Safe Haskell	None
Language	Haskell2010

Avers

Contents

The Avers Monad
Types
Object
Patch
Snapshot
Release
Patching
Session
Blob
Secret
Views
Index
Metrics

Synopsis

The Avers Monad

data Avers a Source

Instances

Monad Avers
Functor Avers
Applicative Avers
MonadIO Avers
MonadAvers Avers
MonadError AversError Avers
MonadState AversState Avers

evalAvers :: AversState -> Avers a -> IO (Either AversError a) Source

Types

newtype Path Source

Path

Constructors

Path
Fields unPath :: Text

Instances

Eq Path
Ord Path
Show Path
IsString Path
ToJSON Path
FromJSON Path
ToDatum Path
FromDatum Path

class Pk a where Source

Pk - Types which can be converted to a database primary key.

Methods

toPk :: a -> Text Source

Instances

Pk Text
Pk ObjectId
Pk RevId
Pk ObjId
Pk Object
Pk Patch
Pk Snapshot
Pk Secret
Pk SecretId
Pk Blob
Pk BlobId
Pk Session
Pk SessionId
Pk (Record a)

newtype ObjId Source

ObjId

Constructors

ObjId
Fields unObjId :: Text

Instances

Eq ObjId
Ord ObjId
Show ObjId
ToJSON ObjId
FromJSON ObjId
ToDatum ObjId
FromDatum ObjId
Pk ObjId

rootObjId :: ObjId Source

The root object id is used for object created internally or when there is no applicable creator.

newtype RevId Source

RevId

Constructors

RevId
Fields unRevId :: Int

Instances

Enum RevId
Eq RevId
Ord RevId
Show RevId
ToJSON RevId
FromJSON RevId
ToDatum RevId
FromDatum RevId
Pk RevId

zeroRevId :: RevId Source

The RevId which is used for the initial snapshot.

data ObjectId Source

ObjectId

Constructors

BaseObjectId !ObjId	The base object whose snapshots contain the actual content.
ReleaseObjectId !ObjId !RevId	An object describing a particualar release of the base object.
AuthorizationObjectId !ObjId	Object which contains authorization rules.

Instances

Eq ObjectId
Ord ObjectId
Show ObjectId
ToJSON ObjectId
FromJSON ObjectId
ToDatum ObjectId
FromDatum ObjectId
Pk ObjectId

data Operation Source

The operations that can be applied to JSON values.

Constructors

Set	Set is applied to `Object`s. It is used for adding, updating and deleting properties from the object.
Fields opPath :: !Path opValue :: !(Maybe Value)
Splice	Splice is used to manipulate `Array`s. It can remove and insert multiple elements in a single operation.
Fields opPath :: !Path opIndex :: !Int opRemove :: !Int opInsert :: ![Value]

Instances

Eq Operation
Show Operation
ToJSON Operation
FromJSON Operation
ToDatum Operation
FromDatum Operation

Object

data Object Source

Constructors

Object
Fields objectId :: !ObjId objectType :: !Text objectCreatedAt :: !UTCTime objectCreatedBy :: !ObjId objectDeleted :: !(Maybe Bool)

Instances

Show Object
ToJSON Object
FromJSON Object
ToDatum Object
FromDatum Object
Pk Object

exists :: ObjId -> Avers Bool Source

True if the object exists.

createObject :: ToJSON a => ObjectType a -> ObjId -> a -> Avers ObjId Source

Create a new object of the given type. An initial snapshot (RevId 0) is created from the supplied content.

createObject' :: ToJSON a => ObjId -> UTCTime -> ObjectType a -> ObjId -> a -> Avers () Source

A more low-level version of createObject, for use when you want to generate your own ObjId or create objects at a specific time.

lookupObject :: ObjId -> Avers Object Source

Lookup an Object by its ObjId. Throws ObjectNotFound if the object doesn't exist.

deleteObject :: ObjId -> Avers () Source

Mark the object as deleted.

pruneObject :: ObjId -> Avers () Source

Prune the object from the database. This is only allowed if the object is marked as deleted. Note that this is a very dangerous operation, it can not be undone.

