NAME
Finance::Currency::Convert::Esunbank - Query currency exchange rates
from Esunbank
VERSION
v0.1.0
DESCRIPTION
This module crawl and parses currency exchange rates listed on this web
page:
https://www.esunbank.com.tw/bank/iframe/widget/rate/foreign-exchange-rate
. All prices on this page are in TWD (Taiwan Dollar.) For this reason,
it can only convert non-TWD currencies to TWD.
FUNCTIONS
The following functions are exportable, but not exported by default.
Some annotations with fictional Types are used in the following
documentation just for the purpose of explaination. No Type-validation
are implemented, nor are they defined. Not in this module.
"Num" referrer to a number, "Currency" is a short string such as 'TWD',
'USD'. The notation `Maybe[T]` means that the variable can contain a
value either be of type T, or undef. See: Types::Standard or
Moose::Util::TypeConstraints for more description of these notations.
convert_currency
Definition:
($error :Maybe[Str], $result :Maybe[Num]) =
convert_currency(
$amount :Num
$from :Currency,
$to :Currency
)
When it is successful, $error is undef and $result contained the parsed
output.
When error of some kind happens, $error contains the error message and
$result is undef.
Example Usage:
# Error-checking
my ($err, $n) = convert_currency(100, 'USD', 'TWD');
die "Error: $err": if $err;
say "100 USD is about $n TWD";
# Ignore error message. Checks the result directly.
my $n = convert_currency(100, 'USD', 'TWD');
if ( defined($n) ) {
say "100 USD is about $n TWD";
} else {
say "Failed to convert 100 USD to TWD";
}
get_currencies
With this function, the entire exchange rate table are parsed and
returned in the special strucutre.
Definition:
($error :Maybe[Str], $result :Maybe[ArrayRef[Rate]]) =
convert_currency(
$amount :Num,
$from :Currency,
$to :Currency
)
When it is successful, $error is undef and $result contained the parsed
output.
When error of some kind happens, $error contains the error message and
$result is undef.
Usage:
# Error-checking
my ($err, $o) = get_currencies();
die "Error: $err": if $err;
do_something($o);
# Ignore error message. Checks the result directly.
my $o = get_currencies();
if ($o) {
...
} else {
...
}
The "Rate" type is a HashRef with 5 specific key-value pairs that looks
like this:
{
currency => "USD",
zh_currency_name => "美金",
en_currency_name => "USD",
buy_at => 33.06,
sell_at => 33.56
}
This structure is just a directly translation of the rate exchange
table shown on the source web page.
AUTHOR
Kang-min Liu <
[email protected]>
LICENSE
This is free software, licensed under:
The MIT (X11) License
