966 lines
32 KiB
Markdown
966 lines
32 KiB
Markdown
# MACH
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C23 web framework. App = `config mach()` returning `(config){...}` of resources, databases, modules, etc. Each request runs a pipeline of steps over a shared context.
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## Guide
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A todo app, built one concept at a time. Each step shows only the new pieces; carry forward the previous code.
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### 1. A Page
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Two resources, each with a GET pipeline. `{{url:name}}` resolves at render time.
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```c
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#include <mach.h>
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config mach(){
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return (config) {
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.resources = {
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{"home", "/",
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.get = { render(.template =
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"<html><body><h1>Welcome</h1>"
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"<a href='{{url:todos}}'>My Todos</a>"
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"</body></html>") }
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},
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{"todos", "/todos",
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.get = { render(.template = "<h1>My Todos</h1><p>Nothing yet.</p>") }
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}
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}
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};
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}
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```
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### 2. Show Data
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Add SQLite. `query()` stores rows under `todos`; template opens the section to iterate.
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```c
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#include <sqlite.h>
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// inside todos resource:
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.get = {
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query({.set_key = "todos", .db = "todos_db",
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.query = "select id, title from todos;"}),
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render(.template =
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"<h1>My Todos</h1>"
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"<ul>{{#todos}}<li>{{title}}</li>{{/todos}}</ul>")
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}
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// inside config:
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.databases = {{
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.engine = sqlite_db,
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.name = "todos_db",
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.connect = "file:todos.db?mode=rwc",
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.migrations = {
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"CREATE TABLE todos ("
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"id INTEGER PRIMARY KEY AUTOINCREMENT,"
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"title TEXT NOT NULL"
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");"
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},
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.seeds = {"INSERT INTO todos(title) VALUES('Learn MACH');"}
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}},
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.modules = {sqlite}
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```
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To fetch two things concurrently, put both items in one `query()`:
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```c
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query(
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{.set_key="todos", .db="todos_db", .query="select id, title from todos;"},
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{.set_key="count", .db="todos_db", .query="select count(*) as n from todos;"}
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)
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```
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### 3. Accept Input
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`validate()` then `query()` then `redirect()` (POST-redirect-GET). On success, `title` is promoted from `input:title` to app scope and bound as a prepared parameter in the SQL.
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```c
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.post = {
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validate({"title",
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.validation = validate_not_empty,
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.message = "title cannot be empty"}),
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query({.db = "todos_db",
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.query = "insert into todos(title) values({{title}});"}),
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redirect("todos")
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}
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```
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Add a form to the GET template; `{{input:title}}` repopulates after errors:
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```html
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<form method='post' action='{{url:todos}}'>
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<input name='title' value='{{input:title}}'>
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<button>Add</button>
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</form>
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```
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### 4. Handle Errors
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`validate()` failure raises `http_bad_request`. A resource-scoped error handler re-enters the GET pipeline with `reroute()`. Both `input:` and `error:` scopes persist through the reroute.
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```c
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.errors = {
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{http_bad_request, { reroute("todos") }}
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}
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```
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Show the error in the template:
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```html
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<input name='title' value='{{input:title}}'>
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{{#error:title}}<span>{{error_message:title}}</span>{{/error:title}}
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```
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### 5. Nested Data
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Fetch parent + children concurrently, `join()` to nest, then enter the parent section to render. Comments live in the same database as todos, so add a migration on the existing `todos_db`.
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```c
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{"todo", "/todos/:id",
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.get = {
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validate({"id", .validation = validate_integer,
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.message = "must be an integer"}),
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query(
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{.set_key = "todo", .db = "todos_db",
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.query = "select id, title from todos where id = {{id}};"},
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{.set_key = "comments", .db = "todos_db",
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.query = "select id, todo_id, body from comments where todo_id = {{id}};"}
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),
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join(
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.target_table_key = "todo",
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.target_field_key = "id",
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.nested_table_key = "comments",
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.nested_field_key = "todo_id",
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.target_join_field_key = "comments"
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),
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render(.template =
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"{{#todo}}"
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"<h1>{{title}}</h1>"
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"<ul>{{#comments}}<li>{{body}}</li>{{/comments}}</ul>"
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"{{/todo}}")
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}
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}
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```
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After `join()`, `comments` lives INSIDE each `todo` record. Reach it from within `{{#todo}}`. Iterating `{{#comments}}` at root after a join renders nothing.
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### 6. Tasks
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Tasks run async on task reactors. Trigger with `task("name")` or via `.cron`. Same task can be both. Tasks are durable — the process can crash mid-task and resume at the failed step on next boot.
