[ Newbie ] [ MongoDB ] Using MongoDB Persistent backend

Kamil Ciemniewski

29 Jun 2011 29 Jun '11

4:17 a.m.

Hi all, I've got some "newbie" problems using MongoDB as backend in Persistent. Basically I've got my app type defined as: data MyApp = MyApp { getStatic :: Static -- ^ Settings for static file serving. , connPool :: ConnPool Host } And I made it an instance of YesodPersist by: instance YesodPersist MyApp where type YesodDB MyApp = MongoDBReader Host runDB db = liftIOHandler $ fmap connPool getYesod >>= (\p -> return (p, "localhost")) >>= runMongoDBConn db And I made it an instance of YesodAuth as well by: instance YesodAuth MyApp where type AuthId MyApp = UserId loginDest _ = RootR logoutDest _ = RootR getAuthId creds = runDB $ do x <- getBy $ UniqueUser $ credsIdent creds case x of Just (uid, _) -> return $ Just uid Nothing -> do fmap Just $ insert $ User (credsIdent creds) Nothing authPlugins = [ authEmail ] I've defined User model as yesod scaffold tool defines it. Now, when I try to compile it i get: No instances for (Control.Monad.Context.Context Database.MongoDB.Connection.MasterOrSlaveOk (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.Database (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Internal.Protocol.Pipe (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.WriteMode (GGHandler s MyApp IO), Control.Monad.Throw.Throw Database.MongoDB.Query.Failure (GGHandler s MyApp IO)) arising from a use of `insert' Possible fix: add instance declarations for (Control.Monad.Context.Context Database.MongoDB.Connection.MasterOrSlaveOk (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.Database (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Internal.Protocol.Pipe (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.WriteMode (GGHandler s MyApp IO), Control.Monad.Throw.Throw Database.MongoDB.Query.Failure (GGHandler s MyApp IO)) In the expression: insert In the second argument of `($)', namely `insert $ User (credsIdent creds) Nothing' In the expression: fmap Just $ insert $ User (credsIdent creds) Nothing The problem is probably very trivial.. But I've got no ideas how to fix it. Best regards Kamil Ciemniewski

Attachments:

attachment.html (text/html — 2.9 KB)

Show replies by date

Max Cantor

29 Jun 29 Jun

4:21 a.m.

New subject: [ Newbie ] [ MongoDB ] Using MongoDB Persistent backend

Its not trivial. Apparently, the mongodb driver isn't exactly ready for showtime. AFAIK, the context monad is a reader monad that contains the connection parameters for mongo. I never got it to work. Greg might know more. Max On Jun 29, 2011, at 4:17 PM, Kamil Ciemniewski wrote:

...

Hi all,

I've got some "newbie" problems using MongoDB as backend in Persistent.

Basically I've got my app type defined as: data MyApp = MyApp { getStatic :: Static -- ^ Settings for static file serving. , connPool :: ConnPool Host }

And I made it an instance of YesodPersist by: instance YesodPersist MyApp where type YesodDB MyApp = MongoDBReader Host runDB db = liftIOHandler $ fmap connPool getYesod >>= (\p -> return (p, "localhost")) >>= runMongoDBConn db

And I made it an instance of YesodAuth as well by: instance YesodAuth MyApp where type AuthId MyApp = UserId

loginDest _ = RootR logoutDest _ = RootR

getAuthId creds = runDB $ do x <- getBy $ UniqueUser $ credsIdent creds case x of Just (uid, _) -> return $ Just uid Nothing -> do fmap Just $ insert $ User (credsIdent creds) Nothing

authPlugins = [ authEmail ]

I've defined User model as yesod scaffold tool defines it.

Now, when I try to compile it i get:

No instances for (Control.Monad.Context.Context Database.MongoDB.Connection.MasterOrSlaveOk (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.Database (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Internal.Protocol.Pipe (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.WriteMode (GGHandler s MyApp IO), Control.Monad.Throw.Throw Database.MongoDB.Query.Failure (GGHandler s MyApp IO)) arising from a use of `insert' Possible fix: add instance declarations for (Control.Monad.Context.Context Database.MongoDB.Connection.MasterOrSlaveOk (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.Database (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Internal.Protocol.Pipe (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.WriteMode (GGHandler s MyApp IO), Control.Monad.Throw.Throw Database.MongoDB.Query.Failure (GGHandler s MyApp IO)) In the expression: insert In the second argument of `($)', namely `insert $ User (credsIdent creds) Nothing' In the expression: fmap Just $ insert $ User (credsIdent creds) Nothing

The problem is probably very trivial.. But I've got no ideas how to fix it.

