PostgreSQL Merkez Bankası Döviz Kurları Stored Procedure

create_exchanges_table.sql

-- auto-generated definition
create table exchanges
(
    id              uuid default uuid_generate_v4() not null
        constraint exchanges_pk
            primary key,
    currency_id     uuid
        constraint exchanges_currencies_id_fk
            references currencies
            on delete restrict,
    date            date                            not null,
    unit            integer                         not null,
    forex_buying    double precision,
    forex_selling   double precision,
    banknote_buying double precision,
    banknot_selling double precision,
    reference_id    uuid
);

alter table exchanges
    owner to postgres;

create unique index exchanges_currency_id_date_uindex
    on exchanges (currency_id, date);

create_raw_data_table.sql

create table raw_data
(
    id            uuid      default uuid_generate_v4() not null
        constraint raw_data_pk
            primary key,
    created_date  timestamp default now()              not null,
    data          json                                 not null,
    exchange_date date                                 not null,
    request_date  date                                 not null
);

alter table raw_data
    owner to postgres;

get_exchange_rates.sql

create or replace procedure get_exchange_rates(request_date date)
language plpgsql
as $$
    declare
        data jsonb;
        err_context text;
        exchange_date text;
        url varchar;
begin
    if date_cmp(request_date, current_date) >= 1 then
        RAISE EXCEPTION 'Date cannot be greater than today.';
    end if;

    if date_cmp(request_date, current_date) = 0 then
        url:= 'https://www.tcmb.gov.tr/kurlar/today.xml';
    else
        url:= 'http://www.tcmb.gov.tr/kurlar/' || date_part('year', request_date) || to_char(request_date, 'mm') || '/' || to_char(request_date, 'dd') || to_char(request_date, 'mm') || date_part('year', request_date) || '.xml';
    end if;

    data:= get(url);

    if data is null then
        RAISE EXCEPTION 'Data not found.';
    end if;

    exchange_date:= data::jsonb->'Tarih_Date'->>'@Tarih';

    insert into raw_data (request_date, exchange_date, data) VALUES (request_date, to_date(exchange_date, 'DD.MMM.YYYY'), data->'Tarih_Date'->'Currency');
exception
    when others then
        GET STACKED DIAGNOSTICS err_context = PG_EXCEPTION_CONTEXT;
        RAISE INFO 'Error Name:%',SQLERRM;
        RAISE INFO 'Error State:%', SQLSTATE;
        RAISE INFO 'Error Context:%', err_context;
end;

$$

get_http_request_procedure.sql

create function get(uri character varying) returns json
    language plpython3u
as
$$
import json
import urllib3
from xmltodict import parse

http = urllib3.PoolManager()
r = http.request('GET', uri)

try:
    return json.dumps(parse(r.data))
except:
    return;

$$;

alter function get(varchar) owner to postgres;

transform_exchange_rate_procedure.sql

create or replace procedure transform_exchange_rate(process_date date)
language plpgsql
as $$
declare
    rec record;
    err_context text;
begin

    SELECT
        t.exchange_date,
        t.data as data
    into rec
    FROM (
        SELECT
               rd.exchange_date,
               rd.data
        FROM raw_data rd
        WHERE rd.exchange_date = process_date LIMIT 1
    ) t;

        IF rec IS NOT NULL THEN
            begin
                INSERT INTO exchanges (currency_id, date, unit, forex_buying, forex_selling, banknote_buying, banknot_selling)
                SELECT
                       c.id,
                       rec.exchange_date,
                       (d#>>'{Unit}')::integer,
                       (d#>>'{ForexBuying}')::double precision,
                       (d#>>'{ForexSelling}')::double precision,
                       (d#>>'{BanknoteBuying}')::double precision,
                       (d#>>'{BanknoteSelling}')::double precision
                FROM currencies c
                INNER JOIN LATERAL json_array_elements(rec.data) d ON (d->>'@Kod') = c.code;

                exception
                    when others then
                    GET STACKED DIAGNOSTICS err_context = PG_EXCEPTION_CONTEXT;
                    RAISE INFO 'Error Name:%',SQLERRM;
                    RAISE INFO 'Error State:%', SQLSTATE;
                    RAISE INFO 'Error Context:%', err_context;
            end;
        ELSE
            INSERT INTO exchanges(currency_id, date, unit, forex_buying, forex_selling, banknote_buying, banknot_selling, reference_id)
            SELECT e.currency_id, process_date, e.unit, e.forex_buying, e.forex_selling, e.banknote_buying, e.banknot_selling, e.id
            FROM exchanges e
            WHERE e.date = (
                SELECT max(e.date) max_date
                FROM exchanges e
                WHERE e.date <= process_date and (process_date - e.date) between 1 and 10 and e.reference_id IS NULL
            );
        END IF;
end; $$;