╭─────────────╮ │scroll to top│ ╰─────────────╯ ╭ web.zig ──────────────────────────────────────────────────────╮ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ ╰───────────────────────────────────────────────────────────────╯
╭────╮ ╭ clone ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ╮ │http│ ssh │ │ ╰────╯ ╰ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ╯
2913 // a page path, not a protocol-relative url 2914 if (url.len > 1 and url[0] == '/' and url[1] != '/') return url; 2915 for ([_][]const u8{ "http://", "https://", "mailto:" }) |scheme| { 2916 if (std.ascii.startsWithIgnoreCase(url, scheme)) return url; 2917 } 2918 return null; 2919 } 2920 2921 fn sameLink(a: ?[]const u8, b: ?[]const u8) bool { 2922 if (a) |x| return if (b) |y| std.mem.eql(u8, x, y) else false; 2923 return b == null; 2924 } 2925 2926 fn appendEscapedHtml(allocator: std.mem.Allocator, out: *std.ArrayList(u8), input: []const u8) !void { 2927 for (input) |ch| { 2928 switch (ch) { 2929 '&' => try out.appendSlice(allocator, "&amp;"), 2930 '<' => try out.appendSlice(allocator, "&lt;"), 2931 '>' => try out.appendSlice(allocator, "&gt;"), 2932 '"' => try out.appendSlice(allocator, "&quot;"), 2933 '\'' => try out.appendSlice(allocator, "&#39;"), 2934 else => try out.append(allocator, ch), 2935 } 2936 } 2937 } 2938 2939 // --- helpers -------------------------------------------------------------- 2940 2941 fn getCookieValue(request: *std.http.Server.Request, name: []const u8) ?[]const u8 { 2942 var iter = request.iterateHeaders(); 2943 while (iter.next()) |header| { 2944 if (!std.ascii.eqlIgnoreCase(header.name, "cookie")) continue; 2945 var pairs = std.mem.splitScalar(u8, header.value, ';'); 2946 while (pairs.next()) |pair| { 2947 const trimmed = std.mem.trim(u8, pair, " \t"); 2948 const eq = std.mem.indexOfScalar(u8, trimmed, '=') orelse continue; 2949 if (std.mem.eql(u8, trimmed[0..eq], name)) { 2950 return trimmed[eq + 1 ..]; 2951 } 2952 } 2953 } 2954 return null; 2955 } 2956 2957 fn parseFormField(allocator: std.mem.Allocator, body: []const u8, key: []const u8) !?[]u8 { 2958 var iter = std.mem.splitScalar(u8, body, '&'); 2959 while (iter.next()) |pair| { 2960 const eq = std.mem.indexOfScalar(u8, pair, '=') orelse continue; 2961 if (std.mem.eql(u8, pair[0..eq], key)) { 2962 return try decodeFormValue(allocator, pair[eq + 1 ..]); 2963 } 2964 } 2965 return null; 2966 } 2967 2968 fn readFormBody(request: *std.http.Server.Request, allocator: std.mem.Allocator) ![]u8 { 2969 var buffer: [256]u8 = undefined; 2970 return request.readerExpectNone(&buffer).allocRemaining(allocator, .limited(65536)); 2971 } 2972 2973 fn decodeFormValue(allocator: std.mem.Allocator, encoded: []const u8) ![]u8 { 2974 var out: std.ArrayList(u8) = .empty; 2975 errdefer out.deinit(allocator); 2976 var i: usize = 0; 2977 while (i < encoded.len) : (i += 1) { 2978 switch (encoded[i]) { 2979 '+' => try out.append(allocator, ' '), 2980 '%' => { 2981 if (i + 2 >= encoded.len) return error.InvalidPercentEncoding; 2982 const hi = std.fmt.charToDigit(encoded[i + 1], 16) catch return error.InvalidPercentEncoding; 2983 const lo = std.fmt.charToDigit(encoded[i + 2], 16) catch return error.InvalidPercentEncoding; 2984 try out.append(allocator, hi * 16 + lo); 2985 i += 2; 2986 }, 2987 else => try out.append(allocator, encoded[i]), 2988 } 2989 } 2990 return try out.toOwnedSlice(allocator); 2991 } 2992 2993 // disk-backed web session store. each login mints a random, opaque token 2994 // (not the user's id) that is stored as a file named by the token hex, whose 2995 // contents are the raw user_id bytes. authenticating a request is a lookup of 2996 // the cookie's token; logout deletes the file, revoking the session. there is 2997 // deliberately no expiry — a session lives until logout. form failures use 2998 // files in the flash subdirectory that the redirected GET consumes. the 2999 // directory is cleared whenever the server starts. 3000 pub const SessionStore = struct { 3001 io: std.Io, 3002 dir: std.Io.Dir, 3003 flash_dir: std.Io.Dir, 3004 auto_login: ?[token_hex_len]u8, 3005 3006 pub const token_hex_len = evt.event_id_size * 2; 3007 3008 pub fn init(io: std.Io, data_dir: std.Io.Dir) !SessionStore { 3009 try data_dir.createDirPath(io, "sessions"); 3010 const dir = try data_dir.openDir(io, "sessions", .{}); 3011 errdefer dir.close(io); 3012 try dir.deleteTree(io, "flash"); 3013 try dir.createDirPath(io, "flash"); 3014 const flash_dir = try dir.openDir(io, "flash", .