Replace comments with zig version

12 files changed, 496 insertions, 227 deletions

diff --git a/comments/src/README.md b/comments/src/README.md
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/comments/src/README.md
diff --git a/comments/src/main.rs b/comments/src/main.rs
deleted file mode 100644
index 50f568f..0000000
--- a/comments/src/main.rs
+++ /dev/null
@@ -1,227 +0,0 @@
-/**
- * Comments generator
- * POST /comment - submits a comment
- * 
- * GET /form - generate html comment form
- * GET /comment - gets html fragment with comments
- * both accept a query parameter ?page=<url>
- */ 
- 
-use askama::Template;
-use axum::{
-    extract::{Query, Form, State},
-    response::{Redirect,Html},
-    http::StatusCode,
-    routing::get,
-    Router,
-};
-use lettre::{
-    AsyncSmtpTransport, AsyncTransport, Message, Tokio1Executor,
-    transport::smtp::authentication::Credentials
-};
-use serde::Deserialize;
-use sqlx::{
-    postgres::{PgPool, PgPoolOptions},
-    types::{
-        time::OffsetDateTime,
-        uuid::Uuid,
-    },
-};
-use std::{net::SocketAddr, time::Duration};
-
-
-// Useful global thingies
-#[derive(Clone)]
-struct Ctx {
-    pool: PgPool,
-    base_path: String,
-    mail_opts: Option<MailCtx>,
-}
-
-#[derive(Clone)]
-struct MailCtx {
-    notification_address: String,
-    smtp_server: String,
-    smtp_credentials: Credentials,
-}
-
-#[tokio::main]
-async fn main() {
-    let base_path = std::env::var("BASE_PATH")
-        .unwrap_or_else(|_| "/api".to_string());
-        
-    let db_connection_str = std::env::var("DATABASE_URL")
-        .unwrap_or_else(|_| "postgres://comments@localhost/comments".to_string());
-
-    let notification_address = std::env::var("NOTIFICATION_ADDRESS").ok();
-    let mail_opts = notification_address.map(|na| {
-        let smtp_server = std::env::var("SMTP_SERVER").expect("SMTP_SERVER  not supplied!");
-        let smtp_username = std::env::var("SMTP_USERNAME").expect("SMTP_USERNAME not supplied!");
-        let smtp_password = std::env::var("SMTP_PASSWORD").expect("SMTP_PASSWORD not supplied!");
-        MailCtx{
-            smtp_server: smtp_server,
-            smtp_credentials: Credentials::new(smtp_username, smtp_password),
-            notification_address: na,
-        }
-    });
-
-    let pool = PgPoolOptions::new()
-        .max_connections(5)
-        .connect_timeout(Duration::from_secs(3))
-        .connect(&db_connection_str)
-        .await
-        .expect("can't connect to database");
-    sqlx::migrate!()
-        .run(&pool)
-        .await
-        .expect("failed to run migrations");
-    
-    let ctx = Ctx {pool, base_path: base_path.clone(), mail_opts};
-
-    let app = Router::new()
-        .nest(&base_path, Router::new()
-            .route(
-                "/form",
-                get(get_form),
-            )
-            .route(
-                "/comment",
-                get(get_comments).post(post_comments),
-            )
-            .with_state(ctx));
-
-    let addr = SocketAddr::from(([127, 0, 0, 1], 5678));
-    axum::Server::bind(&addr)
-        .serve(app.into_make_service())
-        .await
-        .unwrap();
-}
-
-#[derive(Deserialize)]
-struct UrlQuery {
-    url: String
-}
-
-#[derive(Template)]
-#[template(path = "form.html")]
-struct CommentForm {
-    url: String,
-    capcha_question: String,
-    capcha_id: Uuid,
-    base_path: String,
-}
-
-async fn get_form(
-    State(ctx): State<Ctx>,
-    Query(uq): Query<UrlQuery>
