280 lines
7.1 KiB
Go
280 lines
7.1 KiB
Go
// yasuc - yet another sprunge.us clone (command line pastebin)
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//
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// Copyright (C) Tom Jakubowski <tom@crystae.net>
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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package main
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import (
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"crypto/sha256"
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"database/sql"
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"encoding/hex"
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"flag"
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"fmt"
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"html/template"
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"log"
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"math/rand"
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"net/http"
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"os"
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"time"
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_ "modernc.org/sqlite"
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)
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const (
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maxPasteSize = 4 * 1024 * 1024
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shortIDLength = 7
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)
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const usageText = `
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<!doctype html>
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<html>
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<head>
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</head>
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<body>
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<pre>
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yasuc(1) YASUC yasuc(1)
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NAME
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yasuc - command line pastebin.
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SYNOPSIS
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<command> | curl -F 'sprunge=<-' {{.BaseURL}}
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DESCRIPTION
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A command line pastebin. Pastes are immutable and created with simple HTTP
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POST requests. The path of a paste's URL is a short unique identifier.
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EXAMPLE
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$ echo 'hello world' | curl -F 'sprunge=<-' {{.BaseURL}}
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{{.BaseURL}}/Ly34kx3
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$ firefox {{.BaseURL}}/Ly34kx3
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COPYRIGHT
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Copyright © Tom Jakubowski. License AGPLv3: GNU Affero GPL Version 3
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<a href="https://www.gnu.org/licenses/agpl-3.0.en.html">https://www.gnu.org/licenses/agpl-3.0.en.html</a>.
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This is free software; you are free to change and redistribute it. There
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is NO WARRANTY, to the extent permitted by law. For copying conditions and
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source, see <a href="https://github.com/tomjakubowski/yasuc">https://github.com/tomjakubowski/yasuc</a>.
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SEE ALSO
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<a href="https://github.com/tomjakubowski/yasuc">http://github.com/tomjakubowski/yasuc</a>
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</pre>
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</body>
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</html>
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`
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type pasteTooLarge struct{}
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func (e pasteTooLarge) Error() string {
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return fmt.Sprintf("paste too large (maximum size %d bytes)", maxPasteSize)
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}
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// generateShortID gera um ID único de 7 caracteres
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func generateShortID() string {
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const charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
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b := make([]byte, shortIDLength)
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for i := range b {
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b[i] = charset[rand.Intn(len(charset))]
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}
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return string(b)
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}
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// generateUniqueShortID gera um ID único que não existe no banco
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func generateUniqueShortID(db *sql.DB) (string, error) {
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maxAttempts := 100
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for i := 0; i < maxAttempts; i++ {
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id := generateShortID()
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// Verificar se o ID já existe
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var exists int
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err := db.QueryRow("SELECT 1 FROM pastes WHERE short_id = ? LIMIT 1", id).Scan(&exists)
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if err == sql.ErrNoRows {
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return id, nil
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}
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if err != nil {
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return "", err
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}
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}
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return "", fmt.Errorf("não foi possível gerar um ID único após %d tentativas", maxAttempts)
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}
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func stashPaste(db *sql.DB, pasteStr string) (key string, err error) {
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if len(pasteStr) > maxPasteSize {
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err = pasteTooLarge{}
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return
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}
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// Gerar ID curto único
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shortID, err := generateUniqueShortID(db)
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if err != nil {
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return "", err
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}
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// Calcular hash SHA-256 para verificação de duplicatas
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paste := []byte(pasteStr)
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hash := sha256.Sum256(paste)
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hashStr := hex.EncodeToString(hash[:])
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// Verificar se já existe um paste com o mesmo conteúdo
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var existingID string
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err = db.QueryRow("SELECT short_id FROM pastes WHERE content_hash = ? LIMIT 1", hashStr).Scan(&existingID)
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if err == nil {
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// Paste já existe, retornar o ID existente
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return existingID, nil
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} else if err != sql.ErrNoRows {
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return "", err
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}
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// Inserir novo paste
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_, err = db.Exec("INSERT INTO pastes (short_id, content, content_hash, created_at) VALUES (?, ?, ?, ?)",
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shortID, pasteStr, hashStr, time.Now().Unix())
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if err != nil {
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return "", err
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}
