[WIP] Partial bot skeleton, non-functional though

vendor/github.com/NicoNex/echotron/v3/simpledsp.go

@@ -0,0 +1,119 @@
+package echotron
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"net/http"
+	"net/url"
+	"time"
+)
+
+// PollingUpdates is a wrapper function for PollingUpdatesOptions.
+func PollingUpdates(token string) <-chan *Update {
+	return PollingUpdatesOptions(token, true, UpdateOptions{Timeout: 120})
+}
+
+// PollingUpdatesOptions returns a read-only channel of incoming  updates from the Telegram API.
+func PollingUpdatesOptions(token string, dropPendingUpdates bool, opts UpdateOptions) <-chan *Update {
+	var updates = make(chan *Update)
+
+	go func() {
+		defer close(updates)
+
+		var (
+			api        = NewAPI(token)
+			timeout    = opts.Timeout
+			isFirstRun = true
+		)
+
+		// deletes webhook if present to run in long polling mode
+		if _, err := api.DeleteWebhook(dropPendingUpdates); err != nil {
+			log.Println("echotron.PollingUpdates", err)
+		}
+
+		for {
+			if isFirstRun {
+				opts.Timeout = 0
+			}
+
+			response, err := api.GetUpdates(&opts)
+			if err != nil {
+				log.Println("echotron.PollingUpdates", err)
+				time.Sleep(5 * time.Second)
+				continue
+			}
+
+			if !dropPendingUpdates || !isFirstRun {
+				for _, u := range response.Result {
+					updates <- u
+				}
+			}
+
+			if l := len(response.Result); l > 0 {
+				opts.Offset = response.Result[l-1].ID + 1
+			}
+
+			if isFirstRun {
+				isFirstRun = false
+				opts.Timeout = timeout
+			}
+		}
+	}()
+
+	return updates
+}
+
+// WebhookUpdates is a wrapper function for WebhookUpdatesOptions.
+func WebhookUpdates(url, token string) <-chan *Update {
+	return WebhookUpdatesOptions(url, token, false, nil)
+}
+
+// WebhookUpdatesOptions returns a read-only channel of incoming updates from the Telegram API.
+// The webhookUrl should be provided in the following format: '<hostname>:<port>/<path>',
+// eg: 'https://example.com:443/bot_token'.
+// WebhookUpdatesOptions will then proceed to communicate the webhook url '<hostname>/<path>'
+// to Telegram and run a webserver that listens to ':<port>' and handles the path.
+func WebhookUpdatesOptions(whURL, token string, dropPendingUpdates bool, opts *WebhookOptions) <-chan *Update {
+	u, err := url.Parse(whURL)
+	if err != nil {
+		panic(err)
+	}
+
+	wURL := u.Hostname() + u.EscapedPath()
+	api := NewAPI(token)
+	if _, err := api.SetWebhook(wURL, dropPendingUpdates, opts); err != nil {
+		panic(err)
+	}
+
+	var updates = make(chan *Update)
+	http.HandleFunc(u.EscapedPath(), func(w http.ResponseWriter, r *http.Request) {
+		var update Update
+
+		jsn, err := readRequest(r)
+		if err != nil {
+			log.Println("echotron.WebhookUpdates", err)
+			return
+		}
+
+		if err := json.Unmarshal(jsn, &update); err != nil {
+			log.Println("echotron.WebhookUpdates", err)
+			return
+		}
+
+		updates <- &update
+	})
+
+	go func() {
+		defer close(updates)
+		port := fmt.Sprintf(":%s", u.Port())
+		for {
+			if err := http.ListenAndServe(port, nil); err != nil {
+				log.Println("echotron.WebhookUpdates", err)
+				time.Sleep(5 * time.Second)
+			}
+		}
+	}()
+
+	return updates
+}