Step by Step Guide to Building a Google Contacts API Integration in C#

Introduction

Hey there, fellow developer! Ready to dive into the world of Google Contacts API integration? You're in for a treat. We'll be using the Google.Apis package to make our lives easier, so buckle up and let's get started!

Prerequisites

Before we jump in, make sure you've got these basics covered:

• Install the Google.Apis.PeopleService.v1 NuGet package
• Set up a Google Cloud Console project (I know, I know, but it's necessary)

Authentication

First things first, let's get that authentication sorted:

1. Head to the Google Cloud Console and create OAuth 2.0 credentials
2. Implement the OAuth 2.0 flow in your C# app

Here's a quick snippet to get you started:

UserCredential credential = await GoogleWebAuthorizationBroker.AuthorizeAsync(
    new ClientSecrets { ClientId = "YOUR_CLIENT_ID", ClientSecret = "YOUR_CLIENT_SECRET" },
    new[] { PeopleServiceService.Scope.ContactsReadonly },
    "user",
    CancellationToken.None);

Setting up the Google Contacts service

Now that we're authenticated, let's set up the service:

var service = new PeopleServiceService(new BaseClientService.Initializer()
{
    HttpClientInitializer = credential,
    ApplicationName = "Your App Name",
});

Basic operations

Retrieving contacts

Let's fetch those contacts:

var request = service.People.Connections.List("people/me");
request.PersonFields = "names,emailAddresses,phoneNumbers";
var response = await request.ExecuteAsync();

foreach (var person in response.Connections)
{
    // Do something with each contact
}

Creating a new contact

Adding a new friend? Here's how:

var person = new Person
{
    Names = new List<Name> { new Name { GivenName = "John", FamilyName = "Doe" } },
    EmailAddresses = new List<EmailAddress> { new EmailAddress { Value = "[email protected]" } }
};

var request = service.People.CreateContact(person);
var createdContact = await request.ExecuteAsync();

Updating and deleting contacts

I'll leave these as an exercise for you (wink, wink). But trust me, they're just as straightforward!

Advanced features

Want to level up? Try these:

• Batch operations for bulk updates
• Handle pagination for large contact lists
• Implement filtering and searching

Error handling and best practices

Remember to:

• Catch and handle GoogleApiExceptions
• Respect rate limits (be nice to Google's servers!)
• Use exponential backoff for retries

Testing and debugging

Pro tip: Use the Google OAuth 2.0 Playground for quick tests. And don't forget to log everything – future you will thank present you!

Conclusion

And there you have it! You're now equipped to build a robust Google Contacts API integration. Remember, the official docs are your best friend for diving deeper.

Happy coding, and may your contacts always be in sync!

Sample code repository

Check out the complete code examples in this GitHub repository.