Google Calendar Connector - Using Stored Procs

T-SQL is a programming language used for managing and querying data in Microsoft SQL Server databases. We provides tools for data integration, automation, and connectivity.

If you want to use T-SQL with ZappySys, you can use our Connector, which allows you to connect to SQL Server databases and execute T-SQL queries from Google Calendar.

Create Data Source in ZappySys Data Gateway based on API Driver

Download and install ZappySys ODBC PowerPack.
Search for gateway in start menu and Open ZappySys Data Gateway:
Go to Users Tab to add our first Gateway user. Click Add; we will give it a name tdsuser and enter password you like to give. Check Admin option and click OK to save. We will use these details later when we create linked server:
Now we are ready to add a data source. Click Add, give data source a name (Copy this name somewhere, we will need it later) and then select Native - ZappySys API Driver. Finally, click OK. And it will create the Data Set for it and open the ZS driver UI.

GoogleCalendarDSN
When the Configuration window appears give your data source a name if you haven't done that already, then select "Google Calendar" from the list of Popular Connectors. If "Google Calendar" is not present in the list, then click "Search Online" and download it. Then set the path to the location where you downloaded it. Finally, click Continue >> to proceed with configuring the DSN:

GoogleCalendarDSN

Google Calendar

Now it's time to configure the Connection Manager. Select Authentication Type, e.g. Token Authentication. Then select API Base URL (in most cases, the default one is the right one). More info is available in the Authentication section.

User Account [OAuth]

Steps to get Google Calendar Credentials

To make this work you will have to create an OAuth application. To register an App, perform the following steps (Detailed steps found in the help link at the end):

Go to Google API Console
From the Project Dropdown (usually found at the top bar) click Select Project
On Project Propup click CREATE PROJECT
Once project is created you can click Select Project to switch the context (You can click on Notification link or Choose from Top Dropdown)
Click ENABLE APIS AND SERVICES
Now we need to enable Google Drive API.
Search Google Drive API. Select and click ENABLE
Go to back to main screen of Google API Console
Click OAuth Concent Screen Tab. Enter necessary details and Save.
Click Credentials Tab
Click CREATE CREDENTIALS (some where in topbar) and select OAuth Client ID option.
When prompted Select Application Type as Desktop App and click Create to receive your ClientID and Secret. Later on you can use this information now to configure Connection with UseCustomApp=true.
Go to OAuth Consent Screen tab. Under Publishing Status click PUBLISH APP to ensure your refresh token doesnt expire often. If you planning to use App for Private use then do not have to worry about Verification Status after Publish.

Fill in all required parameters and set optional parameters if needed:

GoogleCalendarDSN

Google Calendar

User Account [OAuth]

https://www.googleapis.com/calendar/v3/

Required Parameters
UseCustomApp	Fill in the parameter...
Optional Parameters
ClientId	Fill in the parameter...
ClientSecret	Fill in the parameter...
Scope	Fill in the parameter...
RetryMode	Fill in the parameter...
RetryStatusCodeList	Fill in the parameter...
RetryCountMax	Fill in the parameter...
RetryMultiplyWaitTime	Fill in the parameter...
Redirect URL (Only for Web App)	Fill in the parameter...

Service Account (Using Private Key File) [OAuth]

Steps to get Google Calendar Credentials
Use these steps to authenticate as service account rather than Google / GSuite User. Learn more about service account here

Basically to call Google API as Service account we need to perform following steps listed in 3 sections (Detailed steps found in the help link at the end)

Create Project

First thing is create a Project so we can call Google API. Skip this section if you already have Project (Go to next section)

Go to Google API Console
From the Project Dropdown (usually found at the top bar) click Select Project
On Project Propup click CREATE PROJECT
Once project is created you can click Select Project to switch the context (You can click on Notification link or Choose from Top Dropdown)
Click ENABLE APIS AND SERVICES
Now we need to enable API - Google Calendar API
Search Drive. Select and click ENABLE

Create Service Account

Once Project is created and APIs are enabled we can now create a service account under that project. Service account has its ID which looks like some email ID (not to confuse with Google /Gmail email ID)

Go to Create Service Account
From the Project Dropdown (usually found at the top bar) click Select Project
Enter Service account name and Service account description
For Role, do not select anything for now and Click Continue and then click Done. Next we will create Key.

