[pbs-devel] [PATCH proxmox v3 0/5] Teach HTTP client how to decode deflate

[pbs-devel] [PATCH proxmox v3 0/5] Teach HTTP client how to decode deflate

[Maximiliano Sandoval]

This patch series adds support for decoding HTTP requests if they contain the
Content-Encoding=deflate header. Deciding on a public API (and implementing it)
to set this header is out-of-scope for this merge request a the moment of
writing 🙈.

Note that currently the proxmox-rest-server replies with deflated replies in the
following functions:

- handle_api_request: Called as part of Formated::handle_request and
  H2Service::handle_request. Always compresses if the client declares that
  supports deflate.
- handle_unformatted_api_request: Called as part of Unformatted::handle_request.
  It decides whether to compress the contents same as before
- simple_static_file_download: Called as part of handle_static_file_download
  which is called in ApiConfig::handle_request, this one decides whether to
  compress based on the fn extension_to_content_type which is a map
  format:should-be-compressed and whether the clients supports it.
- chunked_static_file_download is called as part of handle_static_file_downloda
  same as before

One thing that might be worth pointing out is that according to [1], when the
client supports `Accept-Encoding=deflate`, the HTTP server can reply with
`Content-Encoding=deflate` and encode the body using zlib, which means that it
should be encoded with deflate with the zlib headers included. This is somewhat
confusing but in short it means that one should use a zlib encoder rather than a
deflate encoder. At the moment the server always compresses using deflate
without the zlib headers, not a zlib encoder.

[1] https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept-Encoding#deflate

Differences from v2:
 - Split into multiple commits
 - More tests
 - Add builders for DeflateEndoder and DeflateDecoder
 - Both the deflate encoder and decoder where moved into a folder

Maximiliano Sandoval (5):
  compression: deflate: Move encoder into a mod
  compression: deflate: add builder pattern
  compression: deflate: add a decoder
  compression: deflate: add test module
  http: teach the Client how to decode deflate content

 proxmox-compression/Cargo.toml                |   3 +-
 .../src/{ => deflate}/compression.rs          |  59 +++++--
 .../src/deflate/decompression.rs              | 141 +++++++++++++++
 proxmox-compression/src/deflate/mod.rs        | 167 ++++++++++++++++++
 proxmox-compression/src/lib.rs                |   4 +-
 proxmox-compression/src/zip.rs                |   2 +-
 proxmox-http/Cargo.toml                       |   7 +
 proxmox-http/src/client/simple.rs             |  65 ++++++-
 8 files changed, 430 insertions(+), 18 deletions(-)
 rename proxmox-compression/src/{ => deflate}/compression.rs (83%)
 create mode 100644 proxmox-compression/src/deflate/decompression.rs
 create mode 100644 proxmox-compression/src/deflate/mod.rs

-- 
2.39.2

[pbs-devel] [PATCH proxmox v3 1/5] compression: deflate: Move encoder into a mod

[Maximiliano Sandoval]

This allows to add a decompression mod inside the deflate mod. This does
not touch the public API.

Signed-off-by: Maximiliano Sandoval <m.sandoval@proxmox.com>
---
 proxmox-compression/src/{ => deflate}/compression.rs | 6 ++----
 proxmox-compression/src/deflate/mod.rs               | 5 +++++
 proxmox-compression/src/lib.rs                       | 4 ++--
 proxmox-compression/src/zip.rs                       | 2 +-
 4 files changed, 10 insertions(+), 7 deletions(-)
 rename proxmox-compression/src/{ => deflate}/compression.rs (97%)
 create mode 100644 proxmox-compression/src/deflate/mod.rs

diff --git a/proxmox-compression/src/compression.rs b/proxmox-compression/src/deflate/compression.rs
similarity index 97%
rename from proxmox-compression/src/compression.rs
rename to proxmox-compression/src/deflate/compression.rs
index 632a5991..6e6a151d 100644
--- a/proxmox-compression/src/compression.rs
+++ b/proxmox-compression/src/deflate/compression.rs
@@ -12,8 +12,6 @@ use tokio::io::{AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt};
 use proxmox_io::ByteBuffer;
 use proxmox_lang::io_format_err;
 
