The solution is based on a new Graph API feature – Sites.Selected and a classic SP-Only app.
Register an Azure App
MS Graph API permissions: add -> Microsoft Graph -> Applications Permissions -> “sites.selected”
Ask SharePoint/Tenant admin run PowerShell code (e.g. this one) to assign proper permissions to your azure app for a specific site collection (consider site owner consent)
SharePoint API permissions: Site Collection Owner/Admin – use https://YourTenant.sharepoint.com/teams/YourSite/_layouts/15/appinv.aspx to add SharePoint API permissions to your app. Consider minimal permissions (e.g. as per Sumit)
you get access to one and only one site collection (“least privilege” principal)
Quick and simple answer: use SharePoint Search center or Microsoft Search, (or Bing if it is integrated).
Detailed explanation on how to find a public Team
In Microsoft Office 365, under MS Teams, there are 3 team types:
Private team: you can only join the team if you are invited or know the team code. SharePoint site behind the private team is shared only to members – not for everyone. You cannot see team name or description or content until you are team member (details). You are not able to search for the team name or content.
Public team: you can join the public team if you wish. The site behind the public team is shared with everyone except external users, so you can see public team name and description, but from MS Teams (desktop or web application) you cannot see public team content until you are team member.
Org-wide team: you are joined the team automatically (details)
From Teams – you can click on “Join or create a team” and you should be able to see some publicteams (but not all):
There is a “Search teams” box at the top right, so what if you are looking for a specific public team (not in the list) …
You know exact team name or at least some first letters. Solution: You are lucky. Just start typing team name in search bar at top right and hit “enter”- you will see shortened list of public teams matching your search criteria:
NB: do not use wildcards, it will not work:
NB: do not use top search bar, it will not work:
You want to join a public team, but you do not know exact team name. You know (or guess) something about the team, like
part of the team name
part of the team description
some keywords from team content files
Unfortunately, in this case both great Microsoft technologies – Search and Team – fail. You will not be able to find a public team:
Solution: use SharePoint search SharePoint site is created once a team is created.
For public teams – SharePoint site has “Everyone except external users” by default in “Members” group:
which means literally “Everyone except external users” has access to the site with “Edit” permissions.
SharePoint search is security-trimmed, i.e. you will see the site content in search results only if you do have access to the site. So just go to the SharePoint or SharePoint search center and search for what you know or guess about the team:
You can use all the power of SharePoint search (wildcards, refiners, keyword query language KQL etc)
Once you found something – you can go to the SharePoint site:
Now from the site – look at the site name and hover the mouse over the site name – you’ll see pop-up window. Now you know exact team name – and you can search for the team under Teams, or, if you are so lucky you see “Join” button – just join the team.click site title or hove over the site title:
One moment – you cannot see team’s chat messages in SharePoint, as chats are kept in Azure. But you can search for chat content after you joint the team.
Somehow both – SharePoint Search and Teams Search are not working against site/team description. Hopefully this bug will be addressed.
You can also search for site Url in teams. When you create a team – Office 365 generates a short team name (removes spaces and adds numbers if the team name is not unique; e.g. if the team name “Test” you might have “test381” as a short name, but if the team name is “This Is My Unique Team” – short name might be “ThisIsMyUniqueTeam”). After you can change team name and/or SharePoint site name. Team search under MS teams work for both names – short name initially assigned (kept as site specific Url) and new team name. But only starting with the beginning of the string.