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Data Source

The ActiGraph CentrePoint connector enables you to ingest data from the ActiGraph CentrePoint API, which provides programmatic access to study management, subject data, and activity monitor information. This connector is particularly useful for healthcare organizations, research institutions, and fitness companies that need to integrate activity monitoring data into their data workflows.
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ActiGraph CentrePoint

Follow the instructions below to create a new data flow that ingests data from an ActiGraph CentrePoint source in Nexla.

Create a New Data Flow​

  1. To create a new data flow, navigate to the Integrate section, and click the New Data Flow button. Then, select the desired flow type from the list, and click the Create button.

  2. Select the ActiGraph CentrePoint connector tile from the list of available connectors. Then, select the credential that will be used to connect to the ActiGraph CentrePoint instance, and click Next; or, create a new ActiGraph CentrePoint credential for use in this flow.

  3. In Nexla, ActiGraph CentrePoint data sources can be created using pre-built endpoint templates, which expedite source setup for common ActiGraph CentrePoint endpoints. Each template is designed specifically for the corresponding ActiGraph CentrePoint endpoint, making source configuration easy and efficient.
    • To configure this source using a template, follow the instructions in Configure Using a Template.

    ActiGraph CentrePoint sources can also be configured manually, allowing you to ingest data from ActiGraph CentrePoint endpoints not included in the pre-built templates or apply further customizations to exactly suit your needs.
    • To configure this source manually, follow the instructions in Configure Manually.

Configure Using a Template​

Nexla provides pre-built templates that can be used to rapidly configure data sources to ingest data from common ActiGraph CentrePoint endpoints. Each template is designed specifically for the corresponding ActiGraph CentrePoint endpoint, making data source setup easy and efficient.

Endpoint Settings​

  • Select the endpoint from which this source will fetch data from the Endpoint pulldown menu. Available endpoint templates are listed in the expandable boxes below. Click on an endpoint to see more information about it and how to configure your data source for this endpoint.

    Get Studies

    This endpoint retrieves a list of studies within your organization. Use this endpoint when you need to access study metadata, including study names, IDs, creation dates, and other study information for analysis or reporting purposes.

    • This endpoint automatically retrieves all studies accessible to your organization. No additional configuration is required beyond selecting this endpoint template.
    • The endpoint uses pagination to handle large datasets efficiently, automatically fetching additional pages as needed.
    • Each study record includes metadata such as study name, ID, description, creation date, and status information.

    This endpoint returns study metadata including study names, IDs, and creation dates. Use the "Get Study Subjects" endpoint to retrieve detailed subject information for specific studies.

    Get Study Subjects

    This endpoint retrieves all subjects within a specific study. Use this endpoint when you need detailed subject information, demographics, or activity data for participants in a particular study.

    • Enter the Study ID in the Study ID field. You can find this ID by first using the "Get Studies" endpoint to retrieve available studies and their corresponding IDs.
    • The endpoint will return all subjects associated with the specified study, including subject demographics, enrollment information, and activity monitor assignments.
    • This endpoint also uses pagination to handle studies with large numbers of subjects efficiently.

    Study IDs are unique identifiers that can be obtained from the "Get Studies" endpoint. Ensure you have the correct Study ID before configuring this endpoint. For complete information about study and subject management, see the ActiGraph CentrePoint API Documentation.

Endpoint Testing​

Once the selected endpoint template has been configured, Nexla can retrieve a sample of the data that will be fetched according to the current settings. This allows users to verify that the source is configured correctly before saving.

  • To test the current endpoint configuration, click the Test button to the right of the endpoint selection menu. Sample data will be fetched & displayed in the Endpoint Test Result panel on the right.

  • If the sample data is not as expected, review the selected endpoint and associated settings, and make any necessary adjustments. Then, click the Test button again, and check the sample data to ensure that the correct information is displayed.

Configure Manually​

ActiGraph CentrePoint data sources can be manually configured to ingest data from any valid ActiGraph CentrePoint API endpoint. Manual configuration provides maximum flexibility for accessing endpoints not covered by pre-built templates or when you need custom API configurations.

With manual configuration, you can also create more complex ActiGraph CentrePoint sources, such as sources that use chained API calls to fetch data from multiple endpoints or sources that require custom authentication headers or request parameters.

