Proof of concept

packages/myid/.gitignore

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+.zig-cache
+*.sock
+*.sqlite3
+*.sqlite3-shm
+*.sqlite3-wal
+zig-out

packages/myid/build.zig

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+const std = @import("std");
+
+pub fn build(b: *std.Build) void {
+    const target = b.standardTargetOptions(.{});
+    const optimize = b.standardOptimizeOption(.{});
+
+    const sqlite_dep = b.dependency("sqlite", .{
+        .target = target,
+        .optimize = optimize,
+    });
+
+    const sqlite_mod = sqlite_dep.module("sqlite");
+
+    const myid_mod = b.addModule("myid", .{
+        .root_source_file = b.path("src/root.zig"),
+        .target = target,
+        .imports = &.{
+            .{ .name = "sqlite", .module = sqlite_mod },
+        },
+    });
+
+    const myid_exe = b.addExecutable(.{
+        .name = "myid",
+        .root_module = b.createModule(.{
+            .root_source_file = b.path("src/main.zig"),
+            .target = target,
+            .optimize = optimize,
+            .imports = &.{
+                .{ .name = "myid", .module = myid_mod },
+                .{ .name = "sqlite", .module = sqlite_mod },
+            },
+        }),
+    });
+
+    b.installArtifact(myid_exe);
+
+    const run_step = b.step("run", "Run the app");
+
+    const run_cmd = b.addRunArtifact(myid_exe);
+    run_step.dependOn(&run_cmd.step);
+
+    run_cmd.step.dependOn(b.getInstallStep());
+
+    if (b.args) |args| {
+        run_cmd.addArgs(args);
+    }
+
+    const mod_tests = b.addTest(.{
+        .root_module = myid_mod,
+    });
+
+    const run_mod_tests = b.addRunArtifact(mod_tests);
+
+    const exe_tests = b.addTest(.{
+        .root_module = myid_exe.root_module,
+    });
+
+    const run_exe_tests = b.addRunArtifact(exe_tests);
+
+    const test_step = b.step("test", "Run tests");
+    test_step.dependOn(&run_mod_tests.step);
+    test_step.dependOn(&run_exe_tests.step);
+}

packages/myid/build.zig.zon

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+.{
+    .name = .myid,
+    .version = "0.0.0",
+    .dependencies = .{
+        .sqlite = .{
+            .url = "git+https://github.com/vrischmann/zig-sqlite#be8b4965b46fc1a7a819bf3cba09f370c0e9c64c",
+            .hash = "sqlite-3.48.0-F2R_a9GLDgAXT-c49TfkFMt6yPOMQAYfp4ig8bRNdZs4",
+        },
+    },
+    .fingerprint = 0x4dc8d6b2af89dd8f, // Changing this has security and trust implications.
+    .minimum_zig_version = "0.15.0-dev.919+044ccf413",
+    .paths = .{
+        "build.zig",
+        "build.zig.zon",
+        "src",
+    },
+}

packages/myid/src/default.zig

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+pub const database_path = "db.sqlite3";
+pub const socket_path = "myid.sock";

