Merge pull request #15123 from truemedian/http-server

std.http: add http server

1 files changed, 842 insertions, 0 deletions

diff --git a/lib/std/http/protocol.zig b/lib/std/http/protocol.zig
new file mode 100644
index 0000000000..5e63d3092b
--- /dev/null
+++ b/lib/std/http/protocol.zig
@@ -0,0 +1,842 @@
+const std = @import("std");
+const testing = std.testing;
+const mem = std.mem;
+
+const assert = std.debug.assert;
+
+pub const State = enum {
+    /// Begin header parsing states.
+    invalid,
+    start,
+    seen_n,
+    seen_r,
+    seen_rn,
+    seen_rnr,
+    finished,
+    /// Begin transfer-encoding: chunked parsing states.
+    chunk_head_size,
+    chunk_head_ext,
+    chunk_head_r,
+    chunk_data,
+    chunk_data_suffix,
+    chunk_data_suffix_r,
+
+    /// Returns true if the parser is in a content state (ie. not waiting for more headers).
+    pub fn isContent(self: State) bool {
+        return switch (self) {
+            .invalid, .start, .seen_n, .seen_r, .seen_rn, .seen_rnr => false,
+            .finished, .chunk_head_size, .chunk_head_ext, .chunk_head_r, .chunk_data, .chunk_data_suffix, .chunk_data_suffix_r => true,
+        };
+    }
+};
+
+pub const HeadersParser = struct {
+    state: State = .start,
+    /// Whether or not `header_bytes` is allocated or was provided as a fixed buffer.
+    header_bytes_owned: bool,
+    /// Either a fixed buffer of len `max_header_bytes` or a dynamic buffer that can grow up to `max_header_bytes`.
+    /// Pointers into this buffer are not stable until after a message is complete.
+    header_bytes: std.ArrayListUnmanaged(u8),
+    /// The maximum allowed size of `header_bytes`.
+    max_header_bytes: usize,
+    next_chunk_length: u64 = 0,
+    /// Whether this parser is done parsing a complete message.
+    /// A message is only done when the entire payload has been read.
+    done: bool = false,
+
+    /// Initializes the parser with a dynamically growing header buffer of up to `max` bytes.
+    pub fn initDynamic(max: usize) HeadersParser {
+        return .{
+            .header_bytes = .{},
+            .max_header_bytes = max,
+            .header_bytes_owned = true,
+        };
+    }
+
+    /// Initializes the parser with a provided buffer `buf`.
+    pub fn initStatic(buf: []u8) HeadersParser {
+        return .{
+            .header_bytes = .{ .items = buf[0..0], .capacity = buf.len },
+            .max_header_bytes = buf.len,
+            .header_bytes_owned = false,
+        };
+    }
+
+    /// Completely resets the parser to it's initial state.
+    /// This must be called after a message is complete.
+    pub fn reset(r: *HeadersParser) void {
+        assert(r.done); // The message must be completely read before reset, otherwise the parser is in an invalid state.
+
+        r.header_bytes.clearRetainingCapacity();
+
+        r.* = .{
+            .header_bytes = r.header_bytes,
+            .max_header_bytes = r.max_header_bytes,
+            .header_bytes_owned = r.header_bytes_owned,
+        };
+    }
+
+    /// Returns the number of bytes consumed by headers. This is always less than or equal to `bytes.len`.
+    /// You should check `r.state.isContent()` after this to check if the headers are done.
+    ///
+    /// If the amount returned is less than `bytes.len`, you may assume that the parser is in a content state and the
+    /// first byte of content is located at `bytes[result]`.
