First Octave Function using Oanda API

As part of my on-going code revision I have written my first Octave function to use the Oanda API. This is just a simple "proof of concept" function which downloads an account summary.

## Copyright (C) 2020 dekalog
## 
## This program is free software: you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation, either version 3 of the License, or
## (at your option) any later version.
## 
## This program is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU General Public License for more details.
## 
## You should have received a copy of the GNU General Public License
## along with this program.  If not, see
## .

## -*- texinfo -*- 
## @deftypefn {} {@var{retval} =} account_summary ()
##
## Returns the Oanda account summary given by the Oanda API call
##
## "https://api-fxtrade.oanda.com/v3/accounts//summary"
##
## Internally the function runs system() which calls the Curl
## library for the actual API download. The function is hard coded
## with the account token and account ID.
## 
## @seealso{}
## @end deftypefn

## Author: dekalog 
## Created: 2020-04-04

function retval = account_summary ()

## set up the headers
query = [ 'curl -s -H "Content-Type: application/json"' ] ; ## -s is silent mode for Curl for no paging to terminal
query = [ query , ' -H "Authorization: Bearer XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"' ] ;

## construct the API call
query = [ query , ' "https://api-fxtrade.oanda.com/v3/accounts/XXX-XXX-XXXXXX-XXX/summary"' ] ;

## call to use external Unix systems/Curl and return result
[ ~ , retval ] = system( query , RETURN_OUTPUT = 'TRUE' ) ;

## convert the returned json object to Octave structure
retval = load_json( retval ) ;

endfunction

The function uses the Curl library, so obviously this must be installed on your system, and to convert the returned JSON object to a native Octave structure the Octave wrapper function available from this Github, https://github.com/Andy1978/octave-rapidjson, is used. For this wrapper function to work rapidjson must also be installed.

I shall probably write more such Octave-OandaAPI functions for my particular use cases and will blog about them as and when I do so.