Best regards Kamil Ciemniewski _______________________________________________ web-devel mailing list web-devel@haskell.org http://www.haskell.org/mailman/listinfo/web-devel

Michael Snoyman

4:25 a.m.

New subject: [ Newbie ] [ MongoDB ] Using MongoDB Persistent backend

On Wed, Jun 29, 2011 at 11:17 AM, Kamil Ciemniewski wrote:

...

Hi all,

I've got some "newbie" problems using MongoDB as backend in Persistent.

Basically I've got my app type defined as: data MyApp = MyApp     { getStatic :: Static -- ^ Settings for static file serving.     , connPool :: ConnPool Host     }

And I made it an instance of YesodPersist by: instance YesodPersist MyApp where type YesodDB MyApp = MongoDBReader Host runDB db = liftIOHandler            $ fmap connPool getYesod >>= (\p -> return (p, "localhost")) >>= runMongoDBConn db

And I made it an instance of YesodAuth as well by: instance YesodAuth MyApp where type AuthId MyApp = UserId

loginDest _ = RootR logoutDest _ = RootR

getAuthId creds = runDB $ do       x <- getBy $ UniqueUser $ credsIdent creds       case x of     Just (uid, _) -> return $ Just uid     Nothing -> do           fmap Just $ insert $ User (credsIdent creds) Nothing

authPlugins = [ authEmail ]

I've defined User model as yesod scaffold tool defines it.

Now, when I try to compile it i get:

No instances for (Control.Monad.Context.Context                         Database.MongoDB.Connection.MasterOrSlaveOk                         (GGHandler s MyApp IO),                       Control.Monad.Context.Context                         Database.MongoDB.Query.Database (GGHandler s MyApp IO),                       Control.Monad.Context.Context                         Database.MongoDB.Internal.Protocol.Pipe (GGHandler s MyApp IO),                       Control.Monad.Context.Context                         Database.MongoDB.Query.WriteMode (GGHandler s MyApp IO),                       Control.Monad.Throw.Throw                         Database.MongoDB.Query.Failure (GGHandler s MyApp IO))       arising from a use of `insert'     Possible fix:       add instance declarations for       (Control.Monad.Context.Context          Database.MongoDB.Connection.MasterOrSlaveOk          (GGHandler s MyApp IO),        Control.Monad.Context.Context          Database.MongoDB.Query.Database (GGHandler s MyApp IO),        Control.Monad.Context.Context          Database.MongoDB.Internal.Protocol.Pipe (GGHandler s MyApp IO),        Control.Monad.Context.Context          Database.MongoDB.Query.WriteMode (GGHandler s MyApp IO),        Control.Monad.Throw.Throw          Database.MongoDB.Query.Failure (GGHandler s MyApp IO))     In the expression: insert     In the second argument of `($)', namely       `insert $ User (credsIdent creds) Nothing'     In the expression:         fmap Just $ insert $ User (credsIdent creds) Nothing

The problem is probably very trivial.. But I've got no ideas how to fix it.

Best regards Kamil Ciemniewski

_______________________________________________ web-devel mailing list web-devel@haskell.org http://www.haskell.org/mailman/listinfo/web-devel

I don't have direct experience with the MongoDB backend, but I can give this a shot if I saw some code. I think one possibility would be to wrap everything in a liftIO, but then you won't have access to the Handler monad features. This would prevent you from doing things like setting messages and sending redirects from the database access itself, but should otherwise be fine. Michael

Greg Weber

30 Jun 30 Jun

11:55 a.m.