-) -> Result<Html<String>, (StatusCode, String)> {
-    let capcha = sqlx::query!("select id, question from capchas order by random() limit 1")
-        .fetch_one(&ctx.pool)
-        .await
-        .map_err(internal_error)?;
-    let c = CommentForm{url: uq.url, capcha_question: capcha.question, capcha_id: capcha.id, base_path: ctx.base_path};
-    let res = c.render().map_err(internal_error)?;
-    Ok(Html(res))
-}
-
-#[derive(Template)]
-#[template(path = "comments.html")]
-struct Comments {
-    comments: Vec<Comment>,
-}
-struct Comment {
-    author: String,
-    comment: String,
-    ts: OffsetDateTime,
-}
-
-async fn get_comments(
-    State(ctx): State<Ctx>,
-    Query(uq): Query<UrlQuery>) -> Result<Html<String>, (StatusCode,String)> {
-    let comments = sqlx::query!("select author,comment,ts from comments where url = $1 order by ts", uq.url)
-        .fetch_all(&ctx.pool)
-        .await
-        .map_err(internal_error)?;
-    let render_comments: Vec<Comment> = comments.into_iter().map(|comment| {
-        Comment {
-            author: comment.author,
-            comment: comment.comment,
-            ts: comment.ts,
-        }
-    }).collect();
-    let c = Comments{comments: render_comments};
-    let res = c.render().map_err(internal_error)?;
-    Ok(Html(res))
-}
-
-#[derive(Deserialize)]
-struct PostComment {
-    url: String,
-    author: String,
-    comment: String,
-    capcha_id: String,
-    capcha_answer: String,
-}
-
-struct CapchaAnswer {
-    answer:String
-}
-
-#[derive(Template)]
-#[template(path = "notification.txt")]
-struct Notification<'a> {
-    url: &'a str,
-    comment: &'a str,
-    author: &'a str,
-}
-
-async fn post_comments(
-    State(ctx): State<Ctx>,
-    Form(post_comment): Form<PostComment>) -> Result<Redirect,(StatusCode,String)> {
-    let capcha_id: Uuid = post_comment.capcha_id.parse()
-        .map_err(|_| {(StatusCode::BAD_REQUEST, "Invalid capcha_id".to_string())})?;
-    let ans: CapchaAnswer = sqlx::query_as!(CapchaAnswer, "select answer from capchas where id = $1", capcha_id)
-        .fetch_one(&ctx.pool)
-        .await
-        .map_err(internal_error)?;
-    if post_comment.capcha_answer != ans.answer {
-        return Err((StatusCode::BAD_REQUEST, "Capcha was wrong!".to_string()));
-    }
-    sqlx::query!("insert into comments(url,author,comment) values($1, $2, $3)", post_comment.url, post_comment.author, post_comment.comment)
-        .execute(&ctx.pool)
-        .await
-        .map_err(internal_error)?;
-
-    if let Some(mail_opts) = ctx.mail_opts {
-        let mail_body = Notification{
-            url: &post_comment.url,
-            author: &post_comment.author,
-            comment: &post_comment.comment
-        }.render().unwrap();
-        let email = Message::builder()
-            // TODO should be a config value
-            .from("Comments Service <comments@mfashby.net>".parse().unwrap())
-            .to(mail_opts.notification_address.parse().unwrap())
-            .subject(format!("New comment on {}", post_comment.url))
-            .body(mail_body)
-            .unwrap();
-        let mailer: AsyncSmtpTransport<Tokio1Executor> =
-            AsyncSmtpTransport::<Tokio1Executor>::relay(&mail_opts.smtp_server)
-                .unwrap()
-                .credentials(mail_opts.smtp_credentials)
-                .build();
-        match mailer.send(email).await {
-            Ok(_) => (),
-            Err(e) => eprintln!("Could not send email: {:?}", e),
-        }