-const BUFFER_SIZE: usize = 8192;
-
 pub enum Level {
     Fastest,
     Best,
@@ -53,7 +51,7 @@ impl<T> DeflateEncoder<T> {
         Self {
             inner,
             compressor: Compress::new(level, false),
-            buffer: ByteBuffer::with_capacity(BUFFER_SIZE),
+            buffer: ByteBuffer::with_capacity(super::BUFFER_SIZE),
             input_buffer: Bytes::new(),
             state: EncoderState::Reading,
         }
@@ -109,7 +107,7 @@ impl<T: AsyncWrite + Unpin> DeflateEncoder<T> {
     where
         R: AsyncRead + Unpin,
     {
-        let mut buffer = ByteBuffer::with_capacity(BUFFER_SIZE);
+        let mut buffer = ByteBuffer::with_capacity(super::BUFFER_SIZE);
         let mut eof = false;
         loop {
             if !eof && !buffer.is_full() {
diff --git a/proxmox-compression/src/deflate/mod.rs b/proxmox-compression/src/deflate/mod.rs
new file mode 100644
index 00000000..514ccbdc
--- /dev/null
+++ b/proxmox-compression/src/deflate/mod.rs
@@ -0,0 +1,5 @@
+mod compression;
+
+pub use compression::{DeflateEncoder, Level};
+
+const BUFFER_SIZE: usize = 8192;
diff --git a/proxmox-compression/src/lib.rs b/proxmox-compression/src/lib.rs
index 1fcfb977..239de623 100644
--- a/proxmox-compression/src/lib.rs
+++ b/proxmox-compression/src/lib.rs
@@ -1,6 +1,6 @@
-mod compression;
-pub use compression::*;
+pub use deflate::{DeflateEncoder, Level};
 
+pub(crate) mod deflate;
 pub mod tar;
 pub mod zip;
 pub mod zstd;
diff --git a/proxmox-compression/src/zip.rs b/proxmox-compression/src/zip.rs
index d2d3fd80..3ccece9b 100644
--- a/proxmox-compression/src/zip.rs
+++ b/proxmox-compression/src/zip.rs
@@ -22,7 +22,7 @@ use tokio::io::{AsyncRead, AsyncWrite, AsyncWriteExt, ReadBuf};
 use crc32fast::Hasher;
 use proxmox_time::gmtime;
 
-use crate::compression::{DeflateEncoder, Level};
+use crate::deflate::{DeflateEncoder, Level};
 
 const LOCAL_FH_SIG: u32 = 0x04034B50;
 const LOCAL_FF_SIG: u32 = 0x08074B50;
-- 
2.39.2

Re: [pbs-devel] [PATCH proxmox v3 1/5] compression: deflate: Move encoder into a mod

[Gabriel Goller]

On Wed Apr 10, 2024 at 4:30 PM CEST, Maximiliano Sandoval wrote:
> diff --git a/proxmox-compression/src/lib.rs b/proxmox-compression/src/lib.rs
> index 1fcfb977..239de623 100644
> --- a/proxmox-compression/src/lib.rs
> +++ b/proxmox-compression/src/lib.rs
> @@ -1,6 +1,6 @@
> -mod compression;
> -pub use compression::*;
> +pub use deflate::{DeflateEncoder, Level};
>  
> +pub(crate) mod deflate;

Whole series looks good, so consider:

Reviewed-by: Gabriel Goller <g.goller@proxmox.com>

The only nit is the above 'pub(crate)', which can be removed!

[pbs-devel] [PATCH proxmox v3 2/5] compression: deflate: add builder pattern

[Maximiliano Sandoval]

This allows creating a encoder in a more general way and allows to
specify whether we want to set zlib headers. This is useful to compress
HTTP traffic, as per [1].

[1] https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Encoding#directives

Signed-off-by: Maximiliano Sandoval <m.sandoval@proxmox.com>
---
 .../src/deflate/compression.rs                | 55 ++++++++++++++++---
 1 file changed, 46 insertions(+), 9 deletions(-)

diff --git a/proxmox-compression/src/deflate/compression.rs b/proxmox-compression/src/deflate/compression.rs
index 6e6a151d..24d2bc99 100644
--- a/proxmox-compression/src/deflate/compression.rs
+++ b/proxmox-compression/src/deflate/compression.rs
@@ -35,27 +35,64 @@ pub struct DeflateEncoder<T> {
     state: EncoderState,
 }
 
