# Ltix v0.2.0 - Table of Contents

> Ltix is an Elixir library for building LTI 1.3 applications.

## Pages

- [Ltix](readme.md)
- [Changelog](changelog.md)

- About
  - [What is Ltix?](what-is-ltix.md)
  - [LTI Advantage Concepts](concepts.md)
  - [Comparing Elixir LTI Libraries](comparing-lti-libraries.md)
  - [Threat Model](threat-model.md)

- Getting started
  - [Getting Started](getting-started.md)
  - [Testing with the IMS Reference Implementation](testing-with-ims-ri.md)
  - [Storage Adapters](storage-adapters.md)
  - [Upgrading to 0.2](upgrading-to-0-2.md)

- Launch flow
  - [Working with Roles](working-with-roles.md)
  - [Custom Role Parsers](custom-role-parsers.md)
  - [Custom Claim Parsers](custom-claim-parsers.md)
  - [Error Handling](error-handling.md)

- Services
  - [Advantage Services](advantage-services.md)
  - [Deep Linking](deep-linking.md)
  - [Memberships Service](memberships-service.md)
  - [Grade Service](grade-service.md)

- Operations
  - [JWK Management](jwk-management.md)
  - [Hardening Your Tool](hardening.md)
  - [Telemetry](telemetry.md)

- Cookbooks
  - [Auto-creating Deployments on First Launch](auto-create-deployments.md)
  - [Testing LTI Launches](testing-lti-launches.md)
  - [Managing JWKs with Ecto](managing-jwks-with-ecto.md)
  - [Building Scores](score-construction.md)
  - [Persisting Service Endpoints](persisting-service-endpoints.md)
  - [Syncing Grades in the Background](background-grade-sync.md)
  - [Using Canvas Grade Extensions](canvas-grade-extensions.md)
  - [Building Content Items](building-content-items.md)
  - [Token Caching and Reuse](token-caching-and-reuse.md)
  - [Building a Custom Advantage Service](custom-advantage-service.md)
  - [Keeping Login State in Platform Storage](platform-storage.md)

## Modules

- [Ltix](Ltix.md): Ltix handles the LTI 1.3 OIDC launch flow for tool applications. It is
built around 4 main components.

- Core
  - [Ltix.Deployable](Ltix.Deployable.md): Protocol for converting your deployment struct to an `Ltix.Deployment`.
  - [Ltix.Deployment](Ltix.Deployment.md): A specific installation of a tool on a platform, identified by an
immutable `deployment_id` assigned by the platform.

  - [Ltix.JWK](Ltix.JWK.md): RSA keys for LTI tool authentication.
  - [Ltix.LaunchContext](Ltix.LaunchContext.md): Validated output of a successful LTI launch.
  - [Ltix.Registerable](Ltix.Registerable.md): Protocol for converting your registration struct to an `Ltix.Registration`.
  - [Ltix.Registration](Ltix.Registration.md): Everything the tool stores about a registered platform, established
out-of-band before any launch occurs.
  - [Ltix.StorageAdapter](Ltix.StorageAdapter.md): Defines callbacks for looking up registrations, deployments, and managing nonces.

- JWT
  - [Ltix.JWT.KeySet](Ltix.JWT.KeySet.md): Platform public keys for verifying ID Token signatures.
  - [Ltix.JWT.Token](Ltix.JWT.Token.md): Decodes and validates LTI ID Tokens (JWTs).

