[pbs-devel] [PATCH proxmox-backup v2 3/5] server/rest: add helper to extract compression headers

Fri Apr 2 14:20:21 CEST 2021

On 01.04.21 16:11, Dominik Csapak wrote:
> for now we only extract 'deflate'
> 
> Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
> ---
>  src/server/rest.rs | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
> 
> diff --git a/src/server/rest.rs b/src/server/rest.rs
> index 1cd26787..00ff6844 100644
> --- a/src/server/rest.rs
> +++ b/src/server/rest.rs
> @@ -39,6 +39,7 @@ use crate::api2::types::{Authid, Userid};
>  use crate::auth_helpers::*;
>  use crate::config::cached_user_info::CachedUserInfo;
>  use crate::tools;
> +use crate::tools::compression::CompressionMethod;
>  use crate::tools::FileLogger;
>  
>  extern "C" {
> @@ -587,6 +588,28 @@ fn extract_lang_header(headers: &http::HeaderMap) -> Option<String> {
>      None
>  }
>  
> +fn extract_compression_method(headers: &http::HeaderMap) -> Option<CompressionMethod> {
> +    let mut compression = None;
> +    if let Some(raw_encoding) = headers.get(header::ACCEPT_ENCODING) {
> +        if let Ok(encoding) = raw_encoding.to_str() {

FWIW, above two lines could be merged with:

if let Some(Ok(encodings)) = headers.get(header::ACCEPT_ENCODING).map(|v| v.to_str()) {

Would reduce a level of indentation, which this fn has quite a few.

> +            for encoding in encoding.split(&[',', ' '][..]) {

as mentioned off-list, the Accept-Encoding allows to add "Quality values" [2], like
`deflate;q=<weight>`[1], to encodings, I haven't seen any browser actually using it
but it is allowed in the RFC[0].

I'd not implement support for it, but we could either adapt the FromStr implementation
or split also by semicolon here.

[0]: https://tools.ietf.org/html/rfc7231#section-5.3.4
[1]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept-Encoding#directives
[2]: https://developer.mozilla.org/en-US/docs/Glossary/Quality_values

> +                if let Ok(method) = encoding.parse() {
> +                    if method != CompressionMethod::Deflate {
> +                        // fixme: implement other compressors
> +                        continue;
> +                    }
> +                    let method = Some(method);
> +                    if method > compression {
> +                        compression = method;
> +                    }
> +                }
> +            }
> +        }
> +    }
> +
> +    return compression;
> +}
> +
>  async fn handle_request(
>      api: Arc<ApiConfig>,
>      req: Request<Body>,
> 