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```c
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// in POST pipeline:
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.post = {
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validate({...}),
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query({...}),
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task("record_daily_stats"),
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redirect("todos")
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}
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// at config level:
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.tasks = {
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{"record_daily_stats", {
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query({.db = "todos_db",
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.query = "insert into daily_stats(todo_count) "
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"select count(*) from todos;"})
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}, .cron = "0 0 * * *"}
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}
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```
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If the task needs caller context, list keys under `.accepts`:
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```c
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{"recount_for_user", {
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query({.db="db", .query="update users set ... where id = {{user_id}};"})
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}, .accepts = {"user_id"}}
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```
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### 7. Modules & Events
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Modules are `.c` files with a function returning `config`. They have their own resources, databases, migrations, tasks, and event subscribers. They communicate ONLY through pub/sub events, never direct calls. `main.c` includes them and registers under `.modules`.
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```
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.
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├── todos/todos.c // config todos() { ... }
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├── activity/activity.c // config activity() { ... }
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└── main.c
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```
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**`main.c`** — includes module sources, registers them.
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```c
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#include <mach.h>
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#include <sqlite.h>
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#include "todos/todos.c"
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#include "activity/activity.c"
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config mach(){
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return (config){
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.resources = {{"home", "/", .get = { render(.template = "<h1>Welcome</h1>") }}},
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.modules = {todos, activity, sqlite}
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};
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}
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```
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**Publisher** declares `.publishes` and calls `emit()`:
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```c
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config todos(){
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return (config){
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.name = "todos",
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.publishes = {{"todo_created", .with = {"title"}}},
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.resources = {
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{"todos", "/todos",
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.post = {
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validate({"title", .validation = validate_not_empty}),
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query({.db = "todos_db",
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.query = "insert into todos(title) values({{title}});"}),
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emit("todo_created"),
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redirect("todos")
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}
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}
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}
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// ... databases, etc.
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};
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}
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```
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**Subscriber** declares an `.events` entry. The published keys (`title`) arrive in context.
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```c
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config activity(){
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return (config){
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.name = "activity",
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.events = {
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{"todo_created", {
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query({.db = "activity_db",
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.query = "insert into activities(kind, ref) "
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"values('created', {{title}});"})
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}}
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}
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// ... own database, own resources
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};
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}
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```
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When `.publishes` exists anywhere, MACH creates a `mach_events` database and tracks delivery; undelivered events replay on next boot.
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### 8. External Assets
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Once templates and SQL grow, extract them into files. Embed with `(asset){#embed "file"}` in `.context`, then reference by name from `render()`, `query()`, `find()`. `.migrations` accepts assets directly.
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```
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todos/
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├── todos.c
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├── todos_list.mustache.html
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├── get_todos.sql
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├── create_todo.sql
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└── create_todos_table.sql
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```
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**`todos/get_todos.sql`**
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```sql
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select id, title from todos;
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```
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**`todos/todos.c`** (excerpt)
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```c
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.resources = {
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{"todos", "/todos",
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.get = { query({"get_todos", .set_key = "todos", .db = "todos_db"}),
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render("todos_list") },
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.post = { validate({"title", .validation = validate_not_empty}),
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query({"create_todo", .db = "todos_db"}),
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redirect("todos") }
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}
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},
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.context = {
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{"todos_list", (asset){#embed "todos_list.mustache.html"}},
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{"get_todos", (asset){#embed "get_todos.sql"}},
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{"create_todo",(asset){#embed "create_todo.sql"}}
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},
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.databases = {{
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.engine = sqlite_db,
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.name = "todos_db",
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.connect = "file:todos.db?mode=rwc",
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.migrations = {(asset){#embed "create_todos_table.sql"}}
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}}
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```
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SQL `{{interpolation}}` works the same as inline.
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### 9. External Data
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`fetch()` makes an HTTP request and stores the response. JSON parses into tables/records (nested JSON → nested context tables); plain text stores as a string.
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```c
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.get = {
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fetch("https://api.quotable.io/random", .set_key = "quote"),
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render("home")
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}
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```
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The Quotable API returns `{"author":"...","content":"..."}`, parsed into a single-row table under `quote`. Template opens the section:
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```html
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{{#quote}}<blockquote>{{content}} — {{author}}</blockquote>{{/quote}}
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```
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Multiple items in one `fetch()` run concurrently. `fetch()` supports POST/PUT/PATCH/DELETE, custom headers, JSON or text bodies, and `{{interpolation}}` in the URL. See [fetch](#fetch) below.
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---
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## Reference
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### Notation
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- `{}` — single value or struct: `.get = { ... }`
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- `{{}}` — array of structs: `.databases = {{ ... }}`
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- Multiple elements: `.databases = {{...}, {...}}`
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- Multiple step items: `query({...}, {...})`
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### Context
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Pipelines read/write a per-request scoped key-value store. Three scopes:
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- `input:xxx` — raw request parameters
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- `error:xxx` — validation/error data
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- (unprefixed) — app scope: query results, validated inputs, `.context` values
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`validate()` promotes from `input:` to app scope. Docker secrets are available in context.
