# Documentation

FIFA Connect Service Bus .NET SDK, v3.1

# 1. Introduction

The main responsibility of FIFA Connect ID Service Bus is to provide unified infrastructure for asynchronous messaging. Using FIFA Connect Service Bus and its SDK it is possible to exchange encrypted messages with other applications connected to the bus.

## 1.1 Prerequisites

The SDK is compatible with .NET Standard 2.0.

The Service Bus SDK NuGet has to be installed in your project. Refer to the instructions for how to do that.

## 1.2 How encryption works in Connect Service Bus

FIFA Connect Service Bus provides end-to-end encryption which means that message is encrypted in SDK of sending party and is decrypted in SDK or receiving party. Consequently none of the devices transferring message (including FIFA Connect Service Bus servers) can read its content.

Such a feature of Connect Service Bus is possible due to usage of infrastructure based on public and private pairs of certificates. This section briefly describes how this is achieved.

1. Using provided tools Administrator of organisation "A" generates pair of public and private certificates. Public certificate can be shared with anyone (e.g. uploaded on a server) but private key should be kept in secret.
2. Administrator of organisation "A" uploads public certificates to FIFA Connect Service Bus server using provided tool.
3. Now application of organisation "B" wants to send an encrypted message to Organisation "A". Then the code in application calls Connect Service Bus SDK which in a seamless way:

- connects to FIFA Connect Service Bus server and downloads public certificate of organisation "A" (which was uploaded in previous step).
- uses downloaded public certificate of Organisation "A" to encrypt content of the message. Due to nature of asymmetric encryption with public-private certificates only holder of private certificate can decrypt that message. Since private key of Organisation "A" was not shared with anyone only Organisation "A" can decrypt that message.
- sends encrypted message to the Organisation A

4. Then application of Organisation A using SDK receives message. Under the hood SDK

- receives message from Connect Service Bus
- uses private certificate of Organisation "A" to decrypt content of the message
- returns decrypted message to application of Organisation A.
- application "A" can decide what to do with received message

# 2. FIFA Connect Service Bus Client

## 2.1 Creating a client

The entry point of the SDK is `FifaConnectServiceBusClient`. With a single instance of this class all the requests can be made. In order to authenticate to the service you have to provide a set of client credentials.

### 2.1.1 Setup private certificate

In order to create a new instance of the client, instance of `IPrivateKeyStorage` must be provided. By default SDK uses `PrivateKeyMemoryStorage` class that implements mentioned interface. Next step is to provide instance(s) of `X509Certificate2` into such container. Each certificate consists of the key (from generated file) and password (optionally). Please take a look at the following example:

    var certificate = new X509Certificate2(privateKey, "password", X509KeyStorageFlags.DefaultKeySet);

    var privateStore = new PrivateKeyMemoryStorage(certificate);

### 2.1.2 Generate new certificate

In order to generate a new certificate follow instructions from `fifa-connectservicebus-certificates-generation.html`. When a new pair of certificates (public and private) is generated and a new public certificate is uploaded, then it's required to update collection of private certificates returned by implementation of `IPrivateKeyStorage`. Since some messages could be encrypted before new public certificate was uploaded, implementation of IPrivateKeyStorage must return current and previous private certificate to ensure that all messages can be decrypted.

Correct order of steps is the following:

1. Generate pair of certificates
2. Modify and deploy code so that `IPrivateKeyStorage` returns old and new private certificates
3. Upload new public certificate to Connect Service Bus

Please take a look at the following example, where two certificates are used by `IPrivateKeyStorage`:

    var environment = ConnectServiceBusEnvironment.Beta;
    var credentials = new ClientCredentials("clientId", "secretKey");

    var certificate = new X509Certificate2(TestResources.cert_pfx, "Testing123", X509KeyStorageFlags.DefaultKeySet);

    var oldCertificate = new X509Certificate2(TestResources.old_cert_pfx, "Testing123", X509KeyStorageFlags.DefaultKeySet);

    var privateStore = new PrivateKeyMemoryStorage(certificate, oldCertificate);

### 2.1.3 Logger implementation

Each SDK client method uses an instance `Fifa.ConnectServiceBus.Sdk.Logging.ILogger` in order to log any errors that might happen during the application runtime. There is no default Logger implementation provided, as different parties could want a different way of storing logs. Implementation of such Logger class is mandatory.

A frequent mistake when implementing the `ILogger` is ignoring the `args` parameter when formatting the message.

Example implementation of the `void Debug(string message, params object[] args)`:

    Console.WriteLine(String.Format(message, args));

There are methods accepting Exception object as the first argument. Please make sure to handle it properly, i.e. include the inner exceptions (if any) and the stack trace. The message itself might not be enough.

