The Freshworks app development platform includes a serverless environment that enables you to build serverless (back-end) apps. Front-end apps run in response to events such as button clicks or page loads that happen on the Freshcaller product’s UI (client). You can also create serverless apps that run in response to events such as app installation and uninstallation, events such as call establishment that occur in the Freshcaller product, or events that occur in an external product or service. To do this, you can configure event listeners that invoke callback methods. Serverless computing does involve servers, but they are abstracted away from developers. When a configured event occurs, the app logic in the callback method is run on a server, with the help of the event-specific payload passed to the callback method.

You can use the Server Method Invocation (SMI) feature, to build front-end apps that invoke a serverless component.

Create a Serverless App

After you install NVM, Node, and the Freshworks CLI, to create a serverless app:

1. From the command line, navigate to the empty directory in which you want to create the app.
2. Run the following command: $ fdk create --product freshcaller --template your_first_serverless_app Or $ fdk create -p freshcaller --template your_first_serverless_app

The following app related files are created, based on the your_first_serverless_app template:

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├── README.md
├── config
|   ├── iparams_test_data.json
│   └── iparams.json
├── manifest.json
└── server
    ├── lib
    │   └── handle-response.js
    ├── server.js
    └── test_data
        ├── onAppInstall.json
        ├── onAppUninstall.json
        ├── onCallCreate.json
        ├── onCallUpdate.json
        ├── onExternalEvent.json
        └── onScheduledEvent.json

4 directories, 12 files

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{
"platform-version": "2.2",
    "product": {
        "freshcaller": {
            "events": {
                "<eventName>": {
                    "handler": "<eventCallbackMethod>"
                },
                "<eventName>": {
                    "handler": "<eventCallbackMethod>"
                }
            }
        }
    },
    "engines": {
        "node": "12.22.6",
        "fdk": "7.0.0"
  },
    "whitelisted-domains": [
        "https://www.google.com"
    ]
}

When creating a serverless custom app, in your app logic (in server.js), you can include the process.env.ENV environment variable to run different app logic in the test and production environments. To do this, you can use the following syntax:

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if(process.env.ENV === "test") {
//do something
}
or
if(process.env.ENV === "production") {
//do something else
}

For a demonstration of this, see the Freshdesk serverless sample app.

Specify Dependencies

In the server.js file, you can use popular npm packages (at least 50 downloads) to leverage the back-end functionalities provided by the packages. You can also modularise and maintain the app-specific code by using helper methods that are available in certain libraries.

The default serverless app created based on the your_first_serverless_app template, uses the helper.js library file.

npm Packages

For information on how to set up a Windows environment before using npm packages, see Environment setup and configuration.

To use an npm package:

1. Navigate to the manifest.json file and specify the package name and corresponding version as a dependency.

Format to specify the request package as a dependency Copied Copy

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"dependencies": {
  "request": "2.72.0"
},

2. Navigate to the server.js file and load the dependencies by using the require() method.
   
   Format to load dependencies Copied Copy

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   var req = require("request");

   Note: Ensure to use the require() method as the first call and not inside functions.

For example npm packages and their usage as dependencies, see External Libraries.

Libraries

To use libraries that contain helper methods:

1. Store the requisite library files in the server/lib directory.
2. Navigate to the server.js file and load a library file by using the require() method.
   
   Format to load the handle-response library file Copied Copy

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   var handler = require("./lib/handle-response");

Test the App

To simulate an event and test your app:

1. From the command line, navigate to the directory that contains the app related files and run the following command.$ fdk run

2. In the address bar of the browser, enter https://localhost:10001/web/test. A dialog box is displayed.

3. Click Select an event. The list of all events configured in the server.js file is displayed.

   Note: To test app setup events, select onAppInstall or onAppUninstall. To test external events, select onExternalEvent. To test scheduled events, select onScheduledEvent. To test a product event, select the corresponding product event’s name. To test the default serverless app created based on the your_first_serverless_app template, select onCallCreate.

4. Select an event. The corresponding payload is displayed. To test a different scenario other than the default, edit the payload.

5. Click Simulate. If the event is successfully simulated, the Simulate button changes to a Success button. If the event simulation fails because of invalid payload data, the Simulate button changes to a Failed button. Modify the payload appropriately and click Simulate.