-    };
-    
-    Ok(Redirect::temporary(&post_comment.url))
-}
-
-fn internal_error<E>(err: E) -> (StatusCode, String)
-where
-    E: std::error::Error,
-{
-    (StatusCode::INTERNAL_SERVER_ERROR, err.to_string())
-}
diff --git a/comments/src/main.zig b/comments/src/main.zig
new file mode 100644
index 0000000..898b689
--- /dev/null
+++ b/comments/src/main.zig
@@ -0,0 +1,294 @@
+const std = @import("std");
+const zws = @import("zws");
+const pq = @import("pq.zig");
+const mustache = @import("mustache");
+
+const Params = zws.Params;
+
+const Err = error{
+    Unexpected,
+    AccessDenied,
+    OutOfMemory,
+    InputOutput,
+    SystemResources,
+    IsDir,
+    OperationAborted,
+    BrokenPipe,
+    ConnectionResetByPeer,
+    ConnectionTimedOut,
+    NotOpenForReading,
+    NetNameDeleted,
+    WouldBlock,
+    StreamTooLong,
+    Malformatted,
+    InvalidLength,
+    InvalidCharacter,
+    NoSpaceLeft,
+    PqError,
+    ColumnNotFound,
+    DiskQuota,
+    FileTooBig,
+    DeviceBusy,
+    InvalidArgument,
+    NotOpenForWriting,
+    LockViolation,
+    InvalidRequestMethod,
+};
+const Ctx = struct {
+    db: pq.Db,
+    pub fn clone(self: @This()) Ctx {
+        return Ctx{
+            .db = self.db,
+        };
+    }
+    pub fn deinit(self: @This()) void {
+        _ = self;
+    }
+};
+
+var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+const Request = struct {
+    method: std.http.Method,
+    target: []const u8,
+};
+const ResponseTransfer = union(enum) {
+    content_length: u64,
+    chunked: void,
+    none: void,
+};
+const Headers = struct {
+    const Entry = struct { key: []const u8, val: []const u8 };
+    _internal: std.ArrayList(Entry),
+
+    fn init(allocator: std.mem.Allocator) Headers {
+        return .{ ._internal = std.ArrayList(Entry).init(allocator) };
+    }
+    fn append(self: *@This(), key: []const u8, val: []const u8) !void {
+        try self._internal.append(.{ .key = key, .val = val });
+    }
+};
+const Response = struct {
+    allocator: std.mem.Allocator,
+    request: Request,
+    // TODO other fields and writer function to write headers and body to stdout
+    status: std.http.Status,
+    transfer_encoding: ResponseTransfer,
+    headers: Headers,
+    fn reader(_: @This()) std.fs.File.Reader {
+        return std.io.getStdIn().reader();
+    }
+    fn do(self: @This()) !void {
+        for (self.headers._internal.items) |tup| {
+            try std.io.getStdOut().writeAll(tup.key);
+            try std.io.getStdOut().writeAll(": ");
+            try std.io.getStdOut().writeAll(tup.val);
+            try std.io.getStdOut().writeAll("\r\n");
+        }
+        try std.io.getStdOut().writeAll("\r\n");
+    }
+    fn writer(_: @This()) std.fs.File.Writer {
+        return std.io.getStdOut().writer();
+    }
+    fn finish(_: @This()) !void {
+        // TODO Write empty lines? or just do nothing
+    }
+};
+
+const Rtr = zws.Router(*Response, Ctx, Err);
+const router = Rtr{
+    .allocator = gpa.allocator(),
+    .handlers = &[_]Rtr.Handler{
+        .{
+            .method = .GET,
+            .pattern = "/api/comment",
+            .handle_fn = get_comment,
+        },
+        .{
+            .method = .POST,
+            .pattern = "/api/comment",
+            .handle_fn = post_comment,
+        },
+        .{
+            .method = .GET,
+            .pattern = "/api/form",
+            .handle_fn = get_form,
+        },
+    },
+    .notfound = notfound,
+};
+
+/// Run as a CGI program!