+    pub fn findHeadersEnd(r: *HeadersParser, bytes: []const u8) u32 {
+        const vector_len: comptime_int = comptime std.math.max(std.simd.suggestVectorSize(u8) orelse 1, 8);
+        const len = @intCast(u32, bytes.len);
+        var index: u32 = 0;
+
+        while (true) {
+            switch (r.state) {
+                .invalid => unreachable,
+                .finished => return index,
+                .start => switch (len - index) {
+                    0 => return index,
+                    1 => {
+                        switch (bytes[index]) {
+                            '\r' => r.state = .seen_r,
+                            '\n' => r.state = .seen_n,
+                            else => {},
+                        }
+
+                        return index + 1;
+                    },
+                    2 => {
+                        const b16 = int16(bytes[index..][0..2]);
+                        const b8 = intShift(u8, b16);
+
+                        switch (b8) {
+                            '\r' => r.state = .seen_r,
+                            '\n' => r.state = .seen_n,
+                            else => {},
+                        }
+
+                        switch (b16) {
+                            int16("\r\n") => r.state = .seen_rn,
+                            int16("\n\n") => r.state = .finished,
+                            else => {},
+                        }
+
+                        return index + 2;
+                    },
+                    3 => {
+                        const b24 = int24(bytes[index..][0..3]);
+                        const b16 = intShift(u16, b24);
+                        const b8 = intShift(u8, b24);
+
+                        switch (b8) {
+                            '\r' => r.state = .seen_r,
+                            '\n' => r.state = .seen_n,
+                            else => {},
+                        }
+
+                        switch (b16) {
+                            int16("\r\n") => r.state = .seen_rn,
+                            int16("\n\n") => r.state = .finished,
+                            else => {},
+                        }
+
+                        switch (b24) {
+                            int24("\r\n\r") => r.state = .seen_rnr,
+                            else => {},
+                        }
+
+                        return index + 3;
+                    },
+                    4...vector_len - 1 => {
+                        const b32 = int32(bytes[index..][0..4]);
+                        const b24 = intShift(u24, b32);
+                        const b16 = intShift(u16, b32);
+                        const b8 = intShift(u8, b32);
+
+                        switch (b8) {
+                            '\r' => r.state = .seen_r,
+                            '\n' => r.state = .seen_n,
+                            else => {},
+                        }
+
+                        switch (b16) {
+                            int16("\r\n") => r.state = .seen_rn,
+                            int16("\n\n") => r.state = .finished,
+                            else => {},
+                        }
+
+                        switch (b24) {
+                            int24("\r\n\r") => r.state = .seen_rnr,
+                            else => {},
+                        }
+
+                        switch (b32) {
+                            int32("\r\n\r\n") => r.state = .finished,
+                            else => {},
+                        }
+
+                        index += 4;
+                        continue;
+                    },
+                    else => {
+                        const Vector = @Vector(vector_len, u8);
+                        // const BoolVector = @Vector(vector_len, bool);
+                        const BitVector = @Vector(vector_len, u1);
+                        const SizeVector = @Vector(vector_len, u8);
+
+                        const chunk = bytes[index..][0..vector_len];
+                        const v: Vector = chunk.*;
+                        const matches_r = @bitCast(BitVector, v == @splat(vector_len, @as(u8, '\r')));
+                        const matches_n = @bitCast(BitVector, v == @splat(vector_len, @as(u8, '\n')));
+                        const matches_or: SizeVector = matches_r | matches_n;
+
+                        const matches = @reduce(.Add, matches_or);
+                        switch (matches) {
+                            0 => {},
+                            1 => switch (chunk[vector_len - 1]) {
+                                '\r' => r.state = .seen_r,
+                                '\n' => r.state = .seen_n,
+                                else => {},
+                            },
+                            2 => {
+                                const b16 = int16(chunk[vector_len - 2 ..][0..2]);
+                                const b8 = intShift(u8, b16);
+
+                                switch (b8) {
+                                    '\r' => r.state = .seen_r,
+                                    '\n' => r.state = .seen_n,
+                                    else => {},
+                                }
+
+                                switch (b16) {
+                                    int16("\r\n") => r.state = .seen_rn,
+                                    int16("\n\n") => r.state = .finished,
+                                    else => {},
+                                }
+                            },
+                            3 => {
+                                const b24 = int24(chunk[vector_len - 3 ..][0..3]);
+                                const b16 = intShift(u16, b24);
+                                const b8 = intShift(u8, b24);
+
+                                switch (b8) {
+                                    '\r' => r.state = .seen_r,
+                                    '\n' => r.state = .seen_n,
+                                    else => {},
+                                }
+
+                                switch (b16) {
+                                    int16("\r\n") => r.state = .seen_rn,
+                                    int16("\n\n") => r.state = .finished,
+                                    else => {},
+                                }
+
+                                switch (b24) {
+                                    int24("\r\n\r") => r.state = .seen_rnr,
+                                    else => {},
+                                }
+                            },
+                            4...vector_len => {