packages/myid/src/http.zig

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+const std = @import("std");
+const main = @import("main.zig");
+
+threadlocal var read_buffer: [2 * 1024 * 1024]u8 = undefined;
+threadlocal var write_buffer: [2 * 1024 * 1024]u8 = undefined;
+
+const http_400 = "HTTP/1.1 400 Bad Request\r\n\r\n";
+const http_404 = "HTTP/1.1 404 Not Found\r\n\r\n";
+const http_413 = "HTTP/1.1 413 Content Too Large\r\n\r\n";
+const http_431 = "HTTP/1.1 431 Request Header Fields Too Large\r\n\r\n";
+const http_500 = "HTTP/1.1 500 Internal Server Error\r\n\r\n";
+
+const log = std.log.scoped(.http);
+
+fn http_200(content_type: []const u8, response_body: []const u8) ![]const u8 {
+    var fbs = std.io.fixedBufferStream(&write_buffer);
+    const writer = fbs.writer();
+
+    try writer.print("HTTP/1.1 200 OK\r\n", .{});
+    try writer.print("Content-Type: {s}\r\n", .{content_type});
+    try writer.print("Content-Length: {d}\r\n", .{response_body.len});
+    try writer.print("\r\n", .{});
+    try writer.print("{s}", .{response_body});
+
+    return fbs.getWritten();
+}
+
+pub fn process(conn: std.net.Server.Connection) !void {
+    defer conn.stream.close();
+
+    var arena = std.heap.ArenaAllocator.init(main.allocator);
+    defer arena.deinit();
+
+    const allocator = arena.allocator();
+    _ = allocator;
+
+    var running = true;
+    while (running) {
+        var header_end: ?usize = null;
+        var request_len: usize = 0;
+
+        const request_head = blk: while (conn.stream.read(read_buffer[request_len..])) |len| {
+            if (len == 0) {
+                running = false;
+                return;
+            }
+
+            header_end = std.mem.indexOfPos(u8, &read_buffer, request_len, "\r\n\r\n");
+            request_len += len;
+
+            if (header_end) |end| {
+                break :blk read_buffer[0..end];
+            }
+        } else |err| {
+            return err;
+        };
+
+        const response = try http_200("text/plain; charset=utf-8", "PONG\n");
+
+        try conn.stream.writeAll(response);
+
+        if (request_len > request_head.len + 4) {
+            @memmove(&read_buffer, read_buffer[request_head.len + 4 .. request_len]);
+        }
+    }
+}

packages/myid/src/main.zig

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+const std = @import("std");
+const default = @import("default.zig");
+const http = @import("http.zig");
+
+pub var allocator: std.mem.Allocator = undefined;
+pub var args: [][:0]u8 = undefined;
+pub var env: std.process.EnvMap = undefined;
+pub var config: struct {
+    database_path: []const u8 = default.database_path,
+    socket_path: []const u8 = default.socket_path,
+} = .{};
+
+pub fn main() !void {
+    var gpa: std.heap.GeneralPurposeAllocator(.{}) = .init;
+    defer _ = gpa.deinit();
+
+    allocator = gpa.allocator();
+
+    // --- READ CONFIG ---------------------------------------------------------
+
+    args = try std.process.argsAlloc(allocator);
+    defer std.process.argsFree(allocator, args);
+
+    env = try std.process.getEnvMap(allocator);
+    defer env.deinit();
+
+    // override config by environment variables
+
+    if (env.get("DATABASE_PATH")) |database_path| {
+        config.database_path = database_path;
+    }
+
+    if (env.get("SOCKET_PATH")) |socket_path| {
+        config.socket_path = socket_path;
+    }
+
+    // override config by args
+
+    var show_help = false;
+
+    var arg_i: usize = 1;
+    while (arg_i < args.len) : (arg_i += 1) {
+        const arg = args[arg_i];
+
+        if (std.mem.eql(u8, arg, "--database-path")) {
+            if (arg_i < args.len - 1) {
+                std.log.err("Missing argument for --database-path", .{});
+                return;
+            }
+
+            arg_i += 1;
+            config.database_path = args[arg_i];
+        } else if (std.mem.eql(u8, arg, "--socket-path")) {
+            if (arg_i < args.len - 1) {
+                std.log.err("Missing argument for --socket-path", .{});
+                return;
+            }
+
+            arg_i += 1;
+            config.socket_path = args[arg_i];
+        } else if (std.mem.eql(u8, arg, "--help") or std.mem.eql(u8, arg, "-h")) {
+            show_help = true;
+        } else {
+            std.log.err("Unrecognized option: {s}", .{arg});
+            return;
+        }
+    }
+
+    if (show_help) {
+        const stderr = std.io.getStdErr().writer();
+        try stderr.print(
+            \\Usage: myid [flags]
+            \\
+            \\Flags:
+            \\    --database-path <path>
+            \\        The path to an SQLite 3 database file. You can specify ":memory:" to use
+            \\        in-memory ephemeral database.
+            \\        Default: "{[default_database_path]s}"
+            \\    --socket-path <path>
+            \\        The path to a unix socket on which the server will listen.
+            \\        Default: "{[default_socket_path]s}"
+            \\
+            \\Environment variables:
+            \\    DATABASE_PATH
+            \\        Equivalent to --database-path flag. When both are present, the flag
+            \\        takes precedence.
+            \\    SOCKET_PATH
+            \\        Equivalent to --socket-path flag. When both are present, the flag takes
+            \\        precedence.
+            \\
+        , .{
+            .default_database_path = default.database_path,
+            .default_socket_path = default.socket_path,
+        });
+        return;
+    }
+
+    // --- INITIALIZE SERVER ---------------------------------------------------
+
+    std.posix.unlink(config.socket_path) catch |err| switch (err) {
+        error.FileNotFound => {},
+        else => return err,
+    };
+
+    const address = try std.net.Address.initUnix(config.socket_path);
+
+    var server = try address.listen(.{});
+    defer {
+        server.deinit();
+        std.log.info("Server stopped", .{});
+    }
+
+    std.log.info("Listening on unix:{s}", .{config.socket_path});
+
+    // --- LOOP ----------------------------------------------------------------
+
+    while (server.accept()) |conn| {
+        const thread = std.Thread.spawn(.{ .allocator = allocator }, process, .{conn}) catch |err| {
+            std.log.err("Error while spawning thread: {}", .{err});
+            continue;
+        };
+        thread.detach();
+    } else |err| {
+        std.log.err("Error while trying to accept connection: {}", .{err});
+    }
+}
+
+fn process(conn: std.net.Server.Connection) void {
+    http.process(conn) catch |err| {
+        // TODO Bandaid spam prevention until we manage closing connections properly
+        if (err == error.ConnectionResetByPeer) {
+            return;
+        }
+        std.log.err("Error while processing connection: {}", .{err});
+    };
+}