New subject: [ Newbie ] [ MongoDB ] Using MongoDB Persistent backend

I think it is about time to finally fix this. I am probably the least knowledgeable about Monad mashing, but seems like a good time to learn! Here is a simple app we can use: https://gist.github.com/1056520 But maybe it is best to use the test suite. Here are all the hacks to get the tests to run right now that need to be removed: instance Context DB.MasterOrSlaveOk IO where context = undefined push = undefined instance Context DB.Database IO where context = undefined push = undefined instance Context DB.WriteMode IO where context = undefined push = undefined instance Context DB.Pipe IO where context = undefined push = undefined instance Control.Monad.Throw.Throw DB.Failure IO where throw = undefined catch = undefined On Wed, Jun 29, 2011 at 1:25 AM, Michael Snoyman wrote:

...

On Wed, Jun 29, 2011 at 11:17 AM, Kamil Ciemniewski wrote:

...
Hi all,

I've got some "newbie" problems using MongoDB as backend in Persistent.

Basically I've got my app type defined as: data MyApp = MyApp { getStatic :: Static -- ^ Settings for static file serving. , connPool :: ConnPool Host }

And I made it an instance of YesodPersist by: instance YesodPersist MyApp where type YesodDB MyApp = MongoDBReader Host runDB db = liftIOHandler $ fmap connPool getYesod >>= (\p -> return (p, "localhost"))

...
= runMongoDBConn db

And I made it an instance of YesodAuth as well by: instance YesodAuth MyApp where type AuthId MyApp = UserId

loginDest _ = RootR logoutDest _ = RootR

getAuthId creds = runDB $ do x <- getBy $ UniqueUser $ credsIdent creds case x of Just (uid, _) -> return $ Just uid Nothing -> do fmap Just $ insert $ User (credsIdent creds) Nothing

authPlugins = [ authEmail ]

I've defined User model as yesod scaffold tool defines it.

Now, when I try to compile it i get:

No instances for (Control.Monad.Context.Context Database.MongoDB.Connection.MasterOrSlaveOk (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.Database (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Internal.Protocol.Pipe (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.WriteMode (GGHandler s MyApp IO), Control.Monad.Throw.Throw Database.MongoDB.Query.Failure (GGHandler s MyApp IO)) arising from a use of `insert' Possible fix: add instance declarations for (Control.Monad.Context.Context Database.MongoDB.Connection.MasterOrSlaveOk (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.Database (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Internal.Protocol.Pipe (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.WriteMode (GGHandler s MyApp IO), Control.Monad.Throw.Throw Database.MongoDB.Query.Failure (GGHandler s MyApp IO)) In the expression: insert In the second argument of `($)', namely `insert $ User (credsIdent creds) Nothing' In the expression: fmap Just $ insert $ User (credsIdent creds) Nothing

The problem is probably very trivial.. But I've got no ideas how to fix it.

Best regards Kamil Ciemniewski

_______________________________________________ web-devel mailing list web-devel@haskell.org http://www.haskell.org/mailman/listinfo/web-devel

I don't have direct experience with the MongoDB backend, but I can give this a shot if I saw some code. I think one possibility would be to wrap everything in a liftIO, but then you won't have access to the Handler monad features. This would prevent you from doing things like setting messages and sending redirects from the database access itself, but should otherwise be fine.

Michael

_______________________________________________ web-devel mailing list web-devel@haskell.org http://www.haskell.org/mailman/listinfo/web-devel

Michael Snoyman

2:26 p.m.

New subject: [ Newbie ] [ MongoDB ] Using MongoDB Persistent backend

OK, simple question: why can't we use a type of MongoDBReader of: newtype MongoDBReader m a = MongoDBReader (Action m a) deriving (Monad, Trans.MonadIO, Functor, Applicative) Michael On Thu, Jun 30, 2011 at 6:55 PM, Greg Weber wrote:

...

I think it is about time to finally fix this. I am probably the least knowledgeable about Monad mashing, but seems like a good time to learn! Here is a simple app we can use: https://gist.github.com/1056520 But maybe it is best to use the test suite. Here are all the hacks to get the tests to run right now that need to be removed: instance Context DB.MasterOrSlaveOk IO where context = undefined push = undefined instance Context DB.Database IO where context = undefined push = undefined instance Context DB.WriteMode IO where context = undefined push = undefined instance Context DB.Pipe IO where context = undefined push = undefined instance Control.Monad.Throw.Throw DB.Failure IO where throw = undefined catch = undefined

On Wed, Jun 29, 2011 at 1:25 AM, Michael Snoyman wrote:

...
On Wed, Jun 29, 2011 at 11:17 AM, Kamil Ciemniewski wrote:

...
Hi all,

I've got some "newbie" problems using MongoDB as backend in Persistent.

