How to start receiving and responding to messages#

Installation#

Before you begin, you need to install the library and initiate the bot; this process is described in detail here: How to import the library and initiate your bot.

How to start receiving and responding to messages#

To start receiving notifications, you need to call the bot.StartReceivingNotifications() method on the bot. But before that you need to add a handler; this can be done in two ways. You can do this directly in the main function as in the base example.

Link to example: base.go.

package base

import (
    "github.com/green-api/whatsapp_chatbot_golang"
)

func main() {
    bot := whatsapp_chatbot_golang.NewBot("INSTANCE_ID", "TOKEN")

    bot.IncomingMessageHandler(func(message *whatsapp_chatbot_golang.Notification) {
        if message.Filter(map[string][]string{"text": {"test"}}) {
            message.AnswerWithText("Well done! You have write \"test\".")
        } else {
            message.AnswerWithText("Write \"test\"!")
        }
    })

    bot.StartReceivingNotifications()
}

If you have complex nested scripts, it is better to use scenes as in the baseScene example. Using scenes is easy - just put the bot logic into a separate structure that implements the Scene interface, and add it to the bot using the bot.SetStartScene(StartScene{}) method. The starting scene can call the next one using the message.ActivateNextScene(NextScene{}) method, then the next webhook will go into the new scene, this will allow you to divide the bot into separate parts and make the code more readable and editable:

Link to example: baseScene.go.

package base

import (
    "github.com/green-api/whatsapp_chatbot_golang"
)

func main() {
    bot := whatsapp_chatbot_golang.NewBot("INSTANCE_ID", "TOKEN")

    bot.SetStartScene(StartScene{})

    bot.StartReceivingNotifications()
}

type StartScene struct {
}

func (s StartScene) Start(bot *whatsapp_chatbot_golang.Bot) {
    bot.IncomingMessageHandler(func(message *whatsapp_chatbot_golang.Notification) {
        if message.Filter(map[string][]string{"text": {"test"}}) {
            message.AnswerWithText("Well done! You have write \"test\".")
            message.AnswerWithText("Now write \"second scene\"")
            message.ActivateNextScene(SecondScene{})
        } else {
            message.AnswerWithText("Write \"test\"!")
        }
    })
}

type SecondScene struct {
}

func (s SecondScene) Start(bot *whatsapp_chatbot_golang.Bot) {
    bot.IncomingMessageHandler(func(message *whatsapp_chatbot_golang.Notification) {
        if message.Filter(map[string][]string{"text": {"second scene"}}) {
            message.AnswerWithText("Well done! You have write \"second scene\".")
            message.ActivateNextScene(StartScene{})
        } else {
            message.AnswerWithText("This is second scene write \"second scene\"!")
        }
    })
}

If you need that when creating a new state, it already has some default values, you need to change the InitData field of the StateManager structure. In the standard implementation of MapStateManager this is done like this:

package main

import (
    "github.com/green-api/whatsapp_chatbot_golang"
    "github.com/green-api/whatsapp_chatbot_golang/examples/full"
)

func main() {
    bot := whatsapp_chatbot_golang.NewBot("INSTANCE_ID", "TOKEN")

    bot.StateManager = whatsapp_chatbot_golang.NewMapStateManager(
        map[string]interface{}{
            "defaultField1": "defaultValue1",
            "defaultField2": "defaultValue2",
            "defaultField3": "defaultValue3",
        })

    bot.SetStartScene(full.StartScene{})

    bot.StartReceivingNotifications()
}

Please note that errors may occur while executing queries so that your program does not break due to them, you need to handle errors. All library errors are sent to the ErrorChannel channel, you can handle them for example in this way:

package main

import (
    "fmt"
    "github.com/green-api/whatsapp_chatbot_golang"
    "github.com/green-api/whatsapp_chatbot_golang/examples/full"
)

func main() {
    bot := whatsapp_chatbot_golang.NewBot("INSTANCE_ID", "TOKEN")

    bot.SetStartScene(full.StartScene{})

    //All errors will simply be output to the console
    go func() {
        select {
        case err := <-bot.ErrorChannel:
            if err != nil {
                fmt.Println(err)
            }
        }
    }()

    bot.StartReceivingNotifications()
}

List of examples#

Description	Link to example
How to initialize a handler	base.go
How to initialize a scene	baseScene.go
Scene "Echo"	echo.go
How to receive other types of notifications	event.go
How to filter incoming messages	filter.go
How to work with bot state	state.go
Example of a ready-made chat bot	full.go