Hello, in this tutorial, I'll show you how to get contents from a Document using the FBP Firebase Plugin for Unreal Engine.
Setup
Auth - Create Account with Email and Password
Auth - Sign In
Auth - Reset Passwords
Auth - Listening to Sign-In States
Auth - Verifying Users
Auth - Utility Nodes
Firestore - Add Documents
Firestore - Update Document
Firestore - Delete Document
Firestore - Get Document
Firestore - Get Collection
Firestore - Batch Operations
Realtime Database - Add Data
Realtime Database - Update Data
Realtime Database - Delete Data
Realtime Database - Get Data
Cloud Storage - Download File
Cloud Storage - Uploading Files
Cloud Storage - Delete File
Packaging your Project
Firestore - Get Document
Using the Get Document and Listen To Document nodes to retrieve contents from a document.
Get Document
To get documents once, use the "Get Document" node.
It has 3 pins:
1 for the Document Path in Firestore
2 callbacks to handle executions after the delete operation is successful or not
The Document Path is a String array that represents the path to the document in Firestore. Every even element points to a collection and every odd element points to a document.
The On Document Retrieved Callback gets called when the contents of the documents are retrieved. It returns the document id and a document snapshot containing all the data.
The On Fail to Retrieve Document Callback gets call when an error occurred during the retrieval process. We can use the Error Message string that it returns to see what type of error occurred.
Adding the Callbacks
To create these callbacks, click and hold on the callback pin from the node. Then drag and let go on an empty spot on the blueprint.
Select “Add Event” then “Add Custom Event.” That will create the event node fit for the callback.
Retrieving the contents
To get the data from the document snapshot, use any of the following nodes:
• Get String
• Get Number
• Get Boolean
• Get String Array
• Get Number Array
• Get Boolean Array
• Get Map
In this sample, it shows how to retrieve a String value with the key “name” from the document.
To get multiple values, chain multiple Get nodes together.
Attaching a listener to a document
You can also attach a listener to a document and listen to any changes made to it by using the “Listen To Document” node. This way, you’ll be able to update information in real-time every time data changes for a document.
It has the same 3 pin as the “Get Document” node.
• Document Path
• On Document Retrieved Callback
• On Fail to Retrieve Document Callback
The only difference is that the On Document Retrieved Callback gets called once at the beginning to get the contents of the document and then it’ll get called every time a change is made to the document.