- Launch Claims
  - [Ltix.LaunchClaims](Ltix.LaunchClaims.md): Structured representation of claims from an LTI launch JWT.
  - [Ltix.LaunchClaims.AGSEndpoint](Ltix.LaunchClaims.AGSEndpoint.md): Assignment and Grade Services (AGS) endpoint claim.
  - [Ltix.LaunchClaims.Context](Ltix.LaunchClaims.Context.md): The context (e.g. course or section) in which the launch occurs.
  - [Ltix.LaunchClaims.DeepLinkingSettings](Ltix.LaunchClaims.DeepLinkingSettings.md): Platform preferences for a Deep Linking content selection.
  - [Ltix.LaunchClaims.LIS](Ltix.LaunchClaims.LIS.md): SIS (Student Information System) integration identifiers from LIS.
  - [Ltix.LaunchClaims.LaunchPresentation](Ltix.LaunchClaims.LaunchPresentation.md): How the platform expects the tool to be presented.
  - [Ltix.LaunchClaims.MembershipsEndpoint](Ltix.LaunchClaims.MembershipsEndpoint.md): Memberships service endpoint claim.
  - [Ltix.LaunchClaims.Parser](Ltix.LaunchClaims.Parser.md): Defines a behavior for parsing a launch claim's raw value.
  - [Ltix.LaunchClaims.ResourceLink](Ltix.LaunchClaims.ResourceLink.md): A placement of an LTI resource link within a context.
  - [Ltix.LaunchClaims.Role](Ltix.LaunchClaims.Role.md): A parsed LTI role with type, name, and optional sub-role.
  - [Ltix.LaunchClaims.ToolPlatform](Ltix.LaunchClaims.ToolPlatform.md): Information about the platform instance that initiated the launch.
  - [Ltix.LaunchClaims.Role.LIS](Ltix.LaunchClaims.Role.LIS.md): LIS (Learning Information Services) role vocabulary parser.
  - [Ltix.LaunchClaims.Role.Parser](Ltix.LaunchClaims.Role.Parser.md): Defines a behaviour for parsing role URIs into `%Role{}` structs.

- Deep Linking
  - [Ltix.DeepLinking](Ltix.DeepLinking.md): Put content items into a signed response JWT for the platform.
  - [Ltix.DeepLinking.ContentItem](Ltix.DeepLinking.ContentItem.md): Protocol for serializing content items in Deep Linking responses.
  - [Ltix.DeepLinking.Response](Ltix.DeepLinking.Response.md): Signed JWT and return URL from a Deep Linking response.
  - [Ltix.DeepLinking.ContentItem.File](Ltix.DeepLinking.ContentItem.File.md): A file content item for Deep Linking responses.
  - [Ltix.DeepLinking.ContentItem.HTMLFragment](Ltix.DeepLinking.ContentItem.HTMLFragment.md): An HTML fragment content item for Deep Linking responses.
  - [Ltix.DeepLinking.ContentItem.Image](Ltix.DeepLinking.ContentItem.Image.md): An image content item for Deep Linking responses.
  - [Ltix.DeepLinking.ContentItem.LTIResourceLink](Ltix.DeepLinking.ContentItem.LTIResourceLink.md): An LTI resource link content item for Deep Linking responses.
  - [Ltix.DeepLinking.ContentItem.Link](Ltix.DeepLinking.ContentItem.Link.md): A URL link content item for Deep Linking responses.

- Advantage Services
  - [Ltix.AdvantageService](Ltix.AdvantageService.md): Behaviour for LTI Advantage service modules.
  - [Ltix.OAuth](Ltix.OAuth.md): OAuth 2.0 client credentials authentication for LTI Advantage services.
  - [Ltix.Pagination](Ltix.Pagination.md): Lazy paginated fetching for LTI Advantage endpoints.
  - [Ltix.OAuth.AccessToken](Ltix.OAuth.AccessToken.md): OAuth 2.0 access token response.
  - [Ltix.OAuth.Client](Ltix.OAuth.Client.md): Authenticated OAuth session for LTI Advantage service calls.

- Memberships Service
  - [Ltix.MembershipsService](Ltix.MembershipsService.md): Query context membership (roster) from a platform using the
[Names and Roles Provisioning Service (NRPS) v2.0](https://www.imsglobal.org/spec/lti-nrps/v2p0/).
  - [Ltix.MembershipsService.Member](Ltix.MembershipsService.Member.md): A single member in a roster response from the memberships service.
  - [Ltix.MembershipsService.MembershipContainer](Ltix.MembershipsService.MembershipContainer.md): A roster response from the memberships service.

- Grade Service
  - [Ltix.GradeService](Ltix.GradeService.md): Manage line items, post scores, and read results from a platform's
gradebook using the
[Assignment and Grade Services (AGS) v2.0](https://www.imsglobal.org/spec/lti-ags/v2p0/).
  - [Ltix.GradeService.LineItem](Ltix.GradeService.LineItem.md): A line item (gradebook column) in the platform's gradebook.
  - [Ltix.GradeService.Result](Ltix.GradeService.Result.md): A result record from the platform's gradebook.
  - [Ltix.GradeService.Score](Ltix.GradeService.Score.md): A score to post to the platform's gradebook.