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return shortID, nil
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}
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type pasteNotFound struct{}
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func (e pasteNotFound) Error() string {
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return "not found"
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}
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func fetchPaste(db *sql.DB, key string) (paste string, err error) {
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var content string
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err = db.QueryRow("SELECT content FROM pastes WHERE short_id = ?", key).Scan(&content)
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if err != nil {
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if err == sql.ErrNoRows {
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return "", pasteNotFound{}
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}
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return "", err
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}
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return content, nil
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}
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type handler struct {
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db *sql.DB
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}
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func (h *handler) alles(w http.ResponseWriter, req *http.Request) {
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if req.URL.Path != "/" {
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paste, err := fetchPaste(h.db, req.URL.Path[1:])
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if err != nil {
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if _, ok := err.(pasteNotFound); ok {
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http.Error(w, "not found", http.StatusNotFound)
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} else {
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http.Error(w, err.Error(), http.StatusInternalServerError)
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}
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return
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}
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fmt.Fprintf(w, "%s", paste)
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return
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}
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if req.Method == http.MethodPost {
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body := req.FormValue("sprunge")
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// sprunge.us proceeds if there's no form data in 'sprunge', and just makes
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// an empty paste.
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key, err := stashPaste(h.db, body)
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if err != nil {
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if _, ok := err.(pasteTooLarge); ok {
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http.Error(w, err.Error(), http.StatusNotAcceptable)
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} else {
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http.Error(w, err.Error(), http.StatusInternalServerError)
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}
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return
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}
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baseURL := fmt.Sprintf("https://%s", req.Host)
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fmt.Fprintf(w, "%s/%s\n", baseURL, key)
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return
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}
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// usage message
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tmpl, err := template.New("usage").Parse(usageText)
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if err != nil {
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http.Error(w, err.Error(), http.StatusInternalServerError)
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return
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}
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baseURL := fmt.Sprintf("https://%s", req.Host)
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data := struct{ BaseURL string }{baseURL}
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_ = tmpl.Execute(w, data)
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}
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func newHandler(db *sql.DB) http.Handler {
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h := handler{db}
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mux := http.NewServeMux()
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mux.HandleFunc("/", h.alles)
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return mux
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}
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func initDatabase(db *sql.DB) error {
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// Create the pastes table if it doesn't exist
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_, err := db.Exec(`
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CREATE TABLE IF NOT EXISTS pastes (
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short_id TEXT PRIMARY KEY,
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content TEXT NOT NULL,
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content_hash TEXT NOT NULL,
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created_at INTEGER NOT NULL
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)
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`)
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if err != nil {
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return err
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}
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// Create indexes for better performance
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_, err = db.Exec(`CREATE INDEX IF NOT EXISTS idx_pastes_content_hash ON pastes(content_hash)`)
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if err != nil {
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return err
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}
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_, err = db.Exec(`CREATE INDEX IF NOT EXISTS idx_pastes_created_at ON pastes(created_at)`)
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return err
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}
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func main() {
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// Initialize random seed
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rand.Seed(time.Now().UnixNano())
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var dbPath, addr string
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var port int
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flag.StringVar(&dbPath, "db", "", "location of database file")
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flag.StringVar(&addr, "addr", "", "bind address")
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flag.IntVar(&port, "port", 9001, "bind port")
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flag.Parse()
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if dbPath == "" {
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fmt.Fprintf(os.Stderr, "db option is required\n")
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os.Exit(1)
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}
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// Open SQLite database
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db, err := sql.Open("sqlite", dbPath)
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if err != nil {
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log.Fatal(err)
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}
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defer func() { _ = db.Close() }()
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// Initialize database schema
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err = initDatabase(db)
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if err != nil {
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log.Fatal(err)
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}
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http.Handle("/", newHandler(db))
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sockAddr := fmt.Sprintf("%s:%d", addr, port)
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log.Fatal(http.ListenAndServe(sockAddr, nil))
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}
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