feat(stdlib): seven Rhai utility modules + register_stdlib hook

Adds the v1.1.0 user-visible stdlib: regex, random, time, json, base64,
hex, url — each exposed as a `::` namespace mirroring the existing
`log::` pattern. Modules register once at engine build via
`Engine::register_static_module`, distinct from the stateful service
modules (KV, docs, …) that hook into `sdk::register_all` per call.

- regex: linear-time, compile-per-call (no cache by design)
- random: OsRng only; bytes/string capped to prevent script-side blow-up
- time: UTC, ms-since-epoch as canonical i64; RFC 3339 strings for I/O
- json: parse/stringify via existing dynamic<->json bridge
- base64: standard + URL-safe alphabets, Blob and String inputs
- hex: lowercase output, case-insensitive decode
- url: RFC 3986 percent-encoding + encode_query for Maps

Stdlib registration runs unconditionally — including in the parse-only
validate path — so scripts get a uniform surface in both phases.

See docs/sdk-shape.md for the stateless-vs-stateful distinction.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/executor-core/src/engine.rs

@@ -143,6 +143,11 @@ fn build_engine(limits: Limits, logs: Option<Arc<Mutex<Vec<LogEntry>>>>) -> Rhai
         engine.register_static_module("log", build_log_module(logs).into());
     }
 
+    // Stateless utility modules — regex::/random::/time::/json::/base64::/
+    // hex::/url::. Always registered, including in the parse-only validate
+    // path, so script authors get consistent surface in both phases.
+    sdk::stdlib::register_stdlib(&mut engine);
+
     engine
 }
 

crates/executor-core/src/sdk/mod.rs

@@ -13,6 +13,7 @@
 
 pub mod bridge;
 pub mod cx;
+pub mod stdlib;
 
 pub use bridge::{dynamic_to_json, json_to_dynamic};
 pub use cx::SdkCallCx;

crates/executor-core/src/sdk/stdlib/base64.rs

@@ -0,0 +1,48 @@
+//! `base64::` — standard and URL-safe Base64.
+//!
+//! Two encoders are exposed: standard alphabet with padding (`encode`/
+//! `decode`) and URL-safe alphabet without padding (`encode_url`/
+//! `decode_url`). Each encoder accepts both `String` and `Blob` inputs
+//! as separate Rhai overloads; decoders always return `Blob` — the
+//! caller knows whether the original bytes were textual.
+
+use base64::engine::general_purpose::{STANDARD, URL_SAFE_NO_PAD};
+use base64::Engine as _;
+use rhai::{Blob, Engine as RhaiEngine, EvalAltResult, Module};
+
+pub fn register(engine: &mut RhaiEngine) {
+    let mut module = Module::new();
+
+    module.set_native_fn("encode", |s: &str| -> Result<String, Box<EvalAltResult>> {
+        Ok(STANDARD.encode(s.as_bytes()))
+    });
+    module.set_native_fn("encode", |b: Blob| -> Result<String, Box<EvalAltResult>> {
+        Ok(STANDARD.encode(&b))
+    });
+    module.set_native_fn("decode", |s: &str| -> Result<Blob, Box<EvalAltResult>> {
+        STANDARD
+            .decode(s)
+            .map_err(|e| format!("base64::decode: {e}").into())
+    });
+
+    module.set_native_fn(
+        "encode_url",
+        |s: &str| -> Result<String, Box<EvalAltResult>> {
+            Ok(URL_SAFE_NO_PAD.encode(s.as_bytes()))
+        },
+    );
+    module.set_native_fn(
+        "encode_url",
+        |b: Blob| -> Result<String, Box<EvalAltResult>> { Ok(URL_SAFE_NO_PAD.encode(&b)) },
+    );
+    module.set_native_fn(
+        "decode_url",
+        |s: &str| -> Result<Blob, Box<EvalAltResult>> {
+            URL_SAFE_NO_PAD
+                .decode(s)
+                .map_err(|e| format!("base64::decode_url: {e}").into())
+        },
+    );
+
+    engine.register_static_module("base64", module.into());
+}

