query

package
v0.0.6 Latest Latest
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 Go to latest Published: Nov 26, 2021 License: Apache-2.0 Imports: 9 Imported by: 0

Documentation

Index

Examples

Constants

View Source 
const DefaultLimit = 100

DefaultLimit is the default `limit` for queries if the `limit` is not supplied, paginate will use `DefaultLimit`

View Source 
const MaxLimit = math.MaxUint64

MaxLimit is the maximum limit the paginate function can handle which equals the maximum value that can be stored in uint64

Variables

View Source 
var (
	ErrInvalidLengthPagination        = fmt.Errorf("proto: negative length found during unmarshaling")
	ErrIntOverflowPagination          = fmt.Errorf("proto: integer overflow")
	ErrUnexpectedEndOfGroupPagination = fmt.Errorf("proto: unexpected end of group")
)

Functions

func ParsePagination 

func ParsePagination(pageReq *PageRequest) (page, limit int, err error)

ParsePagination validate PageRequest and returns page number & limit.

Types

type PageRequest 

type PageRequest struct {
	// key is a value returned in PageResponse.next_key to begin
	// querying the next page most efficiently. Only one of offset or key
	// should be set.
	Key []byte `protobuf:"bytes,1,opt,name=key,proto3" json:"key,omitempty"`
	// offset is a numeric offset that can be used when key is unavailable.
	// It is less efficient than using key. Only one of offset or key should
	// be set.
	Offset uint64 `protobuf:"varint,2,opt,name=offset,proto3" json:"offset,omitempty"`
	// limit is the total number of results to be returned in the result page.
	// If left empty it will default to a value to be set by each app.
	Limit uint64 `protobuf:"varint,3,opt,name=limit,proto3" json:"limit,omitempty"`
	// count_total is set to true  to indicate that the result set should include
	// a count of the total number of items available for pagination in UIs.
	// count_total is only respected when offset is used. It is ignored when key
	// is set.
	CountTotal bool `protobuf:"varint,4,opt,name=count_total,json=countTotal,proto3" json:"count_total,omitempty"`
	// reverse is set to true if results are to be returned in the descending order.
	Reverse bool `protobuf:"varint,5,opt,name=reverse,proto3" json:"reverse,omitempty"`
}

PageRequest is to be embedded in gRPC request messages for efficient pagination. Ex: 

message SomeRequest {
        Foo some_parameter = 1;
        PageRequest pagination = 2;
}

func (*PageRequest) Descriptor 

func (*PageRequest) Descriptor() ([]byte, []int)

func (*PageRequest) GetCountTotal 

func (m *PageRequest) GetCountTotal() bool

func (*PageRequest) GetKey 

func (m *PageRequest) GetKey() []byte

func (*PageRequest) GetLimit 

func (m *PageRequest) GetLimit() uint64

func (*PageRequest) GetOffset 

func (m *PageRequest) GetOffset() uint64

func (*PageRequest) GetReverse 

func (m *PageRequest) GetReverse() bool

func (*PageRequest) Marshal 

func (m *PageRequest) Marshal() (dAtA []byte, err error)

func (*PageRequest) MarshalTo 

func (m *PageRequest) MarshalTo(dAtA []byte) (int, error)

func (*PageRequest) MarshalToSizedBuffer 

func (m *PageRequest) MarshalToSizedBuffer(dAtA []byte) (int, error)

func (*PageRequest) ProtoMessage 

func (*PageRequest) ProtoMessage()

func (*PageRequest) Reset 

func (m *PageRequest) Reset()

func (*PageRequest) Size 

func (m *PageRequest) Size() (n int)

func (*PageRequest) String 

func (m *PageRequest) String() string

func (*PageRequest) Unmarshal 

func (m *PageRequest) Unmarshal(dAtA []byte) error

func (*PageRequest) XXX_DiscardUnknown 

func (m *PageRequest) XXX_DiscardUnknown()

func (*PageRequest) XXX_Marshal 

func (m *PageRequest) XXX_Marshal(b []byte, deterministic bool) ([]byte, error)

func (*PageRequest) XXX_Merge 

func (m *PageRequest) XXX_Merge(src proto.Message)

func (*PageRequest) XXX_Size 

func (m *PageRequest) XXX_Size() int

func (*PageRequest) XXX_Unmarshal 

func (m *PageRequest) XXX_Unmarshal(b []byte) error

type PageResponse 

type PageResponse struct {
	// next_key is the key to be passed to PageRequest.key to
	// query the next page most efficiently
	NextKey []byte `protobuf:"bytes,1,opt,name=next_key,json=nextKey,proto3" json:"next_key,omitempty"`
	// total is total number of results available if PageRequest.count_total
	// was set, its value is undefined otherwise
	Total uint64 `protobuf:"varint,2,opt,name=total,proto3" json:"total,omitempty"`
}

