offline-messages.go

package main

import (
	"database/sql"
	"encoding/gob"
	//	"fmt"
	"github.com/dustin/go-humanize"
	"github.com/gin-contrib/sessions"
	"github.com/gin-gonic/gin"
	"html/template"
	"log"
	"strconv"
)

type OfflineIM struct {
	ID          string        `json:"ID"`
	PrincipalID string        `json:"PrincipalID"`
	Username    string        `json:"Username"` // will be constructed by getting it from the UserAccounts table
	Libravatar  string        `json:"Libravatar"`
	FromID      string        `json:"FromID"`
	Message     template.HTML `json:"Message"` // may contain HTML, so it will be sanitised later on (gwyneth 20200815)
	TMStamp     string        `json:"TMStamp"`
}
type OfflineIMList []OfflineIM

const MaxNumberMessages int = 5 // maximum number of messages to retrieve

// For some very, very, very stupid reason, we need to register our message type (and probably others) when starting...
func init() {
	gob.RegisterName("listOfOfflineIMs", OfflineIMList{})
}

// GetTopOfflineMessages will retrieve the top first 5 messages and put it on the session, to avoid constant reloading
func GetTopOfflineMessages(c *gin.Context) {
	session := sessions.Default(c)
	username := session.Get("Username")
	uuid := session.Get("UUID")

	if uuid == "" {
		log.Println("[WARN]: GetTopOfflineMessages(): No UUID stored; messages for this user cannot get retrieved")
	}

	if *config["dsn"] == "" {
		log.Fatal("Please configure the DSN for accessing your OpenSimulator database; this application won't work without that")
	}
	db, err := sql.Open("mysql", *config["dsn"]+"?parseTime=true") // this will allow parsing MySQL timestamps into Time vars; see https://stackoverflow.com/a/46613451/1035977
	checkErrFatal(err)

	defer db.Close()

	// first count how many messages we have, we will need this later.
	// According to the Internet, current versions of MariaDB/MySQL are actually much faster doing _two_ queries, one just for counting rows, since it's allegedly optimised; in this case, we can simplify the whole query as well.

	var numberMessages int

	err = db.QueryRow("SELECT COUNT(*) FROM im_offline WHERE im_offline.PrincipalID = ?", uuid).Scan(&numberMessages)
	checkErr(err)

	if numberMessages > 0 {
		rows, err := db.Query("SELECT ID, im_offline.PrincipalID, FromID, Message, TMStamp, FirstName, LastName, Email FROM im_offline, UserAccounts WHERE im_offline.PrincipalID = ? AND UserAccounts.PrincipalID = im_offline.FromID ORDER BY TMStamp ASC LIMIT ?", uuid, strconv.Itoa(MaxNumberMessages))
		checkErr(err)

		defer rows.Close()

		var (
			oneMessage                                OfflineIM
			messages                                  OfflineIMList
			firstName, lastName, email, unsafeMessage string
			messageTimeStamp                          sql.NullTime // sql.NullTime will match timestamps with NULLs without crashing; see https://stackoverflow.com/a/60293251/1035977
		)

		for /* i := 1; */ rows.Next() /* ; i++ */ { // uncomment for special
			err = rows.Scan(
				&oneMessage.ID,
				&oneMessage.PrincipalID,
				&oneMessage.FromID,
				&unsafeMessage,
				&messageTimeStamp,
				&firstName,
				&lastName,
				&email,
			)
			oneMessage.Message = template.HTML(bluemondaySafeHTML.Sanitize(unsafeMessage))
			oneMessage.Username = firstName + " " + lastName
			oneMessage.Libravatar = getLibravatar(email, oneMessage.Username, 60)
			// do something to the time
			if messageTimeStamp.Valid {
				oneMessage.TMStamp = humanize.Time(messageTimeStamp.Time)
			} else {
				oneMessage.TMStamp = ""
			}

			// if *config["ginMode"] == "debug" {
			// 	log.Printf("[DEBUG]: message # %d from user %q <%s> to %q is: %q\n", i, oneMessage.Username, email, username, oneMessage.Message)
			// }
			messages = append(messages, oneMessage)
		}
		checkErr(err)

		// if *config["ginMode"] == "debug" {
		// 	log.Printf("[DEBUG]: GetTopOfflineMessages(): All messages for user %q: %+v\n", username, messages)
		// }

		session.Set("Messages", messages)
		session.Set("numberMessages", numberMessages)
	} else { // no messages for this user
		session.Set("Messages", nil)
		session.Set("numberMessages", numberMessages)
	}
	if err := session.Save(); err != nil {
		log.Printf("[WARN]: GetTopOfflineMessages(): Could not save messages to user %q on the session, error was: %q\n", username, err)
	}
}