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`.context` seeds variables and assets at the root. Assets baked at compile time with `(asset){#embed "file"}`.
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```c
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.context = {
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{"site_name", "MACH App"},
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{"layout", (asset){#embed "static/layout.mustache.html"}},
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{"get_todos", (asset){#embed "todos/get_todos.sql"}}
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}
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```
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### Databases
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Migrations are forward-only, index-based, applied once each in array order, tracked in `mach_meta`. Seeds are idempotent. Multi-tenant via `{{interpolation}}` in `.connect`; connections pooled with LRU eviction.
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```c
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.databases = {{
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.engine = sqlite_db,
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.name = "blog_db",
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.connect = "file:{{user_id}}_blog.db?mode=rwc",
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.migrations = {
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"CREATE TABLE blogs (id INTEGER PRIMARY KEY AUTOINCREMENT, title TEXT NOT NULL);",
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"CREATE TABLE comments ("
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"id INTEGER PRIMARY KEY AUTOINCREMENT,"
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"blog_id INTEGER NOT NULL REFERENCES blogs(id),"
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"body TEXT NOT NULL"
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");"
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},
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.seeds = {"INSERT OR IGNORE INTO blogs(id, title) VALUES(1, 'Hello');"}
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}}
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```
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**One database per domain, many tables.** Related tables (`blogs`, `comments`) go as separate migrations on the same database.
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**Engines:** `sqlite_db`, `postgres_db`, `mysql_db`, `redis_db`, `duckdb_db`
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### Resource Pipelines
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Each `.resources` entry is a named URL endpoint. Identified by name in `{{url:name}}`, `redirect()`, `reroute()` with colon-separated positional args (`name:arg1:arg2`). Args fill `:params` in the URL pattern in order. Args can be literals or context keys.
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- `{{url:todos}}` → `/todos`
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- `{{url:todo:5}}` → `/todos/5` (literal)
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- `{{url:todo:id}}` → reads `id` from current scope
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- `{{url:org_todo:acme:5}}` → fills multiple `:params`
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Path specificity is automatic: `/todos/active` beats `/todos/:id`. Verb selection: HTTP method, or `?http_method=...` parameter (lets HTML forms reach PATCH/DELETE/SSE).
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**Fields:**
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- `.name` *(pos)* — identifier
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- `.url` *(pos)* — pattern with `:params`
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- `.steps` *(pos)* — shared steps run before every verb pipeline (middleware slot)
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- `.mime` — default response content type
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- `.get .post .put .patch .delete` — verb pipelines (arrays of steps)
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- `.sse` — persistent SSE channel; first positional is channel name with `{{interpolation}}`
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- `.errors` — terminal handlers keyed by error code
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- `.repairs` — resumable handlers keyed by error code
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Example:
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```c
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{"todo", "/todos/:id", {
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validate({"id", .validation = "^\\d+$", .message = "must be a number"})
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},
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.mime = mime_html,
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.get = { find({"get_todo", .set_key = "todo", .db = "todos_db"}),
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render("todo") },
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.patch = { validate({"title", .validation = validate_not_empty, .message = "required"}),
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query({.db = "todos_db",
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.query = "update todos set title = {{title}} where id = {{id}};"}),
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redirect("todo:{{id}}") },
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.delete = { query({.db = "todos_db",
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.query = "delete from todos where id = {{id}};"}),
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redirect("todos") },
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.sse = {"todo/{{id}}", sse(.event = "ready") },
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.errors = {{http_not_found, { render("404") }}}
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}
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```
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**MIME types:** `mime_html`, `mime_txt`, `mime_sse`, `mime_json`, `mime_js`
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### Template Helpers
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`{{helper:args}}`, positional, colon-separated. Each arg is a literal or a context key.
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| Helper | Purpose | Example |
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|---|---|---|
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| `{{raw:field}}` | emit without HTML-escape (default escapes) | `<div>{{raw:body_html}}</div>` |
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| `{{precision:field:N}}` | numeric format with N decimals | `${{precision:total:2}}` |
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| `{{input:field}}` | raw request param (for repopulating forms) | `<input value='{{input:title}}'>` |
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| `{{error:field}}` | truthy when field has an error (use as section) | `{{#error:title}}!{{/error:title}}` |
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| `{{error_message:field}}` | the validation/error message string | `<span>{{error_message:title}}</span>` |
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| `{{error_code:field}}` | HTTP status code for the field error | `{{error_code:title}}` |
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| `{{url:name[:args]}}` | resource URL by name with positional args | `<a href='{{url:todo:id}}'>...</a>` |
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| `{{asset:filename}}` | cache-busted URL for `public/` file | `<link href='{{asset:styles.css}}'>` |
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| `{{csrf:token}}` | CSRF token (for query strings); sets cookie | `?csrf={{csrf:token}}` |
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| `{{csrf:input}}` | hidden `<input>` carrying CSRF token | `<form>{{csrf:input}}...</form>` |
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CSRF verification is automatic: MACH compares the incoming token to the cookie (httponly/secure/samesite) and returns 403 on mismatch. Just emit `{{csrf:token}}` or `{{csrf:input}}`.
