[GNC-dev] Robust error handling and respecting the Apha Vantage API limits in gnc-fq-helper.

[David H]

Mike/Edward, I'm not sure if either of you have seen Vince's posting in
Finance-quote-devel <finance-quote-devel at lists.sourceforge.net> which seems
like he's working on a similar thing?

Copy below....

Cheers Dave H


Hi,

In June, Erik sent a message about his idea for cleaning up the FQ API to
have consistent ways to set/get instance variables and expand new to allow
for named parameters and module specific data.

One benefit is a sustainable way to enable users to register API keys for
specific modules.

I just pushed the branch "new-new" to explore these ideas.

See the file
https://raw.githubusercontent.com/finance-quote/finance-quote/new-new/new-API-notes.txt
for
details about the set/get methods.


I used the new API to thread an API key to the IEXCloud module from the
test suite as an example:
https://raw.githubusercontent.com/finance-quote/finance-quote/new-new/t/iexcloud.t


If there is agreement to proceed with the API update there are a few things
to do and I can help:

- updating the POD documentation for Quote.pm
- enabling AlphaVantage to use the module specific data as another source
for its API key
- renew discussion with gnucash developers on enabling users to specify API
keys for more modules



Best,

Vince


On Sun, 19 Jan 2020 at 12:52, Mike Alexander <mike at msalexander.com> wrote:

> I'm glad you're looking at this since it does need some work.  However I
> think there are a couple of things you're not aware of.  I, too, have
> quite a ffew currencies in my file (around 30) and by coincidence I was
> running a price fetch in the background when I first saw your message.
> It completed successfully after fetching all currency quotes as usual.
>
> You're right that GnuCash fetches one currency per call, but this is the
> only API for currencies that F::Q provides.  It fetches all the other
> quotes for a given source in one call to F::Q.  The F::Q currency quote
> code has a test for the rate limiting message that AlphaVantage returns
> when currency quote fetches come too fast.  However at some time in the
> past AlphaVantage changed this message.  I updated F::Q to look for the
> new message and sent a pull request upstream.  This pul request has
> never been applied which means that the current F::Q does not recognize
> when AlphaVantage is trying to tell it to slow down.  My copy of F::Q
> has this change which is probably why it works for me and not for you.
>
> The patch is simple, just change it to look for a "Note" field in the
> returned data instead of an "Information" field.
>
> Try this and see if it helps.
>
> Your change to make GnuCash handle F::Q failures better seems like a
> good idea.  Putting the delay on GnuCash's side of the API might also be
> a good idea, but really shouldn't be necessary.  It also would be a
> problem for someone who has actually paid for an AlphaVantage
> subscription and hence can get currency quotes faster.  Some day I hope
> that F::Q will find a currency quote source that works better and faster
> at which time you wouldn't want the delay in GnuCash.
>
>          Mike
>
> diff --git a/lib/Finance/Quote.pm b/lib/Finance/Quote.pm
> index b66bca9..6703935 100644
> --- lib/Finance/Quote.pm
> +++ lib/Finance/Quote.pm
> @@ -274,9 +274,9 @@ sub currency {
>       if ( !$json_data || $json_data->{'Error Message'} ) {
>         return undef;
>       }
> -#     print "Failed: " . $json_data->{'Information'} . "\n" if
> (($try_cnt < 5) && ($json_data->{'Information'}));
> -    sleep (20) if (($try_cnt < 5) && ($json_data->{'Information'}));
> -  } while (($try_cnt < 5) && ($json_data->{'Information'}));
> +#     print "Failed: " . $json_data->{'Note'} . "\n" if (($try_cnt < 5)
> && ($json_data->{'Note'}));
> +    sleep (20) if (($try_cnt < 5) && ($json_data->{'Note'}));
> +  } while (($try_cnt < 5) && ($json_data->{'Note'}));
>
>     my $exchange_rate = $json_data->{'Realtime Currency Exchange
> Rate'}->{'5. Exchange Rate'};
>
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