常见的概念
分析连接字符串
若要访问通知中心，您必须具有两条信息: (可以是路径，如"a/b/c") 的中心名称和连接字符串。 连接字符串包含有关该终结点的信息你的中心，并用它的安全凭据来对其进行访问 (就 SAS 而言，它包含规则名称和密钥值)。
下面的代码来分析连接字符串以提取相关信息:
public partial class ConnectionStringUtility { public string Endpoint { get; private set; } public string SasKeyName { get; private set; } public string SasKeyValue { get; private set; } public ConnectionStringUtility(string connectionString) { //Parse Connectionstring char[] separator = { ';' }; string[] parts = connectionString.Split(separator); for (int i = 0; i < parts.Length; i++) { if (parts[i].StartsWith("Endpoint")) Endpoint = "https" + parts[i].Substring(11); if (parts[i].StartsWith("SharedAccessKeyName")) SasKeyName = parts[i].Substring(20); if (parts[i].StartsWith("SharedAccessKey")) SasKeyValue = parts[i].Substring(16); } } }
String[] parts = connectionString.split(";"); if (parts.length != 3) throw new RuntimeException("Error parsing connection string: " + connectionString); for (int i = 0; i < parts.length; i++) { if (parts[i].startsWith("Endpoint")) { this.endpoint = "https" + parts[i].substring(11); } else if (parts[i].startsWith("SharedAccessKeyName")) { this.SasKeyName = parts[i].substring(20); } else if (parts[i].startsWith("SharedAccessKey")) { this.SasKeyValue = parts[i].substring(16); } }
var parts = connectionString.split(';'); if (parts.length != 3) throw "Error parsing connection string"; parts.forEach(function(part) { if (part.indexOf('Endpoint') == 0) { endpoint = 'https' + part.substring(11); } else if (part.indexOf('SharedAccessKeyName') == 0) { sasKeyName = part.substring(20); } else if (part.indexOf('SharedAccessKey') == 0) { sasKeyValue = part.substring(16); } });
创建 SAS 安全令牌
若要使用 SAS 进行身份验证，客户端必须指定在一个 SAS 令牌 Authorization 其请求标头。 从连接字符串和当前需要进行身份验证的请求中提取的信息来构造令牌。 该令牌具有以下形式:
SharedAccessSignature sig=<signature-string>&se=<expiry>&skn=<keyName>&sr=<URL-encoded-resourceURI>
请注意，该令牌是指 keyName (若要发送通知，您通常使用 DefaultFullSharedAccessSignature 所有通知中心自动创建的属性)。
SAS 令牌的签名使用某一签名字符串值的 hmac-sha256 计算得出 PrimaryKey 授权规则的属性。 签名字符串值组成一个资源 URI 和一个过期时间，格式如下:
StringToSign = <resourceURI> + "\n" + expiry;
请注意，您应使用此操作未编码的资源 URI。 资源 URI 是完整的 URI 的 Service Bus 向其声明访问权限的资源。 形式为，如下所示:
http://<namespace>.servicebus.windows.net/<hubName>
例如:
http://contoso.servicebus.windows.net/myHub
到期时间表示为 epoch 00:00:00 UTC 开始算自 1970 年 1 月 1 以来的秒数。
必须在此 URI 指定实体上配置用于签名的共享的访问授权规则。 在上例中，这是 http://contoso.servicebus.windows.net/myHub 或 http://contoso.servicebus.windows.net。
URL 编码 resourceURI 必须与计算签名期间签名字符串到签名中使用的 URI 相同。 它应该是百分比编码形式和小写。
下面的代码，给定的请求 URI，创建一个 SAS 令牌。 Java 版本使用 Apache 通用编解码器和 Javascript 版本使用 CryptoJS。
public partial class ConnectionStringUtility { public string getSaSToken(string uri, int minUntilExpire) { string targetUri = Uri.EscapeDataString(uri.ToLower()).ToLower(); // Add an expiration in seconds to it. long expiresOnDate = DateTime.Now.Ticks / TimeSpan.TicksPerMillisecond; expiresOnDate += minUntilExpire * 60 * 1000; long expires_seconds = expiresOnDate / 1000; String toSign = targetUri + "\n" + expires_seconds; // Generate a HMAC-SHA256 hash or the uri and expiration using your secret key. MacAlgorithmProvider macAlgorithmProvider = MacAlgorithmProvider.OpenAlgorithm(MacAlgorithmNames.HmacSha256); BinaryStringEncoding encoding = BinaryStringEncoding.Utf8; var messageBuffer = CryptographicBuffer.ConvertStringToBinary(toSign, encoding); IBuffer keyBuffer = CryptographicBuffer.ConvertStringToBinary(SasKeyValue, encoding); CryptographicKey hmacKey = macAlgorithmProvider.CreateKey(keyBuffer); IBuffer signedMessage = CryptographicEngine.Sign(hmacKey, messageBuffer); string signature = Uri.EscapeDataString(CryptographicBuffer.EncodeToBase64String(signedMessage)); return "SharedAccessSignature sr=" + targetUri + "&sig=" + signature + "&se=" + expires_seconds + "&skn=" + SasKeyName; } }
private String generateSasToken(URI uri) { String targetUri; try { targetUri = URLEncoder .encode(uri.toString().toLowerCase(), "UTF-8") .toLowerCase(); long expiresOnDate = System.currentTimeMillis(); int expiresInMins = 60; // 1 hour expiresOnDate += expiresInMins * 60 * 1000; long expires = expiresOnDate / 1000; String toSign = targetUri + "\n" + expires; // Get an hmac_sha1 key from the raw key bytes byte[] keyBytes = SasKeyValue.getBytes("UTF-8"); SecretKeySpec signingKey = new SecretKeySpec(keyBytes, "HmacSHA256"); // Get an hmac_sha1 Mac instance and initialize with the signing key Mac mac = Mac.getInstance("HmacSHA256"); mac.init(signingKey); // Compute the hmac on input data bytes byte[] rawHmac = mac.doFinal(toSign.getBytes("UTF-8")); // using Apache commons codec for base64 String signature = URLEncoder.encode( Base64.encodeBase64String(rawHmac), "UTF-8"); // construct authorization string String token = "SharedAccessSignature sr=" + targetUri + "&sig=" + signature + "&se=" + expires + "&skn=" + SasKeyName; return token; } catch (Exception e) { throw new RuntimeException(e); } }
var getSelfSignedToken = function(targetUri, sharedKey, ruleId, expiresInMins) { targetUri = encodeURIComponent(targetUri.toLowerCase()).toLowerCase(); // Set expiration in seconds var expireOnDate = new Date(); expireOnDate.setMinutes(expireOnDate.getMinutes() + expiresInMins); var expires = Date.UTC(expireOnDate.getUTCFullYear(), expireOnDate .getUTCMonth(), expireOnDate.getUTCDate(), expireOnDate .getUTCHours(), expireOnDate.getUTCMinutes(), expireOnDate .getUTCSeconds()) / 1000; var tosign = targetUri + '\n' + expires; // using CryptoJS var signature = CryptoJS.HmacSHA256(tosign, sharedKey); var base64signature = signature.toString(CryptoJS.enc.Base64); var base64UriEncoded = encodeURIComponent(base64signature); // construct autorization string var token = "SharedAccessSignature sr=" + targetUri + "&sig=" + base64UriEncoded + "&se=" + expires + "&skn=" + ruleId; // console.log("signature:" + token); return token; };