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package main
import (
"database/sql"
"fmt"
"os"
_ "modernc.org/sqlite"
shell "github.com/ipfs/go-ipfs-api"
"git.kiefte.eu/lapingvino/infodump/message"
)
var DatabasePath = "infodump.db"
var DB *sql.DB
// StartOLNListener starts a PubSub listener that listens for messages from the network
// and adds them to LocalMessages
// For this it uses the IPFS gateway and listens on the topic "OLN", as well as
// the list of followed tags from the database
func StartOLNListener() {
// Get the IPFS gateway
gateway := message.IPFSGateway
// Get the database
db := GetDatabase()
// Get the list of followed tags
followedTags := GetFollowedTags(db)
// Create a new IPFS client
myIPFS := shell.NewShell(gateway)
var subs []*shell.PubSubSubscription
olnsub, err := myIPFS.PubSubSubscribe("OLN")
if err != nil {
fmt.Println(err)
return
}
subs = append(subs, olnsub)
for _, tag := range followedTags {
tagssub, err := myIPFS.PubSubSubscribe("oln-" + tag)
if err != nil {
fmt.Println(err)
} else {
subs = append(subs, tagssub)
}
}
// Start a goroutine for each of the subscriptions in subs,
// read the CID from the Next method, look up the CID on IPFS,
// read this in via message.MessagesFromIPFS and add the message to LocalMessages
for _, sub := range subs {
go func(sub *shell.PubSubSubscription) {
for {
msg, err := sub.Next()
if err != nil {
fmt.Println("Error reading from PubSub:", err)
return
}
msgs, err := message.MessagesFromIPFS(string(msg.Data))
if err != nil {
fmt.Println("Error reading from IPFS:", err)
return
}
LocalMessages.AddMany(msgs)
}
}(sub)
}
}
// GetDatabase checks if DB is already set and opened, if not it Sets the database first
func GetDatabase() *sql.DB {
if DB == nil {
fmt.Println("Database not set, setting database...")
SetDatabase()
}
return DB
}
func GetMessagesFromDatabase(db *sql.DB) *message.Messages {
// Get all messages from the database
rows, err := db.Query("SELECT hash, message, nonce, timestamp FROM messages")
if err != nil {
fmt.Println(err)
}
defer rows.Close()
// Create a new Messages object
msgs := message.Messages{}
// Loop through all messages
fmt.Println("Getting messages from database...")
for rows.Next() {
var hash, msg string
var nonce int
var timestamp int64
// Get the values from the database
err := rows.Scan(&hash, &msg, &nonce, &timestamp)
if err != nil {
fmt.Println(err)
}
fmt.Println("Got message from database:", hash)
// Create a new message object
m := message.Message{
Message: msg,
Nonce: nonce,
Timestamp: timestamp,
}
// Add the message to the Messages object
fmt.Println("Adding message to Messages object...")
msgs.Add(&m)
}
return &msgs
}
func InitDatabase(db *sql.DB) {
var err error
// Create the table "messages"
_, err = db.Exec("CREATE TABLE messages(hash TEXT PRIMARY KEY, message TEXT, nonce INTEGER, timestamp INTEGER)")
if err != nil {
fmt.Println(err)
}
// Create the table "followed_tags"
_, err = db.Exec("CREATE TABLE followed_tags(tag TEXT)")
if err != nil {
fmt.Println(err)
}
}
// SetDatabase configures DB to be the database to use
// The name used is DatabasePath, but the user will be asked if this correct or if they want to change it
// If the database is already set, it will ask the user if they want to overwrite it
// If the database is not set, it will ask the user if they want to create it
// If the database is set but it doesn't contain the tables "messages" and "followed_tags",
// it will create them
func SetDatabase() {
// First check if the user is okay with the database path
fmt.Println("Database path: ", DatabasePath)
fmt.Println("Is this correct? (y/n)")
answer := Readline()
if answer == "n" {
fmt.Println("Enter the database path: ")
DatabasePath = Readline()
}
// Open the database
db, err := sql.Open("sqlite", DatabasePath)
if err != nil {
fmt.Println(err)
return
}
// Check if the database is already set
if DB != nil {
fmt.Println("Database already set, overwrite? (y/n)")
answer := Readline()
if answer == "n" {
return
}
}
// Check if the database exists
if _, err := os.Stat(DatabasePath); os.IsNotExist(err) {
fmt.Println("Database does not exist, create? (y/n)")
answer := Readline()
if answer == "n" {
return
}
}
// Set the database
DB = db
// Check if the database contains the tables "messages" and "followed_tags"
// If not, create them
InitDatabase(DB)
}
func TrimDatabase() {
// Ask how many messages to keep
fmt.Println("How many messages to keep?")
var num int
fmt.Scan(&num)
// Get the database
db := GetDatabase()
// Get the list of messages
msgs := GetMessagesFromDatabase(db)
// Trim the list of messages
msgs.Trim(num)
// Delete all messages from the database
_, err := db.Exec("DELETE FROM messages")
if err != nil {
fmt.Println(err)
}
// Add the trimmed list of messages to the database
msgs.Each(func(m *message.Message) {
_, err := db.Exec("INSERT INTO messages(hash, message, nonce, timestamp) VALUES(?, ?, ?, ?)", m.Stamp(), m.Message, m.Nonce, m.Timestamp)
if err != nil {
fmt.Println(err)
}
})
}