Develop a Client Application With the IoT SDK

This section shows you how to create a client application for a Thing, named Gopher. The Thing is manually registered in AM and authenticated with a username/password authentication flow. For more information about the IoT SDK API, see the Go package documentation.

Develop a ForgeRock IoT Application

These steps assume that you have installed the required software and cloned the Things GitHub repository:

Create a directory structure for your Go project:
```
mkdir -p things/cmd/gopher
```
Create an empty project file (main.go ):
```
cd things
touch cmd/gopher/main.go
```

Open main.go in a text editor, and add the following code:

package main

import (
    "github.com/ForgeRock/iot-edge/v7/pkg/builder"
    "github.com/ForgeRock/iot-edge/v7/pkg/callback"
    "log"
    "net/url"
)

func main() {
    amURL, err := url.Parse("http://am.localtest.me:8080/openam")
    if err != nil {
        log.Fatal(err)
    }
    _, err = builder.Thing().
        ConnectTo(amURL).
        InRealm("/").
        WithTree("Example").
        HandleCallbacksWith(
            callback.NameHandler{Name: "Gopher"},
            callback.PasswordHandler{Password: "5tr0ngG3n3r@ted"}).
        Create()
    if err != nil {
        log.Fatal(err)
    }
    log.Println("Gopher successfully authenticated.")
}

Create a Go module:
```
go mod init example.com/things
go: creating new go.mod: module example.com/things
```
This step creates a go.mod file that specifies your project dependencies and versions.

Build an executable for your client application:

go build example.com/things/cmd/gopher
go: finding module for package github.com/ForgeRock/iot-edge/v7/pkg/callback
go: finding module for package github.com/ForgeRock/iot-edge/v7/pkg/builder
go: downloading github.com/ForgeRock/iot-edge v0.0.0-20200812141306-ee64981fa05f
go: downloading github.com/ForgeRock/iot-edge/v7 v7.1.0
go: found github.com/ForgeRock/iot-edge/v7/pkg/builder in github.com/ForgeRock/iot-edge/v7 v7.1.0
go: found github.com/ForgeRock/iot-edge/v7/pkg/callback in github.com/ForgeRock/iot-edge/v7 v7.1.0

This step builds an executable gopher application in the things directory.

Run the Client Application

Before you can run the application, you must register an identity for Gopher in AM:

Obtain an admin SSO token from AM:

curl \
--header 'X-OpenAM-Username: amAdmin' \
--header 'X-OpenAM-Password: changeit' \
--header 'Content-Type: application/json' \
--header 'Accept-API-Version: resource=2.0, protocol=1.0' \
--request POST \
'http://am.localtest.me:8080/openam/json/authenticate'
{
 "tokenId": "qGAzvBw20z5...AAA.*",
 "successUrl": "/openam/console",
 "realm": "/"
}

Save the tokenId returned in this request as a variable, for example:

export tokenId=qGAzvBw20z5...AAA.*
echo $tokenId
qGAzvBw20z5...AAA.*

curl \
--header 'Content-Type: application/json' \
--header 'Accept-Api-Version: resource=4.0, protocol=2.1' \
--cookie "iPlanetDirectoryPro=${tokenId}" \
--data '{
    "userPassword": "5tr0ngG3n3r@ted",
    "thingType": "device"
}' \
--request PUT \
"http://am.localtest.me:8080/openam/json/realms/root/users/Gopher"
{
  "_id": "Gopher",
  "_rev": "-1",
  "realm": "/",
  "username": "Gopher",
  "uid": [
    "Gopher"
  ],
  "universalid": [
    "id=Gopher,ou=user,dc=openam,dc=forgerock,dc=org"
  ],
  "objectClass": [
    "iplanet-am-managed-person",
    "inetuser",
    "fr-iot",
    "sunFMSAML2NameIdentifier",
    "inetorgperson",
    "devicePrintProfilesContainer",
    "iplanet-am-user-service",
    "iPlanetPreferences",
    "pushDeviceProfilesContainer",
    "forgerock-am-dashboard-service",
    "organizationalperson",
    "top",
    "kbaInfoContainer",
    "person",
    "sunAMAuthAccountLockout",
    "oathDeviceProfilesContainer",
    "webauthnDeviceProfilesContainer",
    "iplanet-am-auth-configuration-service",
    "deviceProfilesContainer"
  ],
  "dn": [
    "uid=Gopher,ou=people,dc=openam,dc=forgerock,dc=org"
  ],
  "inetUserStatus": [
    "Active"
  ],
  "cn": [
    "Gopher"
  ],
  "sn": [
    "Gopher"
  ],
  "thingType": [
    "device"
  ],
  "createTimestamp": [
    "20200831103235Z"
  ]
}

Run the executable to authenticate your application to AM:

./gopher
2020/09/01 11:09:49 Gopher successfully authenticated.