[GNC] Adding Transactions From Another Program

Tue Apr 28 18:07:50 EDT 2020

David, I did look at the Python bindings info a while back but at the time
did not feel like getting started with Python because I just wanted to get
done what I wanted to get done.  I'm mostly a .NET & SQL guy so I stuck
with what I knew.  Fast forward a few months and add in the bounty of extra
time that the quarantine has afforded and I have since started dipping my
toes into Python a bit.  I'm actually kind of excited now to take a fresh
look at the Python bindings capabilities for GC.  I agree with you 100%
that there may be no need for me nor for Hal to do our own things if there
is an existing way!

On Tue, Apr 28, 2020 at 5:59 PM David H <hellvee at gmail.com> wrote:

> Have you checked out the GnuCash Python Bindings -
> https://code.gnucash.org/docs/MAINT/python_bindings_page.html - no point
> in re-inventing the wheel :-)
>
> Cheers David H.
>
> What can Python Bindings be used for ?
>
> The python bindings supply the ability to access a wide range of the core
> functions of GnuCash. You can read and write Transactions, Commodities,
> Lots, access the business stuff... You gain the ability to manipulate your
> financial data with a flexible scripting language.
>
> Not everything GnuCash can is possible to access though. The bindings
> focus on basic accounting functions. Have a look at the examples to get an
> impression.
>
> Some functions are broken because they have not been wrapped properly.
> They may crash the program or return unaccessible values. Please file a bug
> report if you find one to help support the development process.
>
> On Wed, 29 Apr 2020 at 07:44, Stu Perlman <sgperlman at gmail.com> wrote:
>
>> Hal,
>>
>> I'm sort of doing a liter version of what you are describing. I do
>> manipulate some GC data from outside of GC.  I have GC setup with the
>> MySQL
>> backend and while I don't create any new transactions from outside of GC I
>> do manipulate them. I have some SQL routines that I created to clean up
>> data points such as the Memo & Notes attributes that are part of each
>> transaction. I have not run into any problems or data corruption after a
>> few months of doing this.  I did put a circuit breaker into my bolt-on app
>> that at startup the 1st thing it does it check the GC lock record and if
>> it
>> detects that GC may still be running it will not allow my SQL routines to
>> do anything.
>>
>> INSERTING new transaction records using SQL on the surface appears like it
>> should be simple enough but I would proceed with extreme caution and a lot
>> of testing as you go.  I did not try creating any new transactions but I
>> did try to create my own little routine  (and then abandoned the effort)
>> to let me set monthly budget amounts. *The reasons for that attempt are
>> not
>> important to this thread but the outcome may be*.
>>
>> I gave up after spending time creating the logic that I needed to insert
>> into and/or change records in the SQL table [budget_amounts].  Everything
>> I
>> tested always looked perfect in the SQL backend until I went to work with
>> that data in GC.  It was like I did not change anything behind the scenes
>> once I opened up GC again.  I would go back to the SQL world and would
>> sometimes notice that my changes to [budget_amounts] were either being a)
>> ignored, b) wiped out or c) some other corruption.  Through trial and
>> error, I discovered that the SQL table [slots] (and it's various
>> pseudo-tables) also maintains budget amount data and that said data in
>> [slots] will persist when GC is restarted after my changes from SQL were
>> executed.  It was then that I decided that the amount of effort that I
>> would spend reverse engineering the logic that GC is using with the
>> [slots]
>> table was never going to be worth the reward nor the risk.
>>
>> I don't know for a fact that for your particular use case that writing to
>> [slots] will even be required because I never dug into the transactions
>> that deeply.  Maybe [transactions] and [splits] are isolated from the
>> apparently superior related data that GC maintains in [slots].  If you
>> happen to know the languages that the GC engine is written in you might be
>> able to get the answer with a little bit of code review instead of the
>> time
>> consumed doing a bunch of testing, observing, and evaluating.
>>
>> Good luck!  I'd love to know how it goes for you if you end up pursuing
>> this idea.
>>
>> - Stu
>>
>>
>>
>> On Tue, Apr 28, 2020 at 3:15 PM Hal Vaughan <hal at hal.dance> wrote:
>>
>> > I’ve done some research on this issue and I’m trying to determine if
>> it’s
>> > worth doing more or if I’d just spend time on this topic and find it
>> won’t
>> > work.
>> >
>> > I have a situation I’ve been told GnuCash can’t handle, but I have a
>> > Python library that can handle it.  (It has to do with calculating
>> interest
>> > on a credit line with a variable balance.)
>> >
>> > Years ago, I remember checking into GnuCash and reading the XML data
>> files
>> > and finding that each transaction seemed to have a UUID with it, but
>> that
>> > the other data in each entry would be easy to generate from my own
>> library
>> > written in Python.  I also know that now the data files can be in SQL,
>> > using several different engines, and that if it’s an XML file, it’s in
>> gzip
>> > format.
>> >
>> > I do not need my program to run as a plug-in or anything like that.
>> (Last
>> > I looked, I had to install MacPorts for that, and last time I installed
>> > MacPorts, it made a mess of the libraries for my old Perl scripts and
>> some
>> > Python ones.)
>> >
>> > But here’s what I’d like to do:
>> > 1. Enter my transactions involving the credit line normally in GnuCash.
>> > 2. Exit GnuCash
>> > 3. Run my Python script that would read the GnuCash data file and find
>> all
>> > transactions with any credit lines.
>> > 4. Do the interest calculations for my credit line
>> > 5. Add a debit transaction for the interest amount before each new
>> > transaction with the credit line
>> > 6. Edit the comment field for each transaction involving the credit line
>> > to include notes on interest and totals
>> > 7. Save the ledger and exit my library script.
>> > 8. Run GnuCash again and have the new transactions included and their
>> > amounts included in any account totals.
>> >
>> > Is this even possible?  I don’t mind doing the research to find out how
>> to
>> > generate a transaction ID and all the rest.  I just want to know if I
>> can
>> > use my own library to add transactions to a file (or edit comments in a
>> > transaction) and, when I’m done, for GnuCash to be able to read that
>> file,
>> > with my new transactions, in and to include the amounts in the added
>> > transactions in account totals.
>> >
>> >
>> >
>> > Hal
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