Resgrid Relay is a .NET 10 solution for creating Resgrid calls from either:

1. Windows audio tone monitoring
2. Direct SMTP ingestion for emails sent to Resgrid dispatch addresses

The project now uses the Resgrid v4 API and OpenID Connect refresh-token authentication instead of the legacy v3 username/password flow.

• Cross-platform
• Intended for Linux/Docker deployments
• Runs an SMTP listener and creates Resgrid calls from inbound mail
• Replaces the old Postmark SMTP email API path

• Windows only
• Uses the existing DTMF/audio watcher flow
• Creates a call in Resgrid and uploads captured dispatch audio as a separate v4 call file

• .NET SDK 10.0.202 or newer compatible .NET 10 SDK
• Windows for the WPF app, tests, and audio mode

• SMTP mode: any platform with .NET 10 runtime
• Audio mode: Windows with an accessible audio input device

Relay authenticates to Resgrid through the v4 OIDC token endpoint:

• Discovery: https://api.resgrid.com/.well-known/openid-configuration
• Token endpoint: https://api.resgrid.com/api/v4/connect/token
• Grant type: refresh_token

You must provide:

• ClientId
• ClientSecret
• RefreshToken

Relay keeps the latest rotated refresh/access token state in a configurable token cache file.

The console worker reads appsettings.json plus environment variables prefixed with RELAY_.

{
  "Mode": "smtp",
  "AudioConfigPath": "settings.json",
  "Resgrid": {
    "BaseUrl": "https://api.resgrid.com",
    "ApiVersion": "4",
    "ClientId": "YOUR_CLIENT_ID",
    "ClientSecret": "YOUR_CLIENT_SECRET",
    "RefreshToken": "YOUR_REFRESH_TOKEN",
    "Scope": "openid profile email offline_access mobile",
    "TokenCachePath": ".\\data\\resgrid-token.json"
  },
  "Telemetry": {
    "Environment": "production",
    "Sentry": {
      "Dsn": "YOUR_SENTRY_DSN",
      "Release": "resgrid-relay@1.0.0",
      "SendDefaultPii": true
    },
    "Countly": {
      "Url": "https://countly.example.com",
      "AppKey": "YOUR_COUNTLY_APP_KEY",
      "DeviceId": "resgrid-relay-prod-01",
      "RequestTimeoutSeconds": 5
    }
  },
  "Smtp": {
    "ServerName": "resgrid-relay",
    "Port": 2525,
    "DataDirectory": ".\\data",
    "DuplicateWindowHours": 72,
    "DefaultCallPriority": 1,
    "MaxAttachmentBytes": 10485760,
    "SaveRawMessages": true,
    "DepartmentDispatchPrefix": "G",
    "DepartmentAddressDomains": [ "dispatch.resgrid.com" ],
    "GroupAddressDomains": [ "groups.resgrid.com" ]
  }
}

$env:RELAY_Mode = "smtp"
$env:RELAY_Resgrid__ClientId = "YOUR_CLIENT_ID"
$env:RELAY_Resgrid__ClientSecret = "YOUR_CLIENT_SECRET"
$env:RELAY_Resgrid__RefreshToken = "YOUR_REFRESH_TOKEN"
$env:RELAY_Telemetry__Sentry__Dsn = "YOUR_SENTRY_DSN"
$env:RELAY_Telemetry__Countly__Url = "https://countly.example.com"
$env:RELAY_Telemetry__Countly__AppKey = "YOUR_COUNTLY_APP_KEY"
$env:RELAY_Smtp__Port = "2525"

SMTP mode now emits structured logging for:

• connection open / close / fault events
• sender and recipient acceptance or rejection
• message receipt, duplicate suppression, routing resolution, and processing lifecycle
• Resgrid call creation, attachment handling, and processing failures

Optional integrations:

• Sentry captures SMTP processing and connection exceptions with message/session context attached.
• Countly records custom events such as smtp_connection_started, smtp_connection_completed, smtp_message_processed, and smtp_message_failed.