packages/myid/src/root.zig

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+const std = @import("std");
+const sqlite = @import("sqlite");
+const uuid = @import("uuid.zig");
+
+fn Id(comptime _tag: @Type(.enum_literal)) type {
+    return struct {
+        pub const tag = _tag;
+
+        bytes: [16]u8,
+
+        pub fn new() @This() {
+            return .{ .bytes = uuid.uuid_v7() };
+        }
+
+        pub fn eql(a: @This(), b: @This()) bool {
+            return std.mem.eql(u8, &a.bytes, &b.bytes);
+        }
+
+        pub fn decode(encoded: *const [22]u8) !@This() {
+            var bytes: [16]u8 = undefined;
+            try std.base64.url_safe_no_pad.Decoder.decode(&bytes, encoded);
+            return .{ .bytes = bytes };
+        }
+
+        pub fn encode(self: @This()) [22]u8 {
+            var text: [22]u8 = undefined;
+            std.base64.url_safe_no_pad.Encoder.encode(&text, self.bytes);
+            return text;
+        }
+    };
+}
+
+pub const AppId = Id(.app_id);
+pub const UserId = Id(.user_id);
+
+pub const CreateAppResult = struct {
+    aid: AppId,
+    plain_secret: [32]u8,
+};
+
+pub const Database = struct {
+    db: sqlite.Db,
+    allocator: std.mem.Allocator,
+
+    pub fn init(path: [:0]const u8, allocator: std.mem.Allocator) !Database {
+        var db = try sqlite.Db.init(.{
+            .mode = .{ .File = path },
+            .open_flags = .{
+                .create = true,
+                .write = true,
+            },
+            .threading_mode = .MultiThread,
+        });
+        errdefer db.deinit();
+
+        _ = try db.one(void, "PRAGMA journal_mode = WAL", .{}, .{});
+        _ = try db.one(void, "PRAGMA foreign_keys = ON", .{}, .{});
+
+        return .{
+            .db = db,
+            .allocator = allocator,
+        };
+    }
+
+    pub fn deinit(self: *Database) void {
+        self.db.deinit();
+        self.* = undefined;
+    }
+
+    // --- MIGRATION -----------------------------------------------------------
+
+    fn getUserVersion(self: *Database) !i32 {
+        const version = try self.db.one(i32, "PRAGMA user_version", .{}, .{});
+        return version.?;
+    }
+
+    fn setUserVersion(self: *Database, version: i32) !void {
+        var buf: [100]u8 = undefined;
+        const query = std.fmt.bufPrint(&buf, "PRAGMA user_version = {d}", .{version}) catch unreachable;
+        _ = try self.db.oneDynamic(void, query, .{}, .{});
+    }
+
+    pub fn migrate(self: *Database) !void {
+        var user_version = try self.getUserVersion();
+
+        if (user_version == 0) {
+            _ = try self.db.exec(
+                \\CREATE TABLE users (
+                \\    uid BLOB NOT NULL,
+                \\    name TEXT NOT NULL,
+                \\    email TEXT NOT NULL UNIQUE,
+                \\    password TEXT NOT NULL,
+                \\    PRIMARY KEY (uid)
+                \\)
+            , .{}, .{});
+            _ = try self.db.exec(
+                \\CREATE TABLE apps (
+                \\    aid BLOB NOT NULL,
+                \\    name TEXT NOT NULL,
+                \\    secret TEXT NOT NULL,
+                \\    PRIMARY KEY (aid)
+                \\)
+            , .{}, .{});
+            _ = try self.db.exec(
+                \\CREATE TABLE app_callbacks (
+                \\    aid BLOB NOT NULL,
+                \\    callback TEXT NOT NULL,
+                \\    PRIMARY KEY (aid, callback),
+                \\    FOREIGN KEY (aid) REFERENCES apps (aid)
+                \\        ON UPDATE CASCADE
+                \\        ON DELETE CASCADE
+                \\)
+            , .{}, .{});
+            user_version += 1;
+            try self.setUserVersion(user_version);
+        }
+    }
+
+    // --- USERS ---------------------------------------------------------------
