Gmail Connector for PowerShell

Read / search Gmail messages, download attachments, send mail and more using Gmail REST API.

In this article you will learn how to quickly and efficiently integrate Gmail data in PowerShell without coding. We will use high-performance Gmail Connector to easily connect to Gmail and then access the data inside PowerShell.

Let's follow the steps below to see how we can accomplish that!

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Create ODBC Data Source (DSN) based on ZappySys API Driver

Step-by-step instructions

To get data from Gmail using PowerShell we first need to create a DSN (Data Source) which will access data from Gmail. We will later be able to read data using PowerShell. Perform these steps:

  1. Download and install ODBC PowerPack.

  2. Open ODBC Data Sources (x64):

    Open ODBC Data Source

  3. Create a User data source (User DSN) based on ZappySys API Driver

    ZappySys API Driver
    Create new User DSN for ZappySys API Driver
    • Create and use User DSN if the client application is run under a User Account. This is an ideal option in design-time, when developing a solution, e.g. in Visual Studio 2019. Use it for both type of applications - 64-bit and 32-bit.
    • Create and use System DSN if the client application is launched under a System Account, e.g. as a Windows Service. Usually, this is an ideal option to use in a production environment. Use ODBC Data Source Administrator (32-bit), instead of 64-bit version, if Windows Service is a 32-bit application.

  4. When the Configuration window appears give your data source a name if you haven't done that already, then select "Gmail" from the list of Popular Connectors. If "Gmail" 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:

    GmailDSN
    Gmail
    ODBC DSN Template Selection

  5. 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

    Gmail authentication

    To make this work you will have to create a Google Cloud project. This project forms the basis for creating, enabling, and using all Google Cloud services, including managing APIs, enabling billing, adding and removing collaborators, and managing permissions.

    1. Go to the Google Cloud Console
    2. In the Google Cloud console, go to menu IAM & Admin, and then Create a Project.
    3. Enter the name of the new project into the Project Name field and select the appropriate organization, then click Create.
    4. The console navigates to the Dashboard page and your project is created within a few minutes.
    5. In the Google Cloud console, go to menu More products, Google Workspace, and then Product Library.
    6. Now we need to enable the Gmail API.
    7. Search for Gmail API. Select it and then click ENABLE.
    8. Select the Credentials tab on the left side of the screen.
    9. Select the + CREATE CREDENTIALS link to reveal a drop down menu.
    10. In the dropdown menu, select OAuth client ID.
    11. If presented, click the CONFIGURE CONSENT SCREEN button and then elect the appropriate User Type based on your business needs. Otherwise, continue to step 16.
    12. In the OAuth consent screen tab fill in your app's website and domain information, and then click SAVE AND CONTINUE.
    13. In the Scopes section of the app registration, click ADD OR REMOVE SCOPES and add the following scopes:
      • openid
      • https://mail.google.com/
      • https://www.googleapis.com/auth/userinfo.email
      • https://www.googleapis.com/auth/userinfo.profile
      • https://www.googleapis.com/auth/gmail.labels
      • https://www.googleapis.com/auth/gmail.send
      • https://www.googleapis.com/auth/gmail.modify
      • https://www.googleapis.com/auth/gmail.compose
      • https://www.googleapis.com/auth/gmail.readonly
    14. After the scopes have been added, click SAVE AND CONTINUE.
    15. Complete the wizard setting up scopes.
    16. Select the Credentials tab on the left side of the screen.
    17. Select the + CREATE CREDENTIALS link to reveal a drop down menu.
    18. In the dropdown menu, select OAuth client ID.
    19. In the Application type drop down, select Desktop application and then give your app client a name.
    20. Select the CREATE button.
    21. A popup window will appear that provides important information you should record for your records:
      • Client ID
      • Client secret
      And then click OK.
    22. 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.
    23. Back to Connection UI, Enter the client ID and client secret into the required parameters.
    API Connection Manager configuration

    Just perform these simple steps to finish authentication configuration:

    1. Set Authentication Type to User Account [OAuth]
    2. Optional step. Modify API Base URL if needed (in most cases default will work).
    3. Fill in all the required parameters and set optional parameters if needed.
    4. Press Generate Token button to generate the tokens.
    5. Finally, hit OK button:
    GmailDSN
    Gmail
    User Account [OAuth]
    https://gmail.googleapis.com/
    Required Parameters
    UseCustomApp Fill-in the parameter...
    Authorization URL Fill-in the parameter...
    Token URL Fill-in the parameter...
    Default API Version Fill-in the parameter...
    Default User Id Fill-in the parameter...
    Scope Fill-in the parameter...
    Optional Parameters
    Client Id
    Client Secret
    RetryMode RetryWhenStatusCodeMatch
    RetryStatusCodeList 429
    RetryCountMax 5
    RetryMultiplyWaitTime True
    Redirect URL (Only for Web App)
    ODBC DSN OAuth Connection Configuration