-impl<T> DeflateEncoder<T> {
-    pub fn new(inner: T) -> Self {
-        Self::with_quality(inner, Level::Default)
+pub struct DeflateEncoderBuilder<T> {
+    inner: T,
+    is_zlib: bool,
+    buffer_size: usize,
+    level: Level,
+}
+
+impl<T> DeflateEncoderBuilder<T> {
+    pub fn zlib(mut self, is_zlib: bool) -> Self {
+        self.is_zlib = is_zlib;
+        self
     }
 
-    pub fn with_quality(inner: T, level: Level) -> Self {
-        let level = match level {
+    pub fn level(mut self, level: Level) -> Self {
+        self.level = level;
+        self
+    }
+
+    pub fn buffer_size(mut self, buffer_size: usize) -> Self {
+        self.buffer_size = buffer_size;
+        self
+    }
+
+    pub fn build(self) -> DeflateEncoder<T> {
+        let level = match self.level {
             Level::Fastest => Compression::fast(),
             Level::Best => Compression::best(),
             Level::Default => Compression::new(3),
             Level::Precise(val) => Compression::new(val),
         };
 
-        Self {
-            inner,
-            compressor: Compress::new(level, false),
-            buffer: ByteBuffer::with_capacity(super::BUFFER_SIZE),
+        DeflateEncoder {
+            inner: self.inner,
+            compressor: Compress::new(level, self.is_zlib),
+            buffer: ByteBuffer::with_capacity(self.buffer_size),
             input_buffer: Bytes::new(),
             state: EncoderState::Reading,
         }
     }
+}
+
+impl<T> DeflateEncoder<T> {
+    pub fn new(inner: T) -> Self {
+        Self::builder(inner).build()
+    }
+
+    pub fn builder(inner: T) -> DeflateEncoderBuilder<T> {
+        DeflateEncoderBuilder {
+            inner,
+            is_zlib: false,
+            buffer_size: super::BUFFER_SIZE,
+            level: Level::Default,
+        }
+    }
+
+    pub fn with_quality(inner: T, level: Level) -> Self {
+        Self::builder(inner).level(level).build()
+    }
 
     pub fn total_in(&self) -> u64 {
         self.compressor.total_in()
-- 
2.39.2

[pbs-devel] [PATCH proxmox v3 3/5] compression: deflate: add a decoder

[Maximiliano Sandoval]

Signed-off-by: Maximiliano Sandoval <m.sandoval@proxmox.com>
---
 .../src/deflate/decompression.rs              | 141 ++++++++++++++++++
 proxmox-compression/src/deflate/mod.rs        |   2 +
 proxmox-compression/src/lib.rs                |   2 +-
 3 files changed, 144 insertions(+), 1 deletion(-)
 create mode 100644 proxmox-compression/src/deflate/decompression.rs

