grpc-swift/docs/tls.md

Using TLS

gRPC calls can be made over a secure channel by configuring TLS. This requires specifying tls on ClientConnection.Configuration or Server.Configuration.

For the client, tls can be as simple as:

let tls = ClientConnection.Configuration.TLS()

For the server, tls is slightly more complicated as it requires a certificate chain and private key:

# Load the certificates from "cert.pem"
let certificates: [NIOSSLCertificate] = try NIOSSLCertificate.fromPEMFile("cert.pem")

let tls = Server.Configuration.TLS(
  certificateChain: certificates.map { .certificate($0) },
  privateKey: .file("key.pem")
)

The TLS configuration is a subset of TLSConfiguration provided by NIOSSL to ensure it meets the gRPC specification. Users may also initialize TLS with TLSConfiguration should they require.

Loading Certificates and Private Keys

Certificate and private key objects (NIOSSLCertificate and NIOSSLPrivateKey) are provided by SwiftNIO SSL.

A certificate or private key may be loaded from:

• a file using NIOSSLCertificate(file:format:) or NIOSSLPrivateKey(file:format:), or
• an array of bytes using NIOSSLCertificate(buffer:format:) or NIOSSLPrivateKey(bytes:format).

It is also possible to load a certificate or private key from a String by constructing an array from its UTF8 view and passing it to the appropriate initializer (NIOSSLCertificate(buffer:format) or NIOSSLPrivateKey(bytes:format:)):

let certificateString = ...
let bytes: = Array(certificateString.utf8)

let certificateFormat = ...
let certificate = try NIOSSLCertificate(buffer: bytes, format: certificateFormat)

Certificate chains may also be loaded from:

• a file: NIOSSLCertificate.fromPEMFile(_:), or
• an array of bytes: NIOSSLCertificate.fromPEMBytes(_:).

These functions return an array of certificates ([NIOSSLCertificate]).

Simillar to loading a certificate, a certificate chain may also be loaded from a String using by using the UTF8 view on the string with the fromPEMBytes(_:) method.

Refer to the certificate or private key documentation for more information.