I'm speaking about Serverless Flow and Azure Functions at Collab365 Free Online Conference

Have you heard about the virtual Collab365 Global Conference 2017 that’s streaming online November 1st – 2nd?

Join me and 120 other speakers from around the world who will be bringing you the very latest content around SharePoint, Office 365, Flow, PowerApps, Azure, OneDrive for Business and of course the increasingly popular Microsoft Teams. The event is produced by the Collab365 Community and is entirely free to attend.

Places are limited to 5000 so be quick and register now.

During the conference I'd love you to watch my session which is called : 

'Serverless with Microsoft Flow and Azure Functions'

Level up your mastery of Microsoft Flow. Switch to Azure Functions only when you need to. No doubt there will be many sessions on Microsoft Flow, introducing you to its wonderful merits and rough edges. This session is for the advanced users - we will see what Microsoft Flow really is, and bend it to our will.

If you join me, you will learn:

• Master JSON in a Flow
• Combining Azure Functions with Flow
• Failure Recovery, in a Flow
• How to handle Binary in a Flow
• How to write HTML and generate PDF in Flow

Topic(s):

• Azure Functions
• Microsoft Flow

Audience :

• Developer
• Power User

Time :

• Thursday, November 2 2017 10:00 AM (UTC)
• Thursday, November 2 2017 09:00 PM (ADST)

How to attend :

1. Register here.
2. At the time listed above go here to watch my session. (you can also add me to your own personal planner from the agenda.
3. Enjoy the demos and ask me questions, I'll put the templates up for download after the session.

Two ways to convert SharePoint files to PDF via Flow

This blog post is divided into three sections: The easy, The Auth and The Complete parts.

Microsoft Flow released a new power to Convert Files to PDF.  This made my October.  So of course we have to play with this.

Part 1. The Easy

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Now this work well, but raises a few questions: 

1. Why do I have to copy to OneDrive for Business?
   Because the Convert File action is also available for OneDrive for consumer, but not SharePoint
    
2. Can I do this without copying to OneDrive for Business
   Not with the default Actions for now.  There's no Convert File for SharePoint Connector.  And SharePoint Connector's Get File Content action doesn't allow a format parameter.

And this is the simplest solution.

Warning: Next be dragons (Auth and API)

We are going to dive in to see what API this uses.  And whether we can call the same API on SharePoint library document directly without copying the file to OneDrive first.

This next part is good for you.  But it is heavy and will look complicated.  Brace yourselves.

...So what API does this use?

https://docs.microsoft.com/en-us/onedrive/developer/rest-api/api/driveitem_get_content_format

GET /drive/items/{item-id}/content?format={format}
GET /drive/root:/{path and filename}:/content?format={format}

Specifically, this uses the Microsoft Graph

Part 2. The Auth

Disclaimer - OAuth looks familiar, but steps are always tricky.  Easy to mess up.  So if you are following this through, walk carefully.

For the next part, we need to connect to MS Graph with AppOnly permissions

In Azure Portal - under Azure AD - create an App Registeration (I'm reusing a powershell-group-app one I had previously baked)

We will be accessing files - so make sure Application Permissions for read files is granted.  This requires admin consent.

Via the Azure AD portal - hit Grant Permissions to perform admin consent directly.

Now we are going to write the Flow with HTTP requests

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hit the token endpoint for our tenant with a POST message.  The Body must be grant_type=client_credential with client_id, client_secret and the resource is https://graph.microsoft.com

this request if successful will give us back a JSON.  Parse JSON with this schema:

{
    "type": "object",
    "properties": {
        "token_type": {
            "type": "string"
        },
        "expires_in": {
            "type": "string"
        },
        "ext_expires_in": {
            "type": "string"
        },
        "expires_on": {
            "type": "string"
        },
        "not_before": {
            "type": "string"
        },
        "resource": {
            "type": "string"
        },
        "access_token": {
            "type": "string"
        }
    }
}

This gives Flow a variable for access_token for the remainder of the steps to use to call Microsoft Graph

Test this by calling the MS Graph endpoint for SharePoint site

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This HTTP request with the Bearer access_token successfully returns SharePoint site data from Microsoft Graph.

Part 3.  The Complete Solution to fetch SharePoint document as PDF

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Call /content?format=PDF

A few things going on in this result.  

1. Flow thinks this request has failed - because it doesn't return a 2xx status.  It returns a 302 redirect.
2. The Response header contains the Location of the redirect, which is where the PDF file is

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Parse JSON again on the Response header.  

{
    "type": "object",
    "properties": {
        "Transfer-Encoding": {
            "type": "string"
        },
        "request-id": {
            "type": "string"
        },
        "client-request-id": {
            "type": "string"
        },
        "x-ms-ags-diagnostic": {
            "type": "string"
        },
        "Duration": {
            "type": "string"
        },
        "Cache-Control": {
            "type": "string"
        },
        "Date": {
            "type": "string"
        },
        "Location": {
            "type": "string"
        },
        "Content-Type": {
            "type": "string"
        },
        "Content-Length": {
            "type": "string"
        }
    }
}

We just want Location.  We also need to configure Continue on previous HTTP error.

And finally, retrieve the file via GET again

When ran, the flow looks like this:

Summary

The complete solution uses HTTP to call MS Graph directly and pulls back the PDF file after a 302 Response.  This is a fairly complex example so please evaluate whether you want the Correct Way or the Easy Way.

Note also that Microsoft Flow has a Premium connector for Azure AD Requests - which will negate the middle part of this blog post re: Auth and let you dive right into MS Graph REST endpoints without worrying about access_tokens.  

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Call this Flow request and it downloads the PDF file, converted from a DOCX document in SharePoint team site.

Review Special Techniques Invoked:

• MS Graph Auth
• The Continue on Error configuration
• Parse JSON on Response Header