+                                inline for (0..vector_len - 3) |i_usize| {
+                                    const i = @truncate(u32, i_usize);
+
+                                    const b32 = int32(chunk[i..][0..4]);
+                                    const b16 = intShift(u16, b32);
+
+                                    if (b32 == int32("\r\n\r\n")) {
+                                        r.state = .finished;
+                                        return index + i + 4;
+                                    } else if (b16 == int16("\n\n")) {
+                                        r.state = .finished;
+                                        return index + i + 2;
+                                    }
+                                }
+
+                                const b24 = int24(chunk[vector_len - 3 ..][0..3]);
+                                const b16 = intShift(u16, b24);
+                                const b8 = intShift(u8, b24);
+
+                                switch (b8) {
+                                    '\r' => r.state = .seen_r,
+                                    '\n' => r.state = .seen_n,
+                                    else => {},
+                                }
+
+                                switch (b16) {
+                                    int16("\r\n") => r.state = .seen_rn,
+                                    int16("\n\n") => r.state = .finished,
+                                    else => {},
+                                }
+
+                                switch (b24) {
+                                    int24("\r\n\r") => r.state = .seen_rnr,
+                                    else => {},
+                                }
+                            },
+                            else => unreachable,
+                        }
+
+                        index += vector_len;
+                        continue;
+                    },
+                },
+                .seen_n => switch (len - index) {
+                    0 => return index,
+                    else => {
+                        switch (bytes[index]) {
+                            '\n' => r.state = .finished,
+                            else => r.state = .start,
+                        }
+
+                        index += 1;
+                        continue;
+                    },
+                },
+                .seen_r => switch (len - index) {
+                    0 => return index,
+                    1 => {
+                        switch (bytes[index]) {
+                            '\n' => r.state = .seen_rn,
+                            '\r' => r.state = .seen_r,
+                            else => r.state = .start,
+                        }
+
+                        return index + 1;
+                    },
+                    2 => {
+                        const b16 = int16(bytes[index..][0..2]);
+                        const b8 = intShift(u8, b16);
+
+                        switch (b8) {
+                            '\r' => r.state = .seen_r,
+                            '\n' => r.state = .seen_rn,
+                            else => r.state = .start,
+                        }
+
+                        switch (b16) {
+                            int16("\r\n") => r.state = .seen_rn,
+                            int16("\n\r") => r.state = .seen_rnr,
+                            int16("\n\n") => r.state = .finished,
+                            else => {},
+                        }
+
+                        return index + 2;
+                    },
+                    else => {
+                        const b24 = int24(bytes[index..][0..3]);
+                        const b16 = intShift(u16, b24);
+                        const b8 = intShift(u8, b24);
+
+                        switch (b8) {
+                            '\r' => r.state = .seen_r,
+                            '\n' => r.state = .seen_n,
+                            else => r.state = .start,
+                        }
+
+                        switch (b16) {
+                            int16("\r\n") => r.state = .seen_rn,
+                            int16("\n\n") => r.state = .finished,
+                            else => {},
+                        }
+
+                        switch (b24) {
+                            int24("\n\r\n") => r.state = .finished,
+                            else => {},
+                        }
+
+                        index += 3;
+                        continue;
+                    },
+                },
+                .seen_rn => switch (len - index) {
+                    0 => return index,
+                    1 => {
+                        switch (bytes[index]) {
+                            '\r' => r.state = .seen_rnr,
+                            '\n' => r.state = .seen_n,
+                            else => r.state = .start,
+                        }
+
+                        return index + 1;
+                    },
+                    else => {
+                        const b16 = int16(bytes[index..][0..2]);
+                        const b8 = intShift(u8, b16);
+
+                        switch (b8) {
+                            '\r' => r.state = .seen_rnr,
+                            '\n' => r.state = .seen_n,
+                            else => r.state = .start,
+                        }
+
+                        switch (b16) {
+                            int16("\r\n") => r.state = .finished,
+                            int16("\n\n") => r.state = .finished,
+                            else => {},
+                        }
+
+                        index += 2;
+                        continue;
+                    },
+                },
+                .seen_rnr => switch (len - index) {
+                    0 => return index,
+                    else => {
+                        switch (bytes[index]) {
+                            '\n' => r.state = .finished,
+                            else => r.state = .start,
+                        }
+
+                        index += 1;
+                        continue;
+                    },
+                },
+                .chunk_head_size => unreachable,
+                .chunk_head_ext => unreachable,
+                .chunk_head_r => unreachable,
+                .chunk_data => unreachable,
+                .chunk_data_suffix => unreachable,
+                .chunk_data_suffix_r => unreachable,
+            }
+
+            return index;
+        }
+    }
+
+    /// Returns the number of bytes consumed by the chunk size. This is always less than or equal to `bytes.len`.