- Errors
  - [Ltix.Errors](Ltix.Errors.md): Structured error types for LTI 1.3 validation.
  - [Ltix.Errors.Invalid](Ltix.Errors.Invalid.md): Error class for spec-violating input data.
  - [Ltix.Errors.Security](Ltix.Errors.Security.md): Error class for security framework violations.
  - [Ltix.Errors.Unknown](Ltix.Errors.Unknown.md): Catch-all error class for unexpected errors.

- Testing
  - [Ltix.Test](Ltix.Test.md): Helpers for testing applications that use Ltix.
  - [Ltix.Test.Platform](Ltix.Test.Platform.md): A simulated LTI platform for testing.
  - [Ltix.Test.StorageAdapter](Ltix.Test.StorageAdapter.md): In-memory `StorageAdapter` for tests.

- Exceptions
  - [Ltix.Errors.Invalid.CollectionTooLarge](Ltix.Errors.Invalid.CollectionTooLarge.md): An eager collection fetch exceeded its safety limit.
  - [Ltix.Errors.Invalid.ContentItemTypeNotAccepted](Ltix.Errors.Invalid.ContentItemTypeNotAccepted.md): Content item type not in the platform's accept_types list.
  - [Ltix.Errors.Invalid.ContentItemsExceedLimit](Ltix.Errors.Invalid.ContentItemsExceedLimit.md): Multiple content items returned when the platform only accepts one.
  - [Ltix.Errors.Invalid.CoupledLineItem](Ltix.Errors.Invalid.CoupledLineItem.md): Attempted to delete the platform-coupled line item without `force: true`.
  - [Ltix.Errors.Invalid.DeploymentNotFound](Ltix.Errors.Invalid.DeploymentNotFound.md): Unknown deployment_id [Core §3.1.3; Core §5.3.3].
  - [Ltix.Errors.Invalid.InvalidClaim](Ltix.Errors.Invalid.InvalidClaim.md): Claim present but wrong value or format.
  - [Ltix.Errors.Invalid.InvalidContentItem](Ltix.Errors.Invalid.InvalidContentItem.md): An item passed to `Ltix.DeepLinking.build_response/3` is not a content item.
  - [Ltix.Errors.Invalid.InvalidEndpoint](Ltix.Errors.Invalid.InvalidEndpoint.md): Wrong endpoint struct passed to an Advantage service.
  - [Ltix.Errors.Invalid.InvalidField](Ltix.Errors.Invalid.InvalidField.md): A field given to a constructor, such as `Ltix.Registration.new/1`, is unknown, missing, or has an invalid value.
  - [Ltix.Errors.Invalid.InvalidJSON](Ltix.Errors.Invalid.InvalidJSON.md): Malformed JSON or JWT structure [Cert §6.1.1].
  - [Ltix.Errors.Invalid.InvalidMessageType](Ltix.Errors.Invalid.InvalidMessageType.md): build_response called on a non-deep-linking launch context.
  - [Ltix.Errors.Invalid.InvalidOption](Ltix.Errors.Invalid.InvalidOption.md): An option passed to an Ltix function is unknown, missing, or has an invalid value.
  - [Ltix.Errors.Invalid.LineItemNotAccepted](Ltix.Errors.Invalid.LineItemNotAccepted.md): Content item includes a line_item but the platform does not accept line items.
  - [Ltix.Errors.Invalid.MalformedResponse](Ltix.Errors.Invalid.MalformedResponse.md): Service returned an unparseable response body.
  - [Ltix.Errors.Invalid.MediaTypeNotAccepted](Ltix.Errors.Invalid.MediaTypeNotAccepted.md): File content item media type not matched by the platform's `accept_media_types`.
  - [Ltix.Errors.Invalid.MissingClaim](Ltix.Errors.Invalid.MissingClaim.md): Missing required LTI claim.
  - [Ltix.Errors.Invalid.MissingLineItemId](Ltix.Errors.Invalid.MissingLineItemId.md): Line item has no `id`.
  - [Ltix.Errors.Invalid.MissingParameter](Ltix.Errors.Invalid.MissingParameter.md): Missing OIDC login parameter [Sec §5.1.1.1].
  - [Ltix.Errors.Invalid.PresentationTargetNotAccepted](Ltix.Errors.Invalid.PresentationTargetNotAccepted.md): Content item presentation not in the platform's `accept_presentation_document_targets` list.
