From 5ed483825a50cadb1d3d2dd55f9e4ebc52716660 Mon Sep 17 00:00:00 2001
From: Martin Ashby <martin@ashbysoft.com>
Date: Mon, 4 Mar 2024 15:55:07 +0000
Subject: Move web server to it's own subdir

---
 server/build.zig     |  36 +++++
 server/build.zig.zon |   9 ++
 server/src/main.zig  | 431 +++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 476 insertions(+)
 create mode 100644 server/build.zig
 create mode 100644 server/build.zig.zon
 create mode 100644 server/src/main.zig

(limited to 'server')

diff --git a/server/build.zig b/server/build.zig
new file mode 100644
index 0000000..1f481c8
--- /dev/null
+++ b/server/build.zig
@@ -0,0 +1,36 @@
+const std = @import("std");
+
+pub fn build(b: *std.Build) void {
+    const target = b.standardTargetOptions(.{});
+    const optimize = b.standardOptimizeOption(.{});
+
+    const exe = b.addExecutable(.{
+        .name = "server",
+        .root_source_file = .{ .path = "src/main.zig" },
+        .target = target,
+        .optimize = optimize,
+    });
+
+    b.installArtifact(exe);
+    const run_cmd = b.addRunArtifact(exe);
+
+    run_cmd.step.dependOn(b.getInstallStep());
+
+    if (b.args) |args| {
+        run_cmd.addArgs(args);
+    }
+
+    const run_step = b.step("run", "Run the app");
+    run_step.dependOn(&run_cmd.step);
+
+    const exe_unit_tests = b.addTest(.{
+        .root_source_file = .{ .path = "src/main.zig" },
+        .target = target,
+        .optimize = optimize,
+    });
+
+    const run_exe_unit_tests = b.addRunArtifact(exe_unit_tests);
+
+    const test_step = b.step("test", "Run unit tests");
+    test_step.dependOn(&run_exe_unit_tests.step);
+}
diff --git a/server/build.zig.zon b/server/build.zig.zon
new file mode 100644
index 0000000..d68b536
--- /dev/null
+++ b/server/build.zig.zon
@@ -0,0 +1,9 @@
+.{
+    .name = "server",
+    .version = "0.0.0",
+    .dependencies = .{
+    },
+    .paths = .{
+        "",
+    },
+}
diff --git a/server/src/main.zig b/server/src/main.zig
new file mode 100644
index 0000000..f9f204b
--- /dev/null
+++ b/server/src/main.zig
@@ -0,0 +1,431 @@
+const std = @import("std");
+const log = std.log.scoped(.server);
+
+// Web server for mfashby.net
+// It does _not_ follow the unix philosophy (:
+// Initially it replaces caddy, and it needs to be capable of these things 
+// to actually be usable
+//  - http(s) (otherwise it's not a web server...) ✅ https isn't supported because zig http server (in fact there's no TLS server implementation). For now I'll have to use haproxy
+//  - routing, including virtual host              ✅
+//  - serving static content from selected folders ✅
+//  - executing CGI programs                       ✅
+//  - reverse proxy                                ❌
+
+// And I should probably test it thoroughly before exposing is to the 'net
+
+// Future possibilities: 
+//  - subsume some CGI programs directly into the web server e.g. my comments program
+//  - and maybe even cgit (although I might scrap it in favour of stagit if I can figure out archive downloads
+//  - do something about efficiency :) it's thread-per-request right now
+pub fn main() !void {
+    var gpa = std.heap.GeneralPurposeAllocator(.{ .thread_safe = true }){};
+    defer _ = gpa.deinit();
+    const a = gpa.allocator();
+    var pool: std.Thread.Pool = undefined;
+    try std.Thread.Pool.init(&pool, .{ .allocator = a, .n_jobs = 32 });
+    defer pool.deinit();
+    var svr = std.http.Server.init(.{ .reuse_address = true, .reuse_port = true });
+    defer svr.deinit();
+    const port = 8081;
+    const addr = std.net.Address.initIp4(.{0,0,0,0}, port);
+    try svr.listen(addr);
+    log.info("listening on {}", .{addr});
+    try acceptLoop(a, &svr, &pool, struct{
+        fn cancelled() bool {
+            return false;
+        }
+    });
+}
+
+fn acceptLoop(a: std.mem.Allocator, svr: *std.http.Server, pool: *std.Thread.Pool, cancel: anytype) !void {
+    while (!cancel.cancelled()) {
+        // Create the Response into the heap so that the ownership goes to the handling thread
+        const res = try a.create(std.http.Server.Response);
+        errdefer a.destroy(res);
+        res.* = try svr.accept(.{ .allocator = a });
+        errdefer res.deinit();
+        if (cancel.cancelled()) {
+            res.deinit();
+            a.destroy(res);
+            break;
+        }
+        try pool.spawn(handle, .{res});
+    }
+}
+
+fn handle(res: *std.http.Server.Response) void {
+    defer res.allocator.destroy(res);
+    defer res.deinit();
+    handleRoute(res) catch |e| {
