Google Cloud Storage event triggers

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Requirements

• An Unstructured account, and an Unstructured API key for your account, as follows:
  1. Sign in to your Unstructured account:
     • If you do not already have an Unstructured account, go to https://unstructured.io/contact and fill out the online form to indicate your interest.
     • If you already have an Unstructured account, sign in by using the URL of the sign in page that Unstructured provided to you when your Unstructured account was created. After you sign in, the Unstructured user interface (UI) then appears, and you can start using it right away. If you do not have this URL, contact Unstructured Sales at sales@unstructured.io.
  2. Get your Unstructured API key: a. In the Unstructured UI, click API Keys on the sidebar.
     b. Click Generate API Key.
     c. Follow the on-screen instructions to finish generating the key.
     d. Click the Copy icon next to your new key to add the key to your system’s clipboard. If you lose this key, simply return and click the Copy icon again.
     
• The Unstructured Workflow Endpoint URL for your account, as follows:
  1. In the Unstructured UI, click API Keys on the sidebar.
     
  2. Note the value of the Unstructured Workflow Endpoint field.
• A Google Cloud Storage source connector in your Unstructured account. Learn how.
• Some available destination connector in your Unstructured account.
• A workflow that uses the preceding source and destination connectors. Learn how.
• An OAuth 2.0 client ID and client secret to call the Google API, as follows:
  1. Sign in to your Google Cloud account.
  2. Go to the Google Cloud APIs dashboard.
  3. Click + Enable APIs and services.
  4. In the Search for APIs & Services box, enter Cloud Storage API.
  5. In the list of search results, click Cloud Storage API.
  6. Make sure that API Enabled is shown. If not, click Enable.
  7. Go to your Google Cloud console welcome page.
  8. In the Search (/) for resources, docs, products, and more box, enter Credentials.
  9. Click Credentials (APIs & Services).
  10. Click + Create credentials > OAuth client ID.
  11. For Application type, select Web application.
  12. (Optional) Enter some non-default Name for this OAuth 2.0 client to be shown in the list of created clients in your Google Cloud Console.
  13. Click Create.
  14. After the OAuth client is created, click Download JSON to save the client ID and client secret values to a JSON file on your local machine. Store this JSON file in a secure location.

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Step 1: Create the Google Apps Script project

1. Go to http://script.google.com/.
2. Click + New project.
3. Click the new project’s default name (such as Untitled project), and change it to something more descriptive, such as Unstructured Scripts for GCS.

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Step 2: Add the script

1. With the project still open, on the sidebar, click the < > (Editor) icon.
2. In the Files tab, click Code.gs.
3. Replace the contents of the Code.gs file with the following code instead:
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   // Configure the OAuth2 service.
   function getOAuthService() {
     return OAuth2.createService('GCS')
       .setAuthorizationBaseUrl('https://accounts.google.com/o/oauth2/auth')
       .setTokenUrl('https://oauth2.googleapis.com/token')
       .setClientId(CLIENT_ID)
       .setClientSecret(CLIENT_SECRET)
       .setCallbackFunction('authCallback')
       .setPropertyStore(PropertiesService.getUserProperties())
       .setScope(OAUTH_SCOPE);
   }
   
   // OAuth2 callback function.
   function authCallback(request) {
     const service = getOAuthService();
     const isAuthorized = service.handleCallback(request);
     return HtmlService.createHtmlOutput(isAuthorized ? 'Success!' : 'Denied');
   }
   
   // Get a valid access token (refreshes automatically if expired).
   function getAccessToken() {
     const service = getOAuthService();
     if (!service.hasAccess()) {
       const authorizationUrl = service.getAuthorizationUrl();
       Logger.log('Open the following URL and re-run the script: %s', authorizationUrl);
       throw new Error('Authorization required. Open the URL in the log.');
     }
     return service.getAccessToken();
   }
   
   // Main function: checks for new or updated files in the bucket.
   function checkForNewOrUpdatedGCSFiles() {
     const thresholdMillis = 5 * 60 * 1000; // 5 minutes.
     const now = new Date();
   
     // Get (and refresh if needed) the access token.
     const accessToken = getAccessToken();
   
     // List objects in the bucket.
     const apiUrl = `https://storage.googleapis.com/storage/v1/b/${BUCKET_PATH}/o`;
     const response = UrlFetchApp.fetch(apiUrl, {
       method: 'get',
       headers: {
         'Authorization': 'Bearer ' + accessToken,
         'Accept': 'application/json'
       }
     });
     const data = JSON.parse(response.getContentText());
     const files = data.items || [];
   
     for (let i = 0; i < files.length; i++) {
       const file = files[i];
       const fileName = file.name;
       const created = new Date(file.timeCreated);
       const updated = new Date(file.updated);
   
       const millisSinceCreated = now - created;
       const createdWithinThreshold = millisSinceCreated < thresholdMillis;
       const millisSinceUpdated = now - updated;
       const updatedWithinThreshold = millisSinceUpdated < thresholdMillis;
   
       console.log('File Name:                       ' + fileName);
       console.log('Created:                         ' + created);
       console.log('Last updated:                    ' + updated);
       console.log('Milliseconds since created:      ' + millisSinceCreated);
       console.log('Milliseconds since last updated: ' + millisSinceUpdated);
       console.log('Created within threshold of ' + thresholdMillis + ' milliseconds? ' + createdWithinThreshold);
       console.log('Updated within threshold of ' + thresholdMillis + ' milliseconds? ' + updatedWithinThreshold);
       console.log('-----');
   
       if (createdWithinThreshold || updatedWithinThreshold) {
         // Trigger your workflow.
         UrlFetchApp.fetch(UNSTRUCTURED_API_URL, {
           method: 'post',
           headers: {
             'accept': 'application/json',
             'unstructured-api-key': UNSTRUCTURED_API_KEY
           }
         });
         console.log('At least one file created or updated within threshold of ' + thresholdMillis + ' milliseconds.');
         console.log('Unstructured workflow request sent to ' + UNSTRUCTURED_API_URL);
         return;
       }
     }
     console.log('No files created or updated within threshold of ' + thresholdMillis + ' milliseconds. No Unstructured workflow request sent.');
   }
   
