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#[macro_use]
extern crate serde_derive;
#[macro_use]
extern crate failure;
extern crate serde;
extern crate serde_json;
extern crate reqwest;
mod types;
pub use types::CurrencyRates;
use types::*;
use std::collections::HashMap;
use std::io::Read;
use failure::Error;
#[derive(Debug, Fail)]
pub enum CurrencyLayerError {
#[fail(display = "Invalid currency symbol: {}", symbol)]
InvalidCurrency {
symbol: String,
},
#[fail(
display = "Currency Layer responded with an error: Code: {}. Message: {}", code, message
)]
ServerError {
code: u16,
message: String,
},
}
pub struct Client {
key: String,
http_client: reqwest::Client,
}
impl Client {
pub fn new(key: &str) -> Client {
Client {
key: String::from(key),
http_client: reqwest::Client::new(),
}
}
pub fn get_live_rates(
&self,
base: &str,
currencies: Vec<&str>,
) -> Result<CurrencyRates, Error> {
return self.get_rates(base, currencies, None, "http://apilayer.net/api/live");
}
pub fn get_historical_rates(
&self,
base: &str,
currencies: Vec<&str>,
date: (u16, u16, u16),
) -> Result<CurrencyRates, Error> {
return self.get_rates(
base,
currencies,
Some(date),
"http://apilayer.net/api/historical",
);
}
fn get_rates(
&self,
base: &str,
currencies: Vec<&str>,
date: Option<(u16, u16, u16)>,
url: &str,
) -> Result<CurrencyRates, Error> {
let mut mut_currencies = currencies.clone();
mut_currencies.push(base);
let currencies_str = mut_currencies.join(",");
let mut query_items = vec![
("currencies", currencies_str),
("format", "1".into()),
("access_key", self.key.clone()),
];
if let Some(d) = date {
query_items.push(("date", format!("{}-{:02}-{:02}", d.0, d.1, d.2)));
}
let request = self.http_client.get(url).query(&query_items).send();
let mut res = request?;
let mut body_buf = String::new();
res.read_to_string(&mut body_buf)?;
let success_guard: SuccessGuard = serde_json::from_str(body_buf.as_str())?;
if success_guard.success {
let result: CurrencyRates = serde_json::from_str(body_buf.as_str())?;
if let Some(base_quote) = result.quotes.get(&format!("USD{}", base)) {
let base_val = 1.0 / base_quote;
let mut res = CurrencyRates {
timestamp: result.timestamp,
quotes: HashMap::new(),
};
for c in currencies {
if let Some(quote) = result.quotes.get(&format!("USD{}", c)) {
res.quotes.insert(String::from(c), base_val * quote);
} else {
return Err(CurrencyLayerError::InvalidCurrency {
symbol: String::from(c),
}.into());
}
}
return Ok(res);
} else {
return Err(CurrencyLayerError::InvalidCurrency {
symbol: String::from(base),
}.into());
}
} else {
let result: ErrorResponse = serde_json::from_str(body_buf.as_str())?;
return Err(CurrencyLayerError::ServerError {
code: result.error.code,
message: result.error.info,
}.into());
}
}
}