text-storage

Text Storage

This example demonstrates an HTTP Trigger Function providing a simple authorized REST API to save and retrieve text files from Firebase Cloud Storage. Client applications pass a matching authorization token pre-defined in the Firebase Realtime Database.

Example uses the Express framework and Firebase Cloud Storage.

Code

See file functions/index.js for the code.

The dependencies are listed in functions/package.json.

Setup

1. Clone or download this repo and open the text-storage directory.
2. If you don't already have one, create a Firebase Project using the Firebase Console.
3. If the Firebase CLI is not install, install it with npm install -g firebase-tools and then configure it with firebase login.
4. Configure the CLI locally by using firebase use --add and select your project in the list.
5. Install dependencies locally by running: cd functions; npm install; cd -
6. Create an authorization token in the Firebase Realtime Database with the name function-token

<database root>
    |
    function-token: "SOME_RANDOM_TOKEN_VALUE_YOU_DEFINE"

IMPORTANT:

• Set the request Authorization header to Bearer <THE_TOKEN_DEFINED_IN_FIREBASE_DATABASE> when making all API calls

• Set the request Content-Type header to text/plain, text/html ... when making Save/(POST) API calls

• Example assumes all files are stored/retrieved from folders one level below the default Firebase Cloud Storage Bucket. Be sure to include a storage folder path when making API requests, e.g. https://<YOUR_FIREBASE_CLOUD_FUNCTIONS_REQUEST_URL>/textStorage/<FOLDER>/somefile.txt

<default-storage-bucket>
    SOME_FOLDER/
        SOME_FILE.txt
    ANOTHER_FOLDER/
        ANOTHER_FILE.md

• (Optional) Example assumes the Firebase Cloud Storage Rules are set to the following so only the function can read/write to storage:

{
  "rules": {
    ".read": false,
    ".write": false
  }
}

Deploy

Deploy project using firebase deploy --only functions

Request from Google Apps Script

Example Google Apps Script to call the deployed Cloud Function to save a text file to Firebase Cloud Storage.

...

function saveTextToStorage() {

   var response, responseCode;

   // DEVELOPER TODO:  Replace "functionUrl" with the deployed Cloud Function URL from the Firebase Console
   // Consider storing URL in a Google Apps Script Properties Store
   var functionUrl = "https://<FIREBASE_CLOUD_FUNCTION_URL>/textStorage";

   // DEVELOPER TODO:  Replace <TOKEN> with user defined token stored in Firebase Realtime Database
   // Consider storing token in a Google Apps Script Properties Store
   var functionToken = "<TOKEN>";

   // DEVELOPER TODO: Replace <FOLDER> with name of the parent folder of the file to be stored in Cloud Storage Bucket e.g. "myfolder"
   var filePath = "<FOLDER>";

   // DEVELOPER TODO: Replace <FILENAME> with the name of the file to be stored in Cloud Storage Bucket e.g. "mydoc.txt"
   var fileName = "<FILENAME>";

   // DEVELOPER TODO: Replace "content" with text content of file to be stored in Cloud Storage Bucket
   var fileContent = "... file content ...";

   var params = {
     'method': 'POST',
     'contentType': 'text/plain',
     'headers': {
         'Authorization': 'Bearer ' + functionToken
      },
     'payload' : fileContent
   };

   response = UrlFetchApp.fetch(functionUrl + "/" + filePath + "/" + fileName, params);
   responseCode = response.getResponseCode();

   if (responseCode == 200) {
      // Success fetching file
      return true;
   } else {
      // Error returned from Cloud Function
      Logger.log('Error saving file.  Response code: ' + responseCode);
      return false;
   }

}

...

Example Google Apps Script to call the deployed Cloud Function to retrieve an existing text file from Firebase Cloud Storage.

...

function getTextFromStorage() {

   var response, responseCode;

   // DEVELOPER TODO:  Replace with deployed Cloud Function URL
   // Consider storing URL in a Google Apps Script Properties Store
   var functionUrl = "https://<FIREBASE_CLOUD_FUNCTION_URL>/textStorage/";

   // DEVELOPER TODO:  Replace <TOKEN> with pre-defined token stored in Firebase Realtime Database
   // Consider storing token in Google Apps Script Properties Store
   var functionToken = "<TOKEN>";

   // DEVELOPER TODO: Replace <FOLDER> and <FILENAME> with path and name of file stored in Cloud Storage Bucket e.g. "myfiles/mydoc.txt"
   var filePath = "<FOLDER>/<FILENAME>";

   var params = {
     'method': 'GET',
     'headers': {
         'Authorization': 'Bearer ' + functionToken
      }
   };

   response = UrlFetchApp.fetch(functionUrl + filePath, params);
   responseCode = response.getResponseCode();

   if (responseCode == 200) {
      // Success fetching file from Cloud Function
      return response.getContentText();
   } else {
      // Error returned from Cloud Function
      Logger.log('Error fetching file.  Response code: ' + responseCode);
      return null;
   }

}

...

License

© Laura Taylor. Licensed under an MIT license.