+        log.info("error {}", .{e});
+        if (@errorReturnTrace()) |trace| {
+            std.debug.dumpStackTrace(trace.*);
+        }
+        sendError(res, e) catch |e2| {
+            log.info("error sending error {}", .{e2});
+            if (@errorReturnTrace()) |trace| {
+                std.debug.dumpStackTrace(trace.*);
+            }
+        };
+    };
+}
+
+fn handleRoute(res: *std.http.Server.Response) !void {
+    try res.wait();
+
+    // Route, virtual host first
+    var host: []const u8 = "";
+    if (res.request.headers.getFirstValue("Host")) |host_header| {
+        var spl = std.mem.splitScalar(u8, host_header, ':');
+        host = spl.first();
+    }
+
+    const uri = std.Uri.parseWithoutScheme(res.request.target) catch {
+        res.status = .bad_request;
+        const msg = "bad request target";
+        res.transfer_encoding = .{ .content_length = msg.len };
+        try res.send();
+        try res.writeAll(msg);
+        try res.finish();
+        return;
+    };
+
+    if (std.mem.eql(u8, host, "localhost")) {
+        if (std.mem.startsWith(u8,  uri.path, "/api")) {
+            try serveCgi(res, "/home/martin/dev/mfashby.net/comments/zig-out/bin/comments",
+                &.{"DATABASE_URL","SMTP_USERNAME","SMTP_PASSWORD","NOTIFICATION_ADDRESS","SMTP_SERVER"});
+        } else {
+            try serveStatic(res, "public");
+        }
+    } else {
+        const ans = "You have reached mfashby.net ... but did you mean to?";
+        res.status = .ok;
+        res.transfer_encoding = .{ .content_length = ans.len };
+        try res.send();
+        try res.writeAll(ans);
+        try res.finish();
+    }
+}
+
+fn serveCgi(res: *std.http.Server.Response, executable: []const u8,
+            comptime env_copy: []const []const u8) !void {
+    var child = std.ChildProcess.init(&.{executable}, res.allocator);
+    child.stdin_behavior = .Pipe;
+    child.stdout_behavior = .Pipe;
+    child.stderr_behavior = .Pipe;
+
+    var env = std.process.EnvMap.init(res.allocator);
+    try env.put("REQUEST_METHOD", @tagName(res.request.method));
+    try env.put("REQUEST_URI", res.request.target);
+    inline for (env_copy) |key| {
+        try env.put(key, std.os.getenv(key) orelse "");
+    }
+    var clb = [_]u8{0}**30;
+    if (res.request.method == .POST) {
+        if (res.request.content_length) |cl| {
+            try env.put("CONTENT_LENGTH", try std.fmt.bufPrint(&clb, "{}", .{cl}));
+        }
+    }
+    child.env_map = &env;
+    try child.spawn();
+    
+    if (res.request.method == .POST) {
+        if (res.request.content_length) |cl| {
+            log.info("sending {} data as CGI body", .{cl});
+            try pump(res.reader(), child.stdin.?.writer(), cl);
+        } else {
+            _ = try pumpUnknown(res.reader(), child.stdin.?.writer());
+        }
+    }
+    var stdout = std.ArrayList(u8).init(res.allocator);
+    var stderr = std.ArrayList(u8).init(res.allocator);
+    defer stdout.deinit();
+    defer stderr.deinit();
+    defer {
+        if (stderr.items.len>0) {
+            log.err("CGI error: {s}", .{stderr.items});
+        }
+    }
+    try child.collectOutput(&stdout, &stderr, 1_000_000);
+    const term = try child.wait();
+    if (term.Exited != 0) {
+        return error.ProcessError;
+    }
+
+    var fbs = std.io.fixedBufferStream(stdout.items);
+    var reader = fbs.reader();
+    var headerLine = std.ArrayList(u8).init(res.allocator);
+    defer headerLine.deinit();
+    while (true) {
+        headerLine.clearRetainingCapacity();
+        try reader.streamUntilDelimiter(headerLine.writer(), '\r', 8192);
+        _ = try reader.skipBytes(1, .{}); // \n
+        if (headerLine.items.len == 0) {
+            break;
+        }
+        var spl = std.mem.splitScalar(u8, headerLine.items, ':');
+        const key = try std.ascii.allocLowerString(res.allocator, spl.first());
+        defer res.allocator.free(key);
+        if (std.mem.eql(u8, key, "status")) {
+            const value = spl.rest();
+            var spl2 = std.mem.splitScalar(u8, std.mem.trim(u8, value, " "), ' ');
+            res.status = @enumFromInt(try std.fmt.parseInt(u16, spl2.first(), 10));
+            log.info("status from CGI {}", .{res.status});
+        } else if (std.mem.eql(u8, key, "content-length")) {
+            const value = spl.rest();
+            res.transfer_encoding = .{.content_length = try std.fmt.parseInt(usize, value, 10)};
+            log.info("transfer_encoding from CGI {}", .{res.transfer_encoding});
+        } else {
+            const value = spl.rest();
