为什么我的函数发送多个cURL请求失败？

Question

I have this function, historicalBootstrap, which I want to use to put three different datasets into a page:

$years = array(
        date('Y-m-d', strtotime('1 year ago')). ".json",
        date('Y-m-d', strtotime('2 years ago')). ".json",
        date('Y-m-d', strtotime('3 years ago')). ".json"    
    );

function historicalBootstrap($years, $id){

    for($i = 0; $i < 3; $i++){

        $date = $years[$i]; 

        $i = curl_init("http://openexchangerates.org/api/historical/{$date}?app_id={$id}");
        curl_setopt($i, CURLOPT_RETURNTRANSFER, 1);

        $jsonHistoricalRates = curl_exec($i);
        curl_close($i);

        $i = json_decode($jsonHistoricalRates);
        echo '<script>_'. $i . 'historical = '. json_encode($historicalRates) . ' ; ' . '</script>';

    }   
}

historicalBootstrap($years, $appId);

It seems I can use this approach to make one request, e.g. outside of the function block. Why is it that when I abstract this approach into the historicalBootstrap function that it fails? I am expecting three (_0 = ... , _1 = ... , _2 = ...) bootstrapped scripts.

Thank you.

Answer 1

You are using $i to control your for loop and also to contain the curl handle and also to contain a json decode result.

You are also decoding the returned json and then straight away encoding it again, not necessary.

Try changing it to

function historicalBootstrap($years, $id){

    for($i = 0; $i < 3; $i++){
        $date = $years[$i]; 
        $ch = curl_init("http://openexchangerates.org/api/historical/{$date}?app_id={$id}");
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        $jsonHistoricalRates = curl_exec($ch);
        curl_close($ch);
        echo '<script>_'. $i . 'historical = '. $jsonHistoricalRates . ';' . '</script>';
    }   
}

You could also make this more flexible by using foreach() instead of for

function historicalBootstrap($years, $id){
    foreach ($years as $i => $year) {
        $ch = curl_init("http://openexchangerates.org/api/historical/{$year}?app_id={$id}");
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        $jsonHistoricalRates = curl_exec($ch);
        curl_close($ch);
        echo '<script>_'. $i . 'historical = '. $jsonHistoricalRates . ';' . '</script>';
    }   
}

Now if you pass 4 years into the function it will not require amending this code.