Connected clients admin API (#217)

* Add support for ending the inbound stream. Closes #191

* Add a simple success response to API requests

* Connected clients API with geo details

* Post-rebase cleanup

* Make setting and reading geo details separate operations to unblock and speed up

* Rename file

* Fire geoip api call behind goroutine

* Add comment

* Post-rebase fixes

* Add support for the MaxMind GeoLite2 GeoIP database

models/client.go

@@ -0,0 +1,36 @@
+package models
+
+import (
+	"net/http"
+	"time"
+
+	"github.com/owncast/owncast/geoip"
+	"github.com/owncast/owncast/utils"
+)
+
+type ConnectedClientsResponse struct {
+	Clients []Client `json:"clients"`
+}
+
+type Client struct {
+	ConnectedAt  time.Time         `json:"connectedAt"`
+	LastSeen     time.Time         `json:"-"`
+	MessageCount int               `json:"messageCount"`
+	UserAgent    string            `json:"userAgent"`
+	IPAddress    string            `json:"ipAddress"`
+	Username     *string           `json:"username"`
+	ClientID     string            `json:"clientID"`
+	Geo          *geoip.GeoDetails `json:"geo"`
+}
+
+func GenerateClientFromRequest(req *http.Request) Client {
+	return Client{
+		ConnectedAt:  time.Now(),
+		LastSeen:     time.Now(),
+		MessageCount: 0,
+		UserAgent:    req.UserAgent(),
+		IPAddress:    utils.GetIPAddressFromRequest(req),
+		Username:     nil,
+		ClientID:     utils.GenerateClientIDFromRequest(req),
+	}
+}