[pitboss] phase 13: Track L.11 — Express / Koa / NestJS / Fastify adapters

src/dynamic/framework/adapters/js_nest.rs

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+//! NestJS [`super::super::FrameworkAdapter`] (Phase 13 — Track L.11).
+//!
+//! Recognises Nest's controller-class decorator surface:
+//!   - `@Controller('users')` on the class establishes the route
+//!     prefix.
+//!   - `@Get(':id')` / `@Post()` / `@Put('/x')` / `@Patch()` /
+//!     `@Delete()` / `@Head()` / `@Options()` / `@All()` on the
+//!     method establishes the verb + sub-path; the full route is the
+//!     concatenation `prefix + path`.
+//!   - Parameter decorators (`@Param('id')`, `@Query('q')`,
+//!     `@Body()`, `@Headers()`, `@Req()`, `@Res()`) bind individual
+//!     formals to request slots.
+//!
+//! NestJS is TypeScript-first.  The adapter is registered under both
+//! [`Lang::TypeScript`] and [`Lang::JavaScript`] so Babel-transpiled
+//! Nest projects (still common in the wild) are not silently
+//! skipped — JS Nest projects emit the same decorator syntax via
+//! `experimentalDecorators` / `legacyDecorators`.  The lang-aware
+//! tree-sitter parser is picked from `summary.lang`.
+
+use crate::dynamic::framework::{
+    FrameworkAdapter, FrameworkBinding, HttpMethod, ParamBinding, ParamSource, RouteShape,
+};
+use crate::evidence::EntryKind;
+use crate::summary::FuncSummary;
+use crate::symbol::Lang;
+use tree_sitter::Node;
+
+use super::js_routes::{
+    bind_path_params, extract_path_placeholders, function_formal_names, http_verb_from_method,
+    source_imports_nest, strip_quotes,
+};
+
+pub struct JsNestAdapter;
+pub struct TsNestAdapter;
+
+const JS_ADAPTER_NAME: &str = "js-nest";
+const TS_ADAPTER_NAME: &str = "ts-nest";
+
+impl FrameworkAdapter for JsNestAdapter {
+    fn name(&self) -> &'static str {
+        JS_ADAPTER_NAME
+    }
+
+    fn lang(&self) -> Lang {
+        Lang::JavaScript
+    }
+
+    fn detect(
+        &self,
+        summary: &FuncSummary,
+        ast: Node<'_>,
+        file_bytes: &[u8],
+    ) -> Option<FrameworkBinding> {
+        detect_nest(summary, ast, file_bytes, JS_ADAPTER_NAME)
+    }
+}
+
+impl FrameworkAdapter for TsNestAdapter {
+    fn name(&self) -> &'static str {
+        TS_ADAPTER_NAME
+    }
+
+    fn lang(&self) -> Lang {
+        Lang::TypeScript
+    }
+
+    fn detect(
+        &self,
+        summary: &FuncSummary,
+        ast: Node<'_>,
+        file_bytes: &[u8],
+    ) -> Option<FrameworkBinding> {
+        detect_nest(summary, ast, file_bytes, TS_ADAPTER_NAME)
+    }
+}
+
+fn detect_nest(
+    summary: &FuncSummary,
+    ast: Node<'_>,
+    file_bytes: &[u8],
+    adapter_name: &'static str,
+) -> Option<FrameworkBinding> {
+    if !source_imports_nest(file_bytes) {
+        return None;
+    }
+    let (class_node, method_node) =
+        find_class_method(ast, file_bytes, &summary.name)?;
+    let prefix = class_controller_prefix(class_node, file_bytes)?;
+    let (method, sub_path) = method_verb_and_path(method_node, file_bytes)?;
+    let full_path = join_paths(&prefix, &sub_path);
+    let formals = method_node
+        .child_by_field_name("parameters")
+        .map(|p| function_formal_names(p, file_bytes))
+        .unwrap_or_default();
+    let mut request_params = bind_path_params(&formals, &full_path);
+    refine_with_param_decorators(method_node, file_bytes, &mut request_params, &full_path);
+    Some(FrameworkBinding {
+        adapter: adapter_name.to_owned(),
+        kind: EntryKind::HttpRoute,
+        route: Some(RouteShape {
+            method,
+            path: full_path,
+        }),
+        request_params,
+        response_writer: None,
+        middleware: Vec::new(),
+    })
+}
+
+/// Find `(class_declaration, method_definition)` where the method's
+/// `name` field equals `target` and the enclosing class is decorated
+/// with `@Controller(...)`.  Returns the first match in document
+/// order.