diff --git a/proxmox-compression/src/deflate/decompression.rs b/proxmox-compression/src/deflate/decompression.rs
new file mode 100644
index 00000000..45ed8579
--- /dev/null
+++ b/proxmox-compression/src/deflate/decompression.rs
@@ -0,0 +1,141 @@
+use std::io;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+
+use anyhow::Error;
+use bytes::Bytes;
+use flate2::{Decompress, FlushDecompress};
+use futures::ready;
+use futures::stream::Stream;
+
+use proxmox_io::ByteBuffer;
+
+#[derive(Eq, PartialEq)]
+enum DecoderState {
+    Reading,
+    Writing,
+    Flushing,
+    Finished,
+}
+
+pub struct DeflateDecoder<T> {
+    inner: T,
+    decompressor: Decompress,
+    buffer: ByteBuffer,
+    input_buffer: Bytes,
+    state: DecoderState,
+}
+
+pub struct DeflateDecoderBuilder<T> {
+    inner: T,
+    is_zlib: bool,
+    buffer_size: usize,
+}
+
+impl<T> DeflateDecoderBuilder<T> {
+    pub fn zlib(mut self, is_zlib: bool) -> Self {
+        self.is_zlib = is_zlib;
+        self
+    }
+
+    pub fn buffer_size(mut self, buffer_size: usize) -> Self {
+        self.buffer_size = buffer_size;
+        self
+    }
+
+    pub fn build(self) -> DeflateDecoder<T> {
+        DeflateDecoder {
+            inner: self.inner,
+            decompressor: Decompress::new(self.is_zlib),
+            buffer: ByteBuffer::with_capacity(self.buffer_size),
+            input_buffer: Bytes::new(),
+            state: DecoderState::Reading,
+        }
+    }
+}
+
+impl<T> DeflateDecoder<T> {
+    pub fn new(inner: T) -> Self {
+        Self::builder(inner).build()
+    }
+
+    pub fn builder(inner: T) -> DeflateDecoderBuilder<T> {
+        DeflateDecoderBuilder {
+            inner,
+            is_zlib: false,
+            buffer_size: super::BUFFER_SIZE,
+        }
+    }
+
+    fn decode(
+        &mut self,
+        inbuf: &[u8],
+        flush: FlushDecompress,
+    ) -> Result<(usize, flate2::Status), io::Error> {
+        let old_in = self.decompressor.total_in();
+        let old_out = self.decompressor.total_out();
+        let res = self
+            .decompressor
+            .decompress(inbuf, self.buffer.get_free_mut_slice(), flush)?;
+        let new_in = (self.decompressor.total_in() - old_in) as usize;
+        let new_out = (self.decompressor.total_out() - old_out) as usize;
+        self.buffer.add_size(new_out);
+
+        Ok((new_in, res))
+    }
+}
+
+impl<T, O, E> Stream for DeflateDecoder<T>
+where
+    T: Stream<Item = Result<O, E>> + Unpin,
+    O: Into<Bytes>,
+    E: Into<Error>,
+{
+    type Item = Result<Bytes, anyhow::Error>;
+
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        let this = self.get_mut();
+
+        loop {
+            match this.state {
+                DecoderState::Reading => {
+                    if let Some(res) = ready!(Pin::new(&mut this.inner).poll_next(cx)) {
+                        let buf = res.map_err(Into::into)?;
+                        this.input_buffer = buf.into();
+                        this.state = DecoderState::Writing;
+                    } else {
+                        this.state = DecoderState::Flushing;
+                    }
+                }
+                DecoderState::Writing => {
+                    if this.input_buffer.is_empty() {
+                        return Poll::Ready(Some(Err(anyhow::format_err!(
+                            "empty input during write"
+                        ))));
+                    }
+                    let mut buf = this.input_buffer.split_off(0);
+                    let (read, res) = this.decode(&buf[..], FlushDecompress::None)?;
+                    this.input_buffer = buf.split_off(read);
+                    if this.input_buffer.is_empty() {
+                        this.state = DecoderState::Reading;
+                    }
+                    if this.buffer.is_full() || res == flate2::Status::BufError {
+                        let bytes = this.buffer.remove_data(this.buffer.len()).to_vec();
+                        return Poll::Ready(Some(Ok(bytes.into())));
+                    }
+                }
+                DecoderState::Flushing => {
+                    let (_read, res) = this.decode(&[][..], FlushDecompress::Finish)?;
+                    if !this.buffer.is_empty() {
+                        let bytes = this.buffer.remove_data(this.buffer.len()).to_vec();
+                        return Poll::Ready(Some(Ok(bytes.into())));
+                    }
+                    if res == flate2::Status::StreamEnd {
+                        this.state = DecoderState::Finished;
+                    }
+                }
+                DecoderState::Finished => return Poll::Ready(None),
+            }
+        }
+    }
+}
diff --git a/proxmox-compression/src/deflate/mod.rs b/proxmox-compression/src/deflate/mod.rs
index 514ccbdc..6867176c 100644
--- a/proxmox-compression/src/deflate/mod.rs
+++ b/proxmox-compression/src/deflate/mod.rs
@@ -1,5 +1,7 @@
 mod compression;
+mod decompression;
 
 pub use compression::{DeflateEncoder, Level};
+pub use decompression::DeflateDecoder;
 
 const BUFFER_SIZE: usize = 8192;
diff --git a/proxmox-compression/src/lib.rs b/proxmox-compression/src/lib.rs
index 239de623..f33212e5 100644
--- a/proxmox-compression/src/lib.rs
+++ b/proxmox-compression/src/lib.rs
@@ -1,4 +1,4 @@
-pub use deflate::{DeflateEncoder, Level};
+pub use deflate::{DeflateDecoder, DeflateEncoder, Level};
 
 pub(crate) mod deflate;
 pub mod tar;
-- 
2.39.2

[pbs-devel] [PATCH proxmox v3 4/5] compression: deflate: add test module

[Maximiliano Sandoval]

We test the deflate encoder against the deflate decoder using (or not)
zlib and with different small buffer sizes. We also test compression and
decompression against the flate2 crate.

