以下代码的货币汇率有时有效，有时无效，不太可靠。有没有更好的方法在PHP中获取货币汇率？
public function getJPYtoUSDExchangeRate(){
$from = 'JPY';
$to = 'USD';
$amount = 1;
$data = file_get_contents("https://finance.google.com/finance/converter?a=$amount&from=$from&to=$to");
preg_match("/<span class=bld>(.*)<\/span>/",$data, $converted);
$converted = preg_replace("/[^0-9.]/", "", $converted[1][0]);
return number_format(round($converted, 3),2);
}
你有几个问题：
你应该做什么：
这样，即使API调用失败，你仍然可以访问略旧的汇率，这在大多数情况下比失败要好。
有很多API（免费或收费）提供此服务。
我知道一个好的数据源是欧洲央行，他们提供了一个XML数据源，已经存在多年，并提供32种货币相对于EUR的汇率。
OpenExchangeRates也提供了一个免费计划，每月限制1000个请求，足以每小时更新汇率。它提供了170种货币相对于USD的汇率。
无论你选择哪个数据源，你都需要解析它（如果是XML）或者使用json_decode()（如果是JSON），并将值存储在你的数据库中。最好设置一个cron job来每天甚至每小时运行你的导入脚本。
实际的解析和导入步骤超出了本问题的范围，但假设有一个简单的MySQL表来保存记录：
CREATE TABLE exchange_rate(
target_currency CHAR(3) COLLATE ascii_bin NOT NULL PRIMARY KEY,
exchange_rate DOUBLE NOT NULL
);
这是我最近回答过的问题。上面的信息提供了将基础货币（EUR或USD）转换为另一种货币的汇率，但没有给出如何在两种任意货币之间进行转换的线索。我建议您使用一个能够为您处理这些转换的适当库，例如brick/money - 免责声明：我是作者。
以下是如何配置它以从上述表格中加载您的汇率：
use Brick\Money\CurrencyConverter;
use Brick\Money\ExchangeRateProvider\PDOProvider;
use Brick\Money\ExchangeRateProvider\PDOProviderConfiguration;
use Brick\Money\ExchangeRateProvider\BaseCurrencyProvider;
// set to whatever your rates are relative to
$baseCurrency = 'USD';
// use your own credentials, or re-use your existing PDO connection
$pdo = new PDO('mysql:host=localhost;dbname=test', 'root', '');
$configuration = new PDOProviderConfiguration();
$configuration->tableName = 'exchange_rate';
$configuration->exchangeRateColumnName = 'exchange_rate';
$configuration->targetCurrencyColumnName = 'target_currency';
$configuration->sourceCurrencyCode = $baseCurrency;
// this provider loads exchange rates from your database
$provider = new PDOProvider($pdo, $configuration);
// this provider calculates exchange rates relative to the base currency
$provider = new BaseCurrencyProvider($provider, $baseCurrency);
// this currency converter can now handle any currency pair
$converter = new CurrencyConverter($provider);
使用方法：
{{你需要在这里添加具体的使用方法}}use Brick\Math\RoundingMode;
use Brick\Money\Money;
$money = Money::of(10, 'EUR'); // EUR 10.00
$converter->convert($money, 'CAD', RoundingMode::DOWN); // CAD 15.27
CurrencyFreaks API提供179种货币的可靠汇率，支持多种编程语言的JSON和XML格式。使用CurrencyFreaks API，您还可以更改“基准”货币，并获取特定货币的汇率。
以下是使用PHP的简单货币汇率终端：
setUrl('https://api.currencyfreaks.com/latest
?apikey=YOUR_APIKEY
&base=GBP');
$request->setMethod(HTTP_Request2::METHOD_GET);
$request->setConfig(array(
'follow_redirects' => TRUE
));
try {
$response = $request->send();
if ($response->getStatus() == 200) {
echo $response->getBody();
}
else {
echo 'Unexpected HTTP status: ' . $response->getStatus() . ' ' .
$response->getReasonPhrase();
}
}
catch(HTTP_Request2_Exception $e) {
echo 'Error: ' . $e->getMessage();
}
JSON响应将是：
{
"date": "2020-10-06 11:22:00+00",
"base": "GBP",
"rates": {
"FJD": "2.737385252915371",
"MXN": "27.74546375788785",
"STD": "27185.017172962733",
"LVL": "0.8482572402792966",
"SCR": "23.257414775003944",
"CDF": "2535.4260357935937",
"BBD": "2.585121591194042",
"GTQ": "10.055244048403818",
"CLP": "1031.8523300993463",
"HNL": "31.82062875327341",
"UGX": "4769.159332676713",
"ZAR": "21.445845580346873",
"TND": "3.542262860333636",
"CUC": "1.2926654930214643",
"BSD": "1.292560795597021",
"SLL": "12676.789824444395",
"SDG": "71.5109260164052",
"IQD": "1542.8992384231794",
"GMD": "66.89002117214584",
"CUP": "34.25286108332106",
"TWD": "37.17921872455271",
"RSD": "128.99756740058268",
"DOP": "75.46618143934401",
"KMF": "540.1610026652604",
.
.
.
[179 Currencies]
}
}
我希望它能够工作。
<?php
class EXCHANGE {
public $Rates;
public $Rate;
public function __construct(){
$this->Rates = $this->fetchAllRates();
foreach($this->Rates as $currency => $rate){
$this->Rate[$currency] = $rate['latest'];
}
}
public function fetchAllRates(){
$currencies = ["AUD","BRL","CNY","EUR","HKD","INR","IDR","JPY","MXN","NZD","NOK","PEN","RUB","SAR","SGD","ZAR","KRW","SEK","CHF","TWD","TRY","GBP","USD"];
$cURL = curl_init();
curl_setopt($cURL, CURLOPT_URL, "https://www.bankofcanada.ca/valet/observations/group/FX_RATES_DAILY/json?start_date=2010-01-01");
curl_setopt($cURL, CURLOPT_RETURNTRANSFER, 1);
$rates = curl_exec($cURL);
curl_close($cURL);
$rates = json_decode($rates,true)['observations'];
foreach($currencies as $currency){
foreach($rates as $rate){
$AllRates[$currency][$rate['d']] = $rate['FX'.$currency.'CAD']['v'];
$AllRates[$currency]['latest'] = $rate['FX'.$currency.'CAD']['v'];
}
}
return $AllRates;
}
public function convert($value,$from,$to){
if($to == "CAD"){ return $value*$this->Rate[$from]; }
else { return ($value*$this->Rate[$from])/$this->Rate[$to]; }
}
}
$Exchange = new EXCHANGE();
foreach($Exchange->Rate as $currency => $rate){
echo $currency.': '.$rate."<br>\n"; // Listing all the exchange rates
}
echo "Converting 2.00 USD to CAD : ".$Exchange->convert(2,"USD","CAD")."\n"; //2022-02-23 = 2.5486
echo "Converting 2.00 USD to AUD : ".$Exchange->convert(2,"USD","AUD")."\n"; //2022-02-23 = 2.7708197434225
更新： 我最初忘记了放置转换方法。
信息： 这个类使用加拿大银行的RSS源。它不是最准确的数据，因为它只在每个工作日更新一次。$Rate属性包含CAD货币的汇率。因此，要转换其他货币，首先将初始货币转换为CAD，然后再转换为新货币。所以在上面提供的例子中，2.00美元被转换为2.5486加元。然后除以澳元的汇率，结果为2.7708197434225澳元。
convert函数。 - loretoparisi