+fn find_class_method<'a>(
+    root: Node<'a>,
+    bytes: &[u8],
+    target: &str,
+) -> Option<(Node<'a>, Node<'a>)> {
+    let mut hit: Option<(Node<'a>, Node<'a>)> = None;
+    walk_for_class_method(root, bytes, target, &mut hit);
+    hit
+}
+
+fn walk_for_class_method<'a>(
+    node: Node<'a>,
+    bytes: &[u8],
+    target: &str,
+    out: &mut Option<(Node<'a>, Node<'a>)>,
+) {
+    if out.is_some() {
+        return;
+    }
+    if node.kind() == "class_declaration"
+        && class_has_controller(node, bytes)
+        && let Some(body) = node.child_by_field_name("body")
+    {
+        let mut cur = body.walk();
+        for child in body.named_children(&mut cur) {
+            if child.kind() == "method_definition"
+                && let Some(name) = child
+                    .child_by_field_name("name")
+                    .and_then(|n| n.utf8_text(bytes).ok())
+                && name == target
+            {
+                *out = Some((node, child));
+                return;
+            }
+        }
+    }
+    let mut cur = node.walk();
+    for child in node.children(&mut cur) {
+        walk_for_class_method(child, bytes, target, out);
+    }
+}
+
+/// True when `class_node` is preceded by (or contains, depending on
+/// grammar version) an `@Controller(...)` decorator.  The walk
+/// inspects both the class's own `decorator` field children
+/// (tree-sitter-typescript) and its preceding siblings in the parent
+/// (tree-sitter-javascript with legacy decorator transform), so the
+/// adapter fires regardless of the grammar's wrapping.
+fn class_has_controller(class_node: Node<'_>, bytes: &[u8]) -> bool {
+    if decorator_named(class_node, bytes, "Controller", &mut |_| {}) {
+        return true;
+    }
+    let mut prev = class_node.prev_named_sibling();
+    while let Some(sib) = prev {
+        if sib.kind() == "decorator" {
+            if decorator_text_is(sib, bytes, "Controller") {
+                return true;
+            }
+            prev = sib.prev_named_sibling();
+            continue;
+        }
+        break;
+    }
+    false
+}
+
+/// Extract the controller-prefix string from a class's
+/// `@Controller(<prefix>)` decorator.  Returns `Some("")` when the
+/// decorator carries no argument (`@Controller()` is valid Nest — it
+/// mounts the controller at root).
+fn class_controller_prefix(class_node: Node<'_>, bytes: &[u8]) -> Option<String> {
+    let mut found: Option<String> = None;
+    let mut catcher = |text: Option<&str>| {
+        if let Some(t) = text {
+            found = Some(t.to_owned());
+        } else if found.is_none() {
+            found = Some(String::new());
+        }
+    };
+    if decorator_named(class_node, bytes, "Controller", &mut catcher) {
+        return found;
+    }
+    let mut prev = class_node.prev_named_sibling();
+    while let Some(sib) = prev {
+        if sib.kind() == "decorator" {
+            if decorator_text_is(sib, bytes, "Controller") {
+                let arg = decorator_first_string_arg(sib, bytes);
+                return Some(arg.unwrap_or_default());
+            }
+            prev = sib.prev_named_sibling();
+            continue;
+        }
+        break;
+    }
+    None
+}
+
+/// Return `Some((verb, sub_path))` when `method_node` is decorated
+/// with one of the Nest verb decorators (`@Get`, `@Post`, ...).  The
+/// `sub_path` is `""` when the decorator carries no argument
+/// (`@Get()` mounts at the controller prefix root).