+            try res.headers.append(key, std.mem.trim(u8, value, " "));
+            log.info("header from CGI {s}: {s}", .{key, value});
+        }
+    }
+
+    if (res.transfer_encoding == .content_length) {
+        try res.send();
+        try pump(reader, res.writer(), res.transfer_encoding.content_length);
+    } else {
+        res.transfer_encoding = .chunked;
+        try res.send();
+        _ = try pumpUnknown(reader, res.writer());
+    }
+    try res.finish();
+}
+
+fn serveStatic(res: *std.http.Server.Response, dirname: []const u8) !void {
+    const dirpath = try std.fs.realpathAlloc(res.allocator, dirname);
+    defer res.allocator.free(dirpath);
+
+    // Path massaging
+    const uri = std.Uri.parseWithoutScheme(res.request.target) catch {
+        res.status = .bad_request;
+        const msg = "bad request target";
+        res.transfer_encoding = .{ .content_length = msg.len };
+        try res.send();
+        try res.writeAll(msg);
+        try res.finish();
+        return;
+    };
+    var requested_path = uri.path;
+    requested_path = try std.fs.path.join(res.allocator, &.{ dirpath, requested_path });
+    defer res.allocator.free(requested_path);
+
+
+    const path = std.fs.realpathAlloc(res.allocator, requested_path) catch |e| {
+        res.status = switch (e) {
+            error.FileNotFound => .not_found,
+            error.AccessDenied => .forbidden,
+            error.BadPathName => .bad_request,
+            else => .internal_server_error,
+        };
+        const msg = try std.fmt.allocPrint(res.allocator, "error: {}", .{e});
+        defer res.allocator.free(msg);
+        res.transfer_encoding = .{ .content_length = msg.len };
+        try res.send();
+        try res.writeAll(msg);
+        try res.finish();
+        return;
+    };
+
+    defer res.allocator.free(path);
+    if (!std.mem.startsWith(u8, path, dirpath)) {
+        res.status = .bad_request;
+        const msg = try std.fmt.allocPrint(res.allocator, "Trying to escape the root directory {s}", .{path});
+        defer res.allocator.free(msg);
+        res.transfer_encoding = .{ .content_length = msg.len };
+        try res.send();
+        try res.writeAll(msg);
+        try res.finish();
+        return;
+    }
+    const f = std.fs.openFileAbsolute(path, .{}) catch |e| {
+        res.status = switch (e) {
+            error.FileNotFound => .not_found,
+            error.AccessDenied => .forbidden,
+            error.BadPathName, error.NameTooLong => .bad_request,
+            else => .internal_server_error,
+        };
+        const msg = try std.fmt.allocPrint(res.allocator, "error: {}", .{e});
+        defer res.allocator.free(msg);
+        res.transfer_encoding = .{ .content_length = msg.len };
+        try res.send();
+        try res.writeAll(msg);
+        try res.finish();
+        return;
+    };
+    defer f.close();
+    const stat = try f.stat();
+    switch (stat.kind) {
+        .file => {
+            res.transfer_encoding = .{ .content_length = stat.size };
+            try res.send();
+            try pump(f.reader(), res.writer(), stat.size);
+            try res.finish();
+        },
+        .directory => {
+            const index_path = try std.fs.path.join(res.allocator, &.{path, "index.html"});
+            defer res.allocator.free(index_path);
+            const index_f = std.fs.openFileAbsolute(index_path, .{}) catch |e| {
+                res.status = switch (e) {
+                    error.FileNotFound => .not_found,
+                    error.AccessDenied => .forbidden,
+                    error.BadPathName, error.NameTooLong => .bad_request,
+                    else => .internal_server_error,
+                };
+                const msg = try std.fmt.allocPrint(res.allocator, "error: {}", .{e});
+                defer res.allocator.free(msg);
+                res.transfer_encoding = .{ .content_length = msg.len };
+                try res.send();
+                try res.writeAll(msg);
+                try res.finish();
+                return;
+            };
+            defer index_f.close();
+            const index_stat = try index_f.stat();
+            res.transfer_encoding = .{ .content_length = index_stat.size };
+            try res.send();
+            try pump(index_f.reader(), res.writer(), index_stat.size);
+            try res.finish();  
+        },
+        else => {
+            const msg = "unable to serve unsupported file kind";
+            res.status = .unavailable_for_legal_reasons;