Basically I've got my app type defined as: data MyApp = MyApp     { getStatic :: Static -- ^ Settings for static file serving.     , connPool :: ConnPool Host     }

And I made it an instance of YesodPersist by: instance YesodPersist MyApp where type YesodDB MyApp = MongoDBReader Host runDB db = liftIOHandler            $ fmap connPool getYesod >>= (\p -> return (p, "localhost"))

...
...
= runMongoDBConn db

And I made it an instance of YesodAuth as well by: instance YesodAuth MyApp where type AuthId MyApp = UserId

loginDest _ = RootR logoutDest _ = RootR

getAuthId creds = runDB $ do       x <- getBy $ UniqueUser $ credsIdent creds       case x of     Just (uid, _) -> return $ Just uid     Nothing -> do           fmap Just $ insert $ User (credsIdent creds) Nothing

authPlugins = [ authEmail ]

I've defined User model as yesod scaffold tool defines it.

Now, when I try to compile it i get:

No instances for (Control.Monad.Context.Context                         Database.MongoDB.Connection.MasterOrSlaveOk                         (GGHandler s MyApp IO),                       Control.Monad.Context.Context                         Database.MongoDB.Query.Database (GGHandler s MyApp IO),                       Control.Monad.Context.Context                         Database.MongoDB.Internal.Protocol.Pipe (GGHandler s MyApp IO),                       Control.Monad.Context.Context                         Database.MongoDB.Query.WriteMode (GGHandler s MyApp IO),                       Control.Monad.Throw.Throw                         Database.MongoDB.Query.Failure (GGHandler s MyApp IO))       arising from a use of `insert'     Possible fix:       add instance declarations for       (Control.Monad.Context.Context          Database.MongoDB.Connection.MasterOrSlaveOk          (GGHandler s MyApp IO),        Control.Monad.Context.Context          Database.MongoDB.Query.Database (GGHandler s MyApp IO),        Control.Monad.Context.Context          Database.MongoDB.Internal.Protocol.Pipe (GGHandler s MyApp IO),        Control.Monad.Context.Context          Database.MongoDB.Query.WriteMode (GGHandler s MyApp IO),        Control.Monad.Throw.Throw          Database.MongoDB.Query.Failure (GGHandler s MyApp IO))     In the expression: insert     In the second argument of `($)', namely       `insert $ User (credsIdent creds) Nothing'     In the expression:         fmap Just $ insert $ User (credsIdent creds) Nothing

The problem is probably very trivial.. But I've got no ideas how to fix it.

Best regards Kamil Ciemniewski

_______________________________________________ web-devel mailing list web-devel@haskell.org http://www.haskell.org/mailman/listinfo/web-devel

I don't have direct experience with the MongoDB backend, but I can give this a shot if I saw some code. I think one possibility would be to wrap everything in a liftIO, but then you won't have access to the Handler monad features. This would prevent you from doing things like setting messages and sending redirects from the database access itself, but should otherwise be fine.

Michael

_______________________________________________ web-devel mailing list web-devel@haskell.org http://www.haskell.org/mailman/listinfo/web-devel

Greg Weber

7 Jul 7 Jul

11:30 a.m.

New subject: [ Newbie ] [ MongoDB ] Using MongoDB Persistent backend

The latest version of persistent-mongoDB on hackage works now. After we get some more usage it will be added as a scaffolding option. Here is some basic runner code: import Database.Persist.MongoDB import Database.MongoDB.Connection import qualified Database.MongoDB as DB runMongo :: MongoDBReader (GGHandler M M IO) a -> GHandler M M a runMongo x = liftIOHandler $ withMongoDBConn (DB.Database "test") "127.0.0.1" $ runMongoDBConn x DB.safe DB.Master On Thu, Jun 30, 2011 at 11:26 AM, Michael Snoyman wrote:

...

