╭─────────────╮ │scroll to top│ ╰─────────────╯ ╭ web.zig ──────────────────────────────────────────────────────╮ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ ╰───────────────────────────────────────────────────────────────╯
╭────╮ ╭ clone ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ╮ │http│ ssh │ │ ╰────╯ ╰ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ╯
2532 '"' => try out.appendSlice(allocator, "&quot;"), 2533 '\'' => try out.appendSlice(allocator, "&#39;"), 2534 else => try out.append(allocator, ch), 2535 } 2536 } 2537 } 2538 2539 // --- helpers -------------------------------------------------------------- 2540 2541 fn getCookieValue(request: *std.http.Server.Request, name: []const u8) ?[]const u8 { 2542 var iter = request.iterateHeaders(); 2543 while (iter.next()) |header| { 2544 if (!std.ascii.eqlIgnoreCase(header.name, "cookie")) continue; 2545 var pairs = std.mem.splitScalar(u8, header.value, ';'); 2546 while (pairs.next()) |pair| { 2547 const trimmed = std.mem.trim(u8, pair, " \t"); 2548 const eq = std.mem.indexOfScalar(u8, trimmed, '=') orelse continue; 2549 if (std.mem.eql(u8, trimmed[0..eq], name)) { 2550 return trimmed[eq + 1 ..]; 2551 } 2552 } 2553 } 2554 return null; 2555 } 2556 2557 fn parseFormField(allocator: std.mem.Allocator, body: []const u8, key: []const u8) !?[]u8 { 2558 var iter = std.mem.splitScalar(u8, body, '&'); 2559 while (iter.next()) |pair| { 2560 const eq = std.mem.indexOfScalar(u8, pair, '=') orelse continue; 2561 if (std.mem.eql(u8, pair[0..eq], key)) { 2562 return try decodeFormValue(allocator, pair[eq + 1 ..]); 2563 } 2564 } 2565 return null; 2566 } 2567 2568 fn readFormBody(request: *std.http.Server.Request, allocator: std.mem.Allocator) ![]u8 { 2569 var buffer: [256]u8 = undefined; 2570 return request.readerExpectNone(&buffer).allocRemaining(allocator, .limited(65536)); 2571 } 2572 2573 fn decodeFormValue(allocator: std.mem.Allocator, encoded: []const u8) ![]u8 { 2574 var out: std.ArrayList(u8) = .empty; 2575 errdefer out.deinit(allocator); 2576 var i: usize = 0; 2577 while (i < encoded.len) : (i += 1) { 2578 switch (encoded[i]) { 2579 '+' => try out.append(allocator, ' '), 2580 '%' => { 2581 if (i + 2 >= encoded.len) return error.InvalidPercentEncoding; 2582 const hi = std.fmt.charToDigit(encoded[i + 1], 16) catch return error.InvalidPercentEncoding; 2583 const lo = std.fmt.charToDigit(encoded[i + 2], 16) catch return error.InvalidPercentEncoding; 2584 try out.append(allocator, hi * 16 + lo); 2585 i += 2; 2586 }, 2587 else => try out.append(allocator, encoded[i]), 2588 } 2589 } 2590 return try out.toOwnedSlice(allocator); 2591 } 2592 2593 // disk-backed web session store. each login mints a random, opaque token 2594 // (not the user's id) that is stored as a file named by the token hex, whose 2595 // contents are the raw user_id bytes. authenticating a request is a lookup of 2596 // the cookie's token; logout deletes the file, revoking the session. there is 2597 // deliberately no expiry — a session lives until logout. form failures use 2598 // files in the flash subdirectory that the redirected GET consumes. the 2599 // directory is cleared whenever the server starts. 2600 pub const SessionStore = struct { 2601 io: std.Io, 2602 dir: std.Io.Dir, 2603 flash_dir: std.Io.Dir, 2604 auto_login: ?[token_hex_len]u8, 2605 2606 pub const token_hex_len = evt.event_id_size * 2; 2607 2608 pub fn init(io: std.Io, data_dir: std.Io.Dir) !SessionStore { 2609 try data_dir.createDirPath(io, "sessions"); 2610 const dir = try data_dir.openDir(io, "sessions", .{}); 2611 errdefer dir.close(io); 2612 try dir.deleteTree(io, "flash"); 2613 try dir.createDirPath(io, "flash"); 2614 const flash_dir = try dir.openDir(io, "flash", .{}); 2615 errdefer flash_dir.close(io); 2616 const auto_login = blk: { 2617 const file = dir.openFile(io, auto_login_name, .{ .mode = .read_only }) catch break :blk null; 2618 defer file.close(io); 2619 var token: [token_hex_len]u8 = undefined; 2620 var storage: [token_hex_len]u8 = undefined; 2621 var reader = file.reader(io, &storage); 2622 reader.interface.readSliceAll(&token) catch break :blk null; 2623 break :blk token; 2624 }; 2625 return .