wip(sendsms): send to a CSV list

cmd/sendsms/go.mod

@@ -0,0 +1,5 @@
+module example.com/sendsms
+
+go 1.24.4
+
+require github.com/joho/godotenv v1.5.1

cmd/sendsms/go.sum

@@ -0,0 +1,2 @@
+github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
+github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=

cmd/sendsms/sendsms.go

@@ -0,0 +1,239 @@
+package main
+
+import (
+	"bytes"
+	"encoding/csv"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"io"
+	"math/rand"
+	"net/http"
+	"os"
+	"slices"
+	"strings"
+	"time"
+
+	"github.com/joho/godotenv"
+)
+
+type SMSSender struct {
+	baseURL  string
+	user     string
+	password string
+}
+
+type SMSMessage struct {
+	FirstName       string
+	PhoneNumber     string
+	MessageTemplate string
+}
+
+type TextMessage struct {
+	Text string `json:"text"`
+}
+
+type Payload struct {
+	TextMessage  TextMessage `json:"textMessage"`
+	PhoneNumbers []string    `json:"phoneNumbers"`
+	Priority     int         `json:"priority,omitempty"`
+}
+
+func cleanPhoneNumber(raw string) string {
+	var cleaned strings.Builder
+	for i, char := range raw {
+		if (i == 0 && char == '+') || (char >= '0' && char <= '9') {
+			cleaned.WriteRune(char)
+		}
+	}
+	return cleaned.String()
+}
+
+func validateAndFormatNumber(number string) string {
+	switch len(number) {
+	case 10:
+		return "+1" + number
+	case 11:
+		if strings.HasPrefix(number, "1") {
+			return "+" + number
+		}
+		fmt.Printf("warning: invalid 11-digit number '%s'\n", number)
+		return ""
+	case 12:
+		if strings.HasPrefix(number, "+1") {
+			return number
+		}
+		fmt.Printf("warning: invalid 12-digit number '%s' does not start with +1\n", number)
+		return ""
+	default:
+		fmt.Printf("warning: invalid number length for '%s'\n", number)
+		return ""
+	}
+}
+
+func (s *SMSSender) printDryRun(number, message string) {
+	url := s.baseURL + "/messages"
+	payload := Payload{
+		TextMessage:  TextMessage{Text: message},
+		PhoneNumbers: []string{number},
+		Priority:     65,
+	}
+	body := bytes.NewBuffer(nil)
+	encoder := json.NewEncoder(body)
+	encoder.SetEscapeHTML(false)
+	_ = encoder.Encode(payload)
+
+	escapedBody := strings.ReplaceAll(body.String(), "'", "'\\''")
+
+	fmt.Printf("curl --fail-with-body --user '%s:%s' -X POST '%s' \\\n", s.user, s.password, url)
+	fmt.Printf("   -H 'Content-Type: application/json' \\\n")
+	fmt.Printf("   --data-binary '%s'\n", escapedBody)
+}
+
+func (s *SMSSender) sendMessage(number, message string) {
+	number = cleanPhoneNumber(number)
+	if len(number) == 0 {
+		panic(fmt.Errorf("non-sanitized number '%s'", number))
+	}
+
+	url := s.baseURL + "/messages"
+	payload := Payload{
+		TextMessage:  TextMessage{Text: message},
+		PhoneNumbers: []string{number},
+		Priority:     65,
+	}
+
+	body := bytes.NewBuffer(nil)
+	encoder := json.NewEncoder(body)
+	encoder.SetEscapeHTML(false)
+	_ = encoder.Encode(payload)
+
+	req, _ := http.NewRequest("POST", url, body)
+	req.SetBasicAuth(s.user, s.password)
+	req.Header.Set("Content-Type", "application/json")
+
+	client := &http.Client{}
+	resp, err := client.Do(req)
+	if err != nil {
+		fmt.Printf("error: failed to send message to '%s': %v\n", number, err)
+		return
+	}
+	defer func() {
+		_ = resp.Body.Close()
+	}()
+
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		body, _ := io.ReadAll(resp.Body)
