[FFmpeg-devel] [PATCH] ipfsgateway: Remove default gateway

[Timo Rothenpieler]

On 11.08.2022 19:21, Mark Gaiser wrote:
> On Thu, Aug 11, 2022 at 6:49 PM Timo Rothenpieler <timo at rothenpieler.org>
> wrote:
> 
>> On 11.08.2022 18:26, Mark Gaiser wrote:
>>> Hi all,
>>>
>>> On the IPFS side we do have a solution for that with CAR files, you can
>>> read more about that here [1].
>>> Within the scope of this ipfs gateway protocol handler there isn't a
>>> solution yet to use CAR files, it is on our radar but still in the
>>> discussion phase.
>>>
>>> On the cURL side we had this same discussion with 2 possible solutions
>> [2].
>>> For completeness, i'll list them here in full too:
>>>
>>> 1. An error message that gives no example but instead points the user to
>>> documentation on how to get it working.
>>> === cURL example
>>> $ curl ipfs://bafkreicysg23kiwv34eg2d7qweipxwosdo2py4ldv42nbauguluen5v6am
>>> Error: local gateway not found and/or IPFS_GATEWAY is not set
>>> Learn how to run one: https://docs.ipfs.tech/install/command-line/
>>> ===
>>>
>>> 2. An error message that makes the user aware of IPFS and provides a
>>> solution to get it working immediately.
>>> === cURL example
>>> $ curl ipfs://bafkreicysg23kiwv34eg2d7qweipxwosdo2py4ldv42nbauguluen5v6am
>>> Error: local gateway not found and/or IPFS_GATEWAY is not set.
>>> Try: IPFS_GATEWAY=https://ipfs.io
>>> or run your own: https://docs.ipfs.tech/install/command-line/
>>> ===
>>>
>>> Within the cURL implementation we're going for point 1.
>>> The same idea can very well apply to ffmpeg too. Different texts that
>> match
>>> the different context, but in the same spirit.
>>>
>>> Now ffmpeg is a bit different here. First and foremost because it
>> predates
>>> the curl.
>>> But also because the default fallback gateway was an explicitly requested
>>> feature from the ffmpeg side to give an "it always works" feeling.
>>> ffmpeg therefore has a fourth option: Do nothing and keep it as-is.
>>
>> I'm not sure who requested that, but I doubt "tunnel all user traffic
>> through some random third parties server" was the idea there.
>>
> 
> Here's the conversation requesting this very feature:
> https://ffmpeg.org/pipermail/ffmpeg-devel/2022-March/293835.html

I generally agree with the points brought up there.
But my conclusion very much is not "just put a somewhat random default 
into the code".
Even a list of defaults is not Okay.
We can't hardcode "magic servers".

If it's not possible to make the protocol work without them, it likely 
shouldn't have been merged in the first place.
Why can't it access the files directly, but only via some magic http 
gateway?
Why does it need special code in ffmpeg in the first place, if you can 
just access it via that http proxy-gateway anyway?