231 lines
5.8 KiB
Go
231 lines
5.8 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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"encoding/hex"
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"errors"
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"flag"
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"fmt"
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"github.com/boltdb/bolt"
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"html/template"
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"log"
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"net/http"
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"os"
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"time"
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)
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const (
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pastesBucket = "pastes"
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maxPasteSize = 4 * 1024 * 1024
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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 the SHA-256 digest of the
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paste's contents.
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EXAMPLE
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$ echo 'hello world' | curl -F 'sprunge=<-' {{.BaseURL}}
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{{.BaseURL}}/a948904f2f0f479b8f8197694b30184b0d2ed1c1cd2a1ec0fb85d299a192a447
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$ firefox {{.BaseURL}}/a948904f2f0f479b8f8197694b30184b0d2ed1c1cd2a1ec0fb85d299a192a447
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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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func stashPaste(db *bolt.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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paste := []byte(pasteStr)
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rawKey := sha256.Sum256(paste)
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// TODO: launch nukes on collision
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err = db.Update(func(tx *bolt.Tx) error {
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b := tx.Bucket([]byte(pastesBucket))
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if b == nil {
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return errors.New("bucket not found??")
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}
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err := b.Put(rawKey[:], paste)
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if err != nil {
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return err
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}
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return nil
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})
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if err != nil {
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return
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}
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key = hex.EncodeToString(rawKey[:])
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return
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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 *bolt.DB, key string) (paste string, err error) {
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rawKey, err := hex.DecodeString(key)
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if err != nil { // bad URL
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err = pasteNotFound{}
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return
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}
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var rawPaste []byte
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err = db.View(func(tx *bolt.Tx) error {
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b := tx.Bucket([]byte(pastesBucket))
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if b == nil {
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return errors.New("bucket not found???")
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}
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rawPaste = b.Get(rawKey)
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paste = string(rawPaste)
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return nil
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})
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if err != nil {
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return
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}
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if rawPaste == nil {
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err = pasteNotFound{}
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return
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}
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return
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}
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type handler struct {
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db *bolt.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 *bolt.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 main() {
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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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db, err := bolt.Open(dbPath, 0600, &bolt.Options{Timeout: 1 * time.Second})
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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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err = db.Update(func(tx *bolt.Tx) error {
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// make all of ze buckets
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_, err := tx.CreateBucketIfNotExists([]byte(pastesBucket))
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if err != nil {
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_ = db.Close()
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log.Fatal(err)
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}
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return nil
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})
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if err != nil {
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_ = db.Close() // deferred functions aren't called for fatal logs :|
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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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