specters 4.2.0

Rust HTTP client with browser-like Chrome and Firefox fingerprints across TLS, HTTP/1.1, HTTP/2, HTTP/3, and WebSockets
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146

use bytes::Bytes;
use std::sync::atomic::{AtomicUsize, Ordering};
use std::sync::Arc;
use tokio::sync::mpsc;
use tokio::sync::Notify;

use crate::error::{Error, Result};

/// Outbound bytes queued by an RFC 8441 tunnel handle for the H2 driver.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct H2TunnelOutbound {
    pub bytes: Bytes,
    pub end_stream: bool,
}

/// Inbound tunnel event delivered by the H2 driver to the tunnel handle.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum H2TunnelEvent {
    Data(Bytes),
    EndStream,
    Reset(String),
    GoAway { last_stream_id: u32 },
}

const MAX_RELEASE_NOTIFY_BYTES: usize = 512 * 1024;

#[derive(Debug)]
pub(crate) struct H2TunnelCredit {
    released_recv_bytes: AtomicUsize,
    release_notify_bytes: usize,
    driver_notify: Arc<Notify>,
}

impl H2TunnelCredit {
    pub(crate) fn new(driver_notify: Arc<Notify>, initial_window_size: u32) -> Arc<Self> {
        let release_notify_bytes =
            ((initial_window_size as usize) / 4).clamp(1, MAX_RELEASE_NOTIFY_BYTES);
        Arc::new(Self {
            released_recv_bytes: AtomicUsize::new(0),
            release_notify_bytes,
            driver_notify,
        })
    }

    pub(crate) fn take_released_recv_bytes(&self) -> usize {
        self.released_recv_bytes.swap(0, Ordering::Relaxed)
    }
}

/// Byte transport for an RFC 8441 tunnel stream.
#[derive(Debug)]
pub struct H2Tunnel {
    outbound_tx: mpsc::Sender<H2TunnelOutbound>,
    inbound_rx: mpsc::Receiver<Result<H2TunnelEvent>>,
    credit: Option<Arc<H2TunnelCredit>>,
    pending_release_bytes: usize,
}

impl H2Tunnel {
    pub fn new(
        outbound_tx: mpsc::Sender<H2TunnelOutbound>,
        inbound_rx: mpsc::Receiver<Result<H2TunnelEvent>>,
    ) -> Self {
        Self {
            outbound_tx,
            inbound_rx,
            credit: None,
            pending_release_bytes: 0,
        }
    }

    pub(crate) fn new_with_credit(
        outbound_tx: mpsc::Sender<H2TunnelOutbound>,
        inbound_rx: mpsc::Receiver<Result<H2TunnelEvent>>,
        credit: Arc<H2TunnelCredit>,
    ) -> Self {
        Self {
            outbound_tx,
            inbound_rx,
            credit: Some(credit),
            pending_release_bytes: 0,
        }
    }

    pub async fn send_bytes(&self, bytes: Bytes, end_stream: bool) -> Result<()> {
        self.outbound_tx
            .send(H2TunnelOutbound { bytes, end_stream })
            .await
            .map_err(|_| Error::HttpProtocol("H2 tunnel outbound channel closed".into()))
    }

    pub async fn close_send(&self) -> Result<()> {
        self.send_bytes(Bytes::new(), true).await
    }

    pub async fn recv_event(&mut self) -> Option<Result<H2TunnelEvent>> {
        let event = self.inbound_rx.recv().await?;
        if let Ok(H2TunnelEvent::Data(bytes)) = &event {
            self.release_recv_bytes(bytes.len());
        }
        Some(event)
    }

    pub async fn recv_bytes(&mut self) -> Option<Result<Bytes>> {
        match self.recv_event().await? {
            Ok(H2TunnelEvent::Data(bytes)) => Some(Ok(bytes)),
            Ok(H2TunnelEvent::EndStream) => None,
            Ok(H2TunnelEvent::Reset(reason)) => Some(Err(Error::HttpProtocol(format!(
                "H2 tunnel reset: {reason}"
            )))),
            Ok(H2TunnelEvent::GoAway { last_stream_id }) => Some(Err(Error::HttpProtocol(
                format!("H2 tunnel closed by GOAWAY last_stream_id={last_stream_id}"),
            ))),
            Err(err) => Some(Err(err)),
        }
    }

    fn release_recv_bytes(&mut self, released: usize) {
        let Some(credit) = self.credit.as_ref() else {
            return;
        };
        self.pending_release_bytes = self.pending_release_bytes.saturating_add(released);
        if self.pending_release_bytes >= credit.release_notify_bytes {
            let released = std::mem::take(&mut self.pending_release_bytes);
            credit
                .released_recv_bytes
                .fetch_add(released, Ordering::Relaxed);
            credit.driver_notify.notify_one();
        }
    }
}

impl Drop for H2Tunnel {
    fn drop(&mut self) {
        let Some(credit) = self.credit.as_ref() else {
            return;
        };
        if self.pending_release_bytes > 0 {
            let released = std::mem::take(&mut self.pending_release_bytes);
            credit
                .released_recv_bytes
                .fetch_add(released, Ordering::Relaxed);
        }
        credit.driver_notify.notify_one();
    }
}