{}); 3015 errdefer flash_dir.close(io); 3016 const auto_login = blk: { 3017 const file = dir.openFile(io, auto_login_name, .{ .mode = .read_only }) catch break :blk null; 3018 defer file.close(io); 3019 var token: [token_hex_len]u8 = undefined; 3020 var storage: [token_hex_len]u8 = undefined; 3021 var reader = file.reader(io, &storage); 3022 reader.interface.readSliceAll(&token) catch break :blk null; 3023 break :blk token; 3024 }; 3025 return .{ .io = io, .dir = dir, .flash_dir = flash_dir, .auto_login = auto_login }; 3026 } 3027 3028 pub fn deinit(self: SessionStore) void { 3029 self.flash_dir.close(self.io); 3030 self.dir.close(self.io); 3031 } 3032 3033 // mint a new session for user_id, returning the token hex to set as the 3034 // cookie value. 3035 pub fn create(self: SessionStore, user_id: *const [evt.event_id_size]u8) ![token_hex_len]u8 { 3036 var token: [evt.event_id_size]u8 = undefined; 3037 self.io.random(&token); 3038 const token_hex = std.fmt.bytesToHex(token, .lower); 3039 const file = try self.dir.createFile(self.io, &token_hex, .{}); 3040 defer file.close(self.io); 3041 try file.writeStreamingAll(self.io, user_id); 3042 return token_hex; 3043 } 3044 3045 fn createFlash(self: SessionStore, allocator: std.mem.Allocator, value: ui.Session.FormFeedback) ![token_hex_len]u8 { 3046 var token: [evt.event_id_size]u8 = undefined; 3047 self.io.random(&token); 3048 const token_hex = std.fmt.bytesToHex(token, .lower); 3049 const file = try self.flash_dir.createFile(self.io, &token_hex, .{}); 3050 errdefer self.flash_dir.deleteFile(self.io, &token_hex) catch {}; 3051 defer file.close(self.io); 3052 3053 var json: std.Io.Writer.Allocating = .init(allocator); 3054 defer json.deinit(); 3055 try std.json.Stringify.value(value, .{}, &json.writer); 3056 try file.writeStreamingAll(self.io, json.written()); 3057 return token_hex; 3058 } 3059 3060 fn takeFlash(self: SessionStore, allocator: std.mem.Allocator, token_hex: []const u8) ?ui.Session.FormFeedback { 3061 if (!isToken(token_hex)) return null; 3062 const file = self.flash_dir.openFile(self.io, token_hex, .{ .mode = .read_only }) catch return null; 3063 defer self.flash_dir.deleteFile(self.io, token_hex) catch {}; 3064 defer file.close(self.io); 3065 3066 var storage: [4096]u8 = undefined; 3067 var reader = file.reader(self.io, &storage); 3068 const bytes = reader.interface.allocRemaining(allocator, .limited(512 * 1024)) catch return null; 3069 return std.json.parseFromSliceLeaky(ui.Session.FormFeedback, allocator, bytes, .{}) catch null; 3070 } 3071 3072 // resolve a cookie's token to its user_id. returns false (logged out) for a 3073 // missing, malformed, or unknown token. 3074 pub fn lookup(self: SessionStore, token_hex: []const u8, out: *[evt.event_id_size]u8) bool { 3075 if (!isToken(token_hex)) return false; 3076 const file = self.dir.openFile(self.io, token_hex, .{ .mode = .read_only }) catch return false; 3077 defer file.close(self.io); 3078 var storage: [evt.event_id_size]u8 = undefined; 3079 var file_reader = file.reader(self.io, &storage); 3080 file_reader.interface.readSliceAll(out) catch return false; 3081 return true; 3082 } 3083 3084 // revoke a session. a no-op for a missing or malformed token. 3085 pub fn remove(self: SessionStore, token_hex: []const u8) void { 3086 if (!isToken(token_hex)) return; 3087 self.dir.deleteFile(self.io, token_hex) catch {}; 3088 } 3089 3090 // leave `token_hex`'s session for visitors arriving without one. only the 3091 // `try` fixture writes one. the name can't collide with a session token. 3092 pub fn offerAutoLogin(self: SessionStore, token_hex: *const [token_hex_len]u8) !void { 3093 const file = try self.dir.createFile(self.io, auto_login_name, .{}); 3094 defer file.close(self.io); 3095 try file.writeStreamingAll(self.io, token_hex); 3096 } 3097 3098 pub fn autoLogin(self: SessionStore, out: *[token_hex_len]u8) bool { 3099 out.* = self.auto_login orelse return false; 3100 return true; 3101 } 3102 3103 const auto_login_name = "auto-login"; 3104 3105 // a token is exactly token_hex_len hex chars. validating before using the 3106 // value as a path keeps attacker-supplied cookies from escaping the 3107 // sessions dir (e.g. via "/" or ".." bytes). 3108 fn isToken(token_hex: []const u8) bool { 3109 if (token_hex.len != token_hex_len) return false; 3110 for (token_hex) |c| if (!std.ascii.isHex(c)) return false; 3111 return true; 3112 } 3113 }; 3114