/otsWebWS/services/OTSWebSvcs/wsdl/OTSW
3. https://intinfo.myqualcomm.com/display/iWebInt/ESS+High-Volume+Deque
4. https://www.myshawtracking.ca/otsWebWS/services/OTSWebSvcs
5. http://www.qualcomm.com/dequeue2
6. http://www.erbgroup.com/
7. https://www.myshawtracking.ca/otsWebWS/services/OTSWebSvcs/wsdl/OTSWebSvcs.wsdl
8. https://intinfo.myqualcomm.com/display/iWebInt/ESS+High-Volume+Dequeue
9. http://www.erbgroup.com/
10. http://www.scottklement.com/mailman/listinfo/ftpapi
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