Loopback: Using the include filter in hasOne relationship

[shalkam]

Hi,
I've created a simple has one realtionship between two models (a user and a team ) like this :

    "managedTeam": {
      "type": "hasOne",
      "model": "Team",
      "foreignKey": "ownerId"
    }

The thing is when I use a hasone relationship the api has no "filter" parameter and it doesn't work instead it has a "refresh" parameter.

So if I need to use the api like this via the angular sdk :

User.managedTeam({
          id: uid,
          filter:
          {
            include: ["owner", "members"]
          }
        });

The only way to go is to change the relationship into hasMany to be able to load the team owner and members relations.
Is this really the only way to go?

regards,
Mostafa

[0candy]

So to clarify, you have an owner model and a members model in addition to the user and team model? Can you provide a sample repo? You can fork this sandbox.
https://github.com/strongloop/loopback-sandbox

[shalkam]

@0candy So to reproduce my problem it's very simple. you can try to create any simple hasone relation then look at it via the api explorer ... you will see that the get request for it doesn't have a filter parameter.

Here is how it looks like on my end :

Just to answer your question it's only two models the user model - acting both like team manager and member - and the team model.

user.json

{
  "name": "user",
  "plural": "users",
  "base": "User",
  "properties": {
    "firstName": {
      "type": "string"
    },
    "lastName": {
      "type": "string"
    }
  },
  "validations": [],
  "relations": {
    "accessTokens": {
      "type": "hasMany",
      "model": "accessToken",
      "foreignKey": "userId"
    },
    "identities": {
      "type": "hasMany",
      "model": "userIdentity",
      "foreignKey": "userId"
    },
    "credentials": {
      "type": "hasMany",
      "model": "userCredential",
      "foreignKey": "userId"
    },
    "roles": {
      "type": "hasMany",
      "model": "role",
      "foreignKey": "principalId",
      "through": "roleMapping"
    },
    "visits": {
      "type": "hasMany",
      "model": "Visit",
      "foreignKey": "userId"
    },
    "team": {
      "type": "hasMany",
      "model": "Team",
      "foreignKey": "memberId",
      "through": "TeamMember"
    },
    "managedTeam": {
      "type": "hasOne",
      "model": "Team",
      "foreignKey": "ownerId"
    }
  },
  "acls": [
    {
      "accessType": "*",
      "principalType": "ROLE",
      "principalId": "admin",
      "permission": "ALLOW"
    },
    {
      "accessType": "READ",
      "principalType": "ROLE",
      "principalId": "$unauthenticated",
      "permission": "DENY"
    },
    {
      "accessType": "READ",
      "principalType": "ROLE",
      "principalId": "$authenticated",
      "permission": "ALLOW"
    },
    {
      "accessType": "*",
      "principalType": "ROLE",
      "principalId": "$owner",
      "permission": "ALLOW"
    }
  ],
  "methods": {
    "info": {
      "description": "Get the roles for this user.",
      "isStatic": false,
      "returns": {
        "arg": "result",
        "type": "Object",
        "root": true
      },
      "http": {
        "path": "/info",
        "verb": "get"
      }
    }
  }
}

team.json

{
  "name": "Team",
  "plural": "teams",
  "base": "PersistedModel",
  "idInjection": true,
  "options": {
    "validateUpsert": true
  },
  "properties": {
    "id": {
      "type": "number",
      "required": true
    },
    "name": {
      "type": "string",
      "required": true
    },
    "ownerId": {
      "type": "number",
      "required": true
    }
  },
  "validations": [],
  "relations": {
    "members": {
      "type": "hasMany",
      "model": "user",
      "foreignKey": "teamId",
      "through": "TeamMember",
      "keyThrough": "memberId"
    },
    "owner": {
      "type": "belongsTo",
      "model": "user",
      "foreignKey": "ownerId"
    }
  },
  "acls": [],
  "methods": {}
}

I hope this helps, and many thanks

[0candy]

Thank you for the info. You are right, hasOne does not take in a filter parameter. We should probably add it for consistency. Would you like to submit a PR?

https://github.com/strongloop/loopback/blob/ca1baee0f9547107bdb54853d49ebce6650a4fbf/lib/model.js#L477

[shalkam]

@0candy thanks for clearing this out. I will give a try and see if I can do it.

[qqilihq]

Any success on implementing that so far?

[ahmed-abdulmoniem]

Any success guys to have this soon? ++++1 @0candy

[0candy]

Unfortunately, we haven't reach this item in our backlog yet as we have some bugs/features to finish to get LB 3.x released. Would you ( @ahmed-abdulmoniem ) be interested in submitting a patch so we can get it in sooner? Thank you for your understanding.

[ahmed-abdulmoniem]

@0candy No problem for sure .. just I would like some guidance .. which part I should change?

[0candy]

For starters, you will need to add the filter arg to accepts: https://github.com/strongloop/loopback/blob/ca1baee0f9547107bdb54853d49ebce6650a4fbf/lib/model.js#L477

@jannyHou Can you point @ahmed-abdulmoniem where he should add the include filter for hasOne in juggler relations?

[ahmed-abdulmoniem]

@jannyHou ?

[jannyHou]

@ahmed-abdulmoniem I am following the context in this issue, will reply asap :)

[ahmed-abdulmoniem]

@jannyHou Thank you waiting :)

[jannyHou]

@ahmed-abdulmoniem Let's say we define a hasOne relation from parentModel to childModel, here is the code of function parent.children():
https://github.com/strongloop/loopback-datasource-juggler/blob/master/lib/relation-definition.js#L1640

It doesn't support filter, only returns you the child instance.

I think a possible approach to add filter is define a scope as what hasMany does, see:
https://github.com/strongloop/loopback-datasource-juggler/blob/master/lib/relation-definition.js#L690

A scope property will take a filter parameter, see line 177 in https://github.com/strongloop/loopback-datasource-juggler/blob/master/lib/scope.js#L173-L177

BTW, embedsOne also doesn't support filter. That's out of scope of this story, filed another issue for it: https://github.com/strongloop/loopback-datasource-juggler/issues/1145

@ahmed-abdulmoniem I know that the logic of defining scope method would be a little complicated here, please tell me if anything confuses you :) I am glad to continue the discussion.

cc @raymondfeng

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[chrisandrews7]

Any updates on this one?