Google Cloud Firestore-Trigger (1. Generation)

/**
 * Background Function triggered by a change to a Firestore document.
 *
 * @param {!Object} event The Cloud Functions event.
 * @param {!Object} context Cloud Functions event metadata.
 */
exports.helloFirestore = (event, context) => {
  const triggerResource = context.resource;

  console.log(`Function triggered by event on: ${triggerResource}`);
  console.log(`Event type: ${context.eventType}`);

  if (event.oldValue && Object.keys(event.oldValue).length) {
    console.log('\nOld value:');
    console.log(JSON.stringify(event.oldValue, null, 2));
  }

  if (event.value && Object.keys(event.value).length) {
    console.log('\nNew value:');
    console.log(JSON.stringify(event.value, null, 2));
  }
};

import json

def hello_firestore(data, context):
    """Triggered by a change to a Firestore document.
    Args:
        data (dict): The event payload.
        context (google.cloud.functions.Context): Metadata for the event.
    """
    trigger_resource = context.resource

    print("Function triggered by change to: %s" % trigger_resource)

    print("\nOld value:")
    print(json.dumps(data["oldValue"]))

    print("\nNew value:")
    print(json.dumps(data["value"]))

// Package hello contains a Cloud Function triggered by a Firestore event.
package hello

import (
	"context"
	"fmt"
	"log"
	"time"

	"cloud.google.com/go/functions/metadata"
)

// FirestoreEvent is the payload of a Firestore event.
type FirestoreEvent struct {
	OldValue   FirestoreValue `json:"oldValue"`
	Value      FirestoreValue `json:"value"`
	UpdateMask struct {
		FieldPaths []string `json:"fieldPaths"`
	} `json:"updateMask"`
}

// FirestoreValue holds Firestore fields.
type FirestoreValue struct {
	CreateTime time.Time `json:"createTime"`
	// Fields is the data for this value. The type depends on the format of your
	// database. Log the interface{} value and inspect the result to see a JSON
	// representation of your database fields.
	Fields     interface{} `json:"fields"`
	Name       string      `json:"name"`
	UpdateTime time.Time   `json:"updateTime"`
}

// HelloFirestore is triggered by a change to a Firestore document.
func HelloFirestore(ctx context.Context, e FirestoreEvent) error {
	meta, err := metadata.FromContext(ctx)
	if err != nil {
		return fmt.Errorf("metadata.FromContext: %w", err)
	}
	log.Printf("Function triggered by change to: %v", meta.Resource)
	log.Printf("Old value: %+v", e.OldValue)
	log.Printf("New value: %+v", e.Value)
	return nil
}

import com.google.cloud.functions.Context;
import com.google.cloud.functions.RawBackgroundFunction;
import com.google.gson.Gson;
import com.google.gson.JsonObject;
import java.util.logging.Logger;

public class FirebaseFirestore implements RawBackgroundFunction {
  private static final Logger logger = Logger.getLogger(FirebaseFirestore.class.getName());

  // Use GSON (https://github.com/google/gson) to parse JSON content.
  private static final Gson gson = new Gson();

  @Override
  public void accept(String json, Context context) {
    JsonObject body = gson.fromJson(json, JsonObject.class);
    logger.info("Function triggered by event on: " + context.resource());
    logger.info("Event type: " + context.eventType());

    if (body != null && body.has("oldValue")) {
      logger.info("Old value:");
      logger.info(body.get("oldValue").getAsString());
    }

    if (body != null && body.has("value")) {
      logger.info("New value:");
      logger.info(body.get("value").getAsString());
    }
  }
}

require "functions_framework"

# Triggered by a change to a Firestore document.
FunctionsFramework.cloud_event "hello_firestore" do |event|
  # The event parameter is a CloudEvents::Event::V1 object.
  # See https://cloudevents.github.io/sdk-ruby/latest/CloudEvents/Event/V1.html
  payload = event.data

  logger.info "Function triggered by change to: #{event.source}"
  logger.info "Old value: #{payload['oldValue']}"
  logger.info "New value: #{payload['value']}"
end

use Google\CloudFunctions\CloudEvent;

function firebaseFirestore(CloudEvent $cloudevent)
{
    $log = fopen(getenv('LOGGER_OUTPUT') ?: 'php://stderr', 'wb');

    fwrite($log, 'Event: ' . $cloudevent->getId() . PHP_EOL);
    fwrite($log, 'Event Type: ' . $cloudevent->getType() . PHP_EOL);

    $data = $cloudevent->getData();