OK, simple question: why can't we use a type of MongoDBReader of:

newtype MongoDBReader m a = MongoDBReader (Action m a) deriving (Monad, Trans.MonadIO, Functor, Applicative)

Michael

On Thu, Jun 30, 2011 at 6:55 PM, Greg Weber wrote:

...
I think it is about time to finally fix this. I am probably the least knowledgeable about Monad mashing, but seems like a good time to learn! Here is a simple app we can use: https://gist.github.com/1056520 But maybe it is best to use the test suite. Here are all the hacks to get the tests to run right now that need to be removed: instance Context DB.MasterOrSlaveOk IO where context = undefined push = undefined instance Context DB.Database IO where context = undefined push = undefined instance Context DB.WriteMode IO where context = undefined push = undefined instance Context DB.Pipe IO where context = undefined push = undefined instance Control.Monad.Throw.Throw DB.Failure IO where throw = undefined catch = undefined

On Wed, Jun 29, 2011 at 1:25 AM, Michael Snoyman wrote:

...
On Wed, Jun 29, 2011 at 11:17 AM, Kamil Ciemniewski wrote:

...
Hi all,

I've got some "newbie" problems using MongoDB as backend in Persistent.

Basically I've got my app type defined as: data MyApp = MyApp { getStatic :: Static -- ^ Settings for static file serving. , connPool :: ConnPool Host }

And I made it an instance of YesodPersist by: instance YesodPersist MyApp where type YesodDB MyApp = MongoDBReader Host runDB db = liftIOHandler $ fmap connPool getYesod >>= (\p -> return (p,

"localhost"))

...
...
...
...
= runMongoDBConn db

And I made it an instance of YesodAuth as well by: instance YesodAuth MyApp where type AuthId MyApp = UserId

loginDest _ = RootR logoutDest _ = RootR

getAuthId creds = runDB $ do x <- getBy $ UniqueUser $ credsIdent creds case x of Just (uid, _) -> return $ Just uid Nothing -> do fmap Just $ insert $ User (credsIdent creds) Nothing

authPlugins = [ authEmail ]

I've defined User model as yesod scaffold tool defines it.

Now, when I try to compile it i get:

No instances for (Control.Monad.Context.Context Database.MongoDB.Connection.MasterOrSlaveOk (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.Database (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Internal.Protocol.Pipe (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.WriteMode (GGHandler s MyApp IO), Control.Monad.Throw.Throw Database.MongoDB.Query.Failure (GGHandler s MyApp IO)) arising from a use of `insert' Possible fix: add instance declarations for (Control.Monad.Context.Context Database.MongoDB.Connection.MasterOrSlaveOk (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.Database (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Internal.Protocol.Pipe (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.WriteMode (GGHandler s MyApp IO), Control.Monad.Throw.Throw Database.MongoDB.Query.Failure (GGHandler s MyApp IO)) In the expression: insert In the second argument of `($)', namely `insert $ User (credsIdent creds) Nothing' In the expression: fmap Just $ insert $ User (credsIdent creds) Nothing

The problem is probably very trivial.. But I've got no ideas how to fix it.

Best regards Kamil Ciemniewski

_______________________________________________ web-devel mailing list web-devel@haskell.org http://www.haskell.org/mailman/listinfo/web-devel

I don't have direct experience with the MongoDB backend, but I can give this a shot if I saw some code. I think one possibility would be to wrap everything in a liftIO, but then you won't have access to the Handler monad features. This would prevent you from doing things like setting messages and sending redirects from the database access itself, but should otherwise be fine.

Michael

_______________________________________________ web-devel mailing list web-devel@haskell.org http://www.haskell.org/mailman/listinfo/web-devel

Greg Weber

3 Aug 3 Aug

12:15 p.m.

New subject: [ Newbie ] [ MongoDB ] Using MongoDB Persistent backend

I upgraded persistent-mongoDB for Persisten 0.6. I also added it to the scaffolding, although there is still an issue with the scaffolded site. I am going to try to upgrade persistent-mongoDB to use the new MongoDB 1.0 driver and then fix the scaffolding. On Thu, Jul 7, 2011 at 8:30 AM, Greg Weber wrote:

...