+pub fn main() !void {
+    const allocator = gpa.allocator();
+    const db_url = std.os.getenv("DATABASE_URL") orelse "postgresql://comments@localhost/comments";
+    var db = try pq.Db.init(db_url);
+    // try db.exec(@embedFile("migrations/0_init.sql"));
+    // try db.exec(@embedFile("migrations/1_capcha.sql"));
+    defer db.deinit();
+    const req = Request{
+        .method = std.meta.stringToEnum(std.http.Method, std.os.getenv("REQUEST_METHOD") orelse "GET") orelse {
+            return error.InvalidRequestMethod;
+        },
+        .target = std.os.getenv("REQUEST_URI") orelse "/",
+    };
+    var res = Response{
+        .allocator = allocator,
+        .request = req,
+        .status = .bad_request,
+        .transfer_encoding = .none,
+        .headers = Headers.init(allocator),
+    };
+    const ctx = Ctx{ .db = db };
+    try router.handle(&res, ctx);
+}
+
+fn notfound(res: *Response, _: Ctx) Err!void {
+    const rr = @embedFile("templates/notfound.html");
+    try constresponse(res, rr, .not_found);
+}
+
+fn badrequest(res: *Response, _: Ctx) Err!void {
+    const rr = @embedFile("templates/badrequest.html");
+    try constresponse(res, rr, .bad_request);
+}
+
+fn constresponse(res: *Response, rr: []const u8, status: std.http.Status) Err!void {
+    res.status = status;
+    res.transfer_encoding = .{ .content_length = rr.len };
+    try res.headers.append("content-type", "text/html");
+    try res.do();
+    try res.writer().writeAll(rr);
+    try res.finish();
+}
+
+fn get_comment(res: *Response, ctx: Ctx, _: Params) Err!void {
+    var p = try zws.Path.parse(res.allocator, res.request.target);
+    defer p.deinit();
+    const url: []const u8 = try p.get_query_param("url") orelse {
+        try badrequest(res, ctx);
+        return;
+    };
+
+    const Comment = struct {
+        author: []const u8,
+        comment: []const u8,
+        ts: []const u8,
+    };
+    var comments = std.ArrayList(Comment).init(res.allocator);
+    var stmt = try ctx.db.prepare_statement(res.allocator,
+        \\ select author,comment,ts from comments where url = $1 order by ts
+    );
+    defer stmt.deinit();
+    try stmt.bind(0, url);
+    while (try stmt.step()) {
+        const cmt = try stmt.read_struct(Comment);
+        try comments.append(cmt);
+    }
+
+    const rr = @embedFile("templates/comments.html");
+    const tt = comptime mustache.parseComptime(rr, .{}, .{});
+    res.transfer_encoding = .chunked;
+    try res.headers.append("content-type", "text/html");
+    try res.do();
+
+    const data = struct {
+        comments: []const Comment,
+    };
+    try mustache.render(tt, data{
+        .comments = comments.items,
+    }, res.writer());
+    try res.finish();
+}
+
+fn post_comment(res: *Response, ctx: Ctx, _: Params) Err!void {
+    var body_aa = std.ArrayList(u8).init(res.allocator);
+    try res.reader().readAllArrayList(&body_aa, 1_000_000);
+    var body = try body_aa.toOwnedSlice();
+    var form = try zws.Form.parse(res.allocator, body);
+    const Form = struct {
+        url: []const u8,
+        capcha_id: []const u8,
+        author: []const u8,
+        comment: []const u8,
+        capcha_answer: []const u8,
+    };
+    const form_val = form.form_to_struct(Form) catch {
+        try badrequest(res, ctx);
+        return;
+    };
+
+    // Validate the capcha
+    {
+        var stmt = try ctx.db.prepare_statement(res.allocator, "select answer from capchas where id = $1");
+        defer stmt.deinit();
+        try stmt.bind(0, form_val.capcha_id);
+        if (!try stmt.step()) {
+            std.log.err("missing capcha_id {s}", .{form_val.capcha_id});
+            try badrequest(res, ctx);
+            return;
+        }
+        const ans = try stmt.read_column(0, []const u8);
+        if (!std.mem.eql(u8, ans, form_val.capcha_answer)) {
+            try constresponse(res, @embedFile("templates/capchainvalid.html"), std.http.Status.unauthorized);
+            return;
+        }
+    }
+
+    // Add the comment...
+    {
+        var stmt = try ctx.db.prepare_statement(res.allocator, "insert into comments(url,author,comment) values($1, $2, $3)");
+        defer stmt.deinit();
+        try stmt.bind(0, form_val.url);
+        try stmt.bind(1, form_val.author);
+        try stmt.bind(2, form_val.comment);
+        _ = try stmt.step();
+    }
+
+    // And redirect!
