feat: add support for zig (vmware-labs#144)

kits/zig/worker/.gitignore

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+zig-cache/
+zig-out/

kits/zig/worker/README.md

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+# Zig kit
+
+This folder contains the Zig kit or SDK for Wasm Workers Server. Currently, it uses the regular STDIN / STDOUT approach to receive the request and provide the response.
+
+## build
+
+To build example in ./examples
+
+```
+$ zig build -Dtarget="wasm32-wasi"
+```

kits/zig/worker/build.zig

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+const std = @import("std");
+
+const package_name = "worker";
+const package_path = "src/worker.zig";
+
+const examples = [2][]const u8{ "main", "basic" };
+
+pub fn build(b: *std.Build) void {
+    const target = b.standardTargetOptions(.{ });
+    const optimize = b.standardOptimizeOption(.{});
+
+    const worker_module = b.createModule(.{
+        .source_file = .{ .path = package_path },
+    });
+
+    inline for (examples) |example| {
+        const exe = b.addExecutable(.{
+            .name = example,
+            .root_source_file = .{ .path = "examples/" ++ example ++ ".zig" },
+            .target = target,
+            .optimize = optimize,
+        });
+
+        exe.addModule("worker", worker_module);
+
+        b.installArtifact(exe);
+    }
+
+    // const exe = b.addExecutable(.{
+    //     .name = "worker",
+    //     // In this case the main source file is merely a path, however, in more
+    //     // complicated build scripts, this could be a generated file.
+    //     .root_source_file = .{ .path = "examples/main.zig" },
+    //     .target = target,
+    //     .optimize = optimize,
+    // });
+
+    // exe.addModule("worker", worker_module);
+    // // exe.install();
+
+    // // This declares intent for the executable to be installed into the
+    // // standard location when the user invokes the "install" step (the default
+    // // step when running `zig build`).
+    // b.installArtifact(exe);
+
+    // // This *creates* a Run step in the build graph, to be executed when another
+    // // step is evaluated that depends on it. The next line below will establish
+    // // such a dependency.
+    // const run_cmd = b.addRunArtifact(exe);
+
+    // // By making the run step depend on the install step, it will be run from the
+    // // installation directory rather than directly from within the cache directory.
+    // // This is not necessary, however, if the application depends on other installed
+    // // files, this ensures they will be present and in the expected location.
+    // run_cmd.step.dependOn(b.getInstallStep());
+
+    // // This allows the user to pass arguments to the application in the build
+    // // command itself, like this: `zig build run -- arg1 arg2 etc`
+    // if (b.args) |args| {
+    //     run_cmd.addArgs(args);
+    // }
+
+    // // This creates a build step. It will be visible in the `zig build --help` menu,
+    // // and can be selected like this: `zig build run`
+    // // This will evaluate the `run` step rather than the default, which is "install".
+    // const run_step = b.step("run", "Run the app");
+    // run_step.dependOn(&run_cmd.step);
+
+    // // Creates a step for unit testing. This only builds the test executable
+    // // but does not run it.
+    // const unit_tests = b.addTest(.{
+    //     .root_source_file = .{ .path = "src/main.zig" },
+    //     .target = target,
+    //     .optimize = optimize,
+    // });
+
+    // const run_unit_tests = b.addRunArtifact(unit_tests);
+
+    // // Similar to creating the run step earlier, this exposes a `test` step to
+    // // the `zig build --help` menu, providing a way for the user to request
+    // // running the unit tests.
+    // const test_step = b.step("test", "Run unit tests");
+    // test_step.dependOn(&run_unit_tests.step);
+}

kits/zig/worker/examples/basic.zig

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+const std = @import("std");
+const w = @import("worker");
+
+pub fn main() !void {
+    var word = w.GetWord();
+    std.debug.print("Hello from {s}!\n", .{ word });
+}

kits/zig/worker/examples/main.zig

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+const std = @import("std");
+const w = @import("worker");
+
+pub fn main() !void {
+    var word = w.GetWord();
+    std.debug.print("Hello from {s}!\n", .{ word });
+}

