mirror of https://github.com/jlelse/GoBlog
63 lines
1.5 KiB
Go
63 lines
1.5 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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)
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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, more, 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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// Flatten redirects
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if more {
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for more == true {
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redirect, more, _ = getRedirect(r.Context(), trimSlash(redirect))
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}
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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, struct {
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Permalink string
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}{
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Permalink: 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, bool, error) {
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var toPath string
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var moreRedirects int
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row := appDb.QueryRowContext(context, "select toPath, (select count(*) from redirects where fromPath=(select toPath from redirects where fromPath=?)) as more from redirects where fromPath=?", fromPath, fromPath)
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err := row.Scan(&toPath, &moreRedirects)
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if err == sql.ErrNoRows {
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return "", false, errRedirectNotFound
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} else if err != nil {
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return "", false, err
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}
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return toPath, moreRedirects > 0, 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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