  6. Once the data source connection has been configured, it's time to configure the SQL query. Select the Preview tab and then click Query Builder button to configure the SQL query:

    ZappySys API Driver - Gmail
    Read / search Gmail messages, download attachments, send mail and more using Gmail REST API.
    GmailDSN
    Open Query Builder in API ODBC Driver to read and write data to REST API

  7. Start by selecting the Table or Endpoint you are interested in and then configure the parameters. This will generate a query that we will use in PowerShell to retrieve data from Gmail. Hit OK button to use this query in the next step. 

    SELECT * FROM Messages
    Configure table/endpoint parameters in ODBC data source based on API Driver
    Some parameters configured in this window will be passed to the Gmail API, e.g. filtering parameters. It means that filtering will be done on the server side (instead of the client side), enabling you to get only the meaningful data much faster.

  8. Now hit Preview Data button to preview the data using the generated SQL query. If you are satisfied with the result, use this query in PowerShell:

    ZappySys API Driver - Gmail
    Read / search Gmail messages, download attachments, send mail and more using Gmail REST API.
    GmailDSN
    SELECT * FROM Messages
    API ODBC Driver-based data source data preview
    You can also access data quickly from the tables dropdown by selecting <Select table>.
    A WHERE clause, LIMIT keyword will be performed on the client side, meaning that the whole result set will be retrieved from the Gmail API first, and only then the filtering will be applied to the data. If possible, it is recommended to use parameters in Query Builder to filter the data on the server side (in Gmail servers).

  9. Click OK to finish creating the data source.

Video Tutorial

Read Gmail data in PowerShell

Sometimes, you need to quickly access and work with your Gmail data in PowerShell. Whether you need a quick data overview or the complete dataset, this article will guide you through the process. Here are some common scenarios:

Viewing data in a terminal
  • Quickly peek at Gmail data
  • Monitor data constantly in your console
Saving data to a file
  • Export data to a CSV file so that it can be sliced and diced in Excel
  • Export data to a JSON file so that it can ingested by other processes
  • Export data to an HTML file for user-friendly view and easy sharing
  • Create a schedule to make it an automatic process
Saving data to a database
  • Store data internally for analysis or for further ETL processes
  • Create a schedule to make it an automatic process
Sending data to another API
  • Integrate data with other systems via external APIs

In this article, we will delve deeper into how to quickly view the data in PowerShell terminal and how to save it to a file. But let's stop talking and get started!

Reading individual fields

  1. Open your favorite PowerShell IDE (we are using Visual Studio Code).
  2. Then simply follow these instructions:
    "DSN=GmailDSN"
    Read API data with PowerShell using ODBC DSN in Visual Code

    For your convenience, here is the whole PowerShell script:

    # Configure connection string and query
$connectionString = "DSN=GmailDSN"
$query = "SELECT * FROM Customers"

# Instantiate OdbcDataAdapter and DataTable
$adapter = New-Object System.Data.Odbc.OdbcDataAdapter($query, $connectionString)
$table = New-Object System.Data.DataTable

# Fill the table with data
$adapter.Fill($table)

# Since we know we will be reading just 4 columns, let's define format for those 4 columns, each separated by a tab
$format = "{0}`t{1}`t{2}`t{3}"

# Display data in the console
foreach ($row in $table.Rows)
{
    # Construct line based on the format and individual Gmail fields
    $line = $format -f ($row["CustomerId"], $row["CompanyName"], $row["Country"], $row["Phone"])
    Write-Host $line
}
    Access specific Gmail table field using this code snippet: 
    $field = $row["ColumnName"]
    You will find more info on how to manipulate DataTable.Rows property in Microsoft .NET reference.
    For demonstration purposes we are using sample tables which may not be available in Gmail.
  3. To read values in a console, save the script to a file and then execute this command inside PowerShell terminal: Read API data in PowerShell using ODBC DSN
    You can also use even a simpler command inside the terminal, e.g.: 
    . 'C:\Users\john\Documents\dsn.ps1'

Retrieving all fields

However, there might be case, when you want to retrieve all columns of a query. Here is how you do it:

"DSN=GmailDSN"
Read all API columns from ODBC data source in PowerShell

Again, for your convenience, here is the whole PowerShell script: 

# Configure connection string and query
$connectionString = "DSN=GmailDSN"
$query = "SELECT CustomerId, CompanyName, Country, Phone FROM Customers"