API Method​

  1. To manually configure this source, select the Advanced tab at the top of the configuration screen.

  2. Select the API method that will be used for calls to the ActiGraph CentrePoint API from the Method pulldown menu. The most common methods are:

    • GET: For retrieving data from the API (most common for ActiGraph CentrePoint)
    • POST: For sending data to the API or triggering actions
    • PUT: For updating existing data
    • PATCH: For partial updates to existing data
    • DELETE: For removing data

API Endpoint URL​

  1. Enter the URL of the ActiGraph CentrePoint API endpoint from which this source will fetch data in the Set API URL field. This should be the complete URL including the protocol (https://) and any required path parameters.

Ensure the API endpoint URL is correct and accessible with your current credentials. You can test the endpoint using the Test button after configuring the URL. The base URL for ActiGraph CentrePoint API is https://api.actigraphcorp.com/centrepoint/v3/.

Rate Limiting Considerations​

The ActiGraph CentrePoint API enforces rate limiting to ensure optimal performance and fair usage across all users.

  1. Rate Limiting Configuration: Plan your API calls to stay within the rate limits:
    • Limit: 500 requests per minute per unique IP address
    • Exceeding the Limit: Requests exceeding the limit will receive a 429 Too Many Requests response
    • Retry-After Header: The response will include a Retry-After header indicating the number of seconds to wait before retrying
    • Best Practice: Implement retry logic with exponential backoff or schedule data ingestion during off-peak hours

For high-volume data ingestion, consider using the pre-built endpoint templates which are optimized for efficient data retrieval and automatically handle pagination to minimize API calls.

Date/Time Macros (API URL)​

Optional

Optionally, the API URL can be customized using macros—all macros added to the API URL will be converted into values when Nexla executes the API call. Macros are dynamic placeholders that allow you to create flexible API endpoints that can adapt to different time periods or data requirements.

For ActiGraph CentrePoint API, macros are particularly useful for creating endpoints that automatically adapt to different study periods, data collection windows, or temporal analysis requirements. This is especially valuable for longitudinal studies where you need to retrieve data for specific time ranges.

Macros are particularly useful for ActiGraph CentrePoint API endpoints that require date ranges for study periods, data collection windows, or temporal analysis. They eliminate the need to manually update URLs for different time periods.

  1. To add a macro, type { at the appropriate position in the API URL (within the Set API URL field), and select the desired macro from the dropdown list.

    • {{now}} – The current datetime
    • {{now-1}} – The datetime one time unit before the current datetime
    • {now+1} – The datetime one time unit after the current datetime
    • custom – Datetime macros can reference any number of time units before or after the current datetime—for example, enter (now-4) to indicate the datetime four time units before the current datetime

  2. Select the format that will be applied to datetime macros from the Date Format for Date/Time Macro pulldown menu. This format will be applied to the base datetime value of the macro—i.e., the value of {{now}} in {{now-1}}.

  3. Select the datetime unit that will be used to perform mathematical operations in the included macro(s) from the Time Unit for Operations pulldown menu—for example, for the macro {{now-1}}, when Day is selected, {{now-1}} will be converted to the datetime one day before the current datetime.

Lookup-Based Macros (API URL)​

Optional

Column values from existing lookups can also be included as macros in the API URL. Lookup-based macros allow you to reference data from previously configured data sources or lookups, enabling dynamic API endpoints that can adapt based on existing data.

For ActiGraph CentrePoint API, lookup-based macros are particularly useful for creating endpoints that reference study IDs, subject IDs, or device IDs from other data sources. This enables you to build dynamic workflows where one data source provides identifiers that are then used to fetch detailed data from ActiGraph CentrePoint.

Lookup-based macros are useful for ActiGraph CentrePoint API endpoints that need to reference study IDs, subject IDs, or device IDs from other data sources. For example, you could use a lookup containing study IDs to dynamically fetch subject data for multiple studies.

  1. To include a lookup column value macro, select the relevant lookup from the Add Lookups to Supported Macros pulldown menu.

  2. Type { at the appropriate position in the API URL, and select the lookup column-based macro from the dropdown list. Lookup-based macros are automatically populated into the macro list when a lookup is selected in the Add Lookups to Supported Macros pulldown menu.

Path to Data​

Optional

If only a subset of the data that will be returned by API endpoint is needed, you can designate the part(s) of the response that should be included in the Nexset(s) produced from this source by specifying the path to the relevant data within the response. This is particularly useful when API responses contain metadata, pagination information, or other data that you don't need for your analysis.