+fn method_verb_and_path(
+    method_node: Node<'_>,
+    bytes: &[u8],
+) -> Option<(HttpMethod, String)> {
+    const VERBS: &[&str] = &[
+        "Get", "Head", "Post", "Put", "Patch", "Delete", "Options", "All",
+    ];
+    for &verb in VERBS {
+        if decorator_named(method_node, bytes, verb, &mut |_| {})
+            && let Some(method) = http_verb_from_method(verb)
+        {
+            let path = method_decorator_path(method_node, bytes, verb);
+            return Some((method, path));
+        }
+    }
+    // Phase 13 v1: also accept preceding-sibling decorators for
+    // grammar variants that hoist method decorators out of the
+    // method_definition node.
+    let mut prev = method_node.prev_named_sibling();
+    while let Some(sib) = prev {
+        if sib.kind() == "decorator" {
+            for &verb in VERBS {
+                if decorator_text_is(sib, bytes, verb)
+                    && let Some(method) = http_verb_from_method(verb)
+                {
+                    let path = decorator_first_string_arg(sib, bytes).unwrap_or_default();
+                    return Some((method, path));
+                }
+            }
+            prev = sib.prev_named_sibling();
+            continue;
+        }
+        break;
+    }
+    None
+}
+
+fn method_decorator_path(method_node: Node<'_>, bytes: &[u8], verb: &str) -> String {
+    let mut cur = method_node.walk();
+    for d in method_node.children_by_field_name("decorator", &mut cur) {
+        if decorator_text_is(d, bytes, verb) {
+            return decorator_first_string_arg(d, bytes).unwrap_or_default();
+        }
+    }
+    String::new()
+}
+
+/// Walk `node`'s `decorator` field children invoking `callback` for
+/// each decorator named `name`.  Returns `true` when at least one
+/// matching decorator was found.  `callback` receives the first
+/// string argument (or `None` when the decorator carries no
+/// arguments).
+fn decorator_named(
+    node: Node<'_>,
+    bytes: &[u8],
+    name: &str,
+    callback: &mut dyn FnMut(Option<&str>),
+) -> bool {
+    let mut found = false;
+    let mut cur = node.walk();
+    for d in node.children_by_field_name("decorator", &mut cur) {
+        if decorator_text_is(d, bytes, name) {
+            found = true;
+            let arg = decorator_first_string_arg(d, bytes);
+            callback(arg.as_deref());
+        }
+    }
+    found
+}
+
+fn decorator_text_is(decorator: Node<'_>, bytes: &[u8], name: &str) -> bool {
+    let mut cur = decorator.walk();
+    for c in decorator.children(&mut cur) {
+        if c.kind() == "@" {
+            continue;
+        }
+        let text = c.utf8_text(bytes).unwrap_or("");
+        // Strip optional `(args)` so `@Get(':id')` matches the name `Get`.
+        let head = text.split('(').next().unwrap_or(text).trim();
+        if head == name {
+            return true;
+        }
+    }
+    false
+}
+
+fn decorator_first_string_arg(decorator: Node<'_>, bytes: &[u8]) -> Option<String> {
+    let mut cur = decorator.walk();
+    for c in decorator.children(&mut cur) {
+        if c.kind() == "call_expression"
+            && let Some(args) = c.child_by_field_name("arguments")
+        {
+            let mut ac = args.walk();
+            for a in args.named_children(&mut ac) {
+                if a.kind() == "string" || a.kind() == "template_string" {
+                    let raw = a.utf8_text(bytes).ok()?;
+                    return Some(strip_quotes(raw).to_owned());
+                }
+            }
+        }
+    }
+    None
+}
+
+/// Refine the per-formal binding shape using Nest's parameter
+/// decorators (`@Param('id')`, `@Query('q')`, `@Body()`, `@Headers()`,
+/// `@Req()` / `@Res()`).  A `@Body()` formal becomes
+/// [`ParamSource::JsonBody`]; a `@Param('x')` formal becomes
+/// [`ParamSource::PathSegment`]; `@Query('q')` keeps
+/// [`ParamSource::QueryParam`]; `@Req()` / `@Res()` becomes
+/// [`ParamSource::Implicit`].