crates/executor-core/src/sdk/stdlib/hex.rs

@@ -0,0 +1,21 @@
+//! `hex::` — hexadecimal encode/decode (lowercase output, case-
+//! insensitive input). String and Blob inputs are both accepted on
+//! encode; decode always returns `Blob`.
+
+use rhai::{Blob, Engine as RhaiEngine, EvalAltResult, Module};
+
+pub fn register(engine: &mut RhaiEngine) {
+    let mut module = Module::new();
+
+    module.set_native_fn("encode", |s: &str| -> Result<String, Box<EvalAltResult>> {
+        Ok(hex::encode(s.as_bytes()))
+    });
+    module.set_native_fn("encode", |b: Blob| -> Result<String, Box<EvalAltResult>> {
+        Ok(hex::encode(&b))
+    });
+    module.set_native_fn("decode", |s: &str| -> Result<Blob, Box<EvalAltResult>> {
+        hex::decode(s).map_err(|e| format!("hex::decode: {e}").into())
+    });
+
+    engine.register_static_module("hex", module.into());
+}

crates/executor-core/src/sdk/stdlib/json.rs

@@ -0,0 +1,43 @@
+//! `json::` — JSON parse and stringify. Reuses the bridge functions in
+//! `crate::sdk::bridge` so script-visible JSON has the same shape
+//! (numbers, maps, arrays, nulls) as `ctx.request.body` already does.
+
+use rhai::{Dynamic, Engine as RhaiEngine, EvalAltResult, Module};
+
+use crate::sdk::bridge::{dynamic_to_json, json_to_dynamic};
+
+pub fn register(engine: &mut RhaiEngine) {
+    let mut module = Module::new();
+    register_parse(&mut module);
+    register_stringify(&mut module);
+    register_stringify_pretty(&mut module);
+    engine.register_static_module("json", module.into());
+}
+
+fn register_parse(module: &mut Module) {
+    module.set_native_fn("parse", |s: &str| -> Result<Dynamic, Box<EvalAltResult>> {
+        let value: serde_json::Value =
+            serde_json::from_str(s).map_err(|e| format!("json::parse: {e}"))?;
+        Ok(json_to_dynamic(value))
+    });
+}
+
+fn register_stringify(module: &mut Module) {
+    module.set_native_fn(
+        "stringify",
+        |v: Dynamic| -> Result<String, Box<EvalAltResult>> {
+            serde_json::to_string(&dynamic_to_json(&v))
+                .map_err(|e| format!("json::stringify: {e}").into())
+        },
+    );
+}
+
+fn register_stringify_pretty(module: &mut Module) {
+    module.set_native_fn(
+        "stringify_pretty",
+        |v: Dynamic| -> Result<String, Box<EvalAltResult>> {
+            serde_json::to_string_pretty(&dynamic_to_json(&v))
+                .map_err(|e| format!("json::stringify_pretty: {e}").into())
+        },
+    );
+}

crates/executor-core/src/sdk/stdlib/mod.rs

@@ -0,0 +1,25 @@
+//! Stateless utility modules registered once at engine build via
+//! `Engine::register_static_module`. They have no per-call state, no
+//! cross-app sensitivity, and no `SdkCallCx` — distinguishing them
+//! from stateful service modules (KV, docs, …) which hook into
+//! `sdk::register_all` instead. See [docs/sdk-shape.md](../../../../../docs/sdk-shape.md).
+
+use rhai::Engine as RhaiEngine;
+
+pub mod base64;
+pub mod hex;
+pub mod json;
+pub mod random;
+pub mod regex;
+pub mod time;
+pub mod url;
+
+pub fn register_stdlib(engine: &mut RhaiEngine) {
+    regex::register(engine);
+    random::register(engine);
+    time::register(engine);
+    json::register(engine);
+    base64::register(engine);
+    hex::register(engine);
+    url::register(engine);
+}