+            res.transfer_encoding = .{.content_length = msg.len};
+            try res.send();
+            try res.writeAll(msg);
+            try res.finish();
+        }
+    }
+    
+}
+
+fn pumpUnknown(reader: anytype, writer: anytype) !usize {
+    var read: usize = 0;
+    var buf: [1024]u8 = undefined;
+    while (true) {
+        const sz = try reader.read(&buf);
+        if (sz == 0) break;
+        read += sz;
+        try writer.writeAll(buf[0..sz]);
+    }
+    return read;
+}
+
+fn pump(reader: anytype, writer: anytype, expected: usize) !void {
+    var read: usize = 0;
+    var buf: [1024]u8 = undefined;
+    while (true) {
+        const sz = try reader.read(&buf);
+        if (sz == 0) break;
+        read += sz;
+        if (read > expected) return error.TooMuchData;
+        try writer.writeAll(buf[0..sz]);
+    }
+    if (read != expected) {
+        return error.NotEnoughData;
+    }
+}
+
+
+fn sendError(res: *std.http.Server.Response, e: anyerror) !void {
+    switch (res.state) {
+        .first, .start, .waited => {
+            if (res.state != .waited) {
+                try res.wait();
+            }
+            const errmsg = try std.fmt.allocPrint(res.allocator, "Error: {}", .{e});
+            defer res.allocator.free(errmsg);
+            // Now send an error
+            res.status = .internal_server_error;
+            res.transfer_encoding = .{ .content_length = errmsg.len };
+            try res.send();
+            try res.writeAll(errmsg);
+            try res.finish();
+        },
+        .responded, .finished => {
+            // Too late!
+            log.err("can't send an error, response already sent, state {}", .{res.state});
+        },
+    }
+}
+
+const Fixture = struct {
+    a: std.mem.Allocator,
+    port: u16,
+    t: std.Thread,
+    cancel: std.atomic.Value(bool),
+    base_url: []const u8,
+    thread_pool: std.Thread.Pool,
+    server: std.http.Server,
+    client: std.http.Client,
+
+    fn init(a: std.mem.Allocator) !*Fixture {
+        var res: *Fixture = try a.create(Fixture);
+        errdefer a.destroy(res);
+        res.a = a;
+        try std.Thread.Pool.init(&res.thread_pool, .{ .allocator = a, .n_jobs = 32 });
+        errdefer res.thread_pool.deinit();
+        res.server = std.http.Server.init(.{ .reuse_address = true, .reuse_port = true });
+        errdefer res.server.deinit();
+        const addr = std.net.Address.initIp4(.{127,0,0,1}, 0);
+        try res.server.listen(addr);
+        res.port = res.server.socket.listen_address.in.getPort();
+        res.base_url = try std.fmt.allocPrint(a, "http://localhost:{}", .{res.port});
+        errdefer a.free(res.base_url);
+        res.cancel = std.atomic.Value(bool).init(false);
+        res.t = try std.Thread.spawn(.{}, acceptLoop, .{a, &res.server, &res.thread_pool, res});
+        res.client = .{.allocator = a};
+        return res;
+    }
+
+    fn deinit(self: *Fixture) void {
+        self.client.deinit();
+        self.a.free(self.base_url);
+        self.cancel.store(true, .Unordered);
+        // Trigger the server's accept() method to wake it up
+        if (std.net.tcpConnectToAddress(std.net.Address.initIp4(.{127,0,0,1}, self.port))) |stream| {
+            stream.close();
+        } else |_| {}
+        self.t.join();
+        self.thread_pool.deinit();
+        self.server.deinit();
+        self.a.destroy(self);
+    }
+
+    fn cancelled(self: *Fixture) bool {
+        return self.cancel.load(.Unordered);
+    }
+};
+
+
+test "static pages" {
+    const a = std.testing.allocator;
+    var f = try Fixture.init(a);
+    defer f.deinit();
+    const TestCase = struct {
+        path: []const u8,
+        file: []const u8,
+    };
+    const test_cases = [_]TestCase{
+        .{ .path = "/", .file = "public/index.html"},
+        .{ .path = "/posts/2018-05-31-new-site/", .file = "public/posts/2018-05-31-new-site/index.html"},
+    };
+
+    for (test_cases) |test_case| {
+        const url = try std.fmt.allocPrint(a, "{s}{s}", .{f.base_url, test_case.path});
+        defer a.free(url);
+        var fr = try f.client.fetch(a, .{
+            .location = .{.url = url}
+            });
+        defer fr.deinit();
+        try std.testing.expectEqual(std.http.Status.ok, fr.status);
+        const expected = try std.fs.cwd().readFileAlloc(a, test_case.file, 1_000_000);
+        defer a.free(expected);
+        try std.testing.expectEqualStrings(expected, fr.body.?);
+    }
+}
+
+// test "404" {
+
+// }
\ No newline at end of file
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