# nahpack

nahpack is an [RFC 7541 HPACK](https://www.rfc-editor.org/rfc/rfc7541.txt)
encoder and decoder library.

It compresses, decompresses, and validates
an [HTTP/2](https://www.rfc-editor.org/rfc/rfc7540.txt) "header block"
as contained in HEADERS, PUSH PROMISE, and CONTINUATION frames.

It is fully compatible with implementations submitted to the
[hpack-test-case repository](https://github.com/http2jp/hpack-test-case).


## Usage

This example decodes the C.3 case given in the
[HPACK RFC](https://www.rfc-editor.org/rfc/rfc7541.txt).

```rust
use nahpack::{decode_block, HpackContext, Headers};

let mut context = HpackContext::new();

{
    // first request
    let block = b"\x82\x86\x84A\x0fwww.example.com";
    let mut headers = Headers::new(block);
    match decode_block(&mut context, &mut headers) {
        Ok(_) => { },
        Err(_) => { }
    }
}
{
    // second request
    let block = b"\x82\x86\x84\xbe\x58\x08no-cache";
    let mut headers = Headers::new(block);
    match decode_block(&mut context, &mut headers) {
        Ok(_) => { },
        Err(_) => { }
    }
}
{
    // third request
    let block = b"\x82\x87\x85\xbf@\x88%\xa8I\xe9[\xa9}\x7f\x89%\xa8I\xe9[\xb8\xe8\xb4\xbf";
    let mut headers = Headers::new(block);
    match decode_block(&mut context, &mut headers) {
        Ok(_) => { },
        Err(_) => { }
    }
}
```

This example implements encoding of an `HpackEncodable` struct.

```rust
use nahpack::{encode_block, HpackEncodable, HpackContext};

struct Header {
    name: &'static [u8],
    value: &'static [u8],
    is_compressable: bool,
}

impl HpackEncodable for Header {

    fn name(&self) -> &'static [u8] { self.name }
    fn value(&self) -> &'static [u8] { self.value }
    fn is_compressable(&self) -> bool { self.is_compressable.clone() }

}

let headers = vec![
    Header { name: b":method", value: b"GET", is_compressable: true },
    Header { name: b":scheme", value: b"http", is_compressable: true },
    Header { name: b":path", value: b"/", is_compressable: true },
    Header { name: b":authority", value: b"www.example.com", is_compressable: true },
];

let mut context = HpackContext::new();
let mut writer: Vec<u8> = Vec::new();

let num_bytes = encode_block(&mut writer, &headers, &mut context, 0);

```


## Misc

nahpack is licensed under the
[Mozilla Public License, Version 2.0](https://www.mozilla.org/MPL/2.0/).

The author's repository is https://github.com/ijl/nahpack, and the
repository's commmits are signed with the below key of ijl@mailbox.org:

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```