+fn refine_with_param_decorators(
+    method_node: Node<'_>,
+    bytes: &[u8],
+    bindings: &mut [ParamBinding],
+    full_path: &str,
+) {
+    let Some(params) = method_node.child_by_field_name("parameters") else {
+        return;
+    };
+    let mut cur = params.walk();
+    let placeholders = extract_path_placeholders(full_path);
+    let formal_param_nodes: Vec<Node<'_>> = params.named_children(&mut cur).collect();
+    for (idx, formal) in formal_param_nodes.iter().enumerate() {
+        if let Some(refinement) = classify_param_decorator(*formal, bytes, &placeholders)
+            && let Some(slot) = bindings.get_mut(idx)
+        {
+            slot.source = refinement;
+        }
+    }
+}
+
+fn classify_param_decorator(
+    formal: Node<'_>,
+    bytes: &[u8],
+    placeholders: &[String],
+) -> Option<ParamSource> {
+    let mut cur = formal.walk();
+    for d in formal.children_by_field_name("decorator", &mut cur) {
+        if let Some(refinement) = decorator_to_param_source(d, bytes, placeholders) {
+            return Some(refinement);
+        }
+    }
+    // Some grammar variants attach the decorator as a preceding
+    // sibling inside the parameter list.
+    let mut prev = formal.prev_named_sibling();
+    while let Some(sib) = prev {
+        if sib.kind() == "decorator" {
+            if let Some(r) = decorator_to_param_source(sib, bytes, placeholders) {
+                return Some(r);
+            }
+            prev = sib.prev_named_sibling();
+            continue;
+        }
+        break;
+    }
+    None
+}
+
+fn decorator_to_param_source(
+    decorator: Node<'_>,
+    bytes: &[u8],
+    placeholders: &[String],
+) -> Option<ParamSource> {
+    let arg = decorator_first_string_arg(decorator, bytes);
+    if decorator_text_is(decorator, bytes, "Body") {
+        return Some(ParamSource::JsonBody);
+    }
+    if decorator_text_is(decorator, bytes, "Param") {
+        let name = arg.unwrap_or_else(|| {
+            placeholders
+                .first()
+                .cloned()
+                .unwrap_or_else(|| "id".to_owned())
+        });
+        return Some(ParamSource::PathSegment(name));
+    }
+    if decorator_text_is(decorator, bytes, "Query") {
+        let name = arg.unwrap_or_else(|| "q".to_owned());
+        return Some(ParamSource::QueryParam(name));
+    }
+    if decorator_text_is(decorator, bytes, "Headers") {
+        let name = arg.unwrap_or_else(|| "x-nyx".to_owned());
+        return Some(ParamSource::Header(name));
+    }
+    if decorator_text_is(decorator, bytes, "Req")
+        || decorator_text_is(decorator, bytes, "Res")
+        || decorator_text_is(decorator, bytes, "Request")
+        || decorator_text_is(decorator, bytes, "Response")
+        || decorator_text_is(decorator, bytes, "Next")
+    {
+        return Some(ParamSource::Implicit);
+    }
+    None
+}
+
+/// Join a controller prefix and method path segment per Nest's own
+/// path normalisation: collapse any double-slash run to a single
+/// slash, ensure the result starts with `/`, and trim a trailing
+/// slash unless the path is `/` itself.