Notes:

• Relay logs message metadata such as sender, recipients, subject, message ids, dispatch targets, and attachment names.
• Relay intentionally does not mirror full email bodies into logs; the imported call note and optional raw .eml retention remain the system-of-record for message content.
• If Telemetry:Countly:DeviceId is blank, Relay derives a stable device id from the machine name and SMTP server name.

Audio mode continues to use settings.json, but now stores Resgrid OIDC settings instead of username/password.

{
  "InputDevice": 0,
  "AudioLength": 120,
  "Multiple": false,
  "Tolerance": 100,
  "Threshold": -50,
  "EnableSilenceDetection": false,
  "Debug": false,
  "DebugKey": "",
  "Resgrid": {
    "BaseUrl": "https://api.resgrid.com",
    "ApiVersion": "4",
    "ClientId": "YOUR_CLIENT_ID",
    "ClientSecret": "YOUR_CLIENT_SECRET",
    "RefreshToken": "YOUR_REFRESH_TOKEN",
    "Scope": "openid profile email offline_access mobile",
    "TokenCachePath": ".\\data\\resgrid-token.json"
  },
  "DispatchMapping": {
    "GroupDispatchPrefix": "G",
    "DepartmentDispatchPrefix": "G"
  },
  "Watchers": [
    {
      "Id": "ee188c37-09f4-47c0-9ff1-fe34c9d6a5f1",
      "Name": "Station 1",
      "Active": true,
      "Code": "ABC123",
      "AdditionalCodes": "",
      "Type": 2,
      "Triggers": [
        {
          "Frequency1": 524.0,
          "Frequency2": 794.0,
          "Time1": 500,
          "Time2": 500,
          "Count": 2
        }
      ]
    }
  ]
}

• Type = 1 means department dispatch code
• Type = 2 means group dispatch code
• AdditionalCodes is treated as extra group dispatch codes

Relay accepts inbound SMTP messages for configured Resgrid-style dispatch domains and converts recipient addresses into v4 DispatchList entries.

Examples:

Notes:

• Duplicate messages are suppressed using a persisted message-id store
• Raw .eml files can be saved for traceability
• Attachments are uploaded to the created call through CallFiles/SaveCallFile
• Structured logs, Sentry exception capture, and Countly custom events are available for SMTP operations
• If your Resgrid department-dispatch code requires a prefix other than G, set Smtp:DepartmentDispatchPrefix

From Resgrid.Audio.Relay.Console:

dotnet run --project .\Resgrid.Audio.Relay.Console\Resgrid.Audio.Relay.Console.csproj -- run
dotnet run --project .\Resgrid.Audio.Relay.Console\Resgrid.Audio.Relay.Console.csproj -- setup
dotnet run --project .\Resgrid.Audio.Relay.Console\Resgrid.Audio.Relay.Console.csproj -- devices
dotnet run --project .\Resgrid.Audio.Relay.Console\Resgrid.Audio.Relay.Console.csproj -- monitor 0
dotnet run --project .\Resgrid.Audio.Relay.Console\Resgrid.Audio.Relay.Console.csproj -- version

Build the Linux SMTP worker image:

docker build -t resgrid-relay .

Run it:

docker run --rm -p 2525:2525 `
  -e RELAY_Mode=smtp `
  -e RELAY_Resgrid__ClientId=YOUR_CLIENT_ID `
  -e RELAY_Resgrid__ClientSecret=YOUR_CLIENT_SECRET `
  -e RELAY_Resgrid__RefreshToken=YOUR_REFRESH_TOKEN `
  resgrid-relay

dotnet build "Resgrid Audio.sln"
dotnet test "Resgrid Audio.sln"

• The worker now creates calls through Calls/SaveCall
• Audio and SMTP attachments are uploaded through CallFiles/SaveCallFile
• The worker derives the current Resgrid user id from the OIDC access token sub claim for file uploads
• The Windows audio path intentionally keeps the legacy DTMF assemblies isolated to the Windows-only project boundary

• Shawn Jackson
• Jason Jarrett

Apache 2.0