Create Key

Once service account is created we need to create key file (i.e. credentials).

In the Cloud Console, click the email address for the service account that you created.
Click Keys.
Click Add key, then click Create new key.
Click Create and select P12 format. A P12 key file is downloaded to your computer. We will use this file in our API connection.
Click Close.
Now you may use downloaded *.p12 key file as secret file and Service Account Email as Client ID (e.g. some-service-account-name@your-project-id.iam.gserviceaccount.com ).

Add Permission

Now last thing is give read/write permission to Service Account for Calendar you like to access using API.

Copy the email address of your service account we created in previous step (its usually like this some-service-account-name@your-project-id.iam.gserviceaccount.com).
Login to https://calendar.google.com/calendar and make sure you see the calendar you like to access via API
On the left, find the "My calendars" section. To expand it, click the Down arrow Down arrow.
Hover over the calendar you want to share, and click 3 dots next to it. Click "Settings and sharing".
Find "Share with specific people", Click Add people button and enter the service account email id we obtained in the previous section.
Select correct permission you like to give for sharing. Click Send button to share. Thats it now we can read / write Calendar Events using Service account approach.
For more information check this link https://support.google.com/calendar/answer/37082?hl=en

Fill in all required parameters and set optional parameters if needed:

GoogleCalendarDSN

Google Calendar

Service Account (Using Private Key File) [OAuth]

https://www.googleapis.com/calendar/v3/

Required Parameters
Service Account Email	Fill in the parameter...
Service Account Private Key Path (i.e. *.p12)	Fill in the parameter...
Optional Parameters
Scope	Fill in the parameter...
RetryMode	Fill in the parameter...
RetryStatusCodeList	Fill in the parameter...
RetryCountMax	Fill in the parameter...
RetryMultiplyWaitTime	Fill in the parameter...

Once the data source has been configured, you can preview data. Select the Preview tab and use settings similar to the following to preview data:
Click OK to finish creating the data source.

Read data in SQL Server from the ZappySys Data Gateway

To read the data in SQL Server the first thing you have to do is create a Linked Server. Go to SQL Server Management Studio and configure it in a similar way:
Then click on Security option and configure username we created in ZappySys Data Gateway in one of the previous steps:
Optional: Under the Server Options, Enable RPC and RPC Out and Disable Promotion of Distributed Transactions(MSDTC).

You need to enable RPC Out if you plan to use EXEC(...) AT [MY_LINKED_SERVER_NAME] rather than OPENQUERY.
If don't enabled it, you will encounter the Server 'MY_LINKED_SERVER_NAME' is not configured for RPC error.

Query Example:
```
EXEC('Select * from Products') AT [MY_LINKED_SERVER_NAME]
```
If you plan to use 'INSERT INTO...EXEC(....) AT [MY_LINKED_SERVER_NAME]' in that case you need to Disable Promotion of Distributed Transactions(MSDTC).
If don't disabled it, you will encounter the The operation could not be performed because OLE DB provider "SQLNCLI11" for linked server "MY_LINKED_SERVER_NAME" was unable to begin a distributed transaction. error.

Query Example:
```
Insert Into dbo.Products
 EXEC('Select * from Products') AT [MY_LINKED_SERVER_NAME]
```
Finally, open a new query and execute a query we saved in one of the previous steps:
```
SELECT * FROM OPENQUERY([MY_LINKED_SERVER_NAME], 'SELECT * FROM Products');
```

Create Linked Server using Code

In previous section you saw how to create a Linked Server from UI. You can do similar action by code too (see below). Run below script after changing necessary parameters. Assuming your Data Source name on ZappySys Data Gateway UI is 'GoogleCalendarDSN'


    USE [master]
    GO
    --///////////////////////////////////////////////////////////////////////////////////////
    --Run below code in SSMS to create Linked Server and use ZappySys Drivers in SQL Server
    --///////////////////////////////////////////////////////////////////////////////////////

    //Replace YOUR_GATEWAY_USER, YOUR_GATEWAY_PASSWORD
    //Replace localhost with IP/Machine name if ZappySys Gateway Running on different machine other than SQL Server
    //Replace Port 5000 if you configured gateway on a different port