Signed-off-by: Maximiliano Sandoval <m.sandoval@proxmox.com>
---
 proxmox-compression/Cargo.toml         |   3 +-
 proxmox-compression/src/deflate/mod.rs | 160 +++++++++++++++++++++++++
 2 files changed, 161 insertions(+), 2 deletions(-)

diff --git a/proxmox-compression/Cargo.toml b/proxmox-compression/Cargo.toml
index 49735cbe..3879ed16 100644
--- a/proxmox-compression/Cargo.toml
+++ b/proxmox-compression/Cargo.toml
@@ -27,5 +27,4 @@ proxmox-io = { workspace = true, features = [ "tokio" ] }
 proxmox-lang.workspace = true
 
 [dev-dependencies]
-tokio = { workspace = true, features = [ "macros" ] }
-
+tokio = { workspace = true, features = [ "macros", "rt-multi-thread" ] }
diff --git a/proxmox-compression/src/deflate/mod.rs b/proxmox-compression/src/deflate/mod.rs
index 6867176c..94faabb3 100644
--- a/proxmox-compression/src/deflate/mod.rs
+++ b/proxmox-compression/src/deflate/mod.rs
@@ -5,3 +5,163 @@ pub use compression::{DeflateEncoder, Level};
 pub use decompression::DeflateDecoder;
 