+fn join_paths(prefix: &str, sub_path: &str) -> String {
+    let mut combined = String::with_capacity(prefix.len() + sub_path.len() + 2);
+    if !prefix.starts_with('/') {
+        combined.push('/');
+    }
+    combined.push_str(prefix);
+    if !prefix.ends_with('/') && !sub_path.is_empty() && !sub_path.starts_with('/') {
+        combined.push('/');
+    }
+    combined.push_str(sub_path);
+    let collapsed = collapse_slashes(&combined);
+    if collapsed.is_empty() {
+        return "/".to_owned();
+    }
+    collapsed
+}
+
+fn collapse_slashes(s: &str) -> String {
+    let mut out = String::with_capacity(s.len());
+    let mut last_was_slash = false;
+    for c in s.chars() {
+        if c == '/' {
+            if !last_was_slash {
+                out.push('/');
+            }
+            last_was_slash = true;
+        } else {
+            out.push(c);
+            last_was_slash = false;
+        }
+    }
+    if out.len() > 1 {
+        while out.ends_with('/') {
+            out.pop();
+        }
+    }
+    if out.is_empty() {
+        return "/".to_owned();
+    }
+    out
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn parse_ts(src: &[u8]) -> tree_sitter::Tree {
+        let mut parser = tree_sitter::Parser::new();
+        let lang =
+            tree_sitter::Language::from(tree_sitter_typescript::LANGUAGE_TYPESCRIPT);
+        parser.set_language(&lang).unwrap();
+        parser.parse(src, None).unwrap()
+    }
+
+    fn summary(name: &str, lang: &str) -> FuncSummary {
+        FuncSummary {
+            name: name.into(),
+            lang: lang.into(),
+            ..Default::default()
+        }
+    }
+
+    #[test]
+    fn collapse_slashes_normalises_join() {
+        assert_eq!(join_paths("users", "id"), "/users/id");
+        assert_eq!(join_paths("/users/", "/:id"), "/users/:id");
+        assert_eq!(join_paths("", ""), "/");
+        assert_eq!(join_paths("/", "/"), "/");
+    }
+
+    #[test]
+    fn fires_on_controller_get_decorator() {
+        let src: &[u8] = b"import { Controller, Get, Param } from '@nestjs/common';\n\
+            @Controller('users')\n\
+            export class UsersController {\n\
+              @Get(':id')\n\
+              getUser(@Param('id') id: string) { return id; }\n\
+            }\n";
+        let tree = parse_ts(src);
+        let binding = TsNestAdapter
+            .detect(&summary("getUser", "typescript"), tree.root_node(), src)
+            .expect("binding");
+        assert_eq!(binding.adapter, "ts-nest");
+        let route = binding.route.as_ref().unwrap();
+        assert_eq!(route.method, HttpMethod::GET);
+        assert_eq!(route.path, "/users/:id");
+        let id_binding = binding
+            .request_params
+            .iter()
+            .find(|p| p.name == "id")
+            .unwrap();
+        assert!(matches!(id_binding.source, ParamSource::PathSegment(_)));
+    }
+
+    #[test]
+    fn fires_on_post_with_body_decorator() {
+        let src: &[u8] = b"import { Controller, Post, Body } from '@nestjs/common';\n\
+            @Controller('items')\n\
+            export class ItemsController {\n\
+              @Post()\n\
+              create(@Body() payload: any) { return payload; }\n\
+            }\n";
+        let tree = parse_ts(src);
+        let binding = TsNestAdapter
+            .detect(&summary("create", "typescript"), tree.root_node(), src)
+            .expect("binding");
+        let route = binding.route.unwrap();
+        assert_eq!(route.method, HttpMethod::POST);
+        assert_eq!(route.path, "/items");
+        let body_binding = binding
+            .request_params
+            .iter()
+            .find(|p| p.name == "payload")
+            .unwrap();
+        assert!(matches!(body_binding.source, ParamSource::JsonBody));
+    }
+
+    #[test]
+    fn fires_on_query_decorator() {
+        let src: &[u8] = b"import { Controller, Get, Query } from '@nestjs/common';\n\
+            @Controller()\n\
+            export class SearchController {\n\
+              @Get('search')\n\
+              search(@Query('q') q: string) { return q; }\n\
+            }\n";
+        let tree = parse_ts(src);
+        let binding = TsNestAdapter
+            .detect(&summary("search", "typescript"), tree.root_node(), src)
+            .expect("binding");
+        assert_eq!(binding.route.unwrap().path, "/search");
+        let q_binding = binding
+            .request_params
+            .iter()
+            .find(|p| p.name == "q")
+            .unwrap();
+        match &q_binding.source {
+            ParamSource::QueryParam(name) => assert_eq!(name, "q"),
+            other => panic!("expected QueryParam, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn skips_when_not_a_nest_controller() {
+        let src: &[u8] = b"import { Injectable } from '@nestjs/common';\n\
+            @Injectable()\n\
+            export class HelperService {\n\
+              compute(x: number) { return x + 1; }\n\
+            }\n";
+        let tree = parse_ts(src);
+        assert!(TsNestAdapter
+            .detect(&summary("compute", "typescript"), tree.root_node(), src)
+            .is_none());
+    }
+}