How to pass SharePoint access token from logic app to HTTP endpoint - sharepoint-2013

Question

I have a logic app which triggers my HTTP endpoint every 15 minutes. Then the endpoint connects to SharePoint using Rest API and gets the data from specific list which is then added to my db.
But to get the data from SharePoint, i need access token. Do i need to write logic to get access token in the endpoint itself? or is there any to pass access token from my logic app while triggering my endpoint ?

Answer 1

As first answer. Yes, implement logic to get access token in HTTP Endpoint using SharePoint Online REST API.
Through such guides may be 1, 2, 3, 4. I think not exists any ways to pass access token from Azure logic app to your endpoint.
As second answer I can suggest to use SharePoint CSOM object model. To using it just install SharePoint Online Client Components SDK on computer where is your HTTP endpoint located and add Microsoft.SharePoint.Client.dll Microsoft.SharePoint.Client.Runtime.dll libraries as references. There exists good SharepointOnlineCredentials class to give credentials to requests.
Or other ways - you can re-architecture your solution:
Azure Logic Apps if I understood correctly must ask you to set connection to SharePoint by out-of-box features. See this article. I think you can get list items from SharePoint by actions in Azure Logic App and pass data to your HTTP endpoint without any additional access token requests just as method arguments.
If you have access to HTTP Endpoint from SharePoint then you can send data from SharePoint to your endpoint directly, not from Azure logic apps. You can do it from list items form pages, from site workflows or may be some Flow templates.
If you don't have access to HTTP Endpoint from SharePoint then you can create Azure hosted web service and call its methods from SharePoint by any ways. This web service will pass data to your HTTP endpoint as method arguments without any additional authentication. Web service call will be done from JavaScript on list item form save, from SharePoint workflow. May be here to get access token to this Azure web service will be easier then from your HTTP Endpoint to SP.
Are you using Azure SQL Database ? If yes then create connection between SharePoint Online and Azure SQL Database through Business Connectivity Services BCS. Like here or here or here. This allow user get, create, update items in your database inline in SharePoint list by out-of-box features.
Create periodically running code (Console App, PowerShell script, Windows Service). Schedule it on some server in your company. That code will use CSOM SharePoint object model and connect to SharePoint more easier through SharepointOnlineCredentials class, get data and connect to your HTTP Endpoint directly or to your database.
If your database is MS SQL Server located on-premise then you can use this guide to create Business Connectivity Services content types between SharePoint Online and on-premise SQL Server.
You can go some extravagant ways: =)
SharePoint by some ways can send emails with data from list items to some inbox and your HTTP endpoint can get these emails, parse data and perform following steps.
May be you can create Sql Server Integration Service (SSIS) package on some company local MS SQL Server that will send data from SharePoint on periodically basis to your database directly or to your HTTP endpoint directly.
Other ways...

Answer 2

"But to get the data from SharePoint, i need access token. Do i need to write logic to get access token in the endpoint itself?"
Correct, you do need a bearer access token. Where are you hosting the code for your HTTP endpoint? If you can put it in Azure as a Function or web API, then you can implement app-only permissions which will give you the necessary access token.
There are 2 options for doing so:
Granting access via Azure AD App-Only
Granting access using SharePoint App-Only
The first one is a bit more involved, because it requires a client secret AND a self-signed security certificate, but it will allow you permissions to any O365 API. The 2nd one is simpler and will only require the app/client ID and secret, but only allows permissions to the SharePoint Rest API.
The MSDN documentation linked above uses a PowerShell script to generate the security cert, but I prefer Bob German's instructions for manually creating/exporting one. He also includes instructions for registering an Azure AD application for your Azure function in his tutorial.