本文為英文版的機器翻譯版本,如內容有任何歧義或不一致之處,概以英文版為準。
使用 建立URL簽章 PHP
執行的任何 Web 伺服器PHP都可以使用此PHP範例程式碼來建立私有 CloudFront 分發的政策陳述式和簽章。完整範例會建立功能正常的網頁,其中包含使用 CloudFront 串流播放影片串流的已簽署URL連結。您可以在 https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/samples/demo-php.zip 下載完整範例。
您也可以URLs使用 中的 UrlSigner
類別建立簽署 AWS SDK for PHP。如需詳細資訊,請參閱 AWS SDK for PHP API 參考 中的類別 UrlSigner。
注意
建立URL簽章只是使用已簽署 提供私有內容程序的一部分URL。如需有關整個程序的詳細資訊,請參閱 使用已簽署的 URLs。
範例:SHA-1 RSA 簽章
在以下的程式碼範例中,函數 rsa_sha1_sign
雜湊並簽署政策陳述式。所需的引數為政策陳述式,以及與您分佈之信任金鑰群組中公有金鑰對應的私有金鑰。接下來,url_safe_base64_encode
函數會建立URL安全版本的簽章。
function rsa_sha1_sign($policy, $private_key_filename) { $signature = ""; // load the private key $fp = fopen($private_key_filename, "r"); $priv_key = fread($fp, 8192); fclose($fp); $pkeyid = openssl_get_privatekey($priv_key); // compute signature openssl_sign($policy, $signature, $pkeyid); // free the key from memory openssl_free_key($pkeyid); return $signature; } function url_safe_base64_encode($value) { $encoded = base64_encode($value); // replace unsafe characters +, = and / with // the safe characters -, _ and ~ return str_replace( array('+', '=', '/'), array('-', '_', '~'), $encoded); }
範例:建立固定政策
下列範例程式碼會建構簽章的標準政策陳述式。如需有關標準政策的詳細資訊,請參閱 URL 使用固定政策建立已簽章。
注意
$expires
變數是日期/時間戳記,必須整數,而不是字串。
function get_canned_policy_stream_name($video_path, $private_key_filename, $key_pair_id, $expires) { // this policy is well known by CloudFront, but you still need to sign it, // since it contains your parameters $canned_policy = '{"Statement":[{"Resource":"' . $video_path . '","Condition":{"DateLessThan":{"AWS:EpochTime":'. $expires . '}}}]}'; // sign the canned policy $signature = rsa_sha1_sign($canned_policy, $private_key_filename); // make the signature safe to be included in a url $encoded_signature = url_safe_base64_encode($signature); // combine the above into a stream name $stream_name = create_stream_name($video_path, null, $encoded_signature, $key_pair_id, $expires); // url-encode the query string characters to work around a flash player bug return encode_query_params($stream_name); }
範例:建立自訂政策
下列範例程式碼會建構簽章的自訂政策陳述式。如需有關自訂政策的詳細資訊,請參閱 URL 使用自訂政策建立已簽署的。
function get_custom_policy_stream_name($video_path, $private_key_filename, $key_pair_id, $policy) { // sign the policy $signature = rsa_sha1_sign($policy, $private_key_filename); // make the signature safe to be included in a url $encoded_signature = url_safe_base64_encode($signature); // combine the above into a stream name $stream_name = create_stream_name($video_path, $encoded_policy, $encoded_signature, $key_pair_id, null); // url-encode the query string characters to work around a flash player bug return encode_query_params($stream_name); }
完整程式碼範例
下列範例程式碼提供URLs使用 CloudFront 簽署建立 的完整示範PHP。您可以在 https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/samples/demo-php.zip 下載此完整範例。
在下列範例中,您可以修改 $policy
Condition
元素以允許 IPv4和 IPv6 地址範圍。如需範例,請參閱 Amazon Simple Storage Service 使用者指南 中的在IAM政策中使用IPv6地址。
<?php function rsa_sha1_sign($policy, $private_key_filename) { $signature = ""; // load the private key $fp = fopen($private_key_filename, "r"); $priv_key = fread($fp, 8192); fclose($fp); $pkeyid = openssl_get_privatekey($priv_key); // compute signature openssl_sign($policy, $signature, $pkeyid); // free the key from memory openssl_free_key($pkeyid); return $signature; } function url_safe_base64_encode($value) { $encoded = base64_encode($value); // replace unsafe characters +, = and / with the safe characters -, _ and ~ return str_replace( array('+', '=', '/'), array('-', '_', '~'), $encoded); } function create_stream_name($stream, $policy, $signature, $key_pair_id, $expires) { $result = $stream; // if the stream already contains query parameters, attach the new query parameters to the end // otherwise, add the query parameters $separator = strpos($stream, '?') == FALSE ? '?' : '&'; // the presence of an expires time means we're using a canned policy if($expires) { $result .= $path . $separator . "Expires=" . $expires . "&Signature=" . $signature . "&Key-Pair-Id=" . $key_pair_id; } // not using a canned policy, include the policy itself in the stream name else { $result .