Add webocket frame header

src/websocket/mod.rs

@@ -1,3 +1,61 @@
 mod handler;
 
 pub use handler::*;
+use crate::http::Stream;
+use crate::error::Error;
+
+pub struct FrameHeader {
+    fin: bool,
+    rsv1: bool,
+    rsv2: bool,
+    rsv3: bool,
+    opcode: u8,
+    mask: bool,
+    payload_len: u8,
+    ex_payload_len: Option<u64>,
+    masking_key: Option<u32>,
+}
+
+impl FrameHeader {
+    pub fn from(socket: &mut Stream) -> Result<Self, Error> {
+        let mut data = [0u8; 2];
+        socket.read_exact(&mut data)?;
+
+        let mut header = FrameHeader {
+            fin: data[0] & 0x80 != 0,
+            rsv1: data[0] & 0x40 != 0,
+            rsv2: data[0] & 0x20 != 0,
+            rsv3: data[0] & 0x10 != 0,
+            opcode: data[0] & 0x0F,
+            mask: data[1] & 0x80 != 0,
+            payload_len: data[1] & 0x7F,
+            ex_payload_len: None,
+            masking_key: None,
+        };
+
+        if header.payload_len == 126 {
+            let mut data = [0u8; 2];
+            socket.read_exact(&mut data)?;
+            header.ex_payload_len = Some(u16::from_be_bytes(data) as u64);
+        } else if header.payload_len == 127 {
+            let mut data = [0u8; 8];
+            socket.read_exact(&mut data)?;
+            header.ex_payload_len = Some(u64::from_be_bytes(data));
+        }
+
+        if header.mask {
+            let mut data =[0u8; 4];
+            socket.read_exact(&mut data)?;
+            header.masking_key = Some(u32::from_be_bytes(data));
+        }
+
+        Ok(header)
+    }
+
+    pub fn payload_len(&self) -> u64 {
+        match self.ex_payload_len {
+            Some(val) => val,
+            None => self.payload_len as u64,
+        }
+    }
+}