    $resource = $data['resource'];
    fwrite($log, 'Function triggered by event on: ' . $resource . PHP_EOL);

    if (isset($data['oldValue'])) {
        fwrite($log, 'Old value: ' . json_encode($data['oldValue']) . PHP_EOL);
    }

    if (isset($data['value'])) {
        fwrite($log, 'New value: ' . json_encode($data['value']) . PHP_EOL);
    }
}

const Firestore = require('@google-cloud/firestore');

const firestore = new Firestore({
  projectId: process.env.GOOGLE_CLOUD_PROJECT,
});

// Converts strings added to /messages/{pushId}/original to uppercase
exports.makeUpperCase = event => {
  const resource = event.value.name;
  const affectedDoc = firestore.doc(resource.split('/documents/')[1]);

  const curValue = event.value.fields.original.stringValue;
  const newValue = curValue.toUpperCase();

  if (curValue !== newValue) {
    console.log(`Replacing value: ${curValue} --> ${newValue}`);

    return affectedDoc.set({
      original: newValue,
    });
  } else {
    // Value is already upper-case
    // Don't perform a(nother) write to avoid infinite loops
    console.log('Value is already upper-case.');
  }
};

from google.cloud import firestore

client = firestore.Client()


# Converts strings added to /messages/{pushId}/original to uppercase
def make_upper_case(data, context):
    path_parts = context.resource.split("/documents/")[1].split("/")
    collection_path = path_parts[0]
    document_path = "/".join(path_parts[1:])

    affected_doc = client.collection(collection_path).document(document_path)

    cur_value = data["value"]["fields"]["original"]["stringValue"]
    new_value = cur_value.upper()

    if cur_value != new_value:
        print(f"Replacing value: {cur_value} --> {new_value}")
        affected_doc.set({"original": new_value})
    else:
        # Value is already upper-case
        # Don't perform a second write (which can trigger an infinite loop)
        print("Value is already upper-case.")

// Package upper contains a Firestore Cloud Function.
package upper

import (
	"context"
	"fmt"
	"log"
	"os"
	"strings"
	"time"

	"cloud.google.com/go/firestore"
	firebase "firebase.google.com/go/v4"
)

// FirestoreEvent is the payload of a Firestore event.
type FirestoreEvent struct {
	OldValue   FirestoreValue `json:"oldValue"`
	Value      FirestoreValue `json:"value"`
	UpdateMask struct {
		FieldPaths []string `json:"fieldPaths"`
	} `json:"updateMask"`
}

// FirestoreValue holds Firestore fields.
type FirestoreValue struct {
	CreateTime time.Time `json:"createTime"`
	// Fields is the data for this value. The type depends on the format of your
	// database. Log an interface{} value and inspect the result to see a JSON
	// representation of your database fields.
	Fields     MyData    `json:"fields"`
	Name       string    `json:"name"`
	UpdateTime time.Time `json:"updateTime"`
}

// MyData represents a value from Firestore. The type definition depends on the
// format of your database.
type MyData struct {
	Original struct {
		StringValue string `json:"stringValue"`
	} `json:"original"`
}

// GOOGLE_CLOUD_PROJECT is automatically set by the Cloud Functions runtime.
var projectID = os.Getenv("GOOGLE_CLOUD_PROJECT")

// client is a Firestore client, reused between function invocations.
var client *firestore.Client

func init() {
	// Use the application default credentials.
	conf := &firebase.Config{ProjectID: projectID}

	// Use context.Background() because the app/client should persist across
	// invocations.
	ctx := context.Background()

	app, err := firebase.NewApp(ctx, conf)
	if err != nil {
		log.Fatalf("firebase.NewApp: %v", err)
	}

	client, err = app.Firestore(ctx)
	if err != nil {
		log.Fatalf("app.Firestore: %v", err)
	}
}

// MakeUpperCase is triggered by a change to a Firestore document. It updates
// the `original` value of the document to upper case.
func MakeUpperCase(ctx context.Context, e FirestoreEvent) error {
	fullPath := strings.Split(e.Value.Name, "/documents/")[1]
	pathParts := strings.Split(fullPath, "/")
	collection := pathParts[0]
	doc := strings.Join(pathParts[1:], "/")

	curValue := e.Value.Fields.Original.StringValue
	newValue := strings.ToUpper(curValue)
	if curValue == newValue {
		log.Printf("%q is already upper case: skipping", curValue)
		return nil
	}
	log.Printf("Replacing value: %q -> %q", curValue, newValue)

	data := map[string]string{"original": newValue}
	_, err := client.Collection(collection).Doc(doc).Set(ctx, data)
	if err != nil {
		return fmt.Errorf("Set: %w", err)
	}
	return nil
}

import com.google.cloud.firestore.Firestore;
import com.google.cloud.firestore.FirestoreOptions;
import com.google.cloud.firestore.SetOptions;
import com.google.cloud.functions.Context;
import com.google.cloud.functions.RawBackgroundFunction;
import com.google.gson.Gson;
import com.google.gson.JsonObject;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import java.util.concurrent.ExecutionException;
import java.util.logging.Level;
import java.util.logging.Logger;

public class FirebaseFirestoreReactive implements RawBackgroundFunction {

  // Use GSON (https://github.com/google/gson) to parse JSON content.
  private static final Gson gson = new Gson();

  private static final Logger logger = Logger.getLogger(FirebaseFirestoreReactive.class.getName());
  private static final Firestore FIRESTORE = FirestoreOptions.getDefaultInstance().getService();

  private final Firestore firestore;

  public FirebaseFirestoreReactive() {
    this(FIRESTORE);
  }

  FirebaseFirestoreReactive(Firestore firestore) {
    this.firestore = firestore;
  }