PageResponse is to be embedded in gRPC response messages where the corresponding request message has used PageRequest. 

message SomeResponse {
        repeated Bar results = 1;
        PageResponse page = 2;
}

func FilteredPaginate 

func FilteredPaginate(
	prefixStore types.KVStore,
	pageRequest *PageRequest,
	onResult func(key []byte, value []byte, accumulate bool) (bool, error),
) (*PageResponse, error)

FilteredPaginate does pagination of all the results in the PrefixStore based on the provided PageRequest. onResult should be used to do actual unmarshaling and filter the results. If key is provided, the pagination uses the optimized querying. If offset is used, the pagination uses lazy filtering i.e., searches through all the records. The accumulate parameter represents if the response is valid based on the offset given. It will be false for the results (filtered) < offset and true for `offset > accumulate <= end`. When accumulate is set to true the current result should be appended to the result set returned to the client.

Example 
package main

import (
	"fmt"

	"github.com/DFWallet/cosmos/codec"
	"github.com/DFWallet/cosmos/simapp"
	"github.com/DFWallet/cosmos/store/prefix"
	sdk "github.com/DFWallet/cosmos/types"
	"github.com/DFWallet/cosmos/types/address"
	"github.com/DFWallet/cosmos/types/query"
	"github.com/DFWallet/cosmos/x/bank/types"
)

var addr1 = sdk.AccAddress([]byte("addr1"))

func (s *paginationTestSuite) TestFilteredPaginations() {
	app, ctx, appCodec := setupTest()

	var balances sdk.Coins
	for i := 0; i < numBalances; i++ {
		denom := fmt.Sprintf("foo%ddenom", i)
		balances = append(balances, sdk.NewInt64Coin(denom, 100))
	}

	for i := 0; i < 4; i++ {
		denom := fmt.Sprintf("test%ddenom", i)
		balances = append(balances, sdk.NewInt64Coin(denom, 250))
	}

	balances = balances.Sort()
	addr1 := sdk.AccAddress([]byte("addr1"))
	acc1 := app.AccountKeeper.NewAccountWithAddress(ctx, addr1)
	app.AccountKeeper.SetAccount(ctx, acc1)
	s.Require().NoError(simapp.FundAccount(app.BankKeeper, ctx, addr1, balances))
	store := ctx.KVStore(app.GetKey(types.StoreKey))

	// verify pagination with limit > total values
	pageReq := &query.PageRequest{Key: nil, Limit: 5, CountTotal: true}
	balances, res, err := execFilterPaginate(store, pageReq, appCodec)
	s.Require().NoError(err)
	s.Require().NotNil(res)
	s.Require().Equal(4, len(balances))

	s.T().Log("verify empty request")
	balances, res, err = execFilterPaginate(store, nil, appCodec)
	s.Require().NoError(err)
	s.Require().NotNil(res)
	s.Require().Equal(4, len(balances))
	s.Require().Equal(uint64(4), res.Total)
	s.Require().Nil(res.NextKey)

	s.T().Log("verify nextKey is returned if there are more results")
	pageReq = &query.PageRequest{Key: nil, Limit: 2, CountTotal: true}
	balances, res, err = execFilterPaginate(store, pageReq, appCodec)
	s.Require().NoError(err)
	s.Require().NotNil(res)
	s.Require().Equal(2, len(balances))
	s.Require().NotNil(res.NextKey)
	s.Require().Equal(string(res.NextKey), fmt.Sprintf("test2denom"))
	s.Require().Equal(uint64(4), res.Total)