  - [Ltix.Errors.Invalid.RegistrationNotFound](Ltix.Errors.Invalid.RegistrationNotFound.md): Unknown issuer/client_id combination [Sec §5.1.1.1].
  - [Ltix.Errors.Invalid.ScopeMismatch](Ltix.Errors.Invalid.ScopeMismatch.md): Client lacks the required OAuth scope.
  - [Ltix.Errors.Invalid.ServiceNotAvailable](Ltix.Errors.Invalid.ServiceNotAvailable.md): An Advantage service or token request cannot be made because an endpoint it needs is missing or unsupported.
  - [Ltix.Errors.Invalid.TokenRequestFailed](Ltix.Errors.Invalid.TokenRequestFailed.md): OAuth token request failed.
  - [Ltix.Errors.Security.AccessDenied](Ltix.Errors.Security.AccessDenied.md): Platform denied access to a service request or key set fetch.
  - [Ltix.Errors.Security.AccessTokenExpired](Ltix.Errors.Security.AccessTokenExpired.md): OAuth access token has expired.
  - [Ltix.Errors.Security.AlgorithmNotAllowed](Ltix.Errors.Security.AlgorithmNotAllowed.md): JWT alg is not RS256 [Sec §5.1.3 step 6; Sec §6.1].
  - [Ltix.Errors.Security.AudienceMismatch](Ltix.Errors.Security.AudienceMismatch.md): Tool's client_id not the only JWT aud, or azp present and not client_id [Sec §5.1.3 step 3; Sec §5.1.3 step 5].
  - [Ltix.Errors.Security.AuthenticationFailed](Ltix.Errors.Security.AuthenticationFailed.md): Platform returned an authentication error response [Sec §5.1.1.5].
  - [Ltix.Errors.Security.IssuerMismatch](Ltix.Errors.Security.IssuerMismatch.md): JWT iss doesn't match registration [Sec §5.1.3 step 2].
  - [Ltix.Errors.Security.KidMissing](Ltix.Errors.Security.KidMissing.md): No kid in JWT header [Cert §6.1.1].
  - [Ltix.Errors.Security.KidNotFound](Ltix.Errors.Security.KidNotFound.md): kid not found in JWKS [Cert §6.1.1].
  - [Ltix.Errors.Security.LocalNetworkAccessDenied](Ltix.Errors.Security.LocalNetworkAccessDenied.md): A platform request connected to a local or loopback address that isn't allowed.
  - [Ltix.Errors.Security.NonceMissing](Ltix.Errors.Security.NonceMissing.md): No nonce claim in JWT [Sec §5.1.3 step 9].
  - [Ltix.Errors.Security.NonceNotFound](Ltix.Errors.Security.NonceNotFound.md): Nonce not issued by this tool [Sec §5.1.3 step 9].
  - [Ltix.Errors.Security.NonceReused](Ltix.Errors.Security.NonceReused.md): Nonce previously seen — replay attack [Sec §5.1.3 step 9].
  - [Ltix.Errors.Security.SignatureInvalid](Ltix.Errors.Security.SignatureInvalid.md): JWT signature verification failed [Sec §5.1.3 step 1].
  - [Ltix.Errors.Security.StateMismatch](Ltix.Errors.Security.StateMismatch.md): CSRF state doesn't match [Sec §7.3.1].
  - [Ltix.Errors.Security.TokenExpired](Ltix.Errors.Security.TokenExpired.md): Token exp claim is in the past, or iat claim is older than the maximum token age [Sec §5.1.3 steps 7-8].
  - [Ltix.Errors.Security.TokenNotYetValid](Ltix.Errors.Security.TokenNotYetValid.md): Token iat or nbf claim is in the future [Sec §5.1.3 step 8; RFC 7519 §4.1.5].
  - [Ltix.Errors.Unknown.KeySetNotStarted](Ltix.Errors.Unknown.KeySetNotStarted.md): The key set a launch needs is not running.
  - [Ltix.Errors.Unknown.RedirectNotAllowed](Ltix.Errors.Unknown.RedirectNotAllowed.md): A platform endpoint returned an unsafe or invalid redirect.

  - [Ltix.Errors.Unknown.StorageError](Ltix.Errors.Unknown.StorageError.md): A storage adapter callback failed or returned an unexpected value.
  - [Ltix.Errors.Unknown.TransportError](Ltix.Errors.Unknown.TransportError.md): HTTP or connection error from a platform endpoint.
  - [Ltix.Errors.Unknown.Unknown](Ltix.Errors.Unknown.Unknown.md): Generic unexpected error.