 const BUFFER_SIZE: usize = 8192;
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    use std::io::Write;
+
+    use flate2::Compression;
+    use futures::StreamExt;
+
+    const BUFFER_SIZE: usize = 25;
+    const BODY: &str = r#"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do
+eiusmod tempor incididunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut
+enim aeque doleamus animo, cum corpore dolemus, fieri tamen permagna accessio potest,
+si aliquod aeternum et infinitum impendere."#;
+
+    fn chunker(content: &[u8]) -> Vec<Result<Vec<u8>, std::io::Error>> {
+        vec![
+            Ok(content[..10].to_vec()),
+            Ok(content[10..20].to_vec()),
+            Ok(content[20..30].to_vec()),
+            Ok(content[30..40].to_vec()),
+            Ok(content[40..].to_vec()),
+        ]
+    }
+
+    #[tokio::test]
+    async fn test_encoder_against_decoder() {
+        // We use mixed sizes for the buffers, on the next test we invert the
+        // sizes.
+        let stream = futures::stream::iter(chunker(BODY.as_bytes()));
+        let encoder = DeflateEncoder::builder(stream)
+            .buffer_size(BUFFER_SIZE * 2)
+            .build();
+        let mut decoder = DeflateDecoder::builder(encoder)
+            .buffer_size(BUFFER_SIZE)
+            .build();
+
+        let mut buf = Vec::with_capacity(BODY.len());
+        while let Some(Ok(res)) = decoder.next().await {
+            buf.write_all(&res).unwrap();
+        }
+
+        assert_eq!(buf, BODY.as_bytes());
+    }
+
+    #[tokio::test]
+    async fn test_zlib_encoder_against_decoder() {
+        let stream = futures::stream::iter(chunker(BODY.as_bytes()));
+        let encoder = DeflateEncoder::builder(stream)
+            .zlib(true)
+            .buffer_size(BUFFER_SIZE)
+            .build();
+        let mut decoder = DeflateDecoder::builder(encoder)
+            .zlib(true)
+            .buffer_size(BUFFER_SIZE * 2)
+            .build();
+
+        let mut buf = Vec::with_capacity(BODY.len());
+        while let Some(Ok(res)) = decoder.next().await {
+            buf.write_all(&res).unwrap();
+        }
+
+        assert_eq!(buf, BODY.as_bytes());
+    }
+
+    #[tokio::test]
+    async fn test_deflate_decompression_against_flate2() {
+        let encoded = flate2_encode(BODY.as_bytes(), false).unwrap();
+        let decoded = decode(&encoded, false, 7).await.unwrap();
+
+        assert_eq!(decoded, BODY.as_bytes());
+    }
+
+    #[tokio::test]
+    async fn test_zlib_decompression_against_flate2() {
+        let encoded = flate2_encode(BODY.as_bytes(), true).unwrap();
+        let decoded = decode(&encoded, true, 4).await.unwrap();
+
+        assert_eq!(decoded, BODY.as_bytes());
+    }
+
+    #[tokio::test]
+    async fn test_deflate_compression_against_flate2() {
+        let encoded = encode(BODY.as_bytes(), false, 5).await.unwrap();
+        let decoded = flate2_decode(&encoded, false).unwrap();
+
+        assert_eq!(decoded, BODY.as_bytes());
+    }
+
+    #[tokio::test]
+    async fn test_zlib_compression_against_flate2() {
+        let encoded = encode(BODY.as_bytes(), true, 3).await.unwrap();
+        let decoded = flate2_decode(&encoded, true).unwrap();
+
+        assert_eq!(decoded, BODY.as_bytes());
+    }
+
+    fn flate2_encode(bytes: &[u8], is_zlib: bool) -> Result<Vec<u8>, std::io::Error> {
+        if is_zlib {
+            let mut e = flate2::write::ZlibEncoder::new(Vec::new(), Compression::default());
+            e.write_all(bytes).unwrap();
+            e.finish()
+        } else {
+            let mut e = flate2::write::DeflateEncoder::new(Vec::new(), Compression::default());
+            e.write_all(bytes).unwrap();
+            e.finish()
+        }
+    }
+
+    fn flate2_decode(bytes: &[u8], is_zlib: bool) -> Result<Vec<u8>, std::io::Error> {
+        if is_zlib {
+            let mut e = flate2::write::ZlibDecoder::new(Vec::new());
+            e.write_all(bytes).unwrap();
+            e.finish()
+        } else {
+            let mut e = flate2::write::DeflateDecoder::new(Vec::new());
+            e.write_all(bytes).unwrap();
+            e.finish()
+        }
+    }
+
+    async fn decode(
+        content: &[u8],
+        is_zlib: bool,
+        buffer_size: usize,
+    ) -> Result<Vec<u8>, std::io::Error> {
+        let stream = futures::stream::iter(chunker(content));
+        let mut decoder = DeflateDecoder::builder(stream)
+            .zlib(is_zlib)
+            .buffer_size(buffer_size)
+            .build();
+        let mut buf = Vec::new();
+
+        while let Some(Ok(res)) = decoder.next().await {
+            buf.write_all(&res)?;
+        }
+
+        Ok(buf)
+    }
+
+    async fn encode(
+        content: &[u8],
+        is_zlib: bool,
+        buffer_size: usize,
+    ) -> Result<Vec<u8>, std::io::Error> {
+        let stream = futures::stream::iter(chunker(content));
+        let mut encoder = DeflateEncoder::builder(stream)
+            .zlib(is_zlib)
+            .buffer_size(buffer_size)
+            .build();
+        let mut buf = Vec::with_capacity(BODY.len());
+
+        while let Some(Ok(res)) = encoder.next().await {
+            buf.write_all(&res)?;
+        }
+
+        Ok(buf)
+    }
+}
-- 
2.39.2

[pbs-devel] [PATCH proxmox v3 5/5] http: teach the Client how to decode deflate content

[Maximiliano Sandoval]

The Backup Server can compress the content using deflate so we teach the
client how to decode it.

If a request is sent with the `Accept-Encoding` [2] header set to
`deflate`, and the response's `Content-Encoding` [1] header is equal to
`deflate` we wrap the Body stream with a stream that can decode `zlib`
on the run.

Note that from the `Accept-Encoding` docs [2], the `deflate` encoding is
actually `zlib`.

This can be also tested against
http://eu.httpbin.org/#/Response_formats/get_deflate by adding the
following test:

```rust
    #[tokio::test]
    async fn test_client() {
        let client = Client::new();
        let headers = HashMap::from([(
            hyper::header::ACCEPT_ENCODING.to_string(),
            "deflate".to_string(),
        )]);
        let response = client
            .get_string("https://eu.httpbin.org/deflate", Some(&headers))
            .await;
        assert!(response.is_ok());
    }
```

at `proxmox-http/src/client/simple.rs` and running

```
cargo test --features=client,client-trait
```

[1] https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Encoding
[2] https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept-Encoding

