casl_flutter library

Flutter bindings for casl.

Put an ability in the tree, then ask what the user may do wherever you are drawing something:

AbilityProvider(
  ability: ability,
  child: MaterialApp(...),
);

// anywhere below it
Can('delete', article, child: DeleteButton(article: article));
CanBuilder('delete', article, builder: (_, allowed) => ...);
if (context.can('create', 'Article')) ...;

Every question here is answered by casl itself, so a rule means the same thing on the server, in a unit test and on screen. This package adds only the wiring: where the ability lives, and how a widget hears that it changed.

package:casl is re-exported, so one import is enough.

Classes

Ability: What a user may do, and the only thing the rest of an app needs to ask.
AbilityBuilder: Collects rules in the order they are written, then builds an ability.
AbilityProvider: Puts an ability in the tree, and rebuilds what depends on it when the rules change.
AbilityScope: The inherited widget AbilityProvider publishes.
AbilityUpdate: A rule change, as reported to an Ability.on listener.
Can: Shows child only when the action is permitted.
CanBuilder: Builds either way, told whether the action is permitted.
CanResult: The answer, and why, handed to a CanBuilder.
CompoundCondition: Several conditions combined — and, or, nor, not.
Condition: A parsed condition, ready to be evaluated.
ConditionInterpreter: Evaluates a parsed Condition against a subject.
ConditionsMatch: The result of compiling one rule's conditions.
FieldCondition: A test applied to one field of the subject.
MongoConditionsMatch: A rule's conditions, parsed once and ready to be asked.
MongoQueryParser: Turns a MongoDB-shaped query into a Condition tree.
OperatorCall: Everything an operator needs in order to parse itself.
ParsedConditions: A ConditionsMatch that can hand back the tree it parsed.
QueryLanguage<R>: How that language combines things.
RawRule: One rule, exactly as it travels over the wire.
Rule: A RawRule compiled for asking questions of.
RuleIndex: Rules, indexed by subject type and action so a check does not scan them all.
RuleRef: A handle on the rule just written, so a reason can be attached to it.
Subject: An object paired with the subject type it should be checked as.

Mixins

CaslRecord: A type whose fields conditions can be matched against.
CaslSubject: A type that knows which subject type rules are written about it.

Extensions

AbilityContext on BuildContext: Asking what the user may do, from anywhere with a BuildContext.
AbilityGuard on Ability: Turns a permission check into a guard that throws.

Constants

alwaysTrue → const Condition: The condition every subject satisfies.
anyAction → const String: The action that stands for every action.
anySubjectType → const String: The subject type that stands for every subject type.
defaultFieldsMatcher → const FieldsMatcher: The default FieldsMatcher — fieldPatternMatcher.
defaultOperators → const Map<String, OperatorParser>: The field operators CASL.js ships with, and only those.

Functions

caslCompare(Object? a, Object? b) → int: Orders two values the way the condition operators need them ordered.
createAliasResolver(Map<String, Object> aliases, {String anyActionName = anyAction, bool validate = true}) → ResolveActions: Builds a resolver from a map of alias to what it means.
createMongoAbility(List<RawRule> rules, {MongoQueryParser parser = const MongoQueryParser(), FieldReader read = readField, String? detectSubjectType(Object value)?, String anyActionName = 'manage', String anySubjectTypeName = 'all', List<String> resolveActions(List<String>)?}) → Ability: An ability that understands MongoDB-style conditions. The usual entry point.
detectSubjectTypeByRuntimeType(Object value) → String: The default, in order of how much it can be trusted.
fieldPatternMatcher(List<String> fields) → bool Function(String field): Matches a field name against patterns, with * and **.
hasField(Object? target, String field) → bool: Whether target has field at all, as $exists means it.
isSubjectType(Object? value) → bool: Whether value names a kind of thing rather than being one.
mongoConditionsMatcher({MongoQueryParser parser = const MongoQueryParser(), FieldReader read = readField}) → ConditionsMatcher: Builds the conditions matcher, optionally over a custom parser or reader.
oneOrMany(Object value, String what) → List<String>: Normalises the one-or-many shape every CASL field accepts.
packRules(List<RawRule> rules, {String packSubject(String subjectType)?}) → List<PackedRule>: Squeezes rules into the array form CASL.js's packRules produces.
permittedFieldsOf(Ability ability, String action, Object? subject, {required List<String> allFields}) → List<String>: Which fields of subject may be touched by action.
readField(Object target, String field) → Object?: Reads a field from a Map or a CaslRecord.
readParent(Object? target, String path, {FieldReader read = readField}) → (Object?, String): The object a path's last segment should be read from, and that segment.
readPath(Object? target, String path, {FieldReader read = readField}) → Object?: Reads path out of target, following dots and flattening lists.
rulesToAst(Ability ability, String action, String subjectType) → Condition?: The Condition form of rulesToCondition — the one most callers want.
rulesToCondition<R>(List<Rule> rules, RuleConverter<R> convert, QueryLanguage<R> language) → R?: Turns a grant into a filter: "which records may this user act on".
rulesToFields(Ability ability, String action, String subjectType) → Map<String, Object?>: The values a new subject must have for action to be permitted on it.
subject(String type, Object? value) → Subject: Pairs value with the subject type it should be checked as.
subjectValue(Object? subject) → Object?: The object conditions should be matched against.
unpackRules(List<Object?> packed, {String unpackSubject(String subjectType)?}) → List<RawRule>: Reads what packRules wrote, or what CASL.js's packRules wrote.

Typedefs

ConditionsMatcher = ConditionsMatch Function(Map<String, Object?> conditions): Compiles a rule's conditions into something that can be asked.
DetectSubjectType = String Function(Object value): Works out which subject type an arbitrary object should be checked as.
FieldReader = Object? Function(Object target, String field): Reads one field from one object.
FieldsMatcher = bool Function(String field) Function(List<String> fields): Compiles a rule's fields into a predicate over one field name.
ForbiddenMessageBuilder = String Function(ForbiddenError error): Builds the message shown when something is refused.
OperatorParser = Condition Function(OperatorCall call): How one $operator becomes a Condition.
PackedRule = List<Object?>: One rule in its compact wire form: a JSON array, not an object.
ResolveActions = List<String> Function(List<String> actions): Expands an action into itself plus everything it stands for.
RuleConverter<R> = R Function(Rule rule): How the conditions of one rule become whatever a query builder speaks.

Exceptions / Errors

ForbiddenError: Thrown when an action is not permitted.

casl_flutter library

Classes

Mixins

Extensions

Constants

Functions

Typedefs

Exceptions / Errors

casl_flutter package

casl_flutter library