+
+    pub fn createUser(self: *Database, name: []const u8, email: []const u8, plain_password: []const u8) !UserId {
+        const uid = UserId.new();
+        var password_buf: [1000]u8 = undefined;
+        const password = try std.crypto.pwhash.argon2.strHash(plain_password, .{
+            .allocator = self.allocator,
+            .mode = .argon2id,
+            .params = .owasp_2id,
+        }, &password_buf);
+
+        try self.db.exec("INSERT INTO users (uid, name, email, password) VALUES (?, ?, ?, ?)", .{}, .{
+            .uid = uid.bytes,
+            .name = name,
+            .email = email,
+            .password = password,
+        });
+
+        return uid;
+    }
+
+    // --- APPS ----------------------------------------------------------------
+
+    pub fn createApp(self: *Database, name: []const u8, callbacks: []const []const u8) !CreateAppResult {
+        _ = try self.db.exec("BEGIN", .{}, .{});
+        errdefer self.db.exec("ROLLBACK", .{}, .{}) catch unreachable;
+
+        const secret_bytes = blk: {
+            var bytes: [24]u8 = undefined;
+            std.crypto.random.bytes(&bytes);
+            break :blk bytes;
+        };
+
+        var plain_secret_buf: [32]u8 = undefined;
+        const plain_secret = std.base64.url_safe_no_pad.Encoder.encode(&plain_secret_buf, &secret_bytes);
+        std.debug.assert(plain_secret_buf.len == plain_secret.len);
+
+        const aid = AppId.new();
+        var secret_buf: [1000]u8 = undefined;
+        const secret = try std.crypto.pwhash.argon2.strHash(plain_secret, .{
+            .allocator = self.allocator,
+            .mode = .argon2id,
+            .params = .owasp_2id,
+        }, &secret_buf);
+
+        try self.db.exec("INSERT INTO apps (aid, name, secret) VALUES (?, ?, ?)", .{}, .{
+            .aid = aid.bytes,
+            .name = name,
+            .secret = secret,
+        });
+
+        var insert_callback = try self.db.prepare("INSERT INTO app_callbacks (aid, callback) VALUES (?, ?)");
+        defer insert_callback.deinit();
+        for (callbacks) |callback| {
+            try insert_callback.exec(.{}, .{ .aid = aid.bytes, .callback = callback });
+            insert_callback.reset();
+        }
+
+        try self.db.exec("COMMIT", .{}, .{});
+        return .{
+            .aid = aid,
+            .plain_secret = plain_secret_buf,
+        };
+    }
+};
+
+test "user version" {
+    var db = try Database.init(":memory:", std.testing.allocator);
+    defer db.deinit();
+
+    try std.testing.expectEqual(0, try db.getUserVersion());
+    try db.setUserVersion(1);
+    try std.testing.expectEqual(1, try db.getUserVersion());
+}
+
+test "migrate" {
+    var db = try Database.init(":memory:", std.testing.allocator);
+    defer db.deinit();
+
+    try db.migrate();
+}
+
+test "create user" {
+    var db = try Database.init(":memory:", std.testing.allocator);
+    defer db.deinit();
+
+    try db.migrate();
+
+    const uid = try db.createUser("admin", "admin@test.invalid", "admin");
+
+    var arena = std.heap.ArenaAllocator.init(std.testing.allocator);
+    const maybe_user = try db.db.oneAlloc(struct {
+        name: []const u8,
+        email: []const u8,
+        password: []const u8,
+    }, arena.allocator(), "SELECT name, email, password FROM users WHERE uid = ?", .{}, .{
+        .uid = uid.bytes,
+    });
+    defer arena.deinit();
+
+    try std.testing.expect(maybe_user != null);
+    if (maybe_user) |user| {
+        try std.testing.expectEqualSlices(u8, "admin", user.name);
+    }
+}
+
+test "create app" {
+    var db = try Database.init(":memory:", std.testing.allocator);
+    defer db.deinit();
+
+    try db.migrate();
+
+    _ = try db.createApp("app", &.{
+        "http://localhost:3000/callback",
+        "https://example.com/callback",
+    });
+}

