Zig 0.15.2 で HTTP クライアント

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Zig 0.15.2 で HTTP クライアント

zig run client.zig

client.zig

const std = @import("std");

fn makeMemWriter(buf: []u8) std.Io.Writer {
    const W = std.Io.Writer;
    const Vt = W.VTable;

    const Adapter = struct {
        fn drain(w: *W, chunks: []const []const u8, start: usize) error{WriteFailed}!usize {
            var written: usize = 0;
            var i: usize = start;
            while (i < chunks.len) : (i += 1) {
                const data = chunks[i];
                const avail = w.buffer.len - w.end;
                if (data.len > avail) return error.WriteFailed;
                @memcpy(w.buffer[w.end .. w.end + data.len], data);
                w.end += data.len;
                written += data.len;
            }
            return written;
        }

        fn flush(_: *W) error{WriteFailed}!void {}
        fn rebase(_: *W, _: usize, _: usize) error{WriteFailed}!void {}

        fn sendFile(_: *W, _: *std.fs.File.Reader, _: std.Io.Limit)
            error{EndOfStream, ReadFailed, Unimplemented, WriteFailed}!usize
        {
            return error.Unimplemented;
        }
    };

    const vt = Vt{
        .drain = Adapter.drain,
        .sendFile = Adapter.sendFile,
        .flush = Adapter.flush,
        .rebase = Adapter.rebase,
    };

    return W{ .vtable = &vt, .buffer = buf, .end = 0 };
}

fn writeStatusLine(file: *std.fs.File, status: std.http.Status) !void {
    var line: [12]u8 = undefined;
    line[0..8].* = "Status: ".*;
    const code: u16 = @intFromEnum(status);
    line[8]  = @as(u8, '0') + @as(u8, @intCast(code / 100));
    line[9]  = @as(u8, '0') + @as(u8, @intCast((code / 10) % 10));
    line[10] = @as(u8, '0') + @as(u8, @intCast(code % 10));
    line[11] = '\n';
    try file.writeAll(&line);
}

pub fn main() !void {
    const allocator = std.heap.page_allocator;

    var stdout_file = std.fs.File.stdout();

    var client = std.http.Client{ .allocator = allocator };
    defer client.deinit();

    // 受信ボディ保存先
    var body_buf: [256 * 1024]u8 = undefined;
    var body_writer = makeMemWriter(&body_buf);

    // ★ここを変える：localhost のポート
    const url = "http://127.0.0.1:8080/";

    const res = try client.fetch(.{
        .location = .{ .url = url },
        .method = .GET,
        .keep_alive = false,
        .response_writer = &body_writer,
    });

    try writeStatusLine(&stdout_file, res.status);
    try stdout_file.writeAll(body_buf[0..body_writer.end]);
}