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### Pipeline Steps
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Every step accepts `.if_context` and `.unless_context` for conditional execution.
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#### validate
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Regex-checks request parameters. On success, promotes `input:name` to app scope. On failure, sets `error:name` and raises `http_bad_request`. All validations in one call complete before the error fires (so all errors are available together). Define your own macros: `#define validate_zipcode "^\\d{5}$"`.
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- `.param_key` *(pos)* — name of param
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- `.validation` — regex string or built-in macro
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- `.message` — human-readable error
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- `.optional` — skip when param absent
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- `.fallback` — default when param absent
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```c
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validate(
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{"email", .validation = validate_email, .message = "must be a valid email"},
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{"title", .validation = validate_not_empty, .message = "cannot be empty"},
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{"page", .fallback = "1",
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.validation = "^\\d+$", .message = "must be a number"},
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{"filter", .optional = true,
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.validation = "^(active|done)$", .message = "must be active or done"}
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)
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```
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**Built-in validators:**
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- Strings: `validate_not_empty`, `validate_alpha`, `validate_alphanumeric`, `validate_slug`, `validate_no_html`
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- Numbers: `validate_integer`, `validate_positive`, `validate_float`, `validate_percentage`
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- Identity: `validate_email`, `validate_uuid`, `validate_username`
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- Dates: `validate_date`, `validate_time`, `validate_datetime`
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- Web: `validate_url`, `validate_ipv4`, `validate_hex_color`
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- Codes: `validate_zipcode_us`, `validate_phone_e164`, `validate_cron`
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- Security: `validate_no_sqli`, `validate_token`, `validate_base64`
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- Boolean: `validate_boolean`, `validate_yes_no`, `validate_on_off`
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#### find & query
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Both run database queries. **`find()` raises `http_not_found` on zero rows; `query()` does not.** Otherwise identical.
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`.set_key` stores result as a TABLE in context (always — even single-row results). Templates open the table as a section to access fields. SQL is either inlined with `.query` OR loaded by name from `.context` as the positional. Multiple items in one step run **concurrently**. Interpolated `{{values}}` are bound as prepared-statement parameters. For transactions, use `BEGIN`/`COMMIT`/`ROLLBACK` in your queries.
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- `.template_key` *(pos)* — SQL asset name in `.context` (mutually exclusive with `.query`)
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|
- `.query` — inline SQL string with `{{interpolation}}` (mutually exclusive with positional)
|
|
- `.set_key` — context key for result table
|
|
- `.db` — database name from `.databases`
|
|
- `.if_context` / `.unless_context` *(per item)* — conditionally include while others run concurrently
|
|
|
|
```c
|
|
query(
|
|
{"get_todos", .set_key = "todos", .db = "todos_db"},
|
|
{.set_key = "count", .db = "todos_db",
|
|
.query = "select count(*) as n from todos where user_id = {{user_id}};"},
|
|
{.if_context = "show_urgent", .set_key = "urgent", .db = "todos_db",
|
|
.query = "select id, title from todos where priority = 'high';"}
|
|
)
|
|
```
|
|
|
|
#### join
|
|
|
|
Nests records from one context table into each matching record of another. After `join()`, the inner records live INSIDE each outer record. Templates must enter the outer section to reach the nested data — `{{#comments}}` at root after a join is empty.
|
|
|
|
- `.target_table_key` — outer table receiving children
|
|
- `.target_field_key` — outer field to match
|
|
- `.nested_table_key` — inner table to nest
|
|
- `.nested_field_key` — inner field that points to outer
|
|
- `.target_join_field_key` — new field on outer holding matched inner records
|
|
|
|
```c
|
|
join(
|
|
.target_table_key = "blog",
|
|
.target_field_key = "id",
|
|
.nested_table_key = "comments",
|
|
.nested_field_key = "blog_id",
|
|
.target_join_field_key = "comments"
|
|
)
|
|
```
|
|
|
|
Pattern is concurrent `query()` → `join()` → `render()`:
|
|
```c
|
|
query(
|
|
{.set_key="blog", .db="blog_db", .query="select id, title from blogs where id = {{id}};"},
|
|
{.set_key="comments", .db="blog_db", .query="select id, blog_id, body from comments where blog_id = {{id}};"}
|
|
),
|
|
join(
|
|
.target_table_key="blog", .target_field_key="id",
|
|
.nested_table_key="comments", .nested_field_key="blog_id",
|
|
.target_join_field_key="comments"
|
|
),
|
|
render(.template =
|
|
"{{#blog}}"
|
|
"<h1>{{title}}</h1>"
|
|
"<ul>{{#comments}}<li>{{body}}</li>{{/comments}}</ul>"
|
|
"{{/blog}}")
|
|
```
|
|
|
|
Context shape:
|
|
```
|
|
after query(): { blog: [{id,title}], comments: [{id,blog_id,body}, ...] }
|
|
after join(): { blog: [{id,title, comments: [{id,blog_id,body}, ...]}] }
|
|
```
|
|
|
|
#### fetch
|
|
|
|
HTTP request → context. JSON parsed into tables/records; text stored as string.
