Implement connection server example

.gitignore

+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Ignore Jetbrains IDE folder
+.idea/*
+
+# Dependency directories (remove the comment below to include it)
+vendor/
+
+# File from testing
+session*/
+*.darwin64
+*.linux64
+*.win64
+*.xxchan
+*.pem
+*.log
\ No newline at end of file

connectServer/go.mod

+module gitlab.com/elixxir/xxdk-examples/connection
+
+go 1.17
+
+require (
+	github.com/spf13/jwalterweatherman v1.1.0
+	gitlab.com/elixxir/client v1.5.1-0.20220705214402-3ebd3c1fcfec
+	gitlab.com/elixxir/crypto v0.0.7-0.20220606201132-c370d5039cea
+	gitlab.com/xx_network/primitives v0.0.4-0.20220630163313-7890038258c6
+)
+
+require (
+	github.com/andres-erbsen/clock v0.0.0-20160526145045-9e14626cd129 // indirect
+	github.com/badoux/checkmail v1.2.1 // indirect
+	github.com/cloudflare/circl v1.1.0 // indirect
+	github.com/elliotchance/orderedmap v1.4.0 // indirect
+	github.com/fsnotify/fsnotify v1.4.9 // indirect
+	github.com/golang-collections/collections v0.0.0-20130729185459-604e922904d3 // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/hashicorp/hcl v1.0.0 // indirect
+	github.com/inconshreveable/mousetrap v1.0.0 // indirect
+	github.com/magiconair/properties v1.8.4 // indirect
+	github.com/mitchellh/go-homedir v1.1.0 // indirect
+	github.com/mitchellh/mapstructure v1.4.0 // indirect
+	github.com/nfnt/resize v0.0.0-20180221191011-83c6a9932646 // indirect
+	github.com/pelletier/go-toml v1.8.1 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e // indirect
+	github.com/spf13/afero v1.5.1 // indirect
+	github.com/spf13/cast v1.3.1 // indirect
+	github.com/spf13/cobra v1.1.1 // indirect
+	github.com/spf13/pflag v1.0.5 // indirect
+	github.com/spf13/viper v1.7.1 // indirect
+	github.com/subosito/gotenv v1.2.0 // indirect
+	github.com/ttacon/builder v0.0.0-20170518171403-c099f663e1c2 // indirect
+	github.com/ttacon/libphonenumber v1.2.1 // indirect
+	github.com/tyler-smith/go-bip39 v1.1.0 // indirect
+	github.com/zeebo/blake3 v0.1.1 // indirect
+	gitlab.com/elixxir/bloomfilter v0.0.0-20211222005329-7d931ceead6f // indirect
+	gitlab.com/elixxir/comms v0.0.4-0.20220603231314-e47e4af13326 // indirect
+	gitlab.com/elixxir/ekv v0.1.7 // indirect
+	gitlab.com/elixxir/primitives v0.0.3-0.20220606195757-40f7a589347f // indirect
+	gitlab.com/xx_network/comms v0.0.4-0.20220630163702-f3d372ef6acd // indirect
+	gitlab.com/xx_network/crypto v0.0.5-0.20220606200528-3f886fe49e81 // indirect
+	gitlab.com/xx_network/ring v0.0.3-0.20220222211904-da613960ad93 // indirect
+	go.uber.org/ratelimit v0.2.0 // indirect
+	golang.org/x/crypto v0.0.0-20220128200615-198e4374d7ed // indirect
+	golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2 // indirect
+	golang.org/x/sys v0.0.0-20211007075335-d3039528d8ac // indirect
+	golang.org/x/text v0.3.6 // indirect
+	google.golang.org/genproto v0.0.0-20210105202744-fe13368bc0e1 // indirect
+	google.golang.org/grpc v1.42.0 // indirect
+	google.golang.org/protobuf v1.27.1 // indirect
+	gopkg.in/ini.v1 v1.62.0 // indirect
+	gopkg.in/yaml.v2 v2.4.0 // indirect
+)