kits/zig/worker/src/worker.zig

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+const std = @import("std");
+const io = std.io;
+const http = std.http;
+
+pub fn GetWord() []const u8 {
+    return "lib";
+}
+
+var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
+const allocator = arena.allocator();
+
+pub var cache = std.StringHashMap([]const u8).init(allocator);
+pub var params = std.StringHashMap([]const u8).init(allocator);
+
+pub const Input = struct {
+    url: []const u8,
+    method: []const u8,
+    headers: std.StringHashMap([]const u8),
+    body: []const u8,
+};
+
+pub const Output = struct {
+	data: []const u8,
+	headers: std.StringArrayHashMap([]const u8),
+	status:  u16,
+	base64:  bool,
+
+	httpHeader: http.Headers,
+
+    const Self = @This();
+
+    pub fn init() Self {
+        return .{
+            .data = "",
+            .headers =  std.StringArrayHashMap([]const u8).init(allocator),
+            .status = 0,
+            .base64 = false,
+            .httpHeader = http.Headers.init(allocator),
+        };
+    }
+
+    pub fn header(self: *Self) http.Headers {
+        if (self.httpHeader == undefined) {
+            self.httpHeader = http.Headers.init(allocator);
+        }
+
+        return self.httpHeader;
+    }
+
+    pub fn writeHeader(self: *Self, statusCode: u16) void {
+        self.status = statusCode;
+    }
+
+    pub fn write(self: *Self, data: []const u8) !u32 {
+        // if (isValidUtf8(data)) {
+        if (isValidUtf8(data)) {
+            self.data = data;
+        } else {
+            self.base64 = true;
+            // is this correct?
+            const enc = std.base64.Base64Encoder.init(std.base64.url_safe_alphabet_chars, '=');
+            var dest: []u8 = undefined;
+            self.data = std.base64.Base64Encoder.encode(&enc, dest, data);
+        }
+
+        if (self.status == 0) {
+            self.status = 200;
+        }
+
+        // self.headers.init(allocator); // can we init thissomewhere else?
+        for (self.httpHeader.list.items) |item| {
+            std.debug.print("Fields: {!}\n", .{item});
+            // try self.headers.put(item.name, item.value);
+        }
+
+        // prepare writer for json
+        var out_buf: [1024]u8 = undefined;
+        var slice_stream = std.io.fixedBufferStream(&out_buf);
+        const out = slice_stream.writer();
+        var w = std.json.writeStream(out, .{ .whitespace = .indent_2 });
+
+        slice_stream.reset();
+        try w.beginObject();
+
+        try w.objectField("data");
+        try w.write(self.data);
+
+        try w.objectField("status");
+        try w.write(self.status);
+
+        try w.objectField("base64");
+        try w.write(self.base64);
+
+        try w.objectField("headers");
+        try self.headers.put("hello", "world");
+        try w.write(try getHeadersJsonObject(self.headers));
+
+        try cache.put("hello", "world");
+        try w.objectField("kv");
+        try w.write(try getCacheJsonObject(cache));
+
+        try w.endObject();
+        const result = slice_stream.getWritten();
+
+        // https://zig.news/kristoff/where-is-print-in-zig-57e9
+        // std.debug.print("{s}", .{out});
+        const stdout = std.io.getStdOut().writer();
+        try stdout.print("{s}", .{result});
+
+        return self.data.len;
+    }
+};
+
+fn getHeadersJsonObject(s: std.StringArrayHashMap([]const u8)) !std.json.Value {
+    var value = std.json.Value{ .object = std.json.ObjectMap.init(allocator) };
+
+    var i = s.iterator();
+    while (i.next()) |kv| {
+        try value.object.put(kv.key_ptr.*, std.json.Value{ .string = kv.value_ptr.*});
+    }
+
+    return value;
+}
+
+fn getCacheJsonObject(s: std.StringHashMap([]const u8)) !std.json.Value {
+    var value = std.json.Value{ .object = std.json.ObjectMap.init(allocator) };
+
+    var i = s.iterator();
+    while (i.next()) |kv| {
+        try value.object.put(kv.key_ptr.*, std.json.Value{ .string = kv.value_ptr.*});
+    }
+
+    return value;
+}
+
+pub fn readInput() !Input {
+    // https://www.openmymind.net/Reading-A-Json-Config-In-Zig/
