package main import ( "bytes" "html/template" "image" "image/png" "io" "net/http" "regexp" "strconv" "github.com/labstack/echo" ) // Template wraps a template.Template for echo. type Template struct { templates *template.Template } type publicTpl struct { Title string Description string } type unsubTpl struct { publicTpl Unsubscribe bool Blacklist bool } type errorTpl struct { publicTpl ErrorTitle string ErrorMessage string } var ( regexValidUUID = regexp.MustCompile("^[a-fA-F0-9]{8}-[a-fA-F0-9]{4}-4[a-fA-F0-9]{3}-[8|9|aA|bB][a-fA-F0-9]{3}-[a-fA-F0-9]{12}$") pixelPNG = drawTransparentImage(3, 14) ) // Render executes and renders a template for echo. func (t *Template) Render(w io.Writer, name string, data interface{}, c echo.Context) error { return t.templates.ExecuteTemplate(w, name, data) } // handleUnsubscribePage unsubscribes a subscriber and renders a view. func handleUnsubscribePage(c echo.Context) error { var ( app = c.Get("app").(*App) campUUID = c.Param("campUUID") subUUID = c.Param("subUUID") unsub, _ = strconv.ParseBool(c.FormValue("unsubscribe")) blacklist, _ = strconv.ParseBool(c.FormValue("blacklist")) out = unsubTpl{} ) out.Unsubscribe = unsub out.Blacklist = blacklist out.Title = "Unsubscribe from mailing list" if !regexValidUUID.MatchString(campUUID) || !regexValidUUID.MatchString(subUUID) { return c.Render(http.StatusBadRequest, "error", makeErrorTpl("Invalid request", "", `The unsubscription request contains invalid IDs. Please click on the correct link.`)) } // Unsubscribe. if unsub { res, err := app.Queries.Unsubscribe.Exec(campUUID, subUUID, blacklist) if err != nil { app.Logger.Printf("Error unsubscribing : %v", err) return echo.NewHTTPError(http.StatusBadRequest, "There was an internal error while unsubscribing you.") } if !blacklist { num, _ := res.RowsAffected() if num == 0 { return c.Render(http.StatusBadRequest, "error", makeErrorTpl("Already unsubscribed", "", `Looks like you are not subscribed to this mailing list. You may have already unsubscribed.`)) } } } return c.Render(http.StatusOK, "unsubscribe", out) } // handleLinkRedirect handles link UUID to real link redirection. func handleLinkRedirect(c echo.Context) error { var ( app = c.Get("app").(*App) linkUUID = c.Param("linkUUID") campUUID = c.Param("campUUID") subUUID = c.Param("subUUID") ) if !regexValidUUID.MatchString(linkUUID) || !regexValidUUID.MatchString(campUUID) || !regexValidUUID.MatchString(subUUID) { return c.Render(http.StatusBadRequest, "error", makeErrorTpl("Invalid link", "", "The link you clicked is invalid.")) } var url string if err := app.Queries.RegisterLinkClick.Get(&url, linkUUID, campUUID, subUUID); err != nil { app.Logger.Printf("error fetching redirect link: %s", err) return c.Render(http.StatusInternalServerError, "error", makeErrorTpl("Error opening link", "", "There was an error opening the link. Please try later.")) } return c.Redirect(http.StatusTemporaryRedirect, url) } // handleRegisterCampaignView registers a campaign view which comes in // the form of an pixel image request. Regardless of errors, this handler // should always render the pixel image bytes. func handleRegisterCampaignView(c echo.Context) error { var ( app = c.Get("app").(*App) campUUID = c.Param("campUUID") subUUID = c.Param("subUUID") ) if regexValidUUID.MatchString(campUUID) && regexValidUUID.MatchString(subUUID) { if _, err := app.Queries.RegisterCampaignView.Exec(campUUID, subUUID); err != nil { app.Logger.Printf("error registering campaign view: %s", err) } } return c.Blob(http.StatusOK, "image/png", pixelPNG) } // drawTransparentImage draws a transparent PNG of given dimensions // and returns the PNG bytes. func drawTransparentImage(h, w int) []byte { var ( img = image.NewRGBA(image.Rect(0, 0, w, h)) out = &bytes.Buffer{} ) png.Encode(out, img) return out.Bytes() }