piotrkowalczuk/charon

package charond

import (
    "context"
    "database/sql"

    "github.com/piotrkowalczuk/charon"
    charonrpc "github.com/piotrkowalczuk/charon/pb/rpc/charond/v1"
    "github.com/piotrkowalczuk/charon/internal/grpcerr"
    "github.com/piotrkowalczuk/charon/internal/mapping"
    "github.com/piotrkowalczuk/charon/internal/model"
    "github.com/piotrkowalczuk/charon/internal/session"

    "google.golang.org/grpc/codes"
)

type getUserHandler struct {
    *handler
}

func (guh *getUserHandler) Get(ctx context.Context, req *charonrpc.GetUserRequest) (*charonrpc.GetUserResponse, error) {
    if req.Id <= 0 {
        return nil, grpcerr.E(codes.InvalidArgument, "user id is missing")
    }

    act, err := guh.Actor(ctx)
    if err != nil {
        return nil, err
    }
    ent, err := guh.repository.user.FindOneByID(ctx, req.Id)
    if err != nil {
        if err == sql.ErrNoRows {
            return nil, grpcerr.E(codes.NotFound, "user does not exists")
        }
        return nil, grpcerr.E(codes.Internal, "user cannot be fetched", err)
    }
    if err = guh.firewall(req, act, ent); err != nil {
        return nil, err
    }

    return guh.response(ent)
}

func (guh *getUserHandler) firewall(req *charonrpc.GetUserRequest, act *session.Actor, ent *model.UserEntity) error {
    if act.User.IsSuperuser {
        return nil
    }
    if ent.IsSuperuser {
        return grpcerr.E(codes.PermissionDenied, "only superuser is permitted to retrieve other superuser")
    }
    if ent.IsStaff {
        if ent.CreatedBy.Int64Or(0) == act.User.ID {
            if !act.Permissions.Contains(charon.UserCanRetrieveStaffAsOwner) {
                return grpcerr.E(codes.PermissionDenied, "staff user cannot be retrieved as an owner, missing permission")
            }
            return nil
        }
        if !act.Permissions.Contains(charon.UserCanRetrieveStaffAsStranger) {
            return grpcerr.E(codes.PermissionDenied, "staff user cannot be retrieved as a stranger, missing permission")
        }
        return nil
    }
    if ent.CreatedBy.Int64Or(0) == act.User.ID {
        if !act.Permissions.Contains(charon.UserCanRetrieveAsOwner) {
            return grpcerr.E(codes.PermissionDenied, "user cannot be retrieved as an owner, missing permission")
        }
        return nil
    }
    if !act.Permissions.Contains(charon.UserCanRetrieveAsStranger) {
        return grpcerr.E(codes.PermissionDenied, "user cannot be retrieved as a stranger, missing permission")
    }
    return nil
}

func (guh *getUserHandler) response(ent *model.UserEntity) (*charonrpc.GetUserResponse, error) {
    msg, err := mapping.ReverseUser(ent)
    if err != nil {
        return nil, grpcerr.E(codes.Internal, "user entity mapping failure", err)
    }
    return &charonrpc.GetUserResponse{
        User: msg,
    }, nil
}