connectServer/listener.go

+package main
+
+import (
+	jww "github.com/spf13/jwalterweatherman"
+	"gitlab.com/elixxir/client/e2e/receive"
+)
+
+// listener adheres to the receive.Listener interface.
+type listener struct {
+	name string
+}
+
+// Hear will be called whenever a message matching the RegisterListener call is
+// received.
+//
+// User-defined message handling logic goes here.
+func (l *listener) Hear(item receive.Message) {
+	jww.INFO.Printf("Message received: %v", item)
+}
+
+// Name is used for debugging purposes.
+func (l *listener) Name() string {
+	return l.name
+}
\ No newline at end of file

connectServer/main.go

+// Starting connection server
+package main
+
+import (
+	"errors"
+	jww "github.com/spf13/jwalterweatherman"
+	"gitlab.com/elixxir/client/catalog"
+	"gitlab.com/elixxir/client/xxdk"
+	"io/fs"
+	"io/ioutil"
+	"os"
+	"time"
+
+	"gitlab.com/elixxir/client/connect"
+)
+
+func main() {
+	// Logging
+	initLog(1, "client.log")
+
+	// Create a new client object-------------------------------------------------------
+
+	// You would ideally use a configuration tool to acquire these parameters
+	statePath := "statePath"
+	statePass := "password"
+	// The following connects to mainnet. For historical reasons it is called a json file
+	// but it is actually a marshalled file with a cryptographic signature attached.
+	// This may change in the future.
+	ndfURL := "https://elixxir-bins.s3.us-west-1.amazonaws.com/ndf/mainnet.json"
+	certificatePath := "../mainnet.crt"
+	ndfPath := "ndf.json"
+
+	// Check if state exists
+	if _, err := os.Stat(statePath); errors.Is(err, fs.ErrNotExist) {
+
+		// Attempt to read the NDF
+		var ndfJSON []byte
+		ndfJSON, err = ioutil.ReadFile(ndfPath)
+		if err != nil {
+			jww.INFO.Printf("NDF does not exist: %+v", err)
+		}
+
+		// If NDF can't be read, retrieve it remotely
+		if ndfJSON == nil {
+			cert, err := ioutil.ReadFile(certificatePath)
+			if err != nil {
+				jww.FATAL.Panicf("Failed to read certificate: %v", err)
+			}
+
+			ndfJSON, err = xxdk.DownloadAndVerifySignedNdfWithUrl(ndfURL, string(cert))
+			if err != nil {
+				jww.FATAL.Panicf("Failed to download NDF: %+v", err)
+			}
+		}
+
+		// Initialize the state
+		err = xxdk.NewCmix(string(ndfJSON), statePath, []byte(statePass), "")
+		if err != nil {
+			jww.FATAL.Panicf("Failed to initialize state: %+v", err)
+		}
+	}
+
+	// Login to your client session-----------------------------------------------------
+
+	// Login with the same sessionPath and sessionPass used to call NewClient()
+	baseClient, err := xxdk.LoadCmix(statePath, []byte(statePass), xxdk.GetDefaultCMixParams())
+	if err != nil {
+		jww.FATAL.Panicf("Failed to load state: %+v", err)
+	}
+
+	// Get reception identity (automatically created if one does not exist)
+	identityStorageKey := "identityStorageKey"
+	identity, err := xxdk.LoadReceptionIdentity(identityStorageKey, baseClient)
+	if err != nil {
+		// If no extant xxdk.ReceptionIdentity, generate and store a new one
+		identity, err = xxdk.MakeReceptionIdentity(baseClient)
+		if err != nil {
+			jww.FATAL.Panicf("Failed to generate reception identity: %+v", err)
+		}
+		err = xxdk.StoreReceptionIdentity(identityStorageKey, identity, baseClient)
+		if err != nil {
+			jww.FATAL.Panicf("Failed to store new reception identity: %+v", err)
+		}
+	}
+
+	// Create an E2E client
+	// The connect packages handles AuthCallbacks, xxdk.DefaultAuthCallbacks is fine here
+	params := xxdk.GetDefaultE2EParams()
+	jww.INFO.Printf("Using E2E parameters: %+v", params)
+	e2eClient, err := xxdk.Login(baseClient, xxdk.DefaultAuthCallbacks{}, identity, params)
+	if err != nil {
+		jww.FATAL.Panicf("Unable to Login: %+v", err)
+	}
+
+	// Save contact file----------------------------------------------------------------
+
+	// Get the contact file path
+	contactFilePath := "connectServer.xxc"
+
+	// Save the contact file so that client can connect to this server
+	writeContact(contactFilePath, identity.GetContact())
+
+	// Handle incoming connections------------------------------------------------------
+
+	// Create callback for incoming connections
+	cb := func(connection connect.Connection) {
+		// Listen for all types of messages using catalog.NoType
+		// User-defined behavior for message reception goes in the listener
+		_, err = connection.RegisterListener(
+			catalog.NoType, &listener{"connection server listener"})
+		if err != nil {
+			jww.FATAL.Panicf("Failed to register listener: %+v", err)
+		}
+	}
+
+	// Start connection server----------------------------------------------------------
+
+	// Start the connection server, which
+	e2eParams := xxdk.GetDefaultE2EParams()
+	connectionListParams := connect.DefaultConnectionListParams()
+	_, err = connect.StartServer(
+		identity, cb, baseClient, e2eParams, connectionListParams)
+	if err != nil {
+		jww.FATAL.Panicf("Unable to start connection server: %+v", err)
+	}
+
+	// Start network threads------------------------------------------------------------
+
+	// Set networkFollowerTimeout to a value of your choice (seconds)
+	networkFollowerTimeout := 5 * time.Second
+	err = e2eClient.StartNetworkFollower(networkFollowerTimeout)
+	if err != nil {
+		jww.FATAL.Panicf("Failed to start network follower: %+v", err)
+	}
+
+	// Set up a wait for the network to be connected
+	waitUntilConnected := func(connected chan bool) {
+		waitTimeout := 30 * time.Second
+		timeoutTimer := time.NewTimer(waitTimeout)
+		isConnected := false
+		// Wait until we connect or panic if we cannot before the timeout
+		for !isConnected {
+			select {
+			case isConnected = <-connected:
+				jww.INFO.Printf("Network Status: %v", isConnected)
+				break
+			case <-timeoutTimer.C:
+				jww.FATAL.Panicf("Timeout on starting network follower")
+			}
+		}
+	}
+
+	// Create a tracker channel to be notified of network changes
+	connected := make(chan bool, 10)
+	// Provide a callback that will be signalled when network health status changes
+	baseClient.GetCmix().AddHealthCallback(
+		func(isConnected bool) {
+			connected <- isConnected
+		})
+	// Wait until connected or crash on timeout
+	waitUntilConnected(connected)
+
+	// Keep app running to receive messages-----------------------------------------------
+
+	select {}
+}