|
|
|
|
- `.url` *(pos)* — URL with `{{interpolation}}`
|
|
- `.set_key` — context key for response
|
|
- `.method` — defaults `http_get`
|
|
- `.headers` — array of `{name, value}` pairs
|
|
- `.json` — context key serialized as JSON request body
|
|
- `.text` — context key sent as plain-text body
|
|
|
|
```c
|
|
fetch("https://api.payments.dev/charge",
|
|
.set_key = "receipt",
|
|
.method = http_post,
|
|
.headers = {
|
|
{"Authorization", "Bearer {{api_key}}"},
|
|
{"Idempotency-Key", "{{order_id}}"}
|
|
},
|
|
.json = "order"
|
|
)
|
|
```
|
|
|
|
**HTTP methods:** `http_get`, `http_post`, `http_put`, `http_patch`, `http_delete`, `http_sse_method`
|
|
|
|
#### exec
|
|
|
|
Calls a C function or block with imperative access to context. Dispatched to shared thread pool (releases reactor); pipeline resumes on original reactor when done. Use for blocking I/O or CPU work. Trigger an error pipeline from inside via `error_set()`.
|
|
|
|
- *Block* *(pos)* — inline block
|
|
- `.call` — named C function
|
|
|
|
```c
|
|
exec(^(){
|
|
auto t = get("challengers");
|
|
record_set(table_get(t, 0), "opponent_id",
|
|
record_get(table_get(t, 1), "id"));
|
|
})
|
|
|
|
exec(.call = assign_opponents)
|
|
```
|
|
|
|
**Imperative API** (in exec blocks/functions):
|
|
- Context: `get(name)`, `set(name, value)`, `has(name)`, `format(fmt)`
|
|
- Memory: `allocate(bytes)`, `defer_free(ptr)`
|
|
- Errors: `error_set(name, err)`, `error_get(name)`, `error_has(name)`
|
|
- Tables: `table_new()`, `table_count(t)`, `table_get(t, i)`, `table_add(t, r)`, `table_remove(t, r)`, `table_remove_at(t, i)`
|
|
- Records: `record_new()`, `record_set(r, name, value)`, `record_get(r, name)`, `record_remove(r, name)`
|
|
|
|
#### emit
|
|
|
|
Triggers a pub/sub event. Subscribers in other modules react via their `.events` pipelines.
|
|
|
|
- *Event name* *(pos)*
|
|
|
|
```c
|
|
emit("todo_created")
|
|
```
|
|
|
|
#### task
|
|
|
|
Enqueues a named job in the task database; calling pipeline continues immediately.
|
|
|
|
- *Task name* *(pos)*
|
|
|
|
```c
|
|
task("recount_todos")
|
|
```
|
|
|
|
#### sse
|
|
|
|
Pushes a Server-Sent Event. With `.channel`, broadcasts. Without, sent to requesting client only.
|
|
|
|
- `.channel` *(pos)* — broadcast channel with `{{interpolation}}`
|
|
- `.event` — SSE `event:` line
|
|
- `.data` — array of strings (one per `data:` line)
|
|
- `.comment` — `:` comment line (keep-alives)
|
|
|
|
```c
|
|
sse(
|
|
.channel = "todos/{{user_id}}",
|
|
.event = "todo_updated",
|
|
.data = {"id: {{todo_id}}", "title: {{title}}"},
|
|
.comment = "broadcast at {{timestamp}}"
|
|
)
|
|
```
|
|
|
|
#### ds_sse
|
|
|
|
Datastar-formatted SSE; provided by `datastar` module. Pushes DOM updates and reactive state. Without channel goes to requesting client; with channel broadcasts.
|
|
|
|
- `.channel` *(pos)* — broadcast channel
|
|
- `.target` — DOM element id
|
|
- `.mode` — fragment insertion mode
|
|
- `.elements` — render_config (positional is asset name, supports `.template`, `.engine`)
|
|
- `.signals` — JSON updating Datastar reactive state
|
|
- `.js` — JS snippet evaluated on client
|
|
|
|
```c
|
|
ds_sse("todos/{{user_id}}",
|
|
.target = "todo-list",
|
|
.mode = mode_prepend,
|
|
.elements = {"todo_row"},
|
|
.signals = "{\"count\": {{count}}}",
|
|
.js = "window.scrollTo(0, 0)"
|
|
)
|
|
```
|
|
|
|
**Modes:** `mode_outer`, `mode_inner`, `mode_replace`, `mode_prepend`, `mode_append`, `mode_before`, `mode_after`, `mode_remove`
|
|
|
|
#### render
|
|
|
|
Outputs a Mustache template. Auto-escapes by default (`{{raw:field}}` to opt out).