	s.T().Log("verify both key and offset can't be given")
	pageReq = &query.PageRequest{Key: res.NextKey, Limit: 1, Offset: 2, CountTotal: true}
	_, _, err = execFilterPaginate(store, pageReq, appCodec)
	s.Require().Error(err)

	s.T().Log("use nextKey for query")
	pageReq = &query.PageRequest{Key: res.NextKey, Limit: 2, CountTotal: true}
	balances, res, err = execFilterPaginate(store, pageReq, appCodec)
	s.Require().NoError(err)
	s.Require().NotNil(res)
	s.Require().Equal(2, len(balances))
	s.Require().Nil(res.NextKey)

	s.T().Log("verify default limit")
	pageReq = &query.PageRequest{Key: nil, Limit: 0}
	balances, res, err = execFilterPaginate(store, pageReq, appCodec)
	s.Require().NoError(err)
	s.Require().NotNil(res)
	s.Require().Equal(4, len(balances))
	s.Require().Equal(uint64(4), res.Total)

	s.T().Log("verify with offset")
	pageReq = &query.PageRequest{Offset: 2, Limit: 2}
	balances, res, err = execFilterPaginate(store, pageReq, appCodec)
	s.Require().NoError(err)
	s.Require().NotNil(res)
	s.Require().LessOrEqual(len(balances), 2)
}

func (s *paginationTestSuite) TestReverseFilteredPaginations() {
	app, ctx, appCodec := setupTest()

	var balances sdk.Coins
	for i := 0; i < numBalances; i++ {
		denom := fmt.Sprintf("foo%ddenom", i)
		balances = append(balances, sdk.NewInt64Coin(denom, 100))
	}

	for i := 0; i < 10; i++ {
		denom := fmt.Sprintf("test%ddenom", i)
		balances = append(balances, sdk.NewInt64Coin(denom, 250))
	}

	balances = balances.Sort()
	addr1 := sdk.AccAddress([]byte("addr1"))
	acc1 := app.AccountKeeper.NewAccountWithAddress(ctx, addr1)
	app.AccountKeeper.SetAccount(ctx, acc1)
	s.Require().NoError(simapp.FundAccount(app.BankKeeper, ctx, addr1, balances))
	store := ctx.KVStore(app.GetKey(types.StoreKey))

	// verify pagination with limit > total values
	pageReq := &query.PageRequest{Key: nil, Limit: 5, CountTotal: true, Reverse: true}
	balns, res, err := execFilterPaginate(store, pageReq, appCodec)
	s.Require().NoError(err)
	s.Require().NotNil(res)
	s.Require().Equal(5, len(balns))

	s.T().Log("verify empty request")
	balns, res, err = execFilterPaginate(store, nil, appCodec)
	s.Require().NoError(err)
	s.Require().NotNil(res)
	s.Require().Equal(10, len(balns))
	s.Require().Equal(uint64(10), res.Total)
	s.Require().Nil(res.NextKey)

	s.T().Log("verify default limit")
	pageReq = &query.PageRequest{Reverse: true}
	balns, res, err = execFilterPaginate(store, pageReq, appCodec)
	s.Require().NoError(err)
	s.Require().NotNil(res)
	s.Require().Equal(10, len(balns))
	s.Require().Equal(uint64(10), res.Total)

	s.T().Log("verify nextKey is returned if there are more results")
	pageReq = &query.PageRequest{Limit: 2, CountTotal: true, Reverse: true}
	balns, res, err = execFilterPaginate(store, pageReq, appCodec)
	s.Require().NoError(err)
	s.Require().NotNil(res)
	s.Require().Equal(2, len(balns))
	s.Require().NotNil(res.NextKey)
	s.Require().Equal(string(res.NextKey), fmt.Sprintf("test7denom"))
	s.Require().Equal(uint64(10), res.Total)

	s.T().Log("verify both key and offset can't be given")
	pageReq = &query.PageRequest{Key: res.NextKey, Limit: 1, Offset: 2, Reverse: true}
	_, _, err = execFilterPaginate(store, pageReq, appCodec)
	s.Require().Error(err)