+    res.transfer_encoding = .none;
+    res.status = .found;
+    try res.headers.append("location", form_val.url);
+    try res.do();
+    try res.finish();
+}
+
+fn get_form(res: *Response, ctx: Ctx, _: Params) Err!void {
+    var p = try zws.Path.parse(res.allocator, res.request.target);
+    defer p.deinit();
+    const url: []const u8 = try p.get_query_param("url") orelse {
+        try badrequest(res, ctx);
+        return;
+    };
+
+    var stmt = try ctx.db.prepare_statement(res.allocator, "select id, question from capchas order by random() limit 1");
+    defer stmt.deinit();
+    if (!try stmt.step()) {
+        std.log.err("no capcha!", .{});
+        try badrequest(res, ctx);
+        return;
+    }
+    const Capcha = struct {
+        id: []const u8,
+        question: []const u8,
+    };
+    const capcha = try stmt.read_struct(Capcha);
+
+    const rr = @embedFile("templates/form.html");
+    const tt = comptime mustache.parseComptime(rr, .{}, .{});
+
+    res.transfer_encoding = .chunked;
+    try res.headers.append("content-type", "text/html");
+    try res.do();
+    // For some reason, mustache.render won't work with anonymous struct
+    const data = struct {
+        capcha_id: []const u8,
+        capcha_question: []const u8,
+        url: []const u8,
+    };
+    try mustache.render(tt, data{
+        .capcha_id = capcha.id,
+        .capcha_question = capcha.question,
+        .url = url,
+    }, res.writer());
+    try res.finish();
+}
diff --git a/comments/src/migrations/0_init.sql b/comments/src/migrations/0_init.sql
new file mode 100644
index 0000000..a799784
--- /dev/null
+++ b/comments/src/migrations/0_init.sql
@@ -0,0 +1,2 @@
+create table if not exists comments (url text not null, author text not null, comment text not null, ts timestamptz not null default now());
+create index if not exists idx_comments_url on comments(url);
\ No newline at end of file
diff --git a/comments/src/migrations/1_capcha.sql b/comments/src/migrations/1_capcha.sql
new file mode 100644
index 0000000..bf43331
--- /dev/null
+++ b/comments/src/migrations/1_capcha.sql
@@ -0,0 +1,6 @@
+create table if not exists capchas(question text not null, answer text not null, id uuid not null default gen_random_uuid()); 
+create unique index if not exists idx_capchas_id on capchas(id);
+insert into capchas(question, answer, id) values ('What is 1 + 3?', '4', 'de850c99-906b-4ff8-b8e7-fce3bccd89bc') on conflict do nothing;
+insert into capchas(question, answer, id) values ('If I have 3 apples and 4 pears, how many fruit do I have?', '7', 'c83e23a8-ec53-48d4-a468-a530dfa634b7') on conflict do nothing;
+insert into capchas(question, answer, id) values ('What is 3 squared?', '9', '798bf299-4e3b-4f98-acac-f0c41201b613') on conflict do nothing;
+insert into capchas(question, answer, id) values ('What is the meaning of life, the universe, and everything?', '42', '7025fcbf-ebe8-4679-809f-08d632591b03') on conflict do nothing;
diff --git a/comments/src/pq.zig b/comments/src/pq.zig
new file mode 100644
index 0000000..a4fc382
--- /dev/null
+++ b/comments/src/pq.zig
@@ -0,0 +1,151 @@
+const std = @import("std");
+const pq = @cImport(
+    @cInclude("libpq-fe.h"),
+);
+
+pub const PqError = error{PqError};
+
+// libpq wrapper
+// later, this could be a pure-zig client implementation
+pub const Db = struct {
+    c_conn: *pq.PGconn,
+    pub fn init(connect_url: [:0]const u8) !Db {
+        if (pq.PQisthreadsafe() == 0) {
+            std.log.err("PQisthreadsafe returned 0, can't use libpq in this program", .{});
+            return PqError.PqError;
+        }
+        var maybe_conn: ?*pq.PGconn = pq.PQconnectdb(connect_url);
+        if (maybe_conn == null) {
+            std.log.err("PQconnectdb returned null", .{});