objectsOfType :: ObjectType a -> Avers (Vector ObjId) Source

allObjectsOfType :: ObjectType a -> Avers (Vector ObjId) Source

Patch

data Patch Source

Patch

Constructors

Patch
Fields patchObjectId :: !ObjectId patchRevisionId :: !RevId patchAuthorId :: !ObjId patchCreatedAt :: !UTCTime patchOperation :: !Operation

Instances

Show Patch
ToJSON Patch
FromJSON Patch
ToDatum Patch
FromDatum Patch
Pk Patch

data PatchError Source

Constructors

UnknownPatchError !Text

Instances

Show PatchError

lookupPatch :: ObjectId -> RevId -> Avers Patch Source

Snapshot

data Snapshot Source

Snapshot

Constructors

Snapshot
Fields snapshotObjectId :: !ObjectId snapshotRevisionId :: !RevId snapshotContent :: !Value

Instances

Show Snapshot
ToJSON Snapshot
FromJSON Snapshot
ToDatum Snapshot
FromDatum Snapshot
Pk Snapshot

lookupLatestSnapshot :: ObjectId -> Avers Snapshot Source

Get the snapshot of the newest revision of the given object.

objectContent :: FromJSON a => ObjectId -> Avers a Source

Fetch the content of the object and try to parse it.

This function will fail with a ParseError if the content can not be decoded into the desired type.

Release

data Release Source

Release

Constructors

Release

Instances

ToJSON Release
FromJSON Release

lookupRelease :: ObjId -> RevId -> Avers Release Source

createRelease :: ObjId -> RevId -> Avers () Source

Create a new release of the given revision. If the object doesn't exist, it will fail with ObjectNotFound.

lookupLatestRelease :: ObjId -> Avers (Maybe RevId) Source

Patching

resolvePathIn :: Path -> Value -> Maybe Value Source

Resolve the path in the object.

Session

newtype SessionId Source

SessionId

Constructors

SessionId
Fields unSessionId :: Text

Instances

ToJSON SessionId
FromJSON SessionId
ToDatum SessionId
FromDatum SessionId
Pk SessionId

data Session Source

The session record that is stored in the database.

A session is a unique identifier attached to a particular object. It contains the creation date and when it was last accessed. If you need to store additional data for a session, we recommend to use cookies.

Constructors

Session
Fields sessionId :: !SessionId sessionObjId :: !ObjId sessionCreatedAt :: !UTCTime sessionLastAccessedAt :: !UTCTime

Instances

ToJSON Session
FromJSON Session
ToDatum Session
FromDatum Session
Pk Session

saveSession :: Session -> Avers () Source

lookupSession :: SessionId -> Avers Session Source

dropSession :: SessionId -> Avers () Source

data ObjectType a Source

An ObjectType describes a particular type of object that is managed by Avers.

Constructors

ObjectType
Fields otType :: !Text The value of the `type` field of the `Object`. otId :: Avers ObjId Action which generates a new id. This is so that object types can have different strategies how to generate ids. otViews :: [SomeView a]

data SomeObjectType where Source

Constructors

SomeObjectType :: (ToDatum a, FromDatum a, FromJSON a, ToJSON a) => ObjectType a -> SomeObjectType

lookupObjectType :: Text -> Avers SomeObjectType Source

Lookup an object type which is registered in the Avers monad.

data AversError Source

Constructors

InternalError !AversError
DatabaseError !Text
PatchError !PatchError
ParseError !Value !Text
UnknownObjectType !Text
ObjectNotFound !ObjId
DocumentNotFound !Text
AversError !Text
NotAuthorized

Instances

Show AversError
MonadError AversError Avers

data AversConfig Source

Configuration of the Avers monad.

Constructors

AversConfig

Fields

databaseHost :: !Text

The hostname where RethinkDB is running. The port is currently not configurable.

databaseName :: !Text

RethinkDB supports multiple databases. This is the name of the one which should be used.

putBlob :: BlobId -> Text -> ByteString -> IO ()

Function which saves the given blob in the blob store. This can be the local filesystem or an external services such as Amazon S3.