{ .io = io, .dir = dir, .flash_dir = flash_dir, .auto_login = auto_login }; 2626 } 2627 2628 pub fn deinit(self: SessionStore) void { 2629 self.flash_dir.close(self.io); 2630 self.dir.close(self.io); 2631 } 2632 2633 // mint a new session for user_id, returning the token hex to set as the 2634 // cookie value. 2635 pub fn create(self: SessionStore, user_id: *const [evt.event_id_size]u8) ![token_hex_len]u8 { 2636 var token: [evt.event_id_size]u8 = undefined; 2637 self.io.random(&token); 2638 const token_hex = std.fmt.bytesToHex(token, .lower); 2639 const file = try self.dir.createFile(self.io, &token_hex, .{}); 2640 defer file.close(self.io); 2641 try file.writeStreamingAll(self.io, user_id); 2642 return token_hex; 2643 } 2644 2645 fn createFlash(self: SessionStore, allocator: std.mem.Allocator, value: ui.Session.FormFeedback) ![token_hex_len]u8 { 2646 var token: [evt.event_id_size]u8 = undefined; 2647 self.io.random(&token); 2648 const token_hex = std.fmt.bytesToHex(token, .lower); 2649 const file = try self.flash_dir.createFile(self.io, &token_hex, .{}); 2650 errdefer self.flash_dir.deleteFile(self.io, &token_hex) catch {}; 2651 defer file.close(self.io); 2652 2653 var json: std.Io.Writer.Allocating = .init(allocator); 2654 defer json.deinit(); 2655 try std.json.Stringify.value(value, .{}, &json.writer); 2656 try file.writeStreamingAll(self.io, json.written()); 2657 return token_hex; 2658 } 2659 2660 fn takeFlash(self: SessionStore, allocator: std.mem.Allocator, token_hex: []const u8) ?ui.Session.FormFeedback { 2661 if (!isToken(token_hex)) return null; 2662 const file = self.flash_dir.openFile(self.io, token_hex, .{ .mode = .read_only }) catch return null; 2663 defer self.flash_dir.deleteFile(self.io, token_hex) catch {}; 2664 defer file.close(self.io); 2665 2666 var storage: [4096]u8 = undefined; 2667 var reader = file.reader(self.io, &storage); 2668 const bytes = reader.interface.allocRemaining(allocator, .limited(512 * 1024)) catch return null; 2669 return std.json.parseFromSliceLeaky(ui.Session.FormFeedback, allocator, bytes, .{}) catch null; 2670 } 2671 2672 // resolve a cookie's token to its user_id. returns false (logged out) for a 2673 // missing, malformed, or unknown token. 2674 pub fn lookup(self: SessionStore, token_hex: []const u8, out: *[evt.event_id_size]u8) bool { 2675 if (!isToken(token_hex)) return false; 2676 const file = self.dir.openFile(self.io, token_hex, .{ .mode = .read_only }) catch return false; 2677 defer file.close(self.io); 2678 var storage: [evt.event_id_size]u8 = undefined; 2679 var file_reader = file.reader(self.io, &storage); 2680 file_reader.interface.readSliceAll(out) catch return false; 2681 return true; 2682 } 2683 2684 // revoke a session. a no-op for a missing or malformed token. 2685 pub fn remove(self: SessionStore, token_hex: []const u8) void { 2686 if (!isToken(token_hex)) return; 2687 self.dir.deleteFile(self.io, token_hex) catch {}; 2688 } 2689 2690 // leave `token_hex`'s session for visitors arriving without one. only the 2691 // `try` fixture writes one. the name can't collide with a session token. 2692 pub fn offerAutoLogin(self: SessionStore, token_hex: *const [token_hex_len]u8) !void { 2693 const file = try self.dir.createFile(self.io, auto_login_name, .{}); 2694 defer file.close(self.io); 2695 try file.writeStreamingAll(self.io, token_hex); 2696 } 2697 2698 pub fn autoLogin(self: SessionStore, out: *[token_hex_len]u8) bool { 2699 out.* = self.auto_login orelse return false; 2700 return true; 2701 } 2702 2703 const auto_login_name = "auto-login"; 2704 2705 // a token is exactly token_hex_len hex chars. validating before using the 2706 // value as a path keeps attacker-supplied cookies from escaping the 2707 // sessions dir (e.g. via "/" or ".." bytes). 2708 fn isToken(token_hex: []const u8) bool { 2709 if (token_hex.len != token_hex_len) return false; 2710 for (token_hex) |c| if (!std.ascii.isHex(c)) return false; 2711 return true; 2712 } 2713 }; 2714