packages/myid/src/uuid.zig

@@ -0,0 +1,41 @@
+const std = @import("std");
+
+var lock: std.Thread.Mutex = .{};
+var last_timestamp: std.atomic.Value(u64) = .{ .raw = 0 };
+var counter: std.atomic.Value(u32) = .{ .raw = 0 };
+
+fn getCount(timestamp: u64) u32 {
+    lock.lock();
+    defer lock.unlock();
+
+    if (last_timestamp.swap(timestamp, .monotonic) != timestamp) {
+        counter.store(0, .monotonic);
+    }
+
+    return counter.fetchAdd(1, .monotonic) % 4096;
+}
+
+pub fn uuid_v7() [16]u8 {
+    const timestamp: u64 = @intCast(@max(0, std.time.milliTimestamp()));
+    const count = getCount(timestamp);
+    const random = blk: {
+        var bytes: [8]u8 = undefined;
+        std.crypto.random.bytes(&bytes);
+        break :blk bytes;
+    };
+
+    var res: [16]u8 = undefined;
+
+    res[0] = @truncate(timestamp >> 40);
+    res[1] = @truncate(timestamp >> 32);
+    res[2] = @truncate(timestamp >> 24);
+    res[3] = @truncate(timestamp >> 16);
+    res[4] = @truncate(timestamp >> 8);
+    res[5] = @truncate(timestamp);
+    res[6] = (@as(u8, 7) << 4) | @as(u8, @truncate((count >> 8) & 0x0F));
+    res[7] = @truncate(count);
+    res[8] = 0x80 | (random[0] & 0x3F);
+    @memcpy(res[9..16], random[1..8]);
+
+    return res;
+}