+		fmt.Printf("error: failed to send message to '%s': %d %s\n", number, resp.StatusCode, string(body))
+	}
+}
+
+func GetFieldIndex(header []string, name string) int {
+	for i, h := range header {
+		if strings.EqualFold(strings.TrimSpace(h), name) {
+			return i
+		}
+	}
+	return -1
+}
+
+func LaxParseCSV(csvr *csv.Reader, csvFile *string) ([]SMSMessage, error) {
+	header, err := csvr.Read()
+	if err != nil {
+		return nil, fmt.Errorf("error: %q header could not be parsed: %w", *csvFile, err)
+	}
+
+	FIELD_NICK := GetFieldIndex(header, "Preferred")
+	FIELD_PHONE := GetFieldIndex(header, "Phone")
+	FIELD_MESSAGE := GetFieldIndex(header, "Message")
+	if FIELD_NICK == -1 || FIELD_PHONE == -1 || FIELD_MESSAGE == -1 {
+		return nil, fmt.Errorf("error: %q is missing one or more of 'Preferred', 'Phone', and/or 'Message'", *csvFile)
+	}
+	FIELD_MIN := 1 + slices.Max([]int{FIELD_NICK, FIELD_PHONE, FIELD_MESSAGE})
+
+	var messages []SMSMessage
+	rowIndex := 1 // 1-index, start at header
+	for {
+		rowIndex++
+		rec, err := csvr.Read()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return nil, fmt.Errorf("error parsing %q row %d: %w", *csvFile, rowIndex, err)
+		}
+
+		if len(rec) < FIELD_MIN {
+			fmt.Printf("skipping row %d (too few fields): %s\n", rowIndex, strings.Join(rec, ","))
+			continue
+		}
+
+		message := SMSMessage{
+			FirstName:       strings.TrimSpace(rec[FIELD_NICK]),
+			PhoneNumber:     strings.TrimSpace(rec[FIELD_PHONE]),
+			MessageTemplate: strings.TrimSpace(rec[FIELD_MESSAGE]),
+		}
+
+		message.PhoneNumber = cleanPhoneNumber(message.PhoneNumber)
+		message.PhoneNumber = validateAndFormatNumber(message.PhoneNumber)
+		if message.PhoneNumber == "" {
+			fmt.Printf("skipping row %d (no phone number): %s\n", rowIndex, strings.Join(rec, ","))
+			continue
+		}
+
+		messages = append(messages, message)
+	}
+
+	return messages, nil
+}
+
+func main() {
+	_ = godotenv.Load("./.env")
+	sender := &SMSSender{
+		baseURL:  os.Getenv("SMSGW_BASEURL"),
+		user:     os.Getenv("SMSGW_USER"),
+		password: os.Getenv("SMSGW_PASSWORD"),
+	}
+
+	dryRun := flag.Bool("dry-run", false, "Print curl commands instead of sending messages")
+	csvFile := flag.String("csv", "./messages.csv", "Path to file with newline-delimited phone numbers")
+	flag.Parse()
+
+	file, err := os.Open(*csvFile)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error: %q could not be read\n", *csvFile)
+		os.Exit(1)
+	}
+	defer func() {
+		_ = file.Close()
+	}()
+
+	csvr := csv.NewReader(file)
+	csvr.FieldsPerRecord = -1
+
+	messages, err := LaxParseCSV(csvr, csvFile)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%v\n", err)
+		os.Exit(1)
+	}
+
+	r := rand.New(rand.NewSource(37))
+	r.Shuffle(len(messages), func(i, j int) {
+		messages[i], messages[j] = messages[j], messages[i]
+	})
+
+	for _, message := range messages {
+		delay := 60 + rand.Float64()*90
+
+		fmt.Fprintf(os.Stderr, "# Send to %s (%s) %s-%s\n", message.PhoneNumber[:2], message.PhoneNumber[2:5], message.PhoneNumber[5:8], message.PhoneNumber[8:])
+		text := strings.ReplaceAll(message.MessageTemplate, "{First}", message.FirstName)
+		if *dryRun {
+			sender.printDryRun(message.PhoneNumber, text)
+			fmt.Printf("sleep %.3f\n\n", delay)
+		} else {
+			sender.sendMessage(message.PhoneNumber, text)
+			fmt.Printf("sleep %.3f\n\n", delay)
+			time.Sleep(time.Duration(delay * float64(time.Second)))
+		}
+	}
+}