[pve-devel] [PATCH http-server v2] http: support Content-Encoding=deflate

[Folke Gleumes]

Gave this a test with:

Accept-encoding: deflate
Accept-encoding: deflate, gzip
Accept-encoding: foobar

Everything worked as expected, the first case returned a zlib
compressed file, the second gzip and the third just plaintext.
Consider this

Tested-by: Folke Gleumes <f.gleumes at proxmox.com>

On Wed, 2024-04-17 at 13:31 +0200, Maximiliano Sandoval wrote:
> Add support for compressing the body of responses with
> `Content-Encoding: deflate` following [RFC9110]. Note that in this
> context `deflate` is actually a "zlib" data format as defined in
> [RFC1950].
> 
> To preserve the current behavior we prefer `Content-Encoding: gzip`
> whenever `gzip` is listed as one of the encodings in the
> `Accept-Encoding` header and the data should be compressed.
> 
> [RFC9110] https://www.rfc-editor.org/rfc/rfc9110#name-deflate-coding
> [RFC1950] https://www.rfc-editor.org/rfc/rfc1950
> 
> Suggested-by: Lukas Wagner <l.wagner at proxmox.com>
> Signed-off-by: Maximiliano Sandoval <m.sandoval at proxmox.com>
> ---
> 
> Differences from v1:
>  - The commit documents the behavior better
>  - Add Suggested-by
>  - We set both gzip and deflate in the Accept-Encoding header if
> available
> 
>  src/PVE/APIServer/AnyEvent.pm | 28 ++++++++++++++++++++++------
>  1 file changed, 22 insertions(+), 6 deletions(-)
> 
> diff --git a/src/PVE/APIServer/AnyEvent.pm
> b/src/PVE/APIServer/AnyEvent.pm
> index b60b825..142c322 100644
> --- a/src/PVE/APIServer/AnyEvent.pm
> +++ b/src/PVE/APIServer/AnyEvent.pm
> @@ -123,6 +123,7 @@ sub cleanup_reqstate {
>      delete $reqstate->{request};
>      delete $reqstate->{proto};
>      delete $reqstate->{accept_gzip};
> +    delete $reqstate->{accept_deflate};
>      delete $reqstate->{starttime};
>  
>      if ($reqstate->{tmpfilename}) {
> @@ -288,7 +289,7 @@ sub response {
>      $reqstate->{hdl}->timeout($self->{timeout});
>  
>      $nocomp = 1 if !$self->{compression};
> -    $nocomp = 1 if !$reqstate->{accept_gzip};
> +    $nocomp = 1 if !$reqstate->{accept_gzip} && !$reqstate-
> >{accept_deflate};
>  
>      my $code = $resp->code;
>      my $msg = $resp->message || HTTP::Status::status_message($code);
> @@ -333,11 +334,17 @@ sub response {
>         $content_length = length($content);
>  
>         if (!$nocomp && ($content_length > 1024)) {
> -           my $comp = Compress::Zlib::memGzip($content);
> -           $resp->header('Content-Encoding', 'gzip');
> -           $content = $comp;
> -           $content_length = length($content);
> +           if ($reqstate->{accept_gzip}) {
> +               my $comp = Compress::Zlib::memGzip($content);
> +               $resp->header('Content-Encoding', 'gzip');
> +               $content = $comp;
> +           } elsif ($reqstate->{accept_deflate}) {
> +               my $comp = Compress::Zlib::compress($content);
> +               $resp->header('Content-Encoding', 'deflate');
> +               $content = $comp;
> +           }
>         }
> +       $content_length = length($content);
>         $resp->header("Content-Length" => $content_length);
>         $reqstate->{log}->{content_length} = $content_length;
>  
> @@ -735,7 +742,15 @@ sub proxy_request {
>             if $auth->{api_token};
>         $headers->{'CSRFPreventionToken'} = $auth->{token}
>             if $auth->{token};
> -       $headers->{'Accept-Encoding'} = 'gzip' if ($reqstate-
> >{accept_gzip} && $self->{compression});
> +       if ($self->{compression}) {
> +           if ($reqstate->{accept_deflate} && $reqstate-
> >{accept_gzip}) {
> +               $headers->{'Accept-Encoding'} = 'gzip, deflate' if
> $reqstate->{accept_deflate};
> +           } elsif ($reqstate->{accept_gzip}) {
> +               $headers->{'Accept-Encoding'} = 'gzip' if $reqstate-
> >{accept_gzip};
> +           } elsif ($reqstate->{accept_deflate}) {
> +               $headers->{'Accept-Encoding'} = 'deflate' if
> $reqstate->{accept_gzip};
> +           }
> +       }
>  
>         if (defined(my $host = $reqstate->{request}->header('Host')))
> {
>             $headers->{Host} = $host;
> @@ -1361,6 +1376,7 @@ sub process_header {
>      my $conn = $request->header('Connection');
>      my $accept_enc = $request->header('Accept-Encoding');
>      $reqstate->{accept_gzip} = ($accept_enc && $accept_enc =~
> m/gzip/) ? 1 : 0;
> +    $reqstate->{accept_deflate} = ($accept_enc && $accept_enc =~
> m/deflate/) ? 1 : 0;
>  
>      if ($conn) {
>         $reqstate->{keep_alive} = 0 if $conn =~ m/close/oi;