TODO: Propagate errors back to the caller.

objectTypes :: ![SomeObjectType]

All the object types which Avers knows about.

emitMeasurement :: Measurement -> Double -> IO ()

This is called when the internal instrumentation code creates a measurement.

data AversState Source

Instances

MonadState AversState Avers

newState :: AversConfig -> IO AversState Source

strErr :: String -> Avers a Source

parseValueAs :: FromJSON a => ObjectType a -> Value -> Either AversError a Source

bootstrap :: Avers () Source

Blob

newtype BlobId Source

BlobId

Constructors

BlobId
Fields unBlobId :: Text

Instances

Show BlobId
ToJSON BlobId
FromJSON BlobId
ToDatum BlobId
FromDatum BlobId
Pk BlobId

data Blob Source

Blob

Constructors

Blob
Fields blobId :: !BlobId blobSize :: !Int blobContentType :: !Text

Instances

Show Blob
ToJSON Blob
FromJSON Blob
ToDatum Blob
FromDatum Blob
Pk Blob

createBlob :: ByteString -> Text -> Avers Blob Source

lookupBlob :: BlobId -> Avers Blob Source

Secret

newtype SecretId Source

SecretId

Constructors

SecretId
Fields unSecretId :: Text

Instances

Show SecretId
ToJSON SecretId
FromJSON SecretId
ToDatum SecretId
FromDatum SecretId
Pk SecretId

data Secret Source

Secret

A Secret is a password (encrypted with scrypt) that is attached to a SecretId (for example the ObjId of an account).

It is up to you to ensure that SecretIds are unique. If you use ObjIds then they by definition are.

Constructors

Secret
Fields secretId :: !SecretId secretValue :: !Text

Instances

ToJSON Secret
FromJSON Secret
ToDatum Secret
FromDatum Secret
Pk Secret

updateSecret :: SecretId -> Text -> Avers () Source

verifySecret :: SecretId -> Text -> Avers () Source

Verify the value against the secret. If that fails, then this function throws an error.

This function automatically updates the secret in the database if the scrypt params have changed.

applyObjectUpdates Source

Arguments

:: ObjectId	The object which you want to update
-> RevId	The `RevId` against which the operations were created
-> ObjId	Committer
-> [Operation]	The operations to apply
-> Bool	True if validation should be skipped
-> Avers ([Patch], Int, [Patch])

runQuery :: FromResponse (Result a) => Exp a -> Avers (Result a) Source

runQueryCollect :: (FromDatum a, IsSequence e, Result e ~ Sequence a) => Exp e -> Avers (Vector a) Source

parseValue :: (FromJSON a, MonadError AversError m) => Value -> m a Source

parseDatum :: (FromDatum a, MonadError AversError m) => Datum -> m a Source

newId :: Int -> IO Text Source

objectsTable :: Exp Table Source

blobsTable :: Exp Table Source

validateObject :: Text -> Value -> Avers () Source

Views

data View obj a Source

Constructors

View

Fields

viewName :: Text: The table name is derived from the view name. Therefore it should be unique amongst all views.
viewParser :: Datum -> Either AversError a: Function which parses objects stored in this view.
viewObjectTransformer :: obj -> Avers (Maybe a): Function which transforms an Avers Object into a type stored in the view.
viewIndices :: [SomeIndex]: Secondary indices defined on the view.

data SomeView obj where Source

Constructors

SomeView :: (ToDatum a, FromDatum a, FromJSON obj, ToJSON a) => View obj a -> SomeView obj

viewTable :: View obj a -> Exp Table Source

Construct the table name for the given view. The table names look something like this: "view_openGames"

updateView :: ToDatum a => View obj a -> ObjId -> Maybe obj -> Avers () Source

Index

data Index a Source

Constructors

Index
Fields indexName :: Text indexExpression :: Exp Object -> Exp a

data SomeIndex where Source

Constructors

SomeIndex :: IsDatum a => Index a -> SomeIndex

Metrics

data Measurement Source

Constructors

M_avers_storage_lookupObject_duration
M_avers_storage_lookupSnapshot_duration
M_avers_storage_lookupLatestSnapshot_duration
M_avers_storage_newestSnapshot_duration
M_avers_storage_patchesAfterRevision_duration
M_avers_storage_lookupPatch_duration
M_avers_storage_applyObjectUpdates_duration
M_avers_storage_applyObjectUpdates_numOperations
M_avers_storage_applyObjectUpdates_numPreviousPatches
M_avers_storage_exists_duration

measurementLabels :: Measurement -> [[Char]] Source