+    /// You should check `r.state == .chunk_data` after this to check if the chunk size has been fully parsed.
+    ///
+    /// If the amount returned is less than `bytes.len`, you may assume that the parser is in the `chunk_data` state
+    /// and that the first byte of the chunk is at `bytes[result]`.
+    pub fn findChunkedLen(r: *HeadersParser, bytes: []const u8) u32 {
+        const len = @intCast(u32, bytes.len);
+
+        for (bytes[0..], 0..) |c, i| {
+            const index = @intCast(u32, i);
+            switch (r.state) {
+                .chunk_data_suffix => switch (c) {
+                    '\r' => r.state = .chunk_data_suffix_r,
+                    '\n' => r.state = .chunk_head_size,
+                    else => {
+                        r.state = .invalid;
+                        return index;
+                    },
+                },
+                .chunk_data_suffix_r => switch (c) {
+                    '\n' => r.state = .chunk_head_size,
+                    else => {
+                        r.state = .invalid;
+                        return index;
+                    },
+                },
+                .chunk_head_size => {
+                    const digit = switch (c) {
+                        '0'...'9' => |b| b - '0',
+                        'A'...'Z' => |b| b - 'A' + 10,
+                        'a'...'z' => |b| b - 'a' + 10,
+                        '\r' => {
+                            r.state = .chunk_head_r;
+                            continue;
+                        },
+                        '\n' => {
+                            r.state = .chunk_data;
+                            return index + 1;
+                        },
+                        else => {
+                            r.state = .chunk_head_ext;
+                            continue;
+                        },
+                    };
+
+                    const new_len = r.next_chunk_length *% 16 +% digit;
+                    if (new_len <= r.next_chunk_length and r.next_chunk_length != 0) {
+                        r.state = .invalid;
+                        return index;
+                    }
+
+                    r.next_chunk_length = new_len;
+                },
+                .chunk_head_ext => switch (c) {
+                    '\r' => r.state = .chunk_head_r,
+                    '\n' => {
+                        r.state = .chunk_data;
+                        return index + 1;
+                    },
+                    else => continue,
+                },
+                .chunk_head_r => switch (c) {
+                    '\n' => {
+                        r.state = .chunk_data;
+                        return index + 1;
+                    },
+                    else => {
+                        r.state = .invalid;
+                        return index;
+                    },
+                },
+                else => unreachable,
+            }
+        }
+
+        return len;
+    }
+
+    /// Returns whether or not the parser has finished parsing a complete message. A message is only complete after the
+    /// entire body has been read and any trailing headers have been parsed.
+    pub fn isComplete(r: *HeadersParser) bool {
+        return r.done and r.state == .finished;
+    }
+
+    pub const CheckCompleteHeadError = mem.Allocator.Error || error{HttpHeadersExceededSizeLimit};
+
+    /// Pushes `in` into the parser. Returns the number of bytes consumed by the header. Any header bytes are appended
+    /// to the `header_bytes` buffer.
+    ///
+    /// This function only uses `allocator` if `r.header_bytes_owned` is true, and may be undefined otherwise.
+    pub fn checkCompleteHead(r: *HeadersParser, allocator: std.mem.Allocator, in: []const u8) CheckCompleteHeadError!u32 {
+        if (r.state.isContent()) return 0;
+
+        const i = r.findHeadersEnd(in);
+        const data = in[0..i];
+        if (r.header_bytes.items.len + data.len > r.max_header_bytes) {
+            return error.HttpHeadersExceededSizeLimit;
+        } else {
+            if (r.header_bytes_owned) try r.header_bytes.ensureUnusedCapacity(allocator, data.len);
+
+            r.header_bytes.appendSliceAssumeCapacity(data);
+        }
+
+        return i;
+    }
+
+    pub const ReadError = error{
+        HttpChunkInvalid,
+    };
+
+    /// Reads the body of the message into `buffer`. Returns the number of bytes placed in the buffer.