	s.T().Log("use nextKey for query and reverse true")
	pageReq = &query.PageRequest{Key: res.NextKey, Limit: 2, Reverse: true}
	balns, res, err = execFilterPaginate(store, pageReq, appCodec)
	s.Require().NoError(err)
	s.Require().NotNil(res)
	s.Require().Equal(2, len(balns))
	s.Require().NotNil(res.NextKey)
	s.Require().Equal(string(res.NextKey), fmt.Sprintf("test5denom"))

	s.T().Log("verify last page records, nextKey for query and reverse true")
	pageReq = &query.PageRequest{Key: res.NextKey, Reverse: true}
	balns, res, err = execFilterPaginate(store, pageReq, appCodec)
	s.Require().NoError(err)
	s.Require().NotNil(res)
	s.Require().Equal(6, len(balns))
	s.Require().Nil(res.NextKey)

	s.T().Log("verify Reverse pagination returns valid result")
	s.Require().Equal(balances[235:241].String(), balns.Sort().String())

}

func main() {
	app, ctx, appCodec := setupTest()

	var balances sdk.Coins
	for i := 0; i < numBalances; i++ {
		denom := fmt.Sprintf("foo%ddenom", i)
		balances = append(balances, sdk.NewInt64Coin(denom, 100))
	}

	for i := 0; i < 5; i++ {
		denom := fmt.Sprintf("test%ddenom", i)
		balances = append(balances, sdk.NewInt64Coin(denom, 250))
	}

	balances = balances.Sort()
	addr1 := sdk.AccAddress([]byte("addr1"))
	acc1 := app.AccountKeeper.NewAccountWithAddress(ctx, addr1)
	app.AccountKeeper.SetAccount(ctx, acc1)
	err := simapp.FundAccount(app.BankKeeper, ctx, addr1, balances)
	if err != nil { // should return no error
		fmt.Println(err)
	}

	pageReq := &query.PageRequest{Key: nil, Limit: 1, CountTotal: true}
	store := ctx.KVStore(app.GetKey(types.StoreKey))
	balancesStore := prefix.NewStore(store, types.BalancesPrefix)
	accountStore := prefix.NewStore(balancesStore, address.MustLengthPrefix(addr1))

	var balResult sdk.Coins
	pageRes, err := query.FilteredPaginate(accountStore, pageReq, func(key []byte, value []byte, accumulate bool) (bool, error) {
		var bal sdk.Coin
		err := appCodec.Unmarshal(value, &bal)
		if err != nil {
			return false, err
		}

		// filter balances with amount greater than 100
		if bal.Amount.Int64() > int64(100) {
			if accumulate {
				balResult = append(balResult, bal)
			}

			return true, nil
		}

		return false, nil
	})

	if err != nil { // should return no error
		fmt.Println(err)
	}
	fmt.Println(&types.QueryAllBalancesResponse{Balances: balResult, Pagination: pageRes})
}

func execFilterPaginate(store sdk.KVStore, pageReq *query.PageRequest, appCodec codec.Codec) (balances sdk.Coins, res *query.PageResponse, err error) {
	balancesStore := prefix.NewStore(store, types.BalancesPrefix)
	accountStore := prefix.NewStore(balancesStore, address.MustLengthPrefix(addr1))

	var balResult sdk.Coins
	res, err = query.FilteredPaginate(accountStore, pageReq, func(key []byte, value []byte, accumulate bool) (bool, error) {
		var bal sdk.Coin
		err := appCodec.Unmarshal(value, &bal)
		if err != nil {
			return false, err
		}

		// filter balances with amount greater than 100
		if bal.Amount.Int64() > int64(100) {
			if accumulate {
				balResult = append(balResult, bal)
			}

			return true, nil
		}

		return false, nil
	})

	return balResult, res, err
}

Output:

balances:<denom:"test0denom" amount:"250" > pagination:<next_key:"test1denom" total:5 >

func Paginate 

func Paginate(
	prefixStore types.KVStore,
	pageRequest *PageRequest,
	onResult func(key []byte, value []byte) error,
) (*PageResponse, error)

Paginate does pagination of all the results in the PrefixStore based on the provided PageRequest. onResult should be used to do actual unmarshaling.