  @Override
  public void accept(String json, Context context) {
    // Get the recently-written value
    JsonObject body = gson.fromJson(json, JsonObject.class);
    JsonObject tempJson = body.getAsJsonObject("value");

    // Verify that value.fields.original.stringValue exists
    String currentValue = null;
    if (tempJson != null) {
      tempJson = tempJson.getAsJsonObject("fields");
    }
    if (tempJson != null) {
      tempJson = tempJson.getAsJsonObject("original");
    }
    if (tempJson != null && tempJson.has("stringValue")) {
      currentValue = tempJson.get("stringValue").getAsString();
    }
    if (currentValue == null) {
      throw new IllegalArgumentException("Malformed JSON: " + json);
    }

    // Convert recently-written value to ALL CAPS
    String newValue = currentValue.toUpperCase(Locale.getDefault());

    // Update Firestore DB with ALL CAPS value
    Map<String, String> newFields = Map.of("original", newValue);

    String affectedDoc = context.resource().split("/documents/")[1].replace("\"", "");

    if (!currentValue.equals(newValue)) {
      // The stored value needs to be updated
      // Write the upper-cased value to Firestore
      logger.info(String.format("Replacing value: %s --> %s", currentValue, newValue));
      try {
        FIRESTORE.document(affectedDoc).set(newFields, SetOptions.merge()).get();
      } catch (ExecutionException | InterruptedException e) {
        logger.log(Level.SEVERE, "Error updating Firestore document: " + e.getMessage(), e);
      }
    } else {
      // The stored value is already upper-case, and doesn't need updating.
      // (Don't perform a "second" write, since that could trigger an infinite loop.)
      logger.info(String.format("Value is already upper-case."));
    }
  }
}

require "functions_framework"

FunctionsFramework.on_startup do
  # Lazily construct a Firestore client when needed, and reuse it on
  # subsequent calls.
  set_global :firestore_client do
    require "google/cloud/firestore"
    Google::Cloud::Firestore.new project_id: ENV["GOOGLE_CLOUD_PROJECT"]
  end
end

# Converts strings added to /messages/{pushId}/original to uppercase
FunctionsFramework.cloud_event "make_upper_case" do |event|
  # Event-triggered Ruby functions receive a CloudEvents::Event::V1 object.
  # See https://cloudevents.github.io/sdk-ruby/latest/CloudEvents/Event/V1.html
  # The Firebase event payload can be obtained from the event data.
  cur_value = event.data["value"]["fields"]["original"]["stringValue"]

  # Compute new value and determine whether it needs to be modified.
  # If the value is already upper-case, don't perform another write,
  # to avoid infinite loops.
  new_value = cur_value.upcase
  if cur_value == new_value
    logger.info "Value is already upper-case"
    return
  end

  # Use the Firestore client library to update the value.
  # The document name can be obtained from the event subject.
  logger.info "Replacing value: #{cur_value} --> #{new_value}"
  doc_name = event.subject.split("documents/").last
  affected_doc = global(:firestore_client).doc doc_name
  new_doc_data = { original: new_value }
  affected_doc.set new_doc_data, merge: false
end

use Google\Cloud\Firestore\FirestoreClient;
use Google\CloudFunctions\CloudEvent;

function firebaseReactive(CloudEvent $cloudevent)
{
    $log = fopen(getenv('LOGGER_OUTPUT') ?: 'php://stderr', 'wb');
    $data = $cloudevent->getData();

    $resource = $data['value']['name'];

    $db = new FirestoreClient();

    $docPath = explode('/documents/', $resource)[1];

    $affectedDoc = $db->document($docPath);

    $curValue = $data['value']['fields']['original']['stringValue'];
    $newValue = strtoupper($curValue);

    if ($curValue !== $newValue) {
        fwrite($log, 'Replacing value: ' . $curValue . ' --> ' . $newValue . PHP_EOL);

        $affectedDoc->set(['original' => $newValue]);
    } else {
        // Value is already upper-case
        // Don't perform another write (it might cause an infinite loop)
        fwrite($log, 'Value is already upper-case.' . PHP_EOL);
    }
}