+    ///
+    /// If `skip` is true, the buffer will be unused and the body will be skipped.
+    ///
+    /// See `std.http.Client.BufferedConnection for an example of `bconn`.
+    pub fn read(r: *HeadersParser, bconn: anytype, buffer: []u8, skip: bool) !usize {
+        assert(r.state.isContent());
+        if (r.done) return 0;
+
+        var out_index: usize = 0;
+        while (true) {
+            switch (r.state) {
+                .invalid, .start, .seen_n, .seen_r, .seen_rn, .seen_rnr => unreachable,
+                .finished => {
+                    const data_avail = r.next_chunk_length;
+
+                    if (skip) {
+                        try bconn.fill();
+
+                        const nread = @min(bconn.peek().len, data_avail);
+                        bconn.clear(@intCast(u16, nread));
+                        r.next_chunk_length -= nread;
+
+                        if (r.next_chunk_length == 0) r.done = true;
+
+                        return 0;
+                    } else {
+                        const out_avail = buffer.len;
+
+                        const can_read = @intCast(usize, @min(data_avail, out_avail));
+                        const nread = try bconn.read(buffer[0..can_read]);
+                        r.next_chunk_length -= nread;
+
+                        if (r.next_chunk_length == 0) r.done = true;
+
+                        return nread;
+                    }
+                },
+                .chunk_data_suffix, .chunk_data_suffix_r, .chunk_head_size, .chunk_head_ext, .chunk_head_r => {
+                    try bconn.fill();
+
+                    const i = r.findChunkedLen(bconn.peek());
+                    bconn.clear(@intCast(u16, i));
+
+                    switch (r.state) {
+                        .invalid => return error.HttpChunkInvalid,
+                        .chunk_data => if (r.next_chunk_length == 0) {
+                            // The trailer section is formatted identically to the header section.
+                            r.state = .seen_rn;
+                            r.done = true;
+
+                            return out_index;
+                        },
+                        else => return out_index,
+                    }
+
+                    continue;
+                },
+                .chunk_data => {
+                    const data_avail = r.next_chunk_length;
+                    const out_avail = buffer.len - out_index;
+
+                    if (skip) {
+                        try bconn.fill();
+
+                        const nread = @min(bconn.peek().len, data_avail);
+                        bconn.clear(@intCast(u16, nread));
+                        r.next_chunk_length -= nread;
+                    } else {
+                        const can_read = @intCast(usize, @min(data_avail, out_avail));
+                        const nread = try bconn.read(buffer[out_index..][0..can_read]);
+                        r.next_chunk_length -= nread;
+                        out_index += nread;
+                    }
+
+                    if (r.next_chunk_length == 0) {
+                        r.state = .chunk_data_suffix;
+                        continue;
+                    }
+
+                    return out_index;
+                },
+            }
+        }
+    }
+};
+
+inline fn int16(array: *const [2]u8) u16 {
+    return @bitCast(u16, array.*);
+}
+
+inline fn int24(array: *const [3]u8) u24 {
+    return @bitCast(u24, array.*);
+}
+
+inline fn int32(array: *const [4]u8) u32 {
+    return @bitCast(u32, array.*);
+}
+
+inline fn intShift(comptime T: type, x: anytype) T {
+    switch (@import("builtin").cpu.arch.endian()) {
+        .Little => return @truncate(T, x >> (@bitSizeOf(@TypeOf(x)) - @bitSizeOf(T))),
+        .Big => return @truncate(T, x),
+    }
+}
+
+/// A buffered (and peekable) Connection.