Suggested-by: Lukas Wagner <l.wagner@proxmox.com>
Signed-off-by: Maximiliano Sandoval <m.sandoval@proxmox.com>
---
 proxmox-http/Cargo.toml           |  7 ++++
 proxmox-http/src/client/simple.rs | 65 ++++++++++++++++++++++++++++++-
 2 files changed, 71 insertions(+), 1 deletion(-)

diff --git a/proxmox-http/Cargo.toml b/proxmox-http/Cargo.toml
index 9ece24eb..4455ba85 100644
--- a/proxmox-http/Cargo.toml
+++ b/proxmox-http/Cargo.toml
@@ -26,6 +26,11 @@ proxmox-async = { workspace = true, optional = true }
 proxmox-sys = { workspace = true, optional = true }
 proxmox-io = { workspace = true, optional = true }
 proxmox-lang = { workspace = true, optional = true }
+proxmox-compression = { workspace = true, optional = true }
+
+[dev-dependencies]
+tokio = { workspace = true, features = [ "macros" ] }
+flate2 = { workspace = true }
 
 [features]
 default = []
@@ -42,12 +47,14 @@ client = [
     "dep:futures",
     "dep:hyper",
     "dep:openssl",
+    "dep:proxmox-compression",
     "dep:tokio",
     "dep:tokio-openssl",
     "http-helpers",
     "hyper?/client",
     "hyper?/http1",
     "hyper?/http2",
+    "hyper?/stream",
     "hyper?/tcp",
     "rate-limited-stream",
     "tokio?/io-util",
diff --git a/proxmox-http/src/client/simple.rs b/proxmox-http/src/client/simple.rs
index e9910802..062889ac 100644
--- a/proxmox-http/src/client/simple.rs
+++ b/proxmox-http/src/client/simple.rs
@@ -78,7 +78,8 @@ impl Client {
 
         self.add_proxy_headers(&mut request)?;
 
-        self.client.request(request).map_err(Error::from).await
+        let encoded_response = self.client.request(request).map_err(Error::from).await?;
+        decode_response(encoded_response).await
     }
 
     pub async fn post(
@@ -245,3 +246,65 @@ impl crate::HttpClient<String, String> for Client {
         })
     }
 }
+
+/// Wraps the `Body` stream in a DeflateDecoder stream if the `Content-Encoding`
+/// header of the response is `deflate`, otherwise returns the original
+/// response.
+async fn decode_response(mut res: Response<Body>) -> Result<Response<Body>, Error> {
+    let Some(content_encoding) = res.headers_mut().remove(&hyper::header::CONTENT_ENCODING) else {
+        return Ok(res);
+    };
+
+    let encodings = content_encoding.to_str()?;
+    if encodings == "deflate" {
+        let (parts, body) = res.into_parts();
+        let decoder = proxmox_compression::DeflateDecoder::builder(body)
+            .zlib(true)
+            .build();
+        let decoded_body = Body::wrap_stream(decoder);
+        Ok(Response::from_parts(parts, decoded_body))
+    } else {
+        bail!("Unknown encoding format: {encodings}");
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    use std::io::Write;
+
+    const BODY: &str = r#"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do
+eiusmod tempor incididunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut
+enim aeque doleamus animo, cum corpore dolemus, fieri tamen permagna accessio potest,
+si aliquod aeternum et infinitum impendere."#;
+
+    #[tokio::test]
+    async fn test_parse_response_deflate() {
+        let encoded = encode_deflate(BODY.as_bytes()).unwrap();
+        let encoded_body = Body::from(encoded);
+        let encoded_response = Response::builder()
+            .header(hyper::header::CONTENT_ENCODING, "deflate")
+            .body(encoded_body)
+            .unwrap();
+
+        let decoded_response = decode_response(encoded_response).await.unwrap();
+
+        assert_eq!(
+            Client::response_body_string(decoded_response)
+                .await
+                .unwrap(),
+            BODY
+        );
+    }
+
+    fn encode_deflate(bytes: &[u8]) -> Result<Vec<u8>, std::io::Error> {
+        use flate2::write::ZlibEncoder;
+        use flate2::Compression;
+
+        let mut e = ZlibEncoder::new(Vec::new(), Compression::default());
+        e.write_all(bytes).unwrap();
+
+        e.finish()
+    }
+}
-- 
2.39.2