crates/executor-core/src/sdk/stdlib/random.rs

@@ -0,0 +1,70 @@
+//! `random::` — CSPRNG primitives (`rand::rngs::OsRng`).
+//!
+//! Only the OS RNG is exposed. No "fast non-crypto" variant — scripts
+//! should not pick between secure and insecure entropy. Output sizes
+//! are capped to keep a single script call from blowing host memory.
+
+use rand::distributions::{Alphanumeric, DistString};
+use rand::{rngs::OsRng, Rng, RngCore};
+use rhai::{Blob, Engine as RhaiEngine, EvalAltResult, Module};
+use uuid::Uuid;
+
+const MAX_BYTES: i64 = 65_536;
+const MAX_STRING: i64 = 4_096;
+
+pub fn register(engine: &mut RhaiEngine) {
+    let mut module = Module::new();
+    register_int(&mut module);
+    register_float(&mut module);
+    register_bytes(&mut module);
+    register_string(&mut module);
+    register_uuid(&mut module);
+    engine.register_static_module("random", module.into());
+}
+
+fn register_int(module: &mut Module) {
+    module.set_native_fn(
+        "int",
+        |min: i64, max: i64| -> Result<i64, Box<EvalAltResult>> {
+            if min > max {
+                return Err(format!("random::int: min ({min}) > max ({max})").into());
+            }
+            Ok(OsRng.gen_range(min..=max))
+        },
+    );
+}
+
+fn register_float(module: &mut Module) {
+    module.set_native_fn("float", || -> Result<f64, Box<EvalAltResult>> {
+        Ok(OsRng.gen::<f64>())
+    });
+}
+
+fn register_bytes(module: &mut Module) {
+    module.set_native_fn("bytes", |n: i64| -> Result<Blob, Box<EvalAltResult>> {
+        if !(0..=MAX_BYTES).contains(&n) {
+            return Err(format!("random::bytes: n must be in 0..={MAX_BYTES}, got {n}").into());
+        }
+        // Safe: n is non-negative and bounded by MAX_BYTES, which fits in usize.
+        let len = usize::try_from(n).expect("n bounded above by MAX_BYTES");
+        let mut buf = vec![0u8; len];
+        OsRng.fill_bytes(&mut buf);
+        Ok(buf)
+    });
+}
+
+fn register_string(module: &mut Module) {
+    module.set_native_fn("string", |n: i64| -> Result<String, Box<EvalAltResult>> {
+        if !(0..=MAX_STRING).contains(&n) {
+            return Err(format!("random::string: n must be in 0..={MAX_STRING}, got {n}").into());
+        }
+        let len = usize::try_from(n).expect("n bounded above by MAX_STRING");
+        Ok(Alphanumeric.sample_string(&mut OsRng, len))
+    });
+}
+
+fn register_uuid(module: &mut Module) {
+    module.set_native_fn("uuid", || -> Result<String, Box<EvalAltResult>> {
+        Ok(Uuid::new_v4().to_string())
+    });
+}

