Manage Topics

A Topic resource represents a group of stream items categorized by similarity, such as the week assigned or course subject.

Each topic is identified by a unique ID assigned by the server. Associated with this ID is the course ID the topic belongs to, the actual topic name displayed on the Classroom UI, and the date and time of the last update.

Create a topic

You can create a new topic in a course using the topics.create() method, as shown in the following sample:

Java

classroom/snippets/src/main/java/CreateTopic.java
Topic topic = null;
try {
  // Create the new Topic.
  Topic content = new Topic().setName("Semester 1");
  topic = service.courses().topics().create(courseId, content).execute();
  System.out.println("Topic id: " + topic.getTopicId() + "\n" + "Course id: " + courseId);
} catch (GoogleJsonResponseException e) {
  // TODO (developer) - handle error appropriately
  GoogleJsonError error = e.getDetails();
  if (error.getCode() == 404) {
    System.out.printf("The courseId does not exist: %s.\n", courseId);
  } else {
    throw e;
  }
} catch (Exception e) {
  throw e;
}
return topic;

Python

topic = {
    "name": 'Example Topic'
}
response = service.courses().topics().create(
  courseId=<course ID or alias>,
  body=topic).execute()
print('Topic created: ', response['name'])

Retrieve topic details

You can retrieve topics of a corresponding course with the topics.get() method, as shown in the following sample:

Java

classroom/snippets/src/main/java/GetTopic.java
Topic topic = null;
try {
  // Get the topic.
  topic = service.courses().topics().get(courseId, topicId).execute();
  System.out.printf("Topic '%s' found.\n", topic.getName());
} catch (GoogleJsonResponseException e) {
  // TODO (developer) - handle error appropriately
  GoogleJsonError error = e.getDetails();
  if (error.getCode() == 404) {
    System.out.printf("The courseId or topicId does not exist: %s, %s.\n", courseId, topicId);
  }
  throw e;
} catch (Exception e) {
  throw e;
}
return topic;

Python

response = service.courses().topics().get(
  courseId=<course ID or alias>,
  id=<topic ID>).execute()
print('{0} ({1})'.format(response['name'], response['topicId']))

For a list of courses, use the topics.list() method, as shown in the following sample:

Java

classroom/snippets/src/main/java/ListTopics.java
List<Topic> topics = new ArrayList<>();
String pageToken = null;

try {
  do {
    ListTopicResponse response =
        service
            .courses()
            .topics()
            .list(courseId)
            .setPageSize(100)
            .setPageToken(pageToken)
            .execute();

    /* Ensure that the response is not null before retrieving data from it to avoid errors. */
    if (response.getTopic() != null) {
      topics.addAll(response.getTopic());
      pageToken = response.getNextPageToken();
    }
  } while (pageToken != null);

  if (topics.isEmpty()) {
    System.out.println("No topics found.");
  } else {
    for (Topic topic : topics) {
      System.out.printf("%s (%s)\n", topic.getName(), topic.getTopicId());
    }
  }
} catch (GoogleJsonResponseException e) {
  // TODO (developer) - handle error appropriately
  GoogleJsonError error = e.getDetails();
  if (error.getCode() == 404) {
    System.out.printf("The courseId does not exist: %s.\n", courseId);
  } else {
    throw e;
  }
} catch (Exception e) {
  throw e;
}
return topics;

Python

topics = []
page_token = None
while True:
    response = service.courses().topics().list(
        pageToken=page_token,
        pageSize=30,
        courseId=<course ID or alias>).execute()
    topics.extend(response.get('topic', []))
    page_token = response.get('nextPageToken', None)
    if not page_token:
        break
if not topics:
    print('No topics found.')
else:
    print('Topics:')
    for topic in topics:
        print('{0} ({1})'.format(topic['name'], topic['topicId']))

Update topics

You can update an existing topic's name with the topics.patch() method, as shown in the following sample:

Java

classroom/snippets/src/main/java/UpdateTopic.java
Topic topic = null;
try {
  // Retrieve the topic to update.
  Topic topicToUpdate = service.courses().topics().get(courseId, topicId).execute();

  // Update the name field for the topic retrieved.
  topicToUpdate.setName("Semester 2");

  /* Call the patch endpoint and set the updateMask query parameter to the field that needs to
  be updated. */
  topic =
      service
          .courses()
          .topics()
          .patch(courseId, topicId, topicToUpdate)
          .set("updateMask", "name")
          .execute();

  /* Prints the updated topic. */
  System.out.printf("Topic '%s' updated.\n", topic.getName());
} catch (GoogleJsonResponseException e) {
  // TODO(developer) - handle error appropriately
  GoogleJsonError error = e.getDetails();
  if (error.getCode() == 404) {
    System.out.printf("The courseId or topicId does not exist: %s, %s.\n", courseId, topicId);
  } else {
    throw e;
  }
} catch (Exception e) {
  throw e;
}
return topic;

Python

topic = {
  "name": "New Topic Name"
}
response = service.courses().topics().patch(
  courseId=<course ID or alias>,
  id=<topic ID>,
  updateMask="name",
  body=topic).execute()
print('{0} ({1})'.format(response['name'], response['topicId']))

Delete topics

You can delete an existing topic with the topics.delete() method, as shown in the following sample:

Java

classroom/snippets/src/main/java/DeleteTopic.java
try {
  service.courses().topics().delete(courseId, topicId).execute();
} catch (GoogleJsonResponseException e) {
  // TODO(developer) - handle error appropriately
  throw e;
} catch (Exception e) {
  throw e;
}
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