+            return PqError.PqError;
+        }
+        if (pq.PQstatus(maybe_conn) == pq.CONNECTION_BAD) {
+            std.log.err("PQstatus returned CONNECTION_BAD: {s}", .{pq.PQerrorMessage(maybe_conn)});
+
+            return PqError.PqError;
+        } else if (pq.PQstatus(maybe_conn) != pq.CONNECTION_OK) {
+            std.log.err("PQstatus returned unknown status {}: {s}", .{ pq.PQstatus(maybe_conn), pq.PQerrorMessage(maybe_conn) });
+            return PqError.PqError;
+        }
+        return Db{
+            .c_conn = maybe_conn.?,
+        };
+    }
+
+    pub fn deinit(self: Db) void {
+        pq.PQfinish(self.c_conn);
+    }
+
+    pub fn exec(self: Db, query: [:0]const u8) !void {
+        var res: ?*pq.PGresult = pq.PQexec(self.c_conn, query);
+        defer pq.PQclear(res);
+        var est: pq.ExecStatusType = pq.PQresultStatus(res);
+        if (est != pq.PGRES_COMMAND_OK) {
+            std.log.err("PQexec error code {} message {s}", .{ est, pq.PQerrorMessage(self.c_conn) });
+            return PqError.PqError;
+        }
+    }
+
+    pub fn prepare_statement(self: Db, allocator: std.mem.Allocator, query: [:0]const u8) PqError!Stmt {
+        return Stmt{
+            .db = self,
+            .aa = std.heap.ArenaAllocator.init(allocator),
+            .query = query,
+        };
+    }
+};
+
+pub const Stmt = struct {
+    const MAX_PARAMS = 128;
+    db: Db,
+    query: [:0]const u8,
+    aa: std.heap.ArenaAllocator,
+
+    n_params: usize = 0,
+    param_values: [MAX_PARAMS][*c]const u8 = undefined,
+    did_exec: bool = false,
+    c_res: ?*pq.PGresult = null,
+    res_index: c_int = -1,
+    n_tuples: c_int = -1,
+    n_fields: c_int = -1,
+
+    pub fn deinit(self: *Stmt) void {
+        self.aa.deinit();
+        if (self.c_res != null) {
+            pq.PQclear(self.c_res);
+        }
+    }
+
+    pub fn step(self: *Stmt) !bool {
+        if (!self.did_exec) {
+            self.did_exec = true;
+            self.c_res = pq.PQexecParams(self.db.c_conn, self.query, @as(c_int, @intCast(self.n_params)), null, &self.param_values, null, null, 0);
+            const rs = pq.PQresultStatus(self.c_res);
+            if (rs != pq.PGRES_TUPLES_OK and rs != pq.PGRES_SINGLE_TUPLE and rs != pq.PGRES_COMMAND_OK) {
+                std.log.err("PQresultStatus {} error: {s}", .{ rs, pq.PQerrorMessage(self.db.c_conn) });
+                return PqError.PqError;
+            }
+            self.n_tuples = pq.PQntuples(self.c_res);
+            self.n_fields = pq.PQnfields(self.c_res);
+        }
+        self.res_index = self.res_index + 1;
+        return self.res_index < self.n_tuples;
+    }
+
+    pub fn read_column(self: Stmt, idx: c_int, comptime T: type) !T {
+        const value_c: [*c]u8 = pq.PQgetvalue(self.c_res, self.res_index, idx);
+        const value: []const u8 = std.mem.sliceTo(value_c, 0);
+        return switch (@typeInfo(T)) {
+            .Int => std.fmt.parseInt(T, value, 10),
+            .Pointer => |ptrinfo| blk: {
+                if (ptrinfo.child != u8) {
+                    @compileError("pointer type []const u8 only is supported in read_column");
+                }
+                if (ptrinfo.size != .Slice) {
+                    @compileError("pointer type []const u8 only is supported in read_column");
+                }
+                break :blk value;
+            },
+            else => @compileError("unhandled type " ++ @tagName(@typeInfo(T)) ++ " in read_column"),
+        };
+    }
+
+    pub fn read_columnN(self: Stmt, name: [:0]const u8, comptime T: type) !T {
+        const idx = pq.PQfnumber(self.c_res, name.ptr);
+        if (idx == -1) {
+            std.log.err("read_columnN ColumnNotFound [{s}]", .{name});