crates/executor-core/src/sdk/stdlib/regex.rs

@@ -0,0 +1,105 @@
+//! `regex::` — non-backtracking regular expressions (Rust `regex` crate).
+//!
+//! Patterns compile per call. No cache: premature for v1.1.0, and the
+//! `regex` crate's linear-time guarantees keep per-call cost bounded.
+//! Catastrophic patterns are rejected at compile time by the crate
+//! itself; no extra defense needed.
+
+use regex::Regex;
+use rhai::{Array, Dynamic, Engine as RhaiEngine, EvalAltResult, Module};
+
+pub fn register(engine: &mut RhaiEngine) {
+    let mut module = Module::new();
+    register_is_match(&mut module);
+    register_find(&mut module);
+    register_find_all(&mut module);
+    register_replace(&mut module);
+    register_replace_all(&mut module);
+    register_split(&mut module);
+    register_captures(&mut module);
+    engine.register_static_module("regex", module.into());
+}
+
+fn compile(pattern: &str) -> Result<Regex, Box<EvalAltResult>> {
+    Regex::new(pattern).map_err(|e| format!("invalid regex: {e}").into())
+}
+
+fn register_is_match(module: &mut Module) {
+    module.set_native_fn(
+        "is_match",
+        |pattern: &str, text: &str| -> Result<bool, Box<EvalAltResult>> {
+            Ok(compile(pattern)?.is_match(text))
+        },
+    );
+}
+
+fn register_find(module: &mut Module) {
+    module.set_native_fn(
+        "find",
+        |pattern: &str, text: &str| -> Result<Dynamic, Box<EvalAltResult>> {
+            Ok(compile(pattern)?
+                .find(text)
+                .map_or(Dynamic::UNIT, |m| Dynamic::from(m.as_str().to_string())))
+        },
+    );
+}
+
+fn register_find_all(module: &mut Module) {
+    module.set_native_fn(
+        "find_all",
+        |pattern: &str, text: &str| -> Result<Array, Box<EvalAltResult>> {
+            Ok(compile(pattern)?
+                .find_iter(text)
+                .map(|m| Dynamic::from(m.as_str().to_string()))
+                .collect())
+        },
+    );
+}
+
+fn register_replace(module: &mut Module) {
+    module.set_native_fn(
+        "replace",
+        |pattern: &str, text: &str, replacement: &str| -> Result<String, Box<EvalAltResult>> {
+            Ok(compile(pattern)?.replace(text, replacement).into_owned())
+        },
+    );
+}
+
+fn register_replace_all(module: &mut Module) {
+    module.set_native_fn(
+        "replace_all",
+        |pattern: &str, text: &str, replacement: &str| -> Result<String, Box<EvalAltResult>> {
+            Ok(compile(pattern)?
+                .replace_all(text, replacement)
+                .into_owned())
+        },
+    );
+}
+
+fn register_split(module: &mut Module) {
+    module.set_native_fn(
+        "split",
+        |pattern: &str, text: &str| -> Result<Array, Box<EvalAltResult>> {
+            Ok(compile(pattern)?
+                .split(text)
+                .map(|s| Dynamic::from(s.to_string()))
+                .collect())
+        },
+    );
+}
+
+fn register_captures(module: &mut Module) {
+    module.set_native_fn(
+        "captures",
+        |pattern: &str, text: &str| -> Result<Dynamic, Box<EvalAltResult>> {
+            let re = compile(pattern)?;
+            Ok(re.captures(text).map_or(Dynamic::UNIT, |caps| {
+                let arr: Array = caps
+                    .iter()
+                    .map(|m| m.map_or(Dynamic::UNIT, |m| Dynamic::from(m.as_str().to_string())))
+                    .collect();
+                Dynamic::from(arr)
+            }))
+        },
+    );
+}

crates/executor-core/src/sdk/stdlib/time.rs

@@ -0,0 +1,68 @@
+//! `time::` — UTC time. The canonical "time value" is milliseconds
+//! since the Unix epoch as `i64`. ISO 8601 strings are for parsing and
+//! display only. UTC only — no timezone support in v1.1.0 (would pull
+//! in chrono-tz, deferred until a real use case demands it).
+
+use chrono::{DateTime, SecondsFormat, Utc};
+use rhai::{Engine as RhaiEngine, EvalAltResult, Module};
+
+pub fn register(engine: &mut RhaiEngine) {
+    let mut module = Module::new();
+    register_now(&mut module);
+    register_now_ms(&mut module);
+    register_parse(&mut module);
+    register_format(&mut module);
+    register_add_seconds(&mut module);
+    register_diff_seconds(&mut module);
+    engine.register_static_module("time", module.into());
+}
+
+fn register_now(module: &mut Module) {
+    module.set_native_fn("now", || -> Result<String, Box<EvalAltResult>> {
+        Ok(Utc::now().to_rfc3339_opts(SecondsFormat::Millis, true))
+    });
+}
+
+fn register_now_ms(module: &mut Module) {
+    module.set_native_fn("now_ms", || -> Result<i64, Box<EvalAltResult>> {
+        Ok(Utc::now().timestamp_millis())
+    });
+}
+
+fn register_parse(module: &mut Module) {
+    module.set_native_fn("parse", |iso: &str| -> Result<i64, Box<EvalAltResult>> {
+        DateTime::parse_from_rfc3339(iso)
+            .map(|dt| dt.timestamp_millis())
+            .map_err(|e| format!("time::parse: invalid ISO 8601 / RFC 3339: {e}").into())
+    });
+}
+
+fn register_format(module: &mut Module) {
+    module.set_native_fn("format", |ms: i64| -> Result<String, Box<EvalAltResult>> {
+        DateTime::<Utc>::from_timestamp_millis(ms)
+            .map(|dt| dt.to_rfc3339_opts(SecondsFormat::Millis, true))
+            .ok_or_else(|| format!("time::format: ms ({ms}) out of representable range").into())
+    });
+}
+
+fn register_add_seconds(module: &mut Module) {
+    module.set_native_fn(
+        "add_seconds",
+        |ms: i64, secs: i64| -> Result<i64, Box<EvalAltResult>> {
+            secs.checked_mul(1000)
+                .and_then(|delta| ms.checked_add(delta))
+                .ok_or_else(|| format!("time::add_seconds: overflow (ms={ms}, secs={secs})").into())
+        },
+    );
+}
+
+fn register_diff_seconds(module: &mut Module) {
+    module.set_native_fn(
+        "diff_seconds",
+        |a_ms: i64, b_ms: i64| -> Result<i64, Box<EvalAltResult>> {
+            b_ms.checked_sub(a_ms)
+                .map(|d| d / 1000)
+                .ok_or_else(|| format!("time::diff_seconds: overflow (a={a_ms}, b={b_ms})").into())
+        },
+    );
+}