|
|
|
|
Fields:
|
|
- `.template_key` *(pos)* — asset name in `.context`
|
|
- `.template` — inline Mustache string
|
|
- `.status` — HTTP status (default `http_ok`)
|
|
- `.mime` — override content type
|
|
- `.engine` — `mustache` (default) or `mdm` (Markdown-with-Mustache)
|
|
- `.json_table_key` — context table to serialize as JSON response (sets `application/json`; nested tables produce nested JSON)
|
|
|
|
```c
|
|
render("todos")
|
|
render(.template = "<h1>{{site_name}}</h1>")
|
|
render("not_found", .status = http_not_found)
|
|
render(.engine = mdm, .template = "# Welcome, {{user_name}}")
|
|
render(.json_table_key = "todos")
|
|
```
|
|
|
|
**HTTP statuses:** `http_ok` (200), `http_created` (201), `http_redirect` (302), `http_bad_request` (400), `http_not_authorized` (401), `http_not_found` (404), `http_error` (500)
|
|
|
|
**MIME types:** `mime_html`, `mime_txt`, `mime_sse`, `mime_json`, `mime_js`
|
|
|
|
#### headers & cookies
|
|
|
|
Set response headers/cookies. Values support `{{interpolation}}`.
|
|
|
|
```c
|
|
headers({{"X-Request-Id", "{{request_id}}"}, {"Cache-Control", "no-store"}})
|
|
cookies({{"session", "{{session_id}}"}})
|
|
```
|
|
|
|
#### redirect & reroute
|
|
|
|
`redirect()` — 302 to client (browser navigates). `reroute()` — server-side re-enter the router, run another resource's pipeline within the same request. Both take a resource identifier `name[:arg1:arg2...]`. Args can be literals or context keys with `{{interpolation}}`.
|
|
|
|
```c
|
|
redirect("todos") // 302 /todos
|
|
redirect("todo:5") // 302 /todos/5
|
|
redirect("todo:{{id}}") // 302 /todos/{id from context}
|
|
redirect("org_todo:acme:5") // 302 /orgs/acme/todos/5
|
|
reroute("todo:{{id}}") // run pipeline in-process
|
|
```
|
|
|
|
#### nest
|
|
|
|
Group steps for a single shared `.if_context` / `.unless_context`.
|
|
|
|
```c
|
|
nest({query({...}), emit("urgent_todo"), render("urgent")},
|
|
.if_context = "is_urgent")
|
|
```
|
|
|
|
### Conditionals
|
|
|
|
Every step accepts `.if_context` (run when key present) and `.unless_context` (run when absent). Works on validated inputs, query results, framework flags (`is_htmx`), or flags set from `exec()`.
|
|
|
|
```c
|
|
render("fragment", .if_context = "is_htmx")
|
|
render("full_page", .unless_context = "is_htmx")
|
|
|
|
// multi-state: set flag in exec, then key off it:
|
|
exec(.call = classify_todo),
|
|
render("urgent_confirmation", .if_context = "is_urgent"),
|
|
render("standard_confirmation", .unless_context = "is_urgent")
|
|
```
|
|
|
|
### Error and Repair Pipelines
|
|
|
|
On failure, MACH searches handlers bottom-up: resource → module → root.
|
|
- **Errors** are terminal: send a response, end request.
|
|
- **Repairs** are resumable: fix context, then resume original pipeline at the step after the failure.
|
|
|
|
If no matching repair, falls through to errors. The `error` scope is shared across `validate()` and `error_set()`: `{{error:name}}`, `{{error_code:name}}`, `{{error_message:name}}`. Raw input remains in `input:name`.
|
|
|
|
```c
|
|
.errors = {
|
|
{http_not_found, { render("404") }},
|
|
{http_bad_request, { render("form") }},
|
|
{http_error, { render("500") }}
|
|
},
|
|
.repairs = {
|
|
{http_not_authorized, { exec(.call = refresh_session_token) }}
|
|
}
|
|
```
|
|
|
|
**Built-in error codes:** `http_ok` (200), `http_created` (201), `http_redirect` (302), `http_bad_request` (400), `http_not_authorized` (401), `http_not_found` (404), `http_error` (500). Any int works; `#define err_quota_exceeded 723` for domain-specific.
|
|
|
|
### Event Pipelines
|
|
|
|
Internal pub/sub for cross-module communication. Publisher doesn't know subscribers; subscribers don't know publishers. Adding a subscriber = new module with `.events`; publisher unchanged.
|
|
|
|
When `.publishes` is defined anywhere, MACH creates `mach_events` to track delivery. Crashes don't drop events — replayed on next boot.