+    const in = std.io.getStdIn();
+    var buf = std.io.bufferedReader(in.reader());
+    var r = buf.reader();
+
+    var msg_buf: [4096]u8 = undefined;
+
+    // delimiter "\n" might not be adequate?
+    if (r.readUntilDelimiterOrEof(&msg_buf, '\n')) |msg| {
+        if (msg) | m | {
+            std.debug.print("json: {s}\n", .{m});
+            return getInput(m);
+        }
+    } else |err| {
+        std.debug.print("error parsing json: {!}\n", .{err});
+    }
+
+    return Input{};
+}
+
+fn getInput(s: []const u8) !Input {
+    var parsed = try std.json.parseFromSlice(std.json.Value, allocator, s, .{});
+    defer parsed.deinit();
+
+    var input = Input{
+        .url = parsed.value.object.get("url").?.string,
+        .method = parsed.value.object.get("method").?.string,
+        .body = parsed.value.object.get("body").?.string,
+        .headers = std.StringHashMap([]const u8).init(allocator),
+    };
+
+    var headers_map = parsed.value.object.get("headers").?.object;
+
+    // can we maybe use an iterator here?
+    for (headers_map.keys()) |key| {
+        var v = try headers_map.getOrPut(key);
+        if (v.found_existing) {
+            var value = v.value_ptr.*.string;
+            std.debug.print("headers key: {s}, value: {s}\n", .{key, value});
+            try input.headers.put(key, value);
+        }
+    }
+
+    return input;
+}
+
+
+
+pub fn createRequest(in: *Input) !http.Client.Request {
+
+    // Create an HTTP client.
+    var client = http.Client{ .allocator = allocator };
+    // Release all associated resources with the client.
+    defer client.deinit();
+    // Parse the URI.
+
+    var req = client.Request{
+        .uri = in.url,
+        .method = in.method,
+        .headers = in.headers,
+    };
+
+    // req = req.WithContext(context.WithValue(req.Context(), CacheKey, cache));
+	// req = req.WithContext(context.WithValue(req.Context(), ParamsKey, params));
+
+    return req;
+}
+
+pub fn getWriterRequest() !@This() {
+    var in = readInput(allocator) catch |err| {
+        std.debug.print("error reading input: {s}\n", .{err});
+        return std.os.exit(1);
+    };
+
+    var req = createRequest(&in, allocator) catch |err| {
+        std.debug.print("error creating request : {s}\n", .{err});
+        return std.os.exit(1);
+    };
+
+    var w = Output{
+        .headers = std.StringHashMap([]const u8).init(allocator),
+    };
+
+    return .{
+        .req = req,
+        .w = w,
+    };
+}
+
+// works
+// pub fn ServeFunc(f: anytype) void {
+//     f();
+// }
+
+
+// works as function budy, must be comptime-known
+// pub fn ServeFunc(comptime cool: fn () void) void {
+//     cool();
+// }
+
+// works as function pointer
+pub fn ServeFunc(cool: *const fn (*http.Server.Response) void) void {
+    var r = try getWriterRequest(allocator);
+    cool(r.req);
+}
+
+
+// This is from ChatGPT - I have no clue whether this works, nor whats going on here :D
+fn isValidUtf8(data: []const u8) bool {
+    var i: usize = 0;
+    while (i < data.len) {
+        const byte: u8 = data[i];
+        if (byte < 0x80) {
+            // ASCII character
+            i += 1;
+        } else if (byte < 0xC2) {
+            // Invalid continuation byte
+            return false;
+        } else if (byte < 0xE0) {
+            // 2-byte sequence
+            if ((i + 1 >= data.len) || ((data[i + 1] & 0xC0) != 0x80)) {
+                return false;
+            }
+            i += 2;
+        } else if (byte < 0xF0) {
+            // 3-byte sequence
+            if ((i + 2 >= data.len) || ((data[i + 1] & 0xC0) != 0x80) || ((data[i + 2] & 0xC0) != 0x80)) {
+                return false;
+            }
+            i += 3;
+        } else if (byte < 0xF5) {
+            // 4-byte sequence
+            if ((i + 3 >= data.len) || ((data[i + 1] & 0xC0) != 0x80) || ((data[i + 2] & 0xC0) != 0x80) || ((data[i + 3] & 0xC0) != 0x80)) {
+                return false;
+            }
+            i += 4;
+        } else {
+            // Invalid UTF-8 byte
+            return false;
+        }
+    }
+    return true;
+}