crates/executor-core/src/sdk/stdlib/url.rs

@@ -0,0 +1,64 @@
+//! `url::` — RFC 3986 percent-encoding.
+//!
+//! `encode`/`decode` operate on opaque component values; `encode_query`
+//! builds an `application/x-www-form-urlencoded`-style query string
+//! from a Rhai `Map`. Key ordering is the map's natural order (Rhai's
+//! `Map` is a `BTreeMap`, so keys come out alphabetically — fine for
+//! query strings, which RFC 3986 leaves unordered).
+
+use percent_encoding::{percent_decode_str, utf8_percent_encode, AsciiSet, NON_ALPHANUMERIC};
+use rhai::{Engine as RhaiEngine, EvalAltResult, Map, Module};
+
+/// RFC 3986 unreserved set: `A-Z / a-z / 0-9 / - / _ / . / ~`.
+/// Everything outside this set gets percent-encoded.
+const UNRESERVED: &AsciiSet = &NON_ALPHANUMERIC
+    .remove(b'-')
+    .remove(b'_')
+    .remove(b'.')
+    .remove(b'~');
+
+pub fn register(engine: &mut RhaiEngine) {
+    let mut module = Module::new();
+    register_encode(&mut module);
+    register_decode(&mut module);
+    register_encode_query(&mut module);
+    engine.register_static_module("url", module.into());
+}
+
+fn register_encode(module: &mut Module) {
+    module.set_native_fn("encode", |s: &str| -> Result<String, Box<EvalAltResult>> {
+        Ok(utf8_percent_encode(s, UNRESERVED).to_string())
+    });
+}
+
+fn register_decode(module: &mut Module) {
+    module.set_native_fn("decode", |s: &str| -> Result<String, Box<EvalAltResult>> {
+        percent_decode_str(s)
+            .decode_utf8()
+            .map(std::borrow::Cow::into_owned)
+            .map_err(|e| format!("url::decode: invalid UTF-8: {e}").into())
+    });
+}
+
+fn register_encode_query(module: &mut Module) {
+    module.set_native_fn(
+        "encode_query",
+        |m: Map| -> Result<String, Box<EvalAltResult>> {
+            let mut out = String::new();
+            for (k, v) in m {
+                if !out.is_empty() {
+                    out.push('&');
+                }
+                out.push_str(&utf8_percent_encode(&k, UNRESERVED).to_string());
+                out.push('=');
+                // Coerce values via `to_string` rather than throwing on
+                // non-strings — scripts commonly pass numbers/bools here
+                // and a forced cast at the call site is friction with
+                // no upside.
+                let value = v.to_string();
+                out.push_str(&utf8_percent_encode(&value, UNRESERVED).to_string());
+            }
+            Ok(out)
+        },
+    );
+}