Re: [OAUTH-WG] TMI BFF - html meta tags over/alternative to discovery

Evert Pot <> Sat, 15 May 2021 15:57 UTC

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From: Evert Pot <>
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Date: Sat, 15 May 2021 11:57:38 -0400
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Subject: Re: [OAUTH-WG] TMI BFF - html meta tags over/alternative to discovery
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On 2021-05-15 11:35 a.m., Filip Skokan wrote:
> Hello Vittorio, Brian, everyone
> This is a followup to my feedback in the TMI BFF interim meeting on 
> April 26th where I mentioned I'd bring this to the list for discussion.
> I proposed an alternative to using fixed endpoint locations and/or 
> discovery. HTML <meta> Tags <>.
> These would be in the returned page HTML's head tag, e.g.
>     <meta name="oauth-bff-token" content="/api/bff-token">
>     <meta name="oauth-bff-sessioninfo" content="/api/bff-sessioninfo">
> The javascript SDK handing TMI BFF would know to look for these 
> defined meta tags to source the location of the different endpoints. I 
> think this could be the primary place an SDK would look at as it 
> doesn't require any upfront external requests.
> For the SDK this is as simple as
>     var bffTokenPath =
>     document.querySelector('meta[name="oauth-bff-token"]').content;
> If this was the only mechanism defined by the document (to be bashed) 
> I think it can save the group a lot of time defining a client 
> discovery document which would be otherwise needed. If discovery as an 
> alternative solution is indeed inevitable, it can be a second in line 
> mechanism the javascript SDK would know to use.
> As discussed in the interim, a well known set of endpoints (or even a 
> single root client discovery document) might not always be available 
> for control to the webpage depending on where and how it is hosted, on 
> the other hand the HTML it serves always, I hope, is.

A more appropriate HTML tag might be the <link> tag.

You would just need to register a link relationship in the IANA registry: