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package main
import (
"context"
"fmt"
"os"
"strconv"
"github.com/jackc/pgx/v5"
)
var conn *pgx.Conn
func main() {
var err error
conn, err = pgx.Connect(context.Background(), os.Getenv("DATABASE_URL"))
if err != nil {
fmt.Fprintf(os.Stderr, "Unable to connection to database: %v\n", err)
os.Exit(1)
}
if len(os.Args) == 1 {
printHelp()
os.Exit(0)
}
switch os.Args[1] {
case "list":
err = listTasks()
if err != nil {
fmt.Fprintf(os.Stderr, "Unable to list tasks: %v\n", err)
os.Exit(1)
}
case "add":
err = addTask(os.Args[2])
if err != nil {
fmt.Fprintf(os.Stderr, "Unable to add task: %v\n", err)
os.Exit(1)
}
case "update":
n, err := strconv.ParseInt(os.Args[2], 10, 32)
if err != nil {
fmt.Fprintf(os.Stderr, "Unable convert task_num into int32: %v\n", err)
os.Exit(1)
}
err = updateTask(int32(n), os.Args[3])
if err != nil {
fmt.Fprintf(os.Stderr, "Unable to update task: %v\n", err)
os.Exit(1)
}
case "remove":
n, err := strconv.ParseInt(os.Args[2], 10, 32)
if err != nil {
fmt.Fprintf(os.Stderr, "Unable convert task_num into int32: %v\n", err)
os.Exit(1)
}
err = removeTask(int32(n))
if err != nil {
fmt.Fprintf(os.Stderr, "Unable to remove task: %v\n", err)
os.Exit(1)
}
default:
fmt.Fprintln(os.Stderr, "Invalid command")
printHelp()
os.Exit(1)
}
}
func listTasks() error {
rows, _ := conn.Query(context.Background(), "select * from tasks")
for rows.Next() {
var id int32
var description string
err := rows.Scan(&id, &description)
if err != nil {
return err
}
fmt.Printf("%d. %s\n", id, description)
}
return rows.Err()
}
func addTask(description string) error {
_, err := conn.Exec(context.Background(), "insert into tasks(description) values($1)", description)
return err
}
func updateTask(itemNum int32, description string) error {
_, err := conn.Exec(context.Background(), "update tasks set description=$1 where id=$2", description, itemNum)
return err
}
func removeTask(itemNum int32) error {
_, err := conn.Exec(context.Background(), "delete from tasks where id=$1", itemNum)
return err
}
func printHelp() {
fmt.Print(`Todo pgx demo
Usage:
todo list
todo add task
todo update task_num item
todo remove task_num
Example:
todo add 'Learn Go'
todo list
`)
}
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