### 2.1.4 Basic instance

    var environment = ConnectServiceBusEnvironment.Beta;
    var credentials = new ClientCredentials("clientId", "secretKey");
    var logger = new YourOwnLogger();

    var client = new FifaConnectServiceBusClient(environment, credentials, privateStore, logger);

where environment is an instance of type `ConnectServiceBusEnvironment`. It provides information about the service to make request to.

### 2.1.5 Certificate client instance

In case of need for upload or download certificate, you have to use an instance of `FifaConnectServiceBusCertificateClient`.

    var environment = ConnectServiceBusEnvironment.Beta;
    var credentials = new ClientCredentials("clientId", "secretKey");
    var logger = new YourOwnLogger();

    var certificateClient = new FifaConnectServiceBusCertificateClient(environment, credentials, logger);

### 2.1.6 Addressing a message

Recipient of the message is specified by the `recipient` parameter. It's actually a name of a queue that acts as an inbox for other client (e.g. registration system in a different MA)

### 2.1.7 Creating custom environment instance

As there are some pre-defined environments defined in the `ConnectServiceBusEnvironment` class, it's also possible to create a custom instance using environment code. In order to achieve that, environment code needs to be provided to the static factory method.

    var environmentCode = "testenv";
    var environment = ConnectServiceBusEnvironment.Create(environmentCode);

Use one of the existing environments:

Environment | Environment code
--- | ---
Integration | int
Test | test
Beta | beta
Preproduction | prep
Production | prod
Sandbox #1 | sbx1

## 2.2 Sending a message

In order to send a message in FIFA Connect Service Bus service, provide `content` as `byte[]`. A `recipient` needs to be provided as well.

By convention value of the `recipient` is the FIFA ID of the receiving organisation. However, for certain applications it may have format of `FIFAID_application`. In case of any doubts, please contact FIFA Connect Service Bus Support team to get proper value of `recipient`.

Example:

    try
    {
        await client.Send(recipient, content);
    }
    catch (InvalidClientDataException ex)
    {
        // data sent to the service was invalid
        var details = ex.BadRequestResponse;
    }
    catch (AuthenticationException ex)
    {
        // invalid client credentials
    }
    catch (UnauthorizedException ex)
    {
        // unauthorized
    }
    catch (PublicCertificateNotFoundException ex)
    {
        // there is no public certificate for given queue
    }
    catch (CryptographyException ex)
    {
        // exception when encrypting content
    }
    catch (QueueNotFoundException ex)
    {
        // there is no queue for specified recipient
    }
    catch (TooManyRequestsException ex)
    {
        // call rate limit was exceeded
        var retryAfterInSeconds = ex.RetryAfter;
    }
    catch (FifaConnectServiceBusException ex)
    {
        // some other error occurred, see the details
        var response = ex.HttpOperationResponse;
    }

To send additional metadata of the message use overloaded `Send` method:

    var action = "/person/getDetails";
    var properties = new Dictionary<string, string>();
    properties.Add("id", "BVGE8T6");

    await client.Send(recipient, content, action, properties);

## 2.3 Transactional receive

In order to receive a message from Connect Service Bus and leave it in the queue use `PeekLock` method. The `timeout` parameter can be specified. In Connect Service Bus context `timeout` defines how long a request waits before returning that there is no message in the queue. When no message is found, `null` will be returned. Received message will not be visible for other Connect Service Bus clients for 120 seconds. The 'timeout' value does not impact this, therefore it is recommended to keep 'timeout' value smaller than 120. During that time period actions like `Delete` or `Unlock` can be triggered. If none of the above actions is taken, message will be returned to the queue.

In the `Message` some metadata can be found in property `BrokerProperties`. The most important are `MessageId` and `LockToken` that are used as required parameters in `Delete` and `Unlock` methods. In addition above properites can be found in instance of `Message` class.

    try
    {
        var timeout = TimeSpan.FromSeconds(60);
        var message = client.PeekLock(timeout);
    }
    catch (InvalidClientDataException ex)
    {
        // data sent to the service was invalid
        var details = ex.BadRequestResponse;
    }
    catch (AuthenticationException ex)
    {
        // invalid client credentials
    }
    catch (UnauthorizedException ex)
    {
        // unauthorized
    }
    catch (CryptographyException ex)
    {
        // exception when decrypting service bus message
    }
    catch (QueueNotFoundException ex)
    {
        // there is no queue for specified recipient
    }
    catch (TooManyRequestsException ex)
    {
        // call rate limit was exceeded
        var retryAfterInSeconds = ex.RetryAfter;
    }
    catch (FifaConnectServiceBusException ex)
    {
        // some other error occurred, see the details
        var response = ex.HttpOperationResponse;
    }

## 2.4 Delete a message

Method used to delete a locked message.