+const MockBufferedConnection = struct {
+    pub const buffer_size = 0x2000;
+
+    conn: std.io.FixedBufferStream([]const u8),
+    buf: [buffer_size]u8 = undefined,
+    start: u16 = 0,
+    end: u16 = 0,
+
+    pub fn fill(bconn: *MockBufferedConnection) ReadError!void {
+        if (bconn.end != bconn.start) return;
+
+        const nread = try bconn.conn.read(bconn.buf[0..]);
+        if (nread == 0) return error.EndOfStream;
+        bconn.start = 0;
+        bconn.end = @truncate(u16, nread);
+    }
+
+    pub fn peek(bconn: *MockBufferedConnection) []const u8 {
+        return bconn.buf[bconn.start..bconn.end];
+    }
+
+    pub fn clear(bconn: *MockBufferedConnection, num: u16) void {
+        bconn.start += num;
+    }
+
+    pub fn readAtLeast(bconn: *MockBufferedConnection, buffer: []u8, len: usize) ReadError!usize {
+        var out_index: u16 = 0;
+        while (out_index < len) {
+            const available = bconn.end - bconn.start;
+            const left = buffer.len - out_index;
+
+            if (available > 0) {
+                const can_read = @truncate(u16, @min(available, left));
+
+                std.mem.copy(u8, buffer[out_index..], bconn.buf[bconn.start..][0..can_read]);
+                out_index += can_read;
+                bconn.start += can_read;
+
+                continue;
+            }
+
+            if (left > bconn.buf.len) {
+                // skip the buffer if the output is large enough
+                return bconn.conn.read(buffer[out_index..]);
+            }
+
+            try bconn.fill();
+        }
+
+        return out_index;
+    }
+
+    pub fn read(bconn: *MockBufferedConnection, buffer: []u8) ReadError!usize {
+        return bconn.readAtLeast(buffer, 1);
+    }
+
+    pub const ReadError = std.io.FixedBufferStream([]const u8).ReadError || error{EndOfStream};
+    pub const Reader = std.io.Reader(*MockBufferedConnection, ReadError, read);
+
+    pub fn reader(bconn: *MockBufferedConnection) Reader {
+        return Reader{ .context = bconn };
+    }
+
+    pub fn writeAll(bconn: *MockBufferedConnection, buffer: []const u8) WriteError!void {
+        return bconn.conn.writeAll(buffer);
+    }
+
+    pub fn write(bconn: *MockBufferedConnection, buffer: []const u8) WriteError!usize {
+        return bconn.conn.write(buffer);
+    }
+
+    pub const WriteError = std.io.FixedBufferStream([]const u8).WriteError;
+    pub const Writer = std.io.Writer(*MockBufferedConnection, WriteError, write);
+
+    pub fn writer(bconn: *MockBufferedConnection) Writer {
+        return Writer{ .context = bconn };
+    }
+};
+
+test "HeadersParser.findHeadersEnd" {
+    var r: HeadersParser = undefined;
+    const data = "GET / HTTP/1.1\r\nHost: localhost\r\n\r\nHello";
+
+    for (0..36) |i| {
+        r = HeadersParser.initDynamic(0);
+        try std.testing.expectEqual(@intCast(u32, i), r.findHeadersEnd(data[0..i]));
+        try std.testing.expectEqual(@intCast(u32, 35 - i), r.findHeadersEnd(data[i..]));
+    }
+}
+
+test "HeadersParser.findChunkedLen" {
+    var r: HeadersParser = undefined;
+    const data = "Ff\r\nf0f000 ; ext\n0\r\nffffffffffffffffffffffffffffffffffffffff\r\n";
+
+    r = HeadersParser.initDynamic(0);
+    r.state = .chunk_head_size;
+    r.next_chunk_length = 0;
+
+    const first = r.findChunkedLen(data[0..]);
+    try testing.expectEqual(@as(u32, 4), first);
+    try testing.expectEqual(@as(u64, 0xff), r.next_chunk_length);
+    try testing.expectEqual(State.chunk_data, r.state);
+    r.state = .chunk_head_size;
+    r.next_chunk_length = 0;
+
+    const second = r.findChunkedLen(data[first..]);
+    try testing.expectEqual(@as(u32, 13), second);
+    try testing.expectEqual(@as(u64, 0xf0f000), r.next_chunk_length);
+    try testing.expectEqual(State.chunk_data, r.state);
+    r.state = .chunk_head_size;
+    r.next_chunk_length = 0;
+
