From 404e14d3eb09dc1a4e54914f767611930801105f Mon Sep 17 00:00:00 2001
From: whyrusleeping <why@ipfs.io>
Date: Tue, 1 Oct 2019 10:28:07 -0600
Subject: [PATCH] Add a command to read an object by its cid

---
 api/api.go              |  1 +
 api/struct.go           |  5 +++++
 cli/chain.go            | 26 ++++++++++++++++++++++++++
 node/impl/full/chain.go |  9 +++++++++
 4 files changed, 41 insertions(+)

diff --git a/api/api.go b/api/api.go
index 330920bf0..b821d01db 100644
--- a/api/api.go
+++ b/api/api.go
@@ -56,6 +56,7 @@ type FullNode interface {
 	ChainGetBlockMessages(context.Context, cid.Cid) (*BlockMessages, error)
 	ChainGetBlockReceipts(context.Context, cid.Cid) ([]*types.MessageReceipt, error)
 	ChainGetTipSetByHeight(context.Context, uint64, *types.TipSet) (*types.TipSet, error)
+	ChainReadObj(context.Context, cid.Cid) ([]byte, error)
 
 	// syncer
 	SyncState(context.Context) (*SyncState, error)
diff --git a/api/struct.go b/api/struct.go
index b4d548f7f..e6798dfe8 100644
--- a/api/struct.go
+++ b/api/struct.go
@@ -46,6 +46,7 @@ type FullNodeStruct struct {
 		ChainGetBlockMessages  func(context.Context, cid.Cid) (*BlockMessages, error)                     `perm:"read"`
 		ChainGetBlockReceipts  func(context.Context, cid.Cid) ([]*types.MessageReceipt, error)            `perm:"read"`
 		ChainGetTipSetByHeight func(context.Context, uint64, *types.TipSet) (*types.TipSet, error)        `perm:"read"`
+		ChainReadObj           func(context.Context, cid.Cid) ([]byte, error)                             `perm:"read"`
 
 		SyncState func(context.Context) (*SyncState, error) `perm:"read"`
 
@@ -286,6 +287,10 @@ func (c *FullNodeStruct) ChainNotify(ctx context.Context) (<-chan []*store.HeadC
 	return c.Internal.ChainNotify(ctx)
 }
 
+func (c *FullNodeStruct) ChainReadObj(ctx context.Context, obj cid.Cid) ([]byte, error) {
+	return c.Internal.ChainReadObj(ctx, obj)
+}
+
 func (c *FullNodeStruct) SyncState(ctx context.Context) (*SyncState, error) {
 	return c.Internal.SyncState(ctx)
 }
diff --git a/cli/chain.go b/cli/chain.go
index 485964758..4562ed5c1 100644
--- a/cli/chain.go
+++ b/cli/chain.go
@@ -16,6 +16,7 @@ var chainCmd = &cli.Command{
 	Subcommands: []*cli.Command{
 		chainHeadCmd,
 		chainGetBlock,
+		chainReadObjCmd,
 	},
 }
 
@@ -113,3 +114,28 @@ var chainGetBlock = &cli.Command{
 
 	},
 }
+
+var chainReadObjCmd = &cli.Command{
+	Name:  "read-obj",
+	Usage: "Read the raw bytes of an object",
+	Action: func(cctx *cli.Context) error {
+		api, err := GetFullNodeAPI(cctx)
+		if err != nil {
+			return err
+		}
+		ctx := ReqContext(cctx)
+
+		c, err := cid.Parse(cctx.Args().First)
+		if err != nil {
+			return fmt.Errorf("failed to parse cid input: %s", err)
+		}
+
+		obj, err := api.ChainReadObj(ctx, c)
+		if err != nil {
+			return err
+		}
+
+		fmt.Printf("%x\n", obj)
+		return nil
+	},
+}
diff --git a/node/impl/full/chain.go b/node/impl/full/chain.go
index 91a6df36c..fccad5fcd 100644
--- a/node/impl/full/chain.go
+++ b/node/impl/full/chain.go
@@ -122,3 +122,12 @@ func (a *ChainAPI) ChainGetBlockReceipts(ctx context.Context, bcid cid.Cid) ([]*
 func (a *ChainAPI) ChainGetTipSetByHeight(ctx context.Context, h uint64, ts *types.TipSet) (*types.TipSet, error) {
 	return a.Chain.GetTipsetByHeight(ctx, h, ts)
 }
+
+func (a *ChainAPI) ChainReadObj(ctx context.Context, obj cid.Cid) ([]byte, error) {
+	blk, err := a.Chain.Blockstore().Get(obj)
+	if err != nil {
+		return nil, xerrors.Errorf("blockstore get: %w", err)
+	}
+
+	return blk.RawData(), nil
+}