+            return error.ColumnNotFound;
+        }
+        return read_column(self, idx, T);
+    }
+
+    pub fn bind(self: *Stmt, idx: usize, t: anytype) !void {
+        const T = @TypeOf(t);
+        const value: [:0]const u8 = switch (@typeInfo(T)) {
+            .Pointer => try std.fmt.allocPrintZ(self.aa.allocator(), "{s}", .{t}),
+            .Int => try std.fmt.allocPrintZ(self.aa.allocator(), "{d}", .{t}),
+            else => @compileError("unhandled type " ++ @tagName(@typeInfo(T) ++ " in bind")),
+        };
+        self.param_values[idx] = value.ptr;
+        self.n_params = @max(self.n_params, idx + 1);
+    }
+
+    pub fn read_struct(self: Stmt, comptime T: type) !T {
+        const ti = @typeInfo(T);
+        var t: T = undefined;
+        inline for (ti.Struct.fields) |field| {
+            const name: [:0]const u8 = &addZ(field.name.len, field.name[0..].*);
+            const val = try self.read_columnN(name, field.type);
+            @field(t, field.name) = val;
+        }
+        return t;
+    }
+};
+
+// https://github.com/ziglang/zig/issues/16116
+pub fn addZ(comptime length: usize, value: [length]u8) [length:0]u8 {
+    var terminated_value: [length:0]u8 = undefined;
+    terminated_value[length] = 0;
+    @memcpy(&terminated_value, &value);
+    return terminated_value;
+}
diff --git a/comments/src/templates/badrequest.html b/comments/src/templates/badrequest.html
new file mode 100644
index 0000000..927e908
--- /dev/null
+++ b/comments/src/templates/badrequest.html
@@ -0,0 +1,6 @@
+<doctype HTML>
+<html>
+<body>
+    <p>Bad Request!</p>
+</body>
+</html>
\ No newline at end of file
diff --git a/comments/src/templates/capchainvalid.html b/comments/src/templates/capchainvalid.html
new file mode 100644
index 0000000..f13899b
--- /dev/null
+++ b/comments/src/templates/capchainvalid.html
@@ -0,0 +1,6 @@
+<doctype HTML>
+<html>
+<body>
+    <p>Capcha invalid!</p>
+</body>
+</html>
\ No newline at end of file
diff --git a/comments/src/templates/comments.html b/comments/src/templates/comments.html
new file mode 100644
index 0000000..e2fc6da
--- /dev/null
+++ b/comments/src/templates/comments.html
@@ -0,0 +1,9 @@
+<ul class="comments">
+{{#comments}}
+  <li class="comment">
+    <span class="comment author">{{author}}</span>
+    <p class="comment content">{{comment}}</p>
+    <span class="comment timestamp">{{ts}}</span>
+  </li>
+{{/comments}}
+</ul>
diff --git a/comments/src/templates/form.html b/comments/src/templates/form.html
new file mode 100644
index 0000000..e7a836f
--- /dev/null
+++ b/comments/src/templates/form.html
@@ -0,0 +1,11 @@
+<form action="/api/comment" method="post">
+  <input type="hidden" name="url" value="{{url}}"><br>
+  <input type="hidden" name="capcha_id" value="{{capcha_id}}"><br>
+  <label for="author">Name:</label><br>
+  <input type="text" id="author" name="author"><br>
+  <label for="comment">Comment:</label><br>
+  <input type="text" id="comment" name="comment"><br>
+  <label for="capcha">{{ capcha_question }}</label><br>
+  <input type="text" id="capcha" name="capcha_answer"><br>
+  <input type="submit" value="Submit">
+</form> 
diff --git a/comments/src/templates/notfound.html b/comments/src/templates/notfound.html
new file mode 100644
index 0000000..795d262
--- /dev/null
+++ b/comments/src/templates/notfound.html
@@ -0,0 +1,6 @@
+<!doctype HTML>
+<html>
+<body>
+    <p>Not found!</p>
+</body>
+</html>
\ No newline at end of file
diff --git a/comments/src/templates/notification.txt b/comments/src/templates/notification.txt
new file mode 100644
index 0000000..ba85056
--- /dev/null
+++ b/comments/src/templates/notification.txt
@@ -0,0 +1,5 @@
+New comment on {{ url }}:
+
+Author: {{ author }} 
+
+Comment: {{ comment }}
\ No newline at end of file