# Instantiate OdbcDataAdapter and DataTable
$adapter = New-Object System.Data.Odbc.OdbcDataAdapter($query, $connectionString)
$table = New-Object System.Data.DataTable

# Fill the table with data
$adapter.Fill($table)

# Display data in the console
foreach ($row in $table.Rows) {
    $line = ""
    foreach ($column in $table.Columns) {
        $value = $row[$column.ColumnName]

        # Let's handle NULL values
        if ($value -is [DBNull])
        {
            $value = "(NULL)"
        }
        $line += $value + "`t"
    }
    Write-Host $line
}
You can limit the numbers of lines to retrieve by using a LIMIT keyword in the query, e.g.: 
SELECT * FROM Customers LIMIT 10

Using a full ODBC connection string

In the previous steps we used a very short format of ODBC connection string - a DSN. Yet sometimes you don't want a dependency on an ODBC data source (and an extra step). In those times, you can define a full connection string and skip creating an ODBC data source entirely. Let's see below how to accomplish that in the below steps:

  1. Open ODBC data source configuration and click Copy settings:
    ZappySys API Driver - Configuration [Version: 2.0.1.10418]
    ZappySys API Driver - Gmail
    Read / search Gmail messages, download attachments, send mail and more using Gmail REST API.
    GmailDSN
    Copy connection string for ODBC application
  2. The window opens, telling us the connection string was successfully copied to the clipboard: Successful connection string copying for ODBC application
  3. Then just paste the connection string into your script: Paste ODBC connection string in PowerShell to read API data
  4. You are good to go! The script will execute the same way as using a DSN.

Have in mind that a full connection string has length limitations.

Proceed to the next step to find out the details.

Limitations of using a full connection string

Despite using a full ODBC connection string may be very convenient it comes with a limitation: it's length is limited to 1024 symbols (or sometimes more). It usually happens when API provider generates a very long Refresh Token when OAuth is at play. If you are using such a long ODBC connection string, you may get this error: 

"Connection string exceeds maximum allowed length of 1024"

But there is a solution to this by storing the full connection string in a file. Follow the steps below to achieve this:

  1. Open your ODBC data source.
  2. Click Copy settings button to copy a full connection string (see the previous section on how to accomplish that).
  3. Then create a new file, let's say, in C:\temp\odbc-connection-string.txt.
  4. Continue by pasting the copied connection string into a newly created file and save it.
  5. Finally, the last step! Just construct a shorter ODBC connection string using this format: 
    DRIVER={ZappySys API Driver};SettingsFile=C:\temp\odbc-connection-string.txt
  6. Our troubles are over! Now you should be able to use this connection string in PowerShell with no problems.
This feature requires ODBC PowerPack v1.9.0 or later.

Write Gmail data to a file in PowerShell

Save data to a CSV file

Export data to a CSV file so that it can be sliced and diced in Excel: 

# Configure connection string and query
$connectionString = "DSN=GmailDSN"
$query = "SELECT * FROM Customers"

# Instantiate OdbcDataAdapter and DataTable
$adapter = New-Object System.Data.Odbc.OdbcDataAdapter($query, $connectionString)
$table = New-Object System.Data.DataTable

# Fill the table with data
$adapter.Fill($table)

# Export table data to a file
$table | ConvertTo-Csv -NoTypeInformation -Delimiter "`t" | Out-File "C:\Users\john\saved-data.csv" -Force

Save data to a JSON file

Export data to a JSON file so that it can ingested by other processes (use the above script, but change this part): 

# Export table data to a file
$table | ConvertTo-Json | Out-File "C:\Users\john\saved-data.json" -Force

Save data to an HTML file

Export data to an HTML file for user-friendly view and easy sharing (use the above script, but change this part): 

# Export table data to a file
$table | ConvertTo-Html | Out-File "C:\Users\john\saved-data.html" -Force
Check useful PowerShell cmdlets other than ConvertTo-Csv, ConvertTo-Json, and ConvertTo-Html for other data manipulation scenarios.

Actions supported by Gmail Connector

Learn how to perform common Gmail actions directly in PowerShell with these how-to guides:

Conclusion

In this article we showed you how to connect to Gmail in PowerShell and integrate data without any coding, saving you time and effort.

We encourage you to download Gmail Connector for PowerShell and see how easy it is to use it for yourself or your team.

If you have any questions, feel free to contact ZappySys support team. You can also open a live chat immediately by clicking on the chat icon below.

Download Gmail Connector for PowerShell Documentation

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Download Gmail Connector for PowerShell Documentation