   

4. Click the Save project to Drive button.

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Step 3: Customize the script for your workflow

1. With the project still open, on the Files tab, click the Add a file button, and then click Script.
2. Name the new file Constants. The .gs extension is added automatically.
3. Replace the contents of the Constants.gs file with the following code instead:
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   const BUCKET_PATH = '<bucket-path>';
   const UNSTRUCTURED_API_URL = '<unstructured-api-url>' + '/workflows/<workflow-id>/run';
   const UNSTRUCTURED_API_KEY = '<unstructured-api-key>';
   const CLIENT_ID = '<client-id>';
   const CLIENT_SECRET = '<client-secret>';
   const OAUTH_SCOPE = 'https://www.googleapis.com/auth/devstorage.read_only'; // Or .read_write or .full_control
   

   Replace the following placeholders:
   • Replace <bucket-path> with the path to your Google Cloud Storage bucket. This is the same path that you specified when you created your Google Cloud Storage source connector in your Unstructured account. Do not include the gs:// prefix here.
   • Replace <unstructured-api-url> with your Unstructured API URL value.
   • Replace <workflow-id> with the ID of your Unstructured workflow.
   • Replace <unstructured-api-key> with your Unstructured API key value.
   • Replace <client-id> with your OAuth 2.0 client ID value.
   • Replace <client-secret> with your OAuth 2.0 client secret value.
4. Click the disk (Save project to Drive) icon.

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Step 4: Generate an initial OAuth 2.0 access token

1. On the sidebar, click the gear (Project Settings) icon.
2. In the IDs area, next to Script ID, click Copy to copy the script’s ID value to your system’s clipboard.
3. In a separate tab in your web browser, open your Google Cloud Console welcome page.
4. In the Search (/) for resources, docs, products, and more box, enter Credentials.
5. Click Credentials (APIs & Services).
6. In the OAuth 2.0 client IDs list, click the link for the client ID that you created earlier in the requirements.
7. Under Authorized redirect URIs, click Add URI.
8. In the URIs 1 box, enter https://script.google.com/macros/d/<script-id>/usercallback, replacing <script-id> with the script’s ID value that you copied earlier.
9. Click Save.
10. On the original tab in your web browser, with the Google Apps Script project still open to the Constants.gs file, on the sidebar, next to Libraries, click the + (Add a library) icon.
11. For Script ID, enter 1B7FSrk5Zi6L1rSxxTDgDEUsPzlukDsi4KGuTMorsTQHhGBzBkMun4iDF, and then click Look up.
12. For Version, make sure the largest number is selected.
13. Click Add.
14. In the sidebar, click the Code.gs file to open it.
15. In the file’s top navigation bar, select getAccessToken.
16. Click the Run icon.
17. In the Execution log area, next to the message Open the following URL and re-run the script, copy the entire URL into a separate tab in your web browser and then browse to that URL.
18. When prompted, click Review permissions, and follow the on-screen instructions to grant the necessary permissions.

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Step 5: Create the script trigger

1. On the original tab in your web browser, with the Google Apps Script project still open, on the sidebar, click the alarm clock (Triggers) icon.
2. Click the + Add Trigger button.
3. Set the following values:
   • For Choose which function to run, select checkForNewOrUpdatedGCSFiles.
   • For Choose which deployment should run, select Head.
   • For Select event source, select Time-driven.
   • For Select type of time based trigger, select Minutes timer.
   • For Select minute interval, select Every 5 minutes.
     If you change Minutes timer or Every 5 minutes to a different interval, you should also go back and change the number 5 in the following line of code in the checkForNewOrUpdatedFiles function. Change the number 5 to the number of minutes that correspond to the alternate interval you selected:

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     const thresholdMillis = 5 * 60 * 1000;
     

   • For Failure notification settings, select an interval such as immediately, hourly, or daily.
4. Click Save.

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Step 6: View trigger results

1. With the Google Apps Script project still open, on the sidebar, click the three lines (Executions) icon.
2. As soon as the first script execution completes, you should see a corresponding message appear in the Executions list. If the Status column shows Completed, then keep going with this procedure. If the Status column shows Failed, expand the message to get any details about the failure. Fix the failure, and then wait for the next script execution to complete.
3. When the Status column shows Completed then, in your Unstructured account’s user interface, click Jobs on the sidebar to see if a new job is running for that worklow. If no new job is running for that workflow, then add at least one new file to—or update at least one existing file within—the Google Cloud Storage bucket, within 5 minutes of the next script execution. After the next script execution, check the Jobs list again.

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Step 7 (Optional): Delete the trigger

1. To stop the script from automatically executing on a regular basis, with the Google Apps Script project still open, on the sidebar, click the alarm clock (Triggers) icon.
2. Rest your mouse pointer on the trigger you created in Step 5.
3. Click the ellipsis (three dots) icon, and then click Delete trigger.