From 74a02b1d2be418505e9d20be4ee5657ba2587998 Mon Sep 17 00:00:00 2001
From: Marko Baricevic <marbar3778@yahoo.com>
Date: Tue, 17 Sep 2019 15:11:04 +0200
Subject: [PATCH] Add pagination to /validators

- closes #3472

Signed-off-by: Marko Baricevic <marbar3778@yahoo.com>
---
 lite/client/provider.go   |  2 +-
 lite/proxy/proxy.go       |  2 +-
 rpc/client/httpclient.go  |  8 ++++++--
 rpc/client/interface.go   |  2 +-
 rpc/client/localclient.go |  4 ++--
 rpc/core/consensus.go     | 24 ++++++++++++++++++++++--
 6 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/lite/client/provider.go b/lite/client/provider.go
index e0c0a331b..475763d6c 100644
--- a/lite/client/provider.go
+++ b/lite/client/provider.go
@@ -106,7 +106,7 @@ func (p *provider) getValidatorSet(chainID string, height int64) (valset *types.
 		err = fmt.Errorf("expected height >= 1, got height %v", height)
 		return
 	}
-	res, err := p.client.Validators(&height)
+	res, err := p.client.Validators(&height, 0, 0) // page & perPage are hard coded to 0 to get the entire validator set in one request
 	if err != nil {
 		// TODO pass through other types of errors.
 		return nil, lerr.ErrUnknownValidators(chainID, height)
diff --git a/lite/proxy/proxy.go b/lite/proxy/proxy.go
index 80343a531..401d128d9 100644
--- a/lite/proxy/proxy.go
+++ b/lite/proxy/proxy.go
@@ -126,7 +126,7 @@ func makeTxFunc(c rpcclient.Client) func(ctx *rpctypes.Context, hash []byte, pro
 
 func makeValidatorsFunc(c rpcclient.Client) func(ctx *rpctypes.Context, height *int64) (*ctypes.ResultValidators, error) {
 	return func(ctx *rpctypes.Context, height *int64) (*ctypes.ResultValidators, error) {
-		return c.Validators(height)
+		return c.Validators(height, 0, 0)
 	}
 }
 
diff --git a/rpc/client/httpclient.go b/rpc/client/httpclient.go
index d1981e1ce..12fe994d4 100644
--- a/rpc/client/httpclient.go
+++ b/rpc/client/httpclient.go
@@ -336,9 +336,13 @@ func (c *baseRPCClient) TxSearch(query string, prove bool, page, perPage int) (*
 	return result, nil
 }
 
-func (c *baseRPCClient) Validators(height *int64) (*ctypes.ResultValidators, error) {
+func (c *baseRPCClient) Validators(height *int64, page, perPage int) (*ctypes.ResultValidators, error) {
 	result := new(ctypes.ResultValidators)
-	_, err := c.caller.Call("validators", map[string]interface{}{"height": height}, result)
+	_, err := c.caller.Call("validators", map[string]interface{}{
+		"height":   height,
+		"page":     page,
+		"per_page": perPage,
+	}, result)
 	if err != nil {
 		return nil, errors.Wrap(err, "Validators")
 	}
diff --git a/rpc/client/interface.go b/rpc/client/interface.go
index c4a7b023d..861aaf3ee 100644
--- a/rpc/client/interface.go
+++ b/rpc/client/interface.go
@@ -66,7 +66,7 @@ type SignClient interface {
 	Block(height *int64) (*ctypes.ResultBlock, error)
 	BlockResults(height *int64) (*ctypes.ResultBlockResults, error)
 	Commit(height *int64) (*ctypes.ResultCommit, error)
-	Validators(height *int64) (*ctypes.ResultValidators, error)
+	Validators(height *int64, page, perPage int) (*ctypes.ResultValidators, error)
 	Tx(hash []byte, prove bool) (*ctypes.ResultTx, error)
 	TxSearch(query string, prove bool, page, perPage int) (*ctypes.ResultTxSearch, error)
 }
diff --git a/rpc/client/localclient.go b/rpc/client/localclient.go
index 3c3a1dcc6..7f74c6014 100644
--- a/rpc/client/localclient.go
+++ b/rpc/client/localclient.go
@@ -145,8 +145,8 @@ func (c *Local) Commit(height *int64) (*ctypes.ResultCommit, error) {
 	return core.Commit(c.ctx, height)
 }
 
-func (c *Local) Validators(height *int64) (*ctypes.ResultValidators, error) {
-	return core.Validators(c.ctx, height)
+func (c *Local) Validators(height *int64, page, perPage int) (*ctypes.ResultValidators, error) {
+	return core.Validators(c.ctx, height, page, perPage)
 }
 
 func (c *Local) Tx(hash []byte, prove bool) (*ctypes.ResultTx, error) {
diff --git a/rpc/core/consensus.go b/rpc/core/consensus.go
index ad23a461c..9bdfe89b8 100644
--- a/rpc/core/consensus.go
+++ b/rpc/core/consensus.go
@@ -2,6 +2,7 @@ package core
 
 import (
 	cm "github.com/tendermint/tendermint/consensus"
+	cmn "github.com/tendermint/tendermint/libs/common"
 	ctypes "github.com/tendermint/tendermint/rpc/core/types"
 	rpctypes "github.com/tendermint/tendermint/rpc/lib/types"
 	sm "github.com/tendermint/tendermint/state"
@@ -50,7 +51,7 @@ import (
 // 	"jsonrpc": "2.0"
 // }
 // ```
-func Validators(ctx *rpctypes.Context, heightPtr *int64) (*ctypes.ResultValidators, error) {
+func Validators(ctx *rpctypes.Context, heightPtr *int64, page, perPage int) (*ctypes.ResultValidators, error) {
 	// The latest validator that we know is the
 	// NextValidator of the last block.
 	height := consensusState.GetState().LastBlockHeight + 1
@@ -63,9 +64,28 @@ func Validators(ctx *rpctypes.Context, heightPtr *int64) (*ctypes.ResultValidato
 	if err != nil {
 		return nil, err
 	}
+	totalCount := len(validators.Validators)
+	perPage = validatePerPage(perPage)
+	page, err = validatePage(page, perPage, totalCount)
+	if err != nil {
+		return nil, err
+	}
+	skipCount := validateSkipCount(page, perPage)
+	apiResults := make([]*types.Validator, cmn.MinInt(perPage, totalCount-skipCount))
+
+	for i := 0; i < len(apiResults); i++ {
+		v := validators.Validators[skipCount+1]
+		apiResults[i] = &types.Validator{
+			Address:          v.Address,
+			PubKey:           v.PubKey,
+			VotingPower:      v.VotingPower,
+			ProposerPriority: v.ProposerPriority,
+		}
+	}
+
 	return &ctypes.ResultValidators{
 		BlockHeight: height,
-		Validators:  validators.Validators}, nil
+		Validators:  apiResults}, nil
 }
 
 // DumpConsensusState dumps consensus state.