For ActiGraph CentrePoint API, this is especially important because API responses often include pagination metadata, study information, and other contextual data alongside the actual subject or activity data you want to analyze. By specifying the correct path, you can ensure that Nexla processes only the relevant data records.

For example, when a request call is used to fetch a list of subjects, the API will typically return an array of subject records, along with metadata such as total count, pagination information, and study context. By entering the path to the relevant data, you can configure Nexla to treat each subject record as a separate data point.

Path to Data is essential when ActiGraph CentrePoint API responses have nested structures. Without specifying the correct path, Nexla might not be able to properly parse and organize your subject or activity data into usable records.

  • To specify which data should be treated as relevant in responses from this source, enter the path to the relevant data in the Set Path to Data in Response field.

    • For responses in JSON format enter the JSON path that points to the object or array that should be treated as relevant data. JSON paths use dot notation (e.g., $.data.items[*] to access an array of items within a data object).

    • For responses in XML format, enter the XPath that points to the object/array containing relevant data. XPath uses slash notation (e.g., /response/data/item to access item elements within a data element).

    Path to Data Example:

    If the ActiGraph CentrePoint API response is in JSON format and includes a top-level array named subjects that contains the subject data, the path to the response would be entered as $.subjects[*]. This would ensure that each subject record is treated as a separate data point for analysis.

Autogenerate Path Suggestions​

Nexla can also autogenerate data path suggestions based on the response from the API endpoint. These suggested paths can be used as-is or modified to exactly suit your needs.

  • To use this feature, click the Test button next to the Set API URL field to fetch a sample response from the API endpoint. Suggested data paths generated based on the content & format of the response will be displayed in the Suggestions box below the Set Path to Data in Response field.

  • Click on a suggestion to automatically populate the Set Path to Data in Response field with the corresponding path. The populated path can be modified directly within the field if further customization is needed.

    PathSuggestions.png

Metadata​

If metadata is included in the response but is located outside of the defined path to relevant data, you can configure Nexla to include this data as common metadata in each record. This is useful when you want to preserve important contextual information that applies to all records but isn't part of the main data array.

For ActiGraph CentrePoint API, this is particularly valuable for preserving study context, request timestamps, pagination information, and other metadata that applies to all subjects or activity records in a response. This metadata can be crucial for data analysis and tracking data lineage.

For example, when a request call is used to fetch a list of subjects, the API response will typically include an array of subject records along with metadata such as study ID, total count, pagination information, or request timestamps. In this case, if you have specified the path to the relevant data but metadata of interest is located in a different part of the response, you can specify a path to this metadata to include it with each record in the generated Nexset(s).

Metadata paths are particularly useful for preserving ActiGraph CentrePoint API response context like study IDs, request timestamps, or summary statistics that apply to all records in the response. This helps maintain data lineage and context for analysis.

  • To specify the location of metadata that should be included with each record, enter the path to the relevant metadata in the Path to Metadata in Response field.

    • For responses in JSON format, enter the JSON path to the object or array that contains the metadata, and for responses in XML format, enter the XPath.

Request Headers​

Optional
  • If Nexla should include any additional request headers in API calls to this source, enter the headers & corresponding values as comma-separated pairs in the Request Headers field (e.g., header1:value1,header2:value2). Additional headers are often required for API versioning, content type specifications, or custom authentication requirements.

For ActiGraph CentrePoint API, you may need to include headers for API versioning, custom content types, or specific request formatting requirements. The API uses standard HTTP headers, but some endpoints may require specific header configurations.

You do not need to include any headers already present in the credentials. Common headers like Authorization, Content-Type, and Accept are typically handled automatically by Nexla based on your credential configuration. For ActiGraph CentrePoint API, the OAuth 2.0 authorization headers are managed automatically.

Endpoint Testing​

After configuring all settings for the selected endpoint, Nexla can retrieve a sample of the data that will be fetched according to the current configuration. This allows users to verify that the source is configured correctly before saving.

  • To test the current endpoint configuration, click the Test button to the right of the endpoint selection menu. Sample data will be fetched & displayed in the Endpoint Test Result panel on the right.

  • If the sample data is not as expected, review the selected endpoint and associated settings, and make any necessary adjustments. Then, click the Test button again, and check the sample data to ensure that the correct information is displayed.

Save & Activate the Source​

  1. Once all of the relevant steps in the above sections have been completed, click the Create button in the upper right corner of the screen to save and create the new ActiGraph CentrePoint data source. Nexla will now begin ingesting data from the configured endpoint and will organize any data that it finds into one or more Nexsets.