MS Project Online API to read calendar information

Aravind470 

You're getting a 404 error, so let's double-check everything.

Check Your URL: Ensure the URL format is correct and consistent:

• Verify the <sitecollection> and <site> values are correct.
• Ensure the calendarid is correctly formatted and exists.
• It should look like this: https://<sitecollection>/<site>/pwa/_api/ProjectServer/Calendars('calendarid')

Use the Correct Endpoints: Sometimes API versions and structures change. Verify the endpoint paths and usage.

Authentication: Ensure your SharePoint Online credentials are correctly configured and have the necessary permissions.

Alternative Endpoints and Approaches:  You might need to use different or additional endpoints to retrieve the detailed calendar information.

1. Get All Calendars:
Start by fetching all calendars to ensure you're using a valid calendar ID.
GET https://<sitecollection>/<site>/pwa/_api/ProjectServer/Calendars

2. Retrieve Calendar Details:
Use the following to get detailed information about a specific calendar:
GET https://<sitecollection>/<site>/pwa/_api/ProjectServer/Calendars('calendarid')

3. Work Weeks and Exceptions:
Sometimes the API paths can be tricky. Try these:

Alternative Work Weeks Endpoint:
GET https://<sitecollection>/<site>/pwa/_api/ProjectData/Calendars(guid'calendarid')/WorkWeeks

Alternative Exceptions Endpoint:
GET https://<sitecollection>/<site>/pwa/_api/ProjectData/Calendars(guid'calendarid')/Exceptions

Example Code (Updated Fetch Requests)
Here's an updated version of the Fetch requests considering possible adjustments:

const siteUrl = 'https://<sitecollection>/<site>';
const calendarId = 'calendarid'; // Ensure this is a valid GUID
const headers = {
'Accept': 'application/json;odata=verbose',
'Authorization': 'Bearer <your_access_token>' // Ensure your access token is valid
};

// Fetch all calendars to verify the calendar ID
fetch(`${siteUrl}/pwa/_api/ProjectServer/Calendars`, { headers })
.then(response => response.json())
.then(data => console.log('All Calendars:', data));

// Fetch basic calendar details
fetch(`${siteUrl}/pwa/_api/ProjectServer/Calendars('${calendarId}')`, { headers })
.then(response => response.json())
.then(data => console.log('Calendar Details:', data));

// Fetch work weeks (alternative endpoint)
fetch(`${siteUrl}/pwa/_api/ProjectData/Calendars(guid'${calendarId}')/WorkWeeks`, { headers })
.then(response => response.json())
.then(data => console.log('Work Weeks:', data));

// Fetch exceptions (alternative endpoint)
fetch(`${siteUrl}/pwa/_api/ProjectData/Calendars(guid'${calendarId}')/Exceptions`, { headers })
.then(response => response.json())
.then(data => console.log('Exceptions:', data));

Permissions. Ensure that:

• Your account has the necessary permissions to access Project Online APIs.
• The access token or credentials used are valid and have the required scopes.

Debugging Tips

• Verify Calendar ID: Make sure it exists.
• Check Permissions: Your account should have the right access.
• Use Postman: Test the API calls manually to see if you get more detailed error messages.

Hopefully, this helps! If you still run into issues, let me know!

Regards, Tony