The latest version of persistent-mongoDB on hackage works now. After we get some more usage it will be added as a scaffolding option. Here is some basic runner code:

import Database.Persist.MongoDB import Database.MongoDB.Connection import qualified Database.MongoDB as DB

runMongo :: MongoDBReader (GGHandler M M IO) a -> GHandler M M a runMongo x = liftIOHandler $ withMongoDBConn (DB.Database "test") "127.0.0.1" $ runMongoDBConn x DB.safe DB.Master

On Thu, Jun 30, 2011 at 11:26 AM, Michael Snoyman wrote:

...
OK, simple question: why can't we use a type of MongoDBReader of:

newtype MongoDBReader m a = MongoDBReader (Action m a) deriving (Monad, Trans.MonadIO, Functor, Applicative)

Michael

On Thu, Jun 30, 2011 at 6:55 PM, Greg Weber wrote:

...
I think it is about time to finally fix this. I am probably the least knowledgeable about Monad mashing, but seems like a good time to learn! Here is a simple app we can use: https://gist.github.com/1056520 But maybe it is best to use the test suite. Here are all the hacks to get the tests to run right now that need to be removed: instance Context DB.MasterOrSlaveOk IO where context = undefined push = undefined instance Context DB.Database IO where context = undefined push = undefined instance Context DB.WriteMode IO where context = undefined push = undefined instance Context DB.Pipe IO where context = undefined push = undefined instance Control.Monad.Throw.Throw DB.Failure IO where throw = undefined catch = undefined

On Wed, Jun 29, 2011 at 1:25 AM, Michael Snoyman wrote:

...
On Wed, Jun 29, 2011 at 11:17 AM, Kamil Ciemniewski wrote:

...
Hi all,

I've got some "newbie" problems using MongoDB as backend in Persistent.

Basically I've got my app type defined as: data MyApp = MyApp { getStatic :: Static -- ^ Settings for static file serving. , connPool :: ConnPool Host }

And I made it an instance of YesodPersist by: instance YesodPersist MyApp where type YesodDB MyApp = MongoDBReader Host runDB db = liftIOHandler $ fmap connPool getYesod >>= (\p -> return (p,

"localhost"))

...
...
...
>= runMongoDBConn db

And I made it an instance of YesodAuth as well by: instance YesodAuth MyApp where type AuthId MyApp = UserId

loginDest _ = RootR logoutDest _ = RootR

getAuthId creds = runDB $ do x <- getBy $ UniqueUser $ credsIdent creds case x of Just (uid, _) -> return $ Just uid Nothing -> do fmap Just $ insert $ User (credsIdent creds) Nothing

authPlugins = [ authEmail ]

I've defined User model as yesod scaffold tool defines it.

Now, when I try to compile it i get:

No instances for (Control.Monad.Context.Context Database.MongoDB.Connection.MasterOrSlaveOk (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.Database (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Internal.Protocol.Pipe (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.WriteMode (GGHandler s MyApp IO), Control.Monad.Throw.Throw Database.MongoDB.Query.Failure (GGHandler s MyApp IO)) arising from a use of `insert' Possible fix: add instance declarations for (Control.Monad.Context.Context Database.MongoDB.Connection.MasterOrSlaveOk (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.Database (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Internal.Protocol.Pipe (GGHandler s MyApp IO), Control.Monad.Context.Context Database.MongoDB.Query.WriteMode (GGHandler s MyApp IO), Control.Monad.Throw.Throw Database.MongoDB.Query.Failure (GGHandler s MyApp IO)) In the expression: insert In the second argument of `($)', namely `insert $ User (credsIdent creds) Nothing' In the expression: fmap Just $ insert $ User (credsIdent creds) Nothing

The problem is probably very trivial.. But I've got no ideas how to fix it.

Best regards Kamil Ciemniewski

_______________________________________________ web-devel mailing list web-devel@haskell.org http://www.haskell.org/mailman/listinfo/web-devel

I don't have direct experience with the MongoDB backend, but I can give this a shot if I saw some code. I think one possibility would be to wrap everything in a liftIO, but then you won't have access to the Handler monad features. This would prevent you from doing things like setting messages and sending redirects from the database access itself, but should otherwise be fine.

Michael

_______________________________________________ web-devel mailing list web-devel@haskell.org http://www.haskell.org/mailman/listinfo/web-devel

5039

Age (days ago)

5074

Last active (days ago)

List overview

Download

6 comments

4 participants

participants (4)

Greg Weber
Kamil Ciemniewski
Max Cantor
Michael Snoyman