|
|
|
|
- `.publishes` — outbound contracts: `.event` name, `.with` keys to pass
|
|
- `.events` — subscriber pipelines keyed by event name
|
|
|
|
```c
|
|
// publisher
|
|
config todos(){
|
|
return (config){
|
|
.name = "todos",
|
|
.publishes = {
|
|
{"todo_created", .with = {"user_id", "title"}},
|
|
{"todo_deleted", .with = {"user_id", "todo_id"}}
|
|
},
|
|
.resources = {
|
|
{"todos", "/todos",
|
|
.post = {
|
|
validate({"title", .validation = validate_not_empty}),
|
|
query({"insert_todo", .db = "todos_db"}),
|
|
emit("todo_created"),
|
|
redirect("todos")
|
|
}
|
|
}
|
|
}
|
|
};
|
|
}
|
|
|
|
// subscriber
|
|
config activity(){
|
|
return (config){
|
|
.name = "activity",
|
|
.events = {
|
|
{"todo_created", {
|
|
query({.db = "activity_db",
|
|
.query = "insert into activities(kind, user_id, ref) "
|
|
"values('created', {{user_id}}, {{title}});"})
|
|
}}
|
|
}
|
|
};
|
|
}
|
|
```
|
|
|
|
### Task Pipelines
|
|
|
|
Named pipelines that run async on task reactors. Fire-and-forget. Defined at module or root level. Triggered with `task("name")` or via `.cron`. Tasks can enqueue more tasks.
|
|
|
|
Durable: `mach_tasks` database checkpoints context after each step. Crash mid-task → resumes at the failed step.
|
|
|
|
- `.name` *(pos)* — identifier called via `task("name")`
|
|
- `.accepts` — context keys to pull from caller into the task
|
|
- `.cron` — standard cron schedule (no caller required)
|
|
- *Steps* *(pos)* — pipeline body, second positional brace block
|
|
|
|
```c
|
|
.tasks = {
|
|
// on-demand
|
|
{"recount_todos", {
|
|
query({.db = "todos_db",
|
|
.query = "update users set todo_count = "
|
|
"(select count(*) from todos where user_id = users.id) "
|
|
"where id = {{user_id}};"})
|
|
}, .accepts = {"user_id"}},
|
|
|
|
// recurring
|
|
{"daily_digest", {
|
|
query({.db = "todos_db",
|
|
.query = "insert into digest_reports(generated_at) values(now());"}),
|
|
emit("digest_ready")
|
|
}, .cron = "0 8 * * *"}
|
|
}
|
|
```
|
|
|
|
### Modules & Composition
|
|
|
|
Every app and module returns a `config`. Root `main.c` defines `mach()`; modules define their own functions with any name. A module owns its resources, databases, migrations, templates, event contracts. **Same-name conflicts: root wins.** Modules communicate ONLY through pub/sub events, never direct calls.
|
|
|
|
- `.name` — module identifier
|
|
- `.modules` — other modules to compose (root or nested)
|
|
|
|
A module file:
|
|
```c
|
|
#include <mach.h>
|
|
#include <sqlite.h>
|
|
|
|
config blogs(){
|
|
return (config){
|
|
.name = "blogs",
|
|
.resources = {
|
|
{"blog", "/blogs/:id",
|
|
.get = { /* validate → query → join → render */ }
|
|
}
|
|
},
|
|
.databases = {{
|
|
.engine = sqlite_db,
|
|
.name = "blog_db",
|
|
.connect = "file:blogs.db?mode=rwc",
|
|
.migrations = {
|
|
"CREATE TABLE blogs (id INTEGER PRIMARY KEY AUTOINCREMENT, title TEXT NOT NULL, content TEXT NOT NULL);",
|
|
"CREATE TABLE comments (id INTEGER PRIMARY KEY AUTOINCREMENT, blog_id INTEGER NOT NULL REFERENCES blogs(id), body TEXT NOT NULL);"
|
|
}
|
|
}}
|
|
};
|
|
}
|
|
```
|
|
|
|
Bring it in from `main.c`:
|
|
```c
|
|
#include <mach.h>
|
|
#include "blogs/blogs.c"
|
|
|
|
config mach(){ return (config){ .modules = {blogs, sqlite} }; }
|
|
```
|
|
|
|
Resource fields like `.url`, `.mime`, `.get` belong INSIDE entries of `.resources`, not at the top level of `config`.
