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Re: A question about Z_BUF_ERROR being ignored

From: Daniel Stenberg via curl-library <curl-library_at_cool.haxx.se>
Date: Tue, 16 Jun 2020 00:22:11 +0200 (CEST)

On Mon, 15 Jun 2020, WGH via curl-library wrote:

> When debugging some issue regarding possibly broken gzipped HTTP response in
> Go[1], I noticed that curl has no problems decompressing it, and returns
> successful exit code.

...

> Does anyone has a clue what's going on? Does curl erroneously not report a
> broken file? Or it's some known workaround for broken web servers?

On the Internet, gzip-compressed content is often sent broken, like this and
other ways, from servers. Browsers are - in their standard anything-goes ways
- masters of hiding such errors and instead just showing the contents they
could extract. Basically not providing any reason for sites to fix their
gzip issues (if the web admins even notice them).

curl often ends up between a rock and a hard place in this battle. We can be
strict and error out as soon as there's a problem, and there's the other side
that sees how the contents is shown in browsers and why report error if the
data could be extracted? It's tricky to say with absolutes what's right and
wrong in a lot of these cases.

Right now, I think we're somewhat in an in-between state where we allow a
certain leeway but we still regularly get reports where browsers allow even
more "rubbish" than we do. There's for example this (non-merged and closed)
PR, that was a take on making libcurl even more liberal in what it accepts:
https://github.com/curl/curl/pull/3825

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Received on 2020-06-16