amethyst/app/src/main/java/com/vitorpamplona/amethyst/model/AntiSpamFilter.kt

93 wiersze
3.3 KiB
Kotlin

package com.vitorpamplona.amethyst.model
import android.util.Log
import android.util.LruCache
import androidx.compose.runtime.Stable
import androidx.lifecycle.LiveData
import com.vitorpamplona.amethyst.OptOutFromFilters
import com.vitorpamplona.amethyst.service.checkNotInMainThread
import com.vitorpamplona.amethyst.service.relays.Relay
import com.vitorpamplona.amethyst.ui.components.BundledUpdate
import com.vitorpamplona.quartz.encoders.HexKey
import com.vitorpamplona.quartz.encoders.Nip19
import com.vitorpamplona.quartz.events.Event
import kotlinx.coroutines.Dispatchers
data class Spammer(val pubkeyHex: HexKey, var duplicatedMessages: Set<HexKey>)
class AntiSpamFilter {
val recentMessages = LruCache<Int, String>(1000)
val spamMessages = LruCache<Int, Spammer>(1000)
fun isSpam(event: Event, relay: Relay?): Boolean {
checkNotInMainThread()
if (!OptOutFromFilters.filterSpamFromStrangers) return false
val idHex = event.id
// if short message, ok
// The idea here is to avoid considering repeated "GM" messages spam.
if (event.content.length < 50) return false
// if the message is actually short but because it cites a user/event, the nostr: string is really long, make it ok.
// The idea here is to avoid considering repeated "@Bot, command" messages spam, while still blocking repeated "lnbc..." invoices or fishing urls
if (event.content.length < 180 && Nip19.nip19regex.matcher(event.content).find()) return false
// double list strategy:
// if duplicated, it goes into spam. 1000 spam messages are saved into the spam list.
// Considers tags so that same replies to different people don't count.
val hash = (event.content + event.tags.flatten().joinToString(",")).hashCode()
if ((recentMessages[hash] != null && recentMessages[hash] != idHex) || spamMessages[hash] != null) {
Log.w("Potential SPAM Message for sharing", "${Nip19.createNEvent(event.id, event.pubKey, event.kind, null)}")
Log.w("Potential SPAM Message", "${event.id} ${recentMessages[hash]} ${spamMessages[hash] != null} ${relay?.url} ${event.content.replace("\n", " | ")}")
// Log down offenders
logOffender(hash, event)
liveSpam.invalidateData()
return true
}
recentMessages.put(hash, idHex)
return false
}
@Synchronized
private fun logOffender(hashCode: Int, event: Event) {
if (spamMessages.get(hashCode) == null) {
spamMessages.put(hashCode, Spammer(event.pubKey, setOf(recentMessages[hashCode], event.id)))
} else {
val spammer = spamMessages.get(hashCode)
spammer.duplicatedMessages = spammer.duplicatedMessages + event.id
}
}
val liveSpam: AntiSpamLiveData = AntiSpamLiveData(this)
}
@Stable
class AntiSpamLiveData(val cache: AntiSpamFilter) : LiveData<AntiSpamState>(AntiSpamState(cache)) {
// Refreshes observers in batches.
private val bundler = BundledUpdate(300, Dispatchers.IO)
fun invalidateData() {
checkNotInMainThread()
bundler.invalidate() {
checkNotInMainThread()
if (hasActiveObservers()) {
postValue(AntiSpamState(cache))
}
}
}
}
class AntiSpamState(val cache: AntiSpamFilter)