+    const third = r.findChunkedLen(data[first + second ..]);
+    try testing.expectEqual(@as(u32, 3), third);
+    try testing.expectEqual(@as(u64, 0), r.next_chunk_length);
+    try testing.expectEqual(State.chunk_data, r.state);
+    r.state = .chunk_head_size;
+    r.next_chunk_length = 0;
+
+    const fourth = r.findChunkedLen(data[first + second + third ..]);
+    try testing.expectEqual(@as(u32, 16), fourth);
+    try testing.expectEqual(@as(u64, 0xffffffffffffffff), r.next_chunk_length);
+    try testing.expectEqual(State.invalid, r.state);
+}
+
+test "HeadersParser.read length" {
+    // mock BufferedConnection for read
+
+    var r = HeadersParser.initDynamic(256);
+    defer r.header_bytes.deinit(std.testing.allocator);
+    const data = "GET / HTTP/1.1\r\nHost: localhost\r\nContent-Length: 5\r\n\r\nHello";
+    var fbs = std.io.fixedBufferStream(data);
+
+    var bconn = MockBufferedConnection{
+        .conn = fbs,
+    };
+
+    while (true) { // read headers
+        try bconn.fill();
+
+        const nchecked = try r.checkCompleteHead(std.testing.allocator, bconn.peek());
+        bconn.clear(@intCast(u16, nchecked));
+
+        if (r.state.isContent()) break;
+    }
+
+    var buf: [8]u8 = undefined;
+
+    r.next_chunk_length = 5;
+    const len = try r.read(&bconn, &buf, false);
+    try std.testing.expectEqual(@as(usize, 5), len);
+    try std.testing.expectEqualStrings("Hello", buf[0..len]);
+
+    try std.testing.expectEqualStrings("GET / HTTP/1.1\r\nHost: localhost\r\nContent-Length: 5\r\n\r\n", r.header_bytes.items);
+}
+
+test "HeadersParser.read chunked" {
+    // mock BufferedConnection for read
+
+    var r = HeadersParser.initDynamic(256);
+    defer r.header_bytes.deinit(std.testing.allocator);
+    const data = "GET / HTTP/1.1\r\nHost: localhost\r\n\r\n2\r\nHe\r\n2\r\nll\r\n1\r\no\r\n0\r\n\r\n";
+    var fbs = std.io.fixedBufferStream(data);
+
+    var bconn = MockBufferedConnection{
+        .conn = fbs,
+    };
+
+    while (true) { // read headers
+        try bconn.fill();
+
+        const nchecked = try r.checkCompleteHead(std.testing.allocator, bconn.peek());
+        bconn.clear(@intCast(u16, nchecked));
+
+        if (r.state.isContent()) break;
+    }
+    var buf: [8]u8 = undefined;
+
+    r.state = .chunk_head_size;
+    const len = try r.read(&bconn, &buf, false);
+    try std.testing.expectEqual(@as(usize, 5), len);
+    try std.testing.expectEqualStrings("Hello", buf[0..len]);
+
+    try std.testing.expectEqualStrings("GET / HTTP/1.1\r\nHost: localhost\r\n\r\n", r.header_bytes.items);
+}
+
+test "HeadersParser.read chunked trailer" {
+    // mock BufferedConnection for read
+
+    var r = HeadersParser.initDynamic(256);
+    defer r.header_bytes.deinit(std.testing.allocator);
+    const data = "GET / HTTP/1.1\r\nHost: localhost\r\n\r\n2\r\nHe\r\n2\r\nll\r\n1\r\no\r\n0\r\nContent-Type: text/plain\r\n\r\n";
+    var fbs = std.io.fixedBufferStream(data);
+
+    var bconn = MockBufferedConnection{
+        .conn = fbs,
+    };
+
+    while (true) { // read headers
+        try bconn.fill();
+
+        const nchecked = try r.checkCompleteHead(std.testing.allocator, bconn.peek());
+        bconn.clear(@intCast(u16, nchecked));
+
+        if (r.state.isContent()) break;
+    }
+    var buf: [8]u8 = undefined;
+
+    r.state = .chunk_head_size;
+    const len = try r.read(&bconn, &buf, false);
+    try std.testing.expectEqual(@as(usize, 5), len);
+    try std.testing.expectEqualStrings("Hello", buf[0..len]);
+
+    while (true) { // read headers
+        try bconn.fill();
+
+        const nchecked = try r.checkCompleteHead(std.testing.allocator, bconn.peek());
+        bconn.clear(@intCast(u16, nchecked));
+
+        if (r.state.isContent()) break;
+    }
+
+    try std.testing.expectEqualStrings("GET / HTTP/1.1\r\nHost: localhost\r\n\r\nContent-Type: text/plain\r\n\r\n", r.header_bytes.items);
+}