|
|
|
|
Project layout:
|
|
```
|
|
├── todos/
|
|
│ ├── todos.c
|
|
│ ├── todos.mustache.html
|
|
│ ├── create_todos_table.sql
|
|
│ └── get_todos.sql
|
|
├── activity/
|
|
│ └── activity.c
|
|
├── static/ # root-level templates (not a module — no .c)
|
|
│ └── home.mustache.html
|
|
├── public/ # static files served directly
|
|
│ └── favicon.png
|
|
└── main.c
|
|
```
|
|
|
|
**Bundled modules** (add to `.modules`): `sqlite`, `postgres`, `mysql`, `redis`, `duckdb`, `htmx`, `datastar`, `tailwind`, `session_auth`
|
|
|
|
**Module-provided steps** ship from modules and plug into pipelines like built-ins. `session_auth` provides:
|
|
- `session()` — attaches current session to context (sets `user_id`, etc.); no-op when unauthenticated
|
|
- `logged_in()` — guard, raises `http_not_authorized` if no session
|
|
- `login()`, `logout()`, `signup()` — for POST pipelines
|
|
|
|
Common as resource-level middleware via `.steps`:
|
|
```c
|
|
{"dashboard", "/dashboard", {session(), logged_in()},
|
|
.get = { render("dashboard") }
|
|
}
|
|
```
|
|
|
|
### Static Files
|
|
|
|
Files in `public/` at project root served directly. Reference with `{{asset:filename}}` — resolves to a content-checksummed URL with immutable cache headers.
|
|
|
|
```
|
|
public/
|
|
├── favicon.png
|
|
├── logo.png
|
|
└── styles.css
|
|
```
|
|
|
|
```html
|
|
<link rel="icon" href="{{asset:favicon.png}}">
|
|
<link rel="stylesheet" href="{{asset:styles.css}}">
|
|
<script src="{{asset:app.js}}"></script>
|
|
```
|
|
|
|
### External Dependencies
|
|
|
|
Containerized dev environment; no local toolchain. Two ways to bring in third-party C libs, plus two memory bridges.
|
|
|
|
**`/vendor` directory** — drop in headers and `.so`/`.a`; auto-compiler discovers, includes, links.
|
|
```
|
|
/vendor/
|
|
├── libsodium.h
|
|
└── libsodium.so
|
|
```
|
|
|
|
**Custom Dockerfile** — inherit from MACH base image, `apt-get` system deps; reference from `compose.yml`.
|
|
```dockerfile
|
|
FROM mach:latest
|
|
RUN apt-get update && apt-get install -y libsodium-dev
|
|
```
|
|
|
|
**`allocate(bytes)`** — buffer from pipeline arena, reclaimed on request completion.
|
|
```c
|
|
char *buf = allocate(256);
|
|
```
|
|
|
|
**`defer_free(ptr)`** — schedule cleanup for pointers from external libs (`malloc`, etc.) when arena is released.
|
|
```c
|
|
char *out = third_party_alloc(256);
|
|
defer_free(out);
|
|
```
|
|
|
|
---
|
|
|
|
## Critical Rules
|
|
|
|
Read these before writing any code. Most bugs come from breaking one of these.
|
|
|
|
1. **SQL `{{values}}` are bound as prepared-statement parameters, never spliced.** Same for `find()`. No SQL injection possible; do not pre-quote values.
|
|
|
|
2. **`query()` / `find()` items take positional asset name OR `.query`, never both.**
|
|
- ✅ `query({"get_todos", .set_key="todos", .db="db"})` (loads SQL from `.context`)
|
|
- ✅ `query({.set_key="todos", .db="db", .query="select ..."})` (inline)
|
|
- Combining the two is rejected at boot.
|
|
|
|
3. **Concurrency = multiple items in ONE step.** `query({a},{b})` runs in parallel. Two `query({a})` `query({b})` steps run serially.
|
|
|
|
4. **MACH doesn't support Mustache dot notation. Don't use it, period.**
|
|
|
|
Don't (dot notation):
|
|
```html
|
|
<div id="blog">
|
|
<p>{{#blog.title}}</p>
|
|
<p>{{#blog.content}}</p>
|
|
</div>
|
|
```
|
|
|
|
Do (When using a # iteration/section block it changes the context of the fields within the block to be scoped to the section):
|
|
```html
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|
{{#blog}}
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|
<!-- blog is now in scope -->
|
|
<div id="blog">
|
|
<!-- blog.title is now in scope -->
|
|
<p>{{title}}</p>
|
|
<!-- blog.content is now in scope -->
|
|
<p>{{content}}</p>
|
|
</div>
|
|
{{/blog}}
|
|
```
|
|
|
|
Don't (repeated section opens):
|
|
```html
|
|
<div id="blog">
|
|
<p>{{#blog}}{{title}}{{/blog}}</p>
|
|
<p>{{#blog}}{{content}}{{/blog}}</p>
|
|
</div>
|
|
```
|
|
|
|
5. **No `malloc`/`free`, no threads, no mutexes.** Per-request arena handles memory; framework handles concurrency. For external buffers: `allocate(bytes)` and `defer_free(ptr)`.
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|
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|
6. **Resource-based, not route-based.** Resources are referenced by NAME (`{{url:todos}}`, `redirect("todo:5")`, `reroute("todos")`), not by path.
|