connectServer/utils.go

+package main
+
+import (
+	jww "github.com/spf13/jwalterweatherman"
+	"gitlab.com/elixxir/crypto/contact"
+	"gitlab.com/xx_network/primitives/utils"
+	"io/ioutil"
+	"log"
+	"os"
+)
+
+func initLog(threshold uint, logPath string) {
+	if logPath != "-" && logPath != "" {
+		// Disable stdout output
+		jww.SetStdoutOutput(ioutil.Discard)
+		// Use log file
+		logOutput, err := os.OpenFile(logPath,
+			os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+		if err != nil {
+			panic(err.Error())
+		}
+		jww.SetLogOutput(logOutput)
+	}
+
+	if threshold > 1 {
+		jww.INFO.Printf("log level set to: TRACE")
+		jww.SetStdoutThreshold(jww.LevelTrace)
+		jww.SetLogThreshold(jww.LevelTrace)
+		jww.SetFlags(log.LstdFlags | log.Lmicroseconds)
+	} else if threshold == 1 {
+		jww.INFO.Printf("log level set to: DEBUG")
+		jww.SetStdoutThreshold(jww.LevelDebug)
+		jww.SetLogThreshold(jww.LevelDebug)
+		jww.SetFlags(log.LstdFlags | log.Lmicroseconds)
+	} else {
+		jww.INFO.Printf("log level set to: INFO")
+		jww.SetStdoutThreshold(jww.LevelInfo)
+		jww.SetLogThreshold(jww.LevelInfo)
+	}
+}
+
+func writeContact(outfilePath string, c contact.Contact) {
+	err := utils.WriteFileDef(outfilePath, c.Marshal())
+
+	if err != nil {
+		jww.ERROR.Printf("could not write contact file: %+v", err)
+	} else {
+		jww.INFO.Printf("contact written to %s successfully", outfilePath)
+	}
+}