    try
    {
        await client.Delete(message.Id, message.LockToken);
    }
    catch (InvalidClientDataException ex)
    {
        // data sent to the service was invalid
        var details = ex.BadRequestResponse;
    }
    catch (AuthenticationException ex)
    {
        // invalid client credentials
    }
    catch (UnauthorizedException ex)
    {
        // unauthorized
    }
    catch (TooManyRequestsException ex)
    {
        // call rate limit was exceeded
        var retryAfterInSeconds = ex.RetryAfter;
    }
    catch (FifaConnectServiceBusException ex)
    {
        // some other error occurred, see the details
        var response = ex.HttpOperationResponse;
    }

## 2.5 Unlock a message

Message can be returned to the queue using `Unlock` method.

    try
    {
        await client.Unlock(message.Id, message.LockToken);
    }
    catch (InvalidClientDataException ex)
    {
        // data sent to the service was invalid
        var details = ex.BadRequestResponse;
    }
    catch (AuthenticationException ex)
    {
        // invalid client credentials
    }
    catch (UnauthorizedException ex)
    {
        // unauthorized
    }
    catch (TooManyRequestsException ex)
    {
        // call rate limit was exceeded
        var retryAfterInSeconds = ex.RetryAfter;
    }
    catch (FifaConnectServiceBusException ex)
    {
        // some other error occurred, see the details
        var response = ex.HttpOperationResponse;
    }

## 2.6 Upload a public certificate

Recommended way to upload a public certificate is the upload using console application located in `certificate-upload-console` folder. For more information please refer to Certificate Generation documentation. If console application can't be used, use `UploadCertificate` method instead. Take a look at the following example:

    var certificateData = File.ReadAllBytes(certificateFilePath); // certificateFilePath: path to public_cert.pem file
    try
    {
        await certificateClient.UploadCertificate(certificateData);
    }
    catch (InvalidClientDataException ex)
    {
        // data sent to the service was invalid
        var details = ex.BadRequestResponse;
    }
    catch (AuthenticationException ex)
    {
        // invalid client credentials
    }
    catch (UnauthorizedException ex)
    {
        // unauthorized
    }
    catch (TooManyRequestsException ex)
    {
        // call rate limit was exceeded
        var retryAfterInSeconds = ex.RetryAfter;
    }
    catch (FifaConnectServiceBusException ex)
    {
        // some other error occurred, see the details
        var response = ex.HttpOperationResponse;
    }

## 2.7 Download a public certificate

To download public certificate for specific organisation use `DownloadCertificate` method. Please take a look at the following example:

    try
    {
        var certificateRawData = await certificateClient.DownloadCertificate(queueIdentifier).ConfigureAwait(false);
    }
    catch (InvalidClientDataException ex)
    {
        // data sent to the service was invalid
        var details = ex.BadRequestResponse;
    }
    catch (AuthenticationException ex)
    {
        // invalid client credentials
    }
    catch (UnauthorizedException ex)
    {
        // unauthorized
    }
    catch (DataNotFoundException ex)
    {
        // certificate has not been found
    }
    catch (TooManyRequestsException ex)
    {
        // call rate limit was exceeded
        var retryAfterInSeconds = ex.RetryAfter;
    }
    catch (FifaConnectServiceBusException ex)
    {
        // some other error occurred, see the details
        var response = ex.HttpOperationResponse;
    }

# 3. Limits

## 3.1 Maximum queue size

Currently each recipient's queue has a quota of 80 GB (both content and message headers size is counted). When queue reaches its limit, new messages cannot be sent to the recipient, so senders get an error from Service Bus API and SDK.

## 3.2. Maximum time-to-live

Each queue stores messages for 7 days. If message is not received by the recipient, it is moved to dead-letter queue and support team receives notification about unprocessed message. On client request support team can move a message to primary queue so that it can be received and processed by an application. Alternatively message can be permanently deleted from a dead-letter queue.

## 3.3. Maximum delivery retries

If client using Connect Service Bus SDK downloads message but fails to process it correctly (i.e. handler throws an exception), the counter of failed delivery is increased. If delivery fails 10 times, message is moved to a dead-letter queue. Depending on the reason different actions can be taken:

- message is invalid or content is malformed, so that message cannot be processed by receiver - support team can delete the message, if needed sender should be notified that the message was invalid and was not processed by recipient
- issue on the receiving side preventing correct message to be processed - support team can move message to primary queue so that message can be reprocessed after the issue is solved on the receiving side

## 3.4 Maximum message size

Maximum message size is 10MB. If this limit is exceeded then Connect Service Bus will return 400 (Bad Request) response code. As a result `InvalidClientDataException` will be thrown.

## 3.5 Thread-safety

Any instance members are not guaranteed to be thread safe. In particular all methods on `FifaConnectServiceBusClient` cannot be called from multiple threads simultaneously. If needed, new instance of `FifaConnectServiceBusClient` should be created per thread.

# 4. Release notes

The following changes were introduced in version 3.0 of the SDK when comparing to version 2.1:

- All occurrences of "organizationId" parameter renamed to "queueIdentifier"
- Added information about thread-safety