Example 
package main

import (
	"fmt"

	tmproto "github.com/DFWallet/tendermint-cosmos/proto/tendermint/types"

	dbm "github.com/tendermint/tm-db"

	"github.com/DFWallet/cosmos/codec"
	"github.com/DFWallet/cosmos/simapp"
	"github.com/DFWallet/cosmos/store"
	"github.com/DFWallet/cosmos/store/prefix"

	sdk "github.com/DFWallet/cosmos/types"
	"github.com/DFWallet/cosmos/types/address"
	"github.com/DFWallet/cosmos/types/query"
	"github.com/DFWallet/cosmos/x/bank/types"
)

func main() {
	app, ctx, _ := setupTest()

	var balances sdk.Coins

	for i := 0; i < 2; i++ {
		denom := fmt.Sprintf("foo%ddenom", i)
		balances = append(balances, sdk.NewInt64Coin(denom, 100))
	}

	balances = balances.Sort()
	addr1 := sdk.AccAddress([]byte("addr1"))
	acc1 := app.AccountKeeper.NewAccountWithAddress(ctx, addr1)
	app.AccountKeeper.SetAccount(ctx, acc1)
	err := simapp.FundAccount(app.BankKeeper, ctx, addr1, balances)
	if err != nil { // should return no error
		fmt.Println(err)
	}
	// Paginate example
	pageReq := &query.PageRequest{Key: nil, Limit: 1, CountTotal: true}
	request := types.NewQueryAllBalancesRequest(addr1, pageReq)
	balResult := sdk.NewCoins()
	authStore := ctx.KVStore(app.GetKey(types.StoreKey))
	balancesStore := prefix.NewStore(authStore, types.BalancesPrefix)
	accountStore := prefix.NewStore(balancesStore, address.MustLengthPrefix(addr1))
	pageRes, err := query.Paginate(accountStore, request.Pagination, func(key []byte, value []byte) error {
		var tempRes sdk.Coin
		err := app.AppCodec().Unmarshal(value, &tempRes)
		if err != nil {
			return err
		}
		balResult = append(balResult, tempRes)
		return nil
	})
	if err != nil { // should return no error
		fmt.Println(err)
	}
	fmt.Println(&types.QueryAllBalancesResponse{Balances: balResult, Pagination: pageRes})
}

func setupTest() (*simapp.SimApp, sdk.Context, codec.Codec) {
	app := simapp.Setup(false)
	ctx := app.BaseApp.NewContext(false, tmproto.Header{Height: 1})
	appCodec := app.AppCodec()

	db := dbm.NewMemDB()
	ms := store.NewCommitMultiStore(db)

	ms.LoadLatestVersion()

	return app, ctx, appCodec
}

Output:

balances:<denom:"foo0denom" amount:"100" > pagination:<next_key:"foo1denom" total:2 >

func (*PageResponse) Descriptor 

func (*PageResponse) Descriptor() ([]byte, []int)

func (*PageResponse) GetNextKey 

func (m *PageResponse) GetNextKey() []byte

func (*PageResponse) GetTotal 

func (m *PageResponse) GetTotal() uint64

func (*PageResponse) Marshal 

func (m *PageResponse) Marshal() (dAtA []byte, err error)

func (*PageResponse) MarshalTo 

func (m *PageResponse) MarshalTo(dAtA []byte) (int, error)

func (*PageResponse) MarshalToSizedBuffer 

func (m *PageResponse) MarshalToSizedBuffer(dAtA []byte) (int, error)

func (*PageResponse) ProtoMessage 

func (*PageResponse) ProtoMessage()

func (*PageResponse) Reset 

func (m *PageResponse) Reset()

func (*PageResponse) Size 

func (m *PageResponse) Size() (n int)

func (*PageResponse) String 

func (m *PageResponse) String() string

func (*PageResponse) Unmarshal 

func (m *PageResponse) Unmarshal(dAtA []byte) error

func (*PageResponse) XXX_DiscardUnknown 

func (m *PageResponse) XXX_DiscardUnknown()

func (*PageResponse) XXX_Marshal 

func (m *PageResponse) XXX_Marshal(b []byte, deterministic bool) ([]byte, error)

func (*PageResponse) XXX_Merge 

func (m *PageResponse) XXX_Merge(src proto.Message)

func (*PageResponse) XXX_Size 

func (m *PageResponse) XXX_Size() int

func (*PageResponse) XXX_Unmarshal 

func (m *PageResponse) XXX_Unmarshal(b []byte) error

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