    --1. Configure your gateway service as per this article https://zappysys.com/links?id=10036

    --2. Make sure you have SQL Server Installed. You can download FREE SQL Server Express Edition from here if you dont want to buy Paid version https://www.microsoft.com/en-us/sql-server/sql-server-editions-express

    --Uncomment below if you like to drop linked server if it already exists
    --EXEC master.dbo.sp_dropserver @server=N'LS_GoogleCalendarDSN', @droplogins='droplogins'

    --3. Create new linked server

    EXEC master.dbo.sp_addlinkedserver
      @server = N'LS_GoogleCalendarDSN'  --Linked server name (this will be used in OPENQUERY sql
    , @srvproduct=N''
    ---- For MSSQL 2012,2014,2016 and 2019 use below (SQL Server Native Client 11.0)---
    , @provider=N'SQLNCLI11'
    ---- For MSSQL 2022 or higher use below (Microsoft OLE DB Driver for SQL Server)---
    --, @provider=N'MSOLEDBSQL'
    , @datasrc=N'localhost,5000' --//Machine / Port where Gateway service is running
    , @provstr=N'Network Library=DBMSSOCN;'
    , @catalog=N'GoogleCalendarDSN' --Data source name you gave on Gateway service settings

    --4. Attach gateway login with linked server

    EXEC master.dbo.sp_addlinkedsrvlogin
    @rmtsrvname=N'LS_GoogleCalendarDSN'  --linked server name
    , @useself=N'False'
    , @locallogin=NULL
    , @rmtuser=N'YOUR_GATEWAY_USER' --enter your Gateway user name
    , @rmtpassword='YOUR_GATEWAY_PASSWORD'  --enter your Gateway user's password
    GO

    --5. Enable RPC OUT (This is Optional - Only needed if you plan to use EXEC(...) AT YourLinkedServerName rather than OPENQUERY
    EXEC sp_serveroption 'LS_GoogleCalendarDSN', 'rpc', true;
    EXEC sp_serveroption 'LS_GoogleCalendarDSN', 'rpc out', true;

    --Disable MSDTC - Below needed to support INSERT INTO from EXEC AT statement
    EXEC sp_serveroption 'LS_GoogleCalendarDSN', 'remote proc transaction promotion', false;

    --Increase query timeout if query is going to take longer than 10 mins (Default timeout is 600 seconds)
    --EXEC sp_serveroption 'LS_GoogleCalendarDSN', 'query timeout', 1200;
    GO

Create Custom Stored Procedure in ZappySys Driver

You can create procedures to encapsulate custom logic and then only pass handful parameters rather than long SQL to execute your API call.

Steps to create Custom Stored Procedure in ZappySys Driver. You can insert Placeholders anywhere inside Procedure Body. Read more about placeholders here

Go to Custom Objects Tab and Click on Add button and Select Add Procedure:
Enter the desired Procedure name and click on OK:
Select the created Stored Procedure and write the your desired stored procedure and Save it and it will create the custom stored procedure in the ZappySys Driver:
Here is an example stored procedure for ZappySys Driver. You can insert Placeholders anywhere inside Procedure Body. Read more about placeholders here
```
CREATE PROCEDURE [usp_get_orders]
    @fromdate = '<<yyyy-MM-dd,FUN_TODAY>>'
 AS
    SELECT * FROM Orders where OrderDate >= '<@fromdate>';
```
That's it now go to Preview Tab and Execute your Stored Procedure using Exec Command. In this example it will extract the orders from the date 1996-01-01:
```
Exec usp_get_orders '1996-01-01';
```
Let's generate the SQL Server Query Code to make the API call using stored procedure. Go to Code Generator Tab, select language as SQL Server and click on Generate button the generate the code.
As we already created the linked server for this Data Source, in that you just need to copy the Select Query and need to use the linked server name which we have apply on the place of [MY_API_SERVICE] placeholder.
```
SELECT * FROM OPENQUERY([MY_API_SERVICE], 'EXEC usp_get_orders @fromdate=''1996-07-30''')
```
Now go to SQL served and execute that query and it will make the API call using stored procedure and provide you the response.