add: filecoin getmessage method for rpc package

rpc/filecoin.go

@@ -2,6 +2,7 @@ package rpc
 
 import (
 	"bytes"
+	"encoding/json"
 	"fmt"
 	"net/http"
 
@@ -9,21 +10,54 @@ import (
 )
 
 // client implements the `Client` interface.
-type lotusClient struct {
+type LotusClient struct {
 	host string
 	jwt  jwt.Token
 }
 
+type RequestBody struct {
+	Jsonrpc string
+	Method  string
+	Params  []string
+	ID      int
+}
+
+func NewRequestBody(method string) *RequestBody {
+	return &RequestBody{
+		Jsonrpc: "2.0",
+		Method:  method,
+		Params:  []string{},
+		ID:      0,
+	}
+}
+
 // NewClient returns a new client.
 func NewLotusClient(host string, token jwt.Token) Client {
-	return &lotusClient{
+	return &LotusClient{
 		host: host,
 		jwt:  token,
 	}
 }
 
+func (c *LotusClient) GetMessage(r *http.Request, txHash string) (*http.Response, error) {
+	requestBody := NewRequestBody("Filecoin.GetMessage")
+	requestBody.Params = append(requestBody.Params, txHash)
+	body, err := json.Marshal(requestBody)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to marshal request body %v", err)
+	}
+	client := http.Client{}
+	req, err := http.NewRequest("POST", c.host, bytes.NewBuffer(body))
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Authentication", "Bearer "+c.jwt.Raw)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to construct lotus node rpc request %v", err)
+	}
+	return client.Do(req)
+}
+
 // HandleRequest implements the `Client` interface.
-func (c *lotusClient) HandleRequest(r *http.Request, data []byte) (*http.Response, error) {
+func (c *LotusClient) HandleRequest(r *http.Request, data []byte) (*http.Response, error) {
 	client := http.Client{}
 	req, err := http.NewRequest("POST", c.host, bytes.NewBuffer(data))
 	req.Header.Set("Content-Type", "application/json")