mirror of https://github.com/jlelse/GoBlog
85 lines
2.0 KiB
Go
85 lines
2.0 KiB
Go
package main
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import (
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"context"
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"database/sql"
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"errors"
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"net/http"
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"strings"
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)
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var errRedirectNotFound = errors.New("redirect not found")
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func serveRedirect(w http.ResponseWriter, r *http.Request) {
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redirect, err := getRedirect(r.Context(), slashTrimmedPath(r))
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if err == errRedirectNotFound {
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serve404(w, r)
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return
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} else 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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// Send redirect
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w.Header().Set("Location", redirect)
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render(w, templateRedirect, &renderData{
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Data: redirect,
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})
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w.WriteHeader(http.StatusFound)
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}
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func getRedirect(context context.Context, fromPath string) (string, error) {
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var toPath string
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row := appDb.QueryRowContext(context, "with recursive f (i, fp, tp) as (select 1, fromPath, toPath from redirects where fromPath = ? union all select f.i + 1, r.fromPath, r.toPath from redirects as r join f on f.tp = r.fromPath) select tp from f order by i desc limit 1", fromPath)
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err := row.Scan(&toPath)
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if err == sql.ErrNoRows {
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return "", errRedirectNotFound
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} else if err != nil {
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return "", err
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}
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return toPath, nil
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}
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func allRedirectPaths() ([]string, error) {
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var redirectPaths []string
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rows, err := appDb.Query("select fromPath from redirects")
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if err != nil {
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return nil, err
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}
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for rows.Next() {
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var path string
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_ = rows.Scan(&path)
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redirectPaths = append(redirectPaths, path)
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}
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return redirectPaths, nil
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}
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func createOrReplaceRedirect(from, to string) error {
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if from == "" || to == "" {
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return errors.New("empty path")
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}
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if from == to {
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// Don't need a redirect
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return nil
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}
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from = strings.TrimSuffix(from, "/")
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startWritingToDb()
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tx, err := appDb.Begin()
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if err != nil {
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finishWritingToDb()
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return err
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}
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_, err = tx.Exec("insert or replace into redirects (fromPath, toPath) values (?, ?)", from, to)
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if err != nil {
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_ = tx.Rollback()
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finishWritingToDb()
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return err
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}
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err = tx.Commit()
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if err != nil {
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finishWritingToDb()
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return err
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}
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finishWritingToDb()
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return reloadRouter()
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}
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