How to Receive and Respond to Incoming MMS Messages in Go with Martini and Plivo

Jun 7, 2022

Overview

This guide shows how to receive and automatically respond to incoming MMS messages on a Plivo number, as you might want to do for someone who’s out of the office or who leaves the company.

Here’s how to use Plivo’s SMS APIs to build this use case.

Prerequisites

To get started, you need a Plivo account — sign up with your work email address if you don’t have one already. To receive incoming messages, you must have a Plivo phone number that supports SMS; you can rent numbers from the Numbers page of the Plivo console or by using the Numbers API. If this is your first time using Plivo APIs, follow our instructions to set up a Go development environment.

Create the autoresponder application

Create a file called autoresponder.go and paste into it this code.

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package main

import (
	"encoding/json"
	"fmt"
	"net/http"
	"strings"

	"github.com/go-martini/martini"
	"github.com/plivo/plivo-go/v7"
)

func main() {
	m := martini.Classic()

	m.Post("/autoresponder/", func(w http.ResponseWriter, r *http.Request) string {
		w.Header().Set("Content-Type", "application/xml")
		from_number := r.FormValue("From")
		to_number := r.FormValue("To")
		text := r.FormValue("Text")
		var body string
		var media string
		if strings.ToLower(text) == "hi" {
			body = "Hello!"
			media = "https://media.giphy.com/media/888R35MJTmDxQfRzfS/giphy.gif"
		} else if strings.ToLower(text) == "bye" {
			body = "Bye and have a nice day!"
			media = "https://media.giphy.com/media/QM5lHSyFjz1XW/giphy.gif"
		} else {
			body = "I'm glad that we connected"
			media = "https://media.giphy.com/media/888R35MJTmDxQfRzfS/giphy.gif"
		}
	
		client, err := plivo.NewClient("<auth_id>", "<auth_token>",
			&plivo.ClientOptions{})
		if err != nil {
			panic(err)
		}
		response, err := client.Messages.Create(plivo.MessageCreateParams{
			Src:       to_number,
			Dst:       from_number,
			Text:      body,
			Type:      "mms",
			MediaUrls: []string{media},
		})
		if err != nil {
			panic(err)
		}
		res, err := json.Marshal(response)
		if err != nil {
			fmt.Println("error:", err)
		}
		fmt.Printf("Response: %#v\n", res)
		return string(res)
	})
	m.Run()
}

Save the file and run it.

go run autoresponder.go

You should see your basic server application in action at http://localhost:3000/autoresponder/.

Set up ngrok to expose your local server to the internet.

Create a Plivo application for the autoresponder

Associate the controller you created with Plivo by creating a Plivo application. Visiting Messaging > Applications and click Add New Application. You can also use Plivo’s Application API.

Give your application a name — we called ours Autoresponder. Enter the server URL you want to use (for example https://<yourdomain>.com/autoresponder/) in the Message URL field and set the method to POST. Click Create Application to save your application.

Note: If you’re using a Plivo Trial account, you can send messages only to phone numbers that have been verified with Plivo. You can verify (sandbox) a number by going to the console’s Phone Numbers > Sandbox Numbers page.

Navigate to the Numbers page and select the phone number you want to use for this application.

From the Application Type drop-down, select XML Application.

From the Plivo Application drop-down, select Autoresponder (the name we gave the application).

Click Update Number to save.