RE: RPG, retrieving JSON data from a web service

Looks like you're using an SQL LOB and then taking a substring of it.
How do you know that 32000 is the correct length for the substring, and won't chop off part of your document?

When accessing a LOB-File, the data length is returned in MYLOB_DL.
So it is possible to read exactly the returned data into a RPG Variable (with an SQL SET Statement).

Mit freundlichen Grüßen / Best regards

Birgitta Hauser

"Shoot for the moon, even if you miss, you'll land among the stars." (Les Brown)
"If you think education is expensive, try ignorance." (Derek Bok)
"What is worse than training your staff and losing them? Not training them and keeping them!"
„Train people well enough so they can leave, treat them well enough so they don't want to.“ (Richard Branson)


-----Original Message-----
From: RPG400-L [mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Scott Klement
Sent: Dienstag, 5. September 2017 22:37
To: RPG programming on the IBM i (AS/400 and iSeries) <rpg400-l@xxxxxxxxxxxx>
Subject: Re: RPG, retrieving JSON data from a web service

Hi Booth,

Looks like you're using an SQL LOB and then taking a substring of it.
Sorry if you've previously explained this (I haven't followed the whole
conversation) but why are you doing that? Seems like a very weird thing to do. How do you know that 32000 is the correct length for the substring, and won't chop off part of your document?

Also, the call to yajl_buf_load_tree seems wrong, you're specifying
%addr(var) instead of %addr(var:*data). That will only work if the variable doesn't store other things besides data in it. Are you sure that's what you want to do?

Honestly, I'm finding this whole thread hard to follow, there's so much "noise" in it. So a full description that doesn't rely on reading other messages in this thread would help a lot :-)

-SK




On 9/4/2017 7:29 PM, Booth Martin wrote:

I've read through Scott's material several times. Used his code.
Clearly I have missed something.

Currently this code:

MyIFSFile_Name = wURI;
MyIFSFile_NL = %Len(%trim(MyIFSFile_Name));
MyIFSFile_FO = SQFRD;

Exec SQL Set :MyText = Substr(:MyIFSFile, 1, 32000);
wLength = %len(MyText);

gives me:

EVAL MyText
MYTEXT =
....5...10...15...20...25...30...35...40...45...50...55...60
1 '[{"name":"George Washington", "life":"1732-1799", "term":"17'
61 '89-04-30 to 1797-03-04", "party":"No Party"},{"name":"John A'
121 'dams", "life":"1735-1826", "term":"1797-03-04 to 1801-03-04"'
181 ', "party":"Federalist"},{"name":"Thomas Jefferson", "life":"'
241 '1743-1826", "term":"1801-03-04 to 1809-03-04", "party":"Demo'
301 'cratic-Republican"},{"name":"James Madison", "life":"1751-18'
361 '36", "term":"1809-03-04 to 1817-03-04", "party":"Democratic-'
421 'Republican"},{"name":"James Monroe", "life":"1758-1831", "te'
481 'rm":"1817-03-04 to 1825-03-04", "party":"Democratic-Republic'
541 'an"},{"name":"John Quincy Adams", "life":"1767-1848", "term"'
601 ':"1825-03-04 to 1829-03-04", "party":"Democratic-Republican"'
661 '},{"name":"Andrew Jackson", "life":"1767-1845", "term":"1829'
721 '-03-04 to 1837-03-04", "party":"Democratic"},{"name":"Martin'
781 ' Van Buren", "life":"1782-1862", "term":"1837-03-04 to 1841-'
841 '04-04", "party":"Democratic"},{"name":"William Henry Harriso'
901 'n", "life":"1773-1841", "term":"1841-03-04 to 1841-04-04", "'
961 'party":"Whig"},{"name":"John Tyler", "life":"1790-1862", "te'
1021 'rm":'

And then this line:

docnode = yajl_buf_load_tree(%addr(MyText): wLength: errMsg );

gets :

EVAL errMsg
ERRMSG =
....5...10...15...20...25...30...35...40...45...50...55...60
1 'lexical error: invalid char in json text. '


On 9/2/2017 8:21 AM, Bradley Stone wrote:

There is no node named success in your JSON. That's why node is null.

Instead, you have an array of objects with name, life, term and
party. You need to process through that array and for each object
individually.

Processing arrays with YAJL is easy, and I think Jon already posted
an example of how to handle that. It should be in the archives or an
older thread.

Here's a great PDF from Scott that maybe you should spend some time
on to understand what JSON is, how it works, and how to use YAJL with it:

http://www.scottklement.com/presentations/Working%20with%20JSON%20in%
20RPG.pdf


Bradley V. Stone
www.bvstools.com
MAILTOOL Benefit #11 <https://www.bvstools.com/mailtool.html>: Save
Emails
- Save emails that are sent out at a global, user or individual email
level.

--
This is the RPG programming on the IBM i (AS/400 and iSeries) (RPG400-L) mailing list To post a message email: RPG400-L@xxxxxxxxxxxx To subscribe, unsubscribe, or change list options,
visit: http://lists.midrange.com/mailman/listinfo/rpg400-l
or email: RPG400-L-request@xxxxxxxxxxxx
Before posting, please take a moment to review the archives at http://archive.midrange.com/rpg400-l.

Please contact support@xxxxxxxxxxxx for any subscription related questions.

Help support midrange.com by shopping at amazon.com with our affiliate link: http://amzn.to/2dEadiD