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package main
import (
"database/sql"
"fmt"
"log"
"crypto/md5"
"strings"
"net"
"encoding/json"
_ "github.com/mattn/go-sqlite3"
)
type Data struct {
Type int `json:"type"`
URL string `json:"url"`
}
var DB *sql.DB
func init_DB() {
var err error;
DB, err = sql.Open("sqlite3", "./app.db");
if err != nil {
log.Fatal(err);
}
sql_q := `
CREATE TABLE IF NOT EXISTS urls (
id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
url TEXT NOT NULL,
short TEXT NOT NULL UNIQUE
)`;
_, err = DB.Exec(sql_q);
if err != nil {
log.Fatal(err);
}
}
var units = [16]string{"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f"};
func gen_hash(url string) string{
data := []byte(url);
hash := md5.Sum(data);
var ret string;
for i := 0; i < 3; i++ {
ret = ret + units[hash[i] / 16];
ret = ret + units[hash[i] % 16];
}
return ret;
}
func correct_url(url string) string {
if(len(url) <= 7) {
return "https://" + url;
}
if(url[:8] != "https://") {
return "https://" + url;
}
return url;
}
func add_url(url string) {
hurl := correct_url(url);
hsh := gen_hash(hurl);
fmt.Printf("adding: %s -> %s \n", hurl, hsh);
_, err := DB.Exec("INSERT INTO urls (url, short) VALUES (?, ?)", hurl, hsh);
if err != nil {
var ok bool;
ok = false;
tmp := strings.Split(err.Error(), " ");
for i := 0; i < len(tmp); i++ {
if tmp[i] == "UNIQUE" {
ok = true;
break;
}
}
if ok{
fmt.Println("hash ja existe na tabela: Deletando valor antigo...");
_, err := DB.Exec("DELETE FROM urls WHERE short = ?", hsh);
if err != nil {
log.Fatal(err);
}
fmt.Println("Adicionando...");
_, err = DB.Exec("INSERT INTO urls (url, short) VALUES (?, ?)", hurl, hsh);
if err != nil {
log.Fatal(err);
}
}else{
log.Fatal(err);
}
}
}
func get_hash_from_db(hash string) string{
rows, err := DB.Query("SELECT url FROM urls WHERE short = ?", hash);
if err != nil {
log.Fatal(err);
}
defer rows.Close();
var url string;
for rows.Next() {
err = rows.Scan(&url);
if err != nil {
log.Fatal(err);
}
fmt.Println(url);
}
return url;
}
func read_json(cont []byte) (Data, error) {
var data Data;
err := json.Unmarshal(cont, &data);
if err != nil {
return data, err;
}
return data, nil;
}
func handle_request(conn net.Conn, data Data) {
if data.Type == 1 {
add_url(data.URL);
}else if data.Type == 2 {
ret := get_hash_from_db(data.URL);
conn.Write([]byte(fmt.Sprintf("%s\n", ret)));
}else {
}
}
func handle_client(conn net.Conn){
defer conn.Close();
buffer := make([]byte, 1024);
for {
n, err := conn.Read(buffer);
if err != nil {
log.Println(err);
return;
}
fmt.Printf("Recebido: %s\n", buffer[:n]);
data, err := read_json(buffer[:n]);
if err != nil {
log.Println(err);
}else {
handle_request(conn, data);
}
}
}
func main() {
init_DB();
/*add_url("google.com");
get_hash_from_db("99999e");*/
ln, err := net.Listen("tcp", "localhost:5555");
defer ln.Close();
fmt.Println("Listen on port 5555");
if err != nil {
log.Fatal(err);
}
for {
conn, err := ln.Accept();
if err != nil {
log.Println(err);
continue;
}
fmt.Println("New connection accepted");
go handle_client(conn);
}
}
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