content-calendar-recurrence

Calendar recurrence: RFC5545 RRULE expansion with timezone/DST handling

What it is for

# content-calendar-recurrence

Calendar recurrence library crate: RFC5545 RRULE expansion with proper timezone/DST handling.

Architecture

This crate handles recurring events WITHOUT materializing instances:

• Series: A template encounter + RRULE + timezone
• Exceptions: Skip or override specific instances
• Expansion: Compute instances on-demand via expand_occurrences()

Key Design Decisions

1. Timezone + Local Timestamp: Store dtstart_local (TIMESTAMP without TZ) plus an IANA timezone name (e.g., America/Chicago). This correctly handles DST: "Every Tuesday at 7pm" stays at 7pm local time even when clocks change.

2. No Materialized Instances: We don't pre-generate occurrence rows. Instead, expand_occurrences() computes them on-demand for a given date range.

3. Exceptions Table: Skip or override specific instances without breaking the series pattern.

4. Real FKs: Series references an encounter as template. No polymorphic linking.

Example

use content_calendar_recurrence::{CalendarSeries, Occurrence, expand_occurrences};
use chrono::{NaiveDateTime, Utc};

// Create a weekly series
let series = CalendarSeries::new(
encounter_template_id,
"FREQ=WEEKLY;BYDAY=TU,TH",
"America/Chicago",
NaiveDateTime::parse_from_str("2026-01-20 19:00:00", "%Y-%m-%d %H:%M:%S").unwrap(),
);

// Expand for January-March 2026
let from = Utc.with_ymd_and_hms(2026, 1, 1, 0, 0, 0).unwrap();
let to = Utc.with_ymd_and_hms(2026, 4, 1, 0, 0, 0).unwrap();
let occurrences = expand_occurrences(&series, &, from, to)?;

Capabilities

Occurrence

RRULE expansion with proper timezone/DST handling.

postgres (other)

PostgreSQL storage for calendar series and exceptions.

How to use it

No examples/ target and no doctest in this crate's rustdoc. The tests listed under Verification are the closest executable usage.

Module structure

content_calendar_recurrence

• expand
• postgres

flowchart TD
  n_content_calendar_recurrence["content_calendar_recurrence"]
  n_content_calendar_recurrence --> n_expand["expand"]
  n_content_calendar_recurrence --> n_postgres["postgres"]

Public surface

`expand`

`postgres`

Re-exports. Exported here, defined elsewhere.

Boundary

Reaches into foundation, identity.

Shares tier content with 5 other crates: content-assets, content-calendar, content-cms, content-directory-listing, content-notes.

_What this crate deliberately does NOT own is a judgment. No committed registry records one for it, so none is stated here._

Where it sits

Tier flow. Which tiers this crate's own edges cross.

flowchart LR
  n_content["content"] --> n_foundation["foundation"]
  n_content["content"] --> n_identity["identity"]

Dependencies

Runtime, in this workspace.

Runtime, from outside the workspace.

Development, from outside the workspace.

Build. None.

Depended on by. 2 workspace crates.

Signal flow — what reaches this crate, and what it reaches.

flowchart LR
  n_application_calendar_recurrence["application-calendar-recurrence"] -->|uses| SELF
  n_foundation_test_support["foundation-test-support"] -->|uses| SELF
  SELF["content-calendar-recurrence"]
  SELF -->|runtime| n_foundation_basemodels["foundation-basemodels"]
  SELF -->|runtime| n_identity_parties["identity-parties"]
  classDef self fill:#1f883d,stroke:#1f883d,color:#fff;
  class SELF self;

Feature flags

flowchart LR
  n_default["default"]
  n_postgres["postgres"] --> n_dep_sqlx["dep:sqlx"]

Targets

Error model

No public error type was detected: no public item declares a type named *Error, and no public signature returns one.

Operational characteristics

No unsafe block, unsafe fn, unsafe impl or unsafe trait was found by the parser anywhere in this crate's source.

Configuration

No environment variable is read with a literal name anywhere in this crate. A variable whose key is computed at run time cannot be listed here, and is not claimed to be absent.

Related capabilities

2 workspace crates depend on this one: application-calendar-recurrence, foundation-test-support.

Verification

Evidence by module. How often each public module is named by something executable.

What the tests establish, by name:

• test_cascade_delete_exceptions — tests/integration.rs
• test_create_override_exception — tests/integration.rs
• test_create_series — tests/integration.rs
• test_create_skip_exception — tests/integration.rs
• test_delete_exception — tests/integration.rs
• test_delete_series — tests/integration.rs
• test_duplicate_exception_fails — tests/integration.rs
• test_expand_across_dst_fall_back — tests/integration.rs
• test_expand_across_dst_spring_forward — tests/integration.rs
• test_expand_weekly_occurrences — tests/integration.rs
• test_expand_with_override_exception — tests/integration.rs
• test_expand_with_skip_exception — tests/integration.rs
• test_get_series_by_encounter — tests/integration.rs
• test_get_series_by_encounter_not_found — tests/integration.rs
• test_get_series_not_found — tests/integration.rs
• test_invalid_timezone_error — tests/integration.rs
• test_list_series — tests/integration.rs
• test_update_series — tests/integration.rs
• test_dst_spring_forward — src/expand.rs
• test_expand_weekly_series — src/expand.rs
• test_expand_with_override_exception — src/expand.rs
• test_expand_with_skip_exception — src/expand.rs
• test_invalid_timezone — src/expand.rs
• test_exports — src/lib.rs
• test_exception_action_parsing — src/models.rs
• test_exception_skip — src/models.rs
• test_series_builder — src/models.rs
• test_exception_action_roundtrip — src/postgres.rs

Documentation coverage

pie showData
    title Public items with rustdoc
    "Documented" : 11
    "No rustdoc detected" : 0

Metrics

pie showData
    title Public API by kind
    "function" : 10
    "struct" : 1

pie showData
    title Rust source composition
    "Code" : 632
    "Blank or comment" : 283

Generation

Rendered by tools-corpus corpus readme from repository evidence alone, renderer schema 2, lexicon current. No model, network service or database was consulted. Regenerate with tools-corpus corpus readme --write; verify with --check.