add send helper function which checks the banphrase api

cmd/bot/command.go

@@ -34,7 +34,15 @@ func (app *application) handleCommand(message twitch.PrivateMessage) {
 	switch commandName {
 	case "":
 		if msgLen == 1 {
-			app.twitchClient.Say(target, "xd")
+			app.Send(target, "xd")
+			return
+		}
+	case "echo":
+		if msgLen < 2 {
+			app.Send(target, "Not enough arguments provided.")
+			return
+		} else {
+			app.Send(target, message.Message[7:len(message.Message)])
 			return
 		}
 	}

cmd/bot/send.go

@@ -0,0 +1,119 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+)
+
+// banphraseResponse is the data we receive back from
+// the banphrase API
+type banphraseResponse struct {
+	Banned        bool          `json:"banned"`
+	InputMessage  string        `json:"input_message"`
+	BanphraseData banphraseData `json:"banphrase_data"`
+}
+
+// banphraseData contains details about why a message
+// was banphrased.
+type banphraseData struct {
+	Id        int    `json:"id"`
+	Name      string `json:"name"`
+	Phrase    string `json:"phrase"`
+	Length    int    `json:"length"`
+	Permanent bool   `json:"permanent"`
+}
+
+var (
+	banPhraseUrl = "https://pajlada.pajbot.com/api/v1/banphrases/test"
+)
+
+// CheckMessage checks a given message against the banphrase api.
+// returns false, "okay" if a message is allowed
+// returns true and a string with the reason if it was banned.
+// More information:
+// https://gist.github.com/pajlada/57464e519ba8d195a97ddcd0755f9715
+func (app *application) checkMessage(text string) (bool, string) {
+
+	// {"message": "AHAHAHAHA LUL"}
+	reqBody, err := json.Marshal(map[string]string{
+		"message": text,
+	})
+	if err != nil {
+		app.logger.Error(err)
+	}
+
+	resp, err := http.Post(banPhraseUrl, "application/json", bytes.NewBuffer(reqBody))
+	if err != nil {
+		app.logger.Error(err)
+	}
+
+	defer resp.Body.Close()
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		app.logger.Error(err)
+	}
+
+	var responseObject banphraseResponse
+	json.Unmarshal(body, &responseObject)
+
+	// Bad Message
+	//
+	// {"phrase": "No gyazo allowed"}
+	reason := responseObject.BanphraseData.Name
+	if responseObject.Banned {
+		return true, fmt.Sprint(reason)
+	} else if !responseObject.Banned {
+		// Good message
+		return false, "okay"
+	}
+
+	// Couldn't contact api so assume it was a bad message
+	return true, "Banphrase API couldn't be reached monkaS"
+}
+
+// Send is used to send twitch replies and contains the necessary
+// safeguards and logic for that.
+func (app *application) Send(target, message string) {
+	// Message we are trying to send is empty.
+	if len(message) == 0 {
+		return
+	}
+
+	// Since messages starting with `.` or `/` are used for special actions
+	// (ban, whisper, timeout) and so on, we place a emote infront of it so
+	// the actions wouldn't execute. `!` and `$` are common bot prefixes so we
+	// don't allow them either.
+	if message[0] == '.' || message[0] == '/' || message[0] == '!' || message[0] == '$' {
+		message = ":tf: " + message
+	}
+
+	// check the message for bad words before we say it
+	messageBanned, banReason := app.checkMessage(message)
+	if messageBanned {
+		// Bad message, replace message and log it.
+		app.twitchClient.Say(target, "[BANPHRASED] monkaS")
+		app.logger.Info("Banned message detected: ", banReason)
+
+		return
+	} else {
+		// In case the message we are trying to send is longer than the
+		// maximum allowed message length on twitch. We split the message
+		// in two parts.
+		if len(message) > 500 {
+			firstMessage := message[0:499]
+			secondMessage := message[499:]
+
+			app.twitchClient.Say(target, firstMessage)
+			app.twitchClient.Say(target, secondMessage)
+
+			return
+		}
+		// Message was fine.
+		app.twitchClient.Say(target, message)
+		return
+	}
+}