= $path . $separator . "Policy=" . $policy . "&Signature=" . $signature . "&Key-Pair-Id=" . $key_pair_id; } // new lines would break us, so remove them return str_replace('\n', '', $result); } function encode_query_params($stream_name) { // Adobe Flash Player has trouble with query parameters being passed into it, // so replace the bad characters with their URL-encoded forms return str_replace( array('?', '=', '&'), array('%3F', '%3D', '%26'), $stream_name); } function get_canned_policy_stream_name($video_path, $private_key_filename, $key_pair_id, $expires) { // this policy is well known by CloudFront, but you still need to sign it, since it contains your parameters $canned_policy = '{"Statement":[{"Resource":"' . $video_path . '","Condition":{"DateLessThan":{"AWS:EpochTime":'. $expires . '}}}]}'; // the policy contains characters that cannot be part of a URL, so we base64 encode it $encoded_policy = url_safe_base64_encode($canned_policy); // sign the original policy, not the encoded version $signature = rsa_sha1_sign($canned_policy, $private_key_filename); // make the signature safe to be included in a URL $encoded_signature = url_safe_base64_encode($signature); // combine the above into a stream name $stream_name = create_stream_name($video_path, null, $encoded_signature, $key_pair_id, $expires); // URL-encode the query string characters to support Flash Player return encode_query_params($stream_name); } function get_custom_policy_stream_name($video_path, $private_key_filename, $key_pair_id, $policy) { // the policy contains characters that cannot be part of a URL, so we base64 encode it $encoded_policy = url_safe_base64_encode($policy); // sign the original policy, not the encoded version $signature = rsa_sha1_sign($policy, $private_key_filename); // make the signature safe to be included in a URL $encoded_signature = url_safe_base64_encode($signature); // combine the above into a stream name $stream_name = create_stream_name($video_path, $encoded_policy, $encoded_signature, $key_pair_id, null); // URL-encode the query string characters to support Flash Player return encode_query_params($stream_name); } // Path to your private key. Be very careful that this file is not accessible // from the web! $private_key_filename = '/home/test/secure/example-priv-key.pem'; $key_pair_id = 'K2JCJMDEHXQW5F'; $video_path = 'example.mp4'; $expires = time() + 300; // 5 min from now $canned_policy_stream_name = get_canned_policy_stream_name($video_path, $private_key_filename, $key_pair_id, $expires); $client_ip = $_SERVER['REMOTE_ADDR']; $policy = '{'. '"Statement":['. '{'. '"Resource":"'. $video_path . '",'. '"Condition":{'. '"IpAddress":{"AWS:SourceIp":"' . $client_ip . '/32"},'. '"DateLessThan":{"AWS:EpochTime":' . $expires . '}'. '}'. '}'. ']' . '}'; $custom_policy_stream_name = get_custom_policy_stream_name($video_path, $private_key_filename, $key_pair_id, $policy); ?> <html> <head> <title>CloudFront</title> <script type='text/javascript' src='https://example.cloudfront.net/player/swfobject.js'></script> </head> <body> <h1>Amazon CloudFront</h1> <h2>Canned Policy</h2> <h3>Expires at <?= gmdate('Y-m-d H:i:s T', $expires) ?></h3> <br /> <div id='canned'>The canned policy video will be here</div> <h2>Custom Policy</h2> <h3>Expires at <?= gmdate('Y-m-d H:i:s T', $expires) ?> only viewable by IP <?= $client_ip ?></h3> <div id='custom'>The custom policy video will be here</div> <!-- ************** Have to update the player.swf path to a real JWPlayer instance. The fake one means that external people cannot watch the video right now --> <script type='text/javascript'> var so_canned = new SWFObject('https://files.example.com/player.swf','mpl','640','360','9'); so_canned.addParam('allowfullscreen','true'); so_canned.addParam('allowscriptaccess','always'); so_canned.addParam('wmode','opaque'); so_canned.addVariable('file','<?= $canned_policy_stream_name ?>'); so_canned.addVariable('streamer','rtmp://example.cloudfront.net/cfx/st'); so_canned.write('canned'); var so_custom = new SWFObject('https://files.example.com/player.swf','mpl','640','360','9'); so_custom.addParam('allowfullscreen','true'); so_custom.addParam('allowscriptaccess','always'); so_custom.addParam('wmode','opaque'); so_custom.addVariable('file','<?= $custom_policy_stream_name ?>'); so_custom.addVariable('streamer','rtmp://example.cloudfront.net/cfx/st'); so_custom.write('custom'); </script> </body> </html>
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