FCM - Getting push notification data twice - firebase

Question

I've been struggling with this issue for a long time so I decided to ask you.
I'm developing a chat app and for push notifications I'm using Firebase Functions. I'm getting always the data from onMessageReceived twice. For some people the solution was removing de gcm dependencies and use only the firebase ones but i think is not my case. Anyway I'm showing you all the code:
This is my index.js:
exports.notifications = functions.database.ref('chats/{chatUid}/messages/{pushId}').onWrite( (change, context) => {
var valueObject = change.after.val();
var chatUid = change.after.ref.parent.parent.key;
var data = {
'data' : {
'conversation_id' : chatUid,
'message_key' : change.after.key,
'message_title' : valueObject.title,
'message_body' : valueObject.message,
'userFrom' : valueObject.userFrom.toString()
}
};
const options = {
priority: "high",
timeToLive: 60 * 60 * 24
};
return admin.messaging().sendToTopic(chatUid, data, options)
});
My gradle settings:
apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
apply plugin: 'com.google.gms.google-services'
android {
compileSdkVersion 27
defaultConfig {
applicationId "xxx"
minSdkVersion 21
targetSdkVersion 27
versionCode xxx
versionName "x.x.x"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
buildToolsVersion '27.0.3'
productFlavors {
}
}
ext {
support_version = '27.1.1'
}
dependencies {
implementation fileTree(include: ['*.jar'], dir: 'libs')
implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
implementation "com.android.support:design:$support_version"
implementation "com.android.support:appcompat-v7:$support_version"
implementation "com.android.support:customtabs:$support_version"
implementation "com.android.support:support-v4:$support_version"
implementation "com.android.support:cardview-v7:$support_version"
implementation 'com.android.support.constraint:constraint-layout:1.1.2'
implementation "com.android.support:percent:$support_version"
implementation "com.android.support:recyclerview-v7:$support_version"
implementation 'com.android.support:support-v4:27.1.1'
testImplementation 'junit:junit:4.12'
implementation 'com.squareup.retrofit2:retrofit:2.3.0'
implementation 'com.google.code.gson:gson:2.8.0'
implementation 'com.squareup.retrofit2:converter-gson:2.3.0'
implementation('com.squareup.retrofit2:retrofit:2.3.0') {
exclude module: 'okhttp'
}
implementation 'com.google.code.gson:gson:2.8.0'
implementation 'com.squareup.retrofit2:converter-gson:2.3.0'
implementation 'com.squareup.okhttp3:logging-interceptor:3.4.1'
implementation 'com.squareup.okhttp3:okhttp:3.9.0'
implementation 'com.squareup.retrofit2:converter-jackson:2.1.0'
implementation 'com.squareup.retrofit2:converter-gson:2.3.0'
implementation 'com.squareup.retrofit2:adapter-rxjava2:2.3.0'
implementation 'io.reactivex.rxjava2:rxandroid:2.0.1'
implementation 'com.squareup.picasso:picasso:2.5.2'
implementation 'de.hdodenhof:circleimageview:2.2.0'
implementation 'com.google.android.gms:play-services-auth:15.0.1'
implementation 'com.google.android.gms:play-services-maps:15.0.1'
implementation 'com.google.android.gms:play-services-location:15.0.1'
implementation 'com.google.maps.android:android-maps-utils:0.5'
implementation 'com.facebook.android:facebook-android-sdk:4.18.0'
implementation 'com.google.firebase:firebase-analytics:16.0.1'
implementation 'com.google.firebase:firebase-database:16.0.1'
implementation 'com.google.firebase:firebase-storage:16.0.1'
implementation 'com.google.firebase:firebase-auth:16.0.2'
implementation 'com.google.firebase:firebase-config:16.0.0'
implementation 'com.google.firebase:firebase-core:16.0.1'
implementation 'com.google.firebase:firebase-messaging:17.1.0'
implementation 'com.firebaseui:firebase-ui-database:3.3.1'
implementation 'com.firebaseui:firebase-ui-storage:3.3.1'
implementation 'commons-codec:commons-codec:1.11'
androidTestImplementation 'androidx.test:runner:1.1.0-alpha3'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.0-alpha3'}
Thank you for your time :D

Answer 1

I'm stupid.
It was my fault in android code, nothing to do with firebase functions:
I was using onWrite(index.js) and in my android code I was writting twice in firebase database, one for writing the message_key(push()) and other for setting the properties(setValue()):
finalReference.push().apply {
val map2 = HashMap<String, Any?>()
val dateFormat = SimpleDateFormat(DATE_FORMAT, Locale.getDefault())
dateFormat.timeZone = TimeZone.getTimeZone("UTC")
map2[FB.DATE] = dateFormat.format(Date())
map2[FB.MESSAGE] = entryText.text.toString()
map2[FB.READ] = false
map2[FB.RECEIVED] = false
map2[FB.TITLE] = fbUser.displayName
map2[FB.USER_FROM] = fbUser.uid.toLong()
map2[FB.USER_TO] = conversation_data!!.users_id.find { it != fbUser.uid }?.toLong()
setValue(map2).addOnSuccessListener {
child(FB.RECEIVED).setValue(true)
}
entryText.setText("")
}
So the solution was to change onWrite for onCreate on index.js.
Hope it helps anybody.