Changelog

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All notable changes to this project will be documented in this file.

v0.2.0

Ltix 0.2 has 60 breaking changes. Upgrading to 0.2 describes each one and what to change in your tool.

Security

  • Ltix rejects a launch whose ID token is for a different login or a different registration than its login request.
  • Ltix rejects an ID token an hour after its iat, and a token with iat or nbf in the future.
  • Ltix rejects an ID token with an untrusted audience in an aud list, with critical header extensions, or with a missing or malformed iss, iat, or exp.
  • Your storage adapter records a nonce only after Ltix has verified the ID token.
  • Ltix sends platform requests only over HTTPS and only to public addresses. It follows a redirect or pagination link only to the scheme, host, and port of the first request.
  • A request configured to skip TLS certificate verification returns an error.
  • Ltix.JWT.KeySet fetches each key set URL at most once every 30 seconds.
  • inspect output omits private keys and access tokens.

Storage adapter and keys

  • Your storage adapter signs each JWT through the key_id and sign callbacks. Ltix.Registration has no tool_jwk field.
  • Storage adapter callbacks receive your registration struct and the options of the call. The registration lookup receives the platform's deployment ID.
  • A failing storage adapter callback returns StorageError.
  • Ltix.JWK is a PEM-based struct that replaces JOSE.JWK. Ltix.JWK.new/1 builds a key from a PEM, a DER, a JWK map, or a public key alone.
  • Ltix.JWT.KeySet is a process your application starts. It replaces the key set caches and the :jwks_cache setting.
  • Ltix.Registration, Ltix.JWK, and Ltix.Deployment validate their fields strictly and report InvalidField. Registration URLs must be HTTPS.
  • Ltix.OAuth and Ltix.Test accept any struct that implements Ltix.Registerable or Ltix.Deployable.

Launch claims and roles

  • Ltix checks the type of each claim, reports every missing or invalid claim by its name in the token, and omits a malformed optional claim.
  • Claim parsers can be modules that implement Ltix.LaunchClaims.Parser, and can override the built-in parsers. A failing claim parser returns InvalidClaim.
  • Ltix tries custom role parsers in order from the longest prefix to the shortest.
  • Role.administrator?/1 checks the institution role. Role.context_administrator?/1 checks the context role.
  • Role.to_uri!/1 returns the URI of any role.
  • The parser options are named claim_parsers and role_parsers in every function and in the application config.

Advantage services

  • Ltix.OAuth.authenticate/2 authenticates a custom Advantage service from a launch context. Client.request/3 and Client.request_pages/3 send its requests.
  • Ltix.OAuth.Client has a token field with an AccessToken. Its access_token, expires_at, and scopes fields are removed.
  • AccessToken.expired?/1, AccessToken.to_map/1, AccessToken.from_map/1, and Client.require_unexpired/1 are added for caching and storing tokens.
  • Client.refresh/1 returns the client unchanged until its token has expired.
  • A client accepts a token with fewer scopes than requested. The require_all_scopes option returns an error when a scope is missing. ScopeMismatch lists the scopes a request needed.
  • Token requests include the deployment ID, and the audience of the registration when it has one.
  • get_results and get_members are renamed to list_results and list_members. stream_line_items, stream_results, and stream_members stream a collection page by page.
  • List functions return CollectionTooLarge above 10,000 entries.
  • Grade operations accept an endpoint option. AGSEndpoint.new/1 and MembershipsEndpoint.new/1 validate their URLs and scopes.
  • delete_line_item/2 takes the line item as a line_item option.
  • Scores are built from keyword lists or maps. Score, line item, and deep linking dates are DateTime values.
  • to_json is replaced by to_map and JSON encoder protocol implementations for scores, line items, and content items. Grade results, members, and contexts have to_map too.
  • Unrecognized member fields are in Member extensions. A malformed member returns an error.
  • Ltix parses Link headers per RFC 8288, resolves relative next links, and stops paginating when a next link repeats a page.

Deep linking

  • build_response/3 enforces accept_presentation_document_targets and accept_media_types, and reports every constraint violation with the index of the item.
  • Content item options accept maps or keyword lists, including nested fields. Unknown options and extensions that would replace standard fields are rejected.
  • A resource link accepts a grade service LineItem as its line item.
  • verify_deep_linking_response returns SignatureInvalid for an invalid or malformed token.

Errors and options

  • Every fallible operation has a bang variant.
  • Functions raise InvalidOption for an unknown or invalid option.
  • A function that finds one error returns it. A function that finds several returns an error class struct with them in errors.
  • HTTP 401 and 403 responses return AccessDenied. A failed request returns TransportError with its URL and response headers.
  • Malformed tokens, token responses, and service responses return Ltix errors.
  • Ltix.Errors.status_code/1 returns the Plug status code of any exception.
  • Abbreviated struct fields are spelled out, and module names use uppercase acronyms such as LIS, AGS, and JSON.

Telemetry

  • Ltix emits telemetry events for OIDC login and callback, key set fetches, OAuth token requests and refreshes, the grade service, the memberships service, and deep linking.

Testing

  • Ltix.Test.assert_storage_adapter! checks a storage adapter, including its signing callbacks.
  • Ltix calls the storage adapter in your test config. setup_platform!/1 takes :registration and :deployment functions that create the records in your storage.
  • Ltix sends each request in a test to the Req.Test stub named after the module that makes it, such as Ltix.GradeService. stub_get_members is renamed to stub_list_members.
  • launch_params/2 and build_launch_context/2 take the same options, default to the instructor role, and include a course context.
  • A test can launch from several test platforms.
  • Ltix.Test compiles without the optional Plug dependency.

Dependencies

  • Jason is an optional dependency for Elixir versions without the built-in JSON module.
  • Ltix is tested on Elixir 1.17 through 1.20.

v0.1.0

Initial release with support for LTI 1.3 and LTI Advantage features:

  • LTI 1.3 Core: OIDC launch flow, launch claim parsing, JWT verification
  • Assignment and Grade Services 2.0
  • Names and Role Provisioning Service 2.0
  • Deep Linking 2.0