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package server
import (
"bytes"
"encoding/json"
"errors"
"fmt"
"io/ioutil"
"net/http"
"reflect"
"sort"
tmjson "github.com/tendermint/tendermint/libs/json"
"github.com/tendermint/tendermint/libs/log"
ctypes "github.com/tendermint/tendermint/rpc/core/types"
"github.com/tendermint/tendermint/rpc/jsonrpc/types"
)
// HTTP + JSON handler
// jsonrpc calls grab the given method's function info and runs reflect.Call
func makeJSONRPCHandler(funcMap map[string]*RPCFunc, logger log.Logger) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
b, err := ioutil.ReadAll(r.Body)
if err != nil {
res := types.RPCInvalidRequestError(nil,
fmt.Errorf("error reading request body: %w", err),
)
if wErr := WriteRPCResponseHTTPError(w, res); wErr != nil {
logger.Error("failed to write response", "res", res, "err", wErr)
}
return
}
// if its an empty request (like from a browser), just display a list of
// functions
if len(b) == 0 {
writeListOfEndpoints(w, r, funcMap)
return
}
// first try to unmarshal the incoming request as an array of RPC requests
var (
requests []types.RPCRequest
responses []types.RPCResponse
)
if err := json.Unmarshal(b, &requests); err != nil {
// next, try to unmarshal as a single request
var request types.RPCRequest
if err := json.Unmarshal(b, &request); err != nil {
res := types.RPCParseError(fmt.Errorf("error unmarshaling request: %w", err))
if wErr := WriteRPCResponseHTTPError(w, res); wErr != nil {
logger.Error("failed to write response", "res", res, "err", wErr)
}
return
}
requests = []types.RPCRequest{request}
}
for _, request := range requests {
request := request
// A Notification is a Request object without an "id" member.
// The Server MUST NOT reply to a Notification, including those that are within a batch request.
if request.ID == nil {
logger.Debug(
"HTTPJSONRPC received a notification, skipping... (please send a non-empty ID if you want to call a method)",
"req", request,
)
continue
}
if len(r.URL.Path) > 1 {
responses = append(
responses,
types.RPCInvalidRequestError(request.ID, fmt.Errorf("path %s is invalid", r.URL.Path)),
)
continue
}
rpcFunc, ok := funcMap[request.Method]
if !ok || rpcFunc.ws {
responses = append(responses, types.RPCMethodNotFoundError(request.ID))
continue
}
ctx := &types.Context{JSONReq: &request, HTTPReq: r}
args := []reflect.Value{reflect.ValueOf(ctx)}
if len(request.Params) > 0 {
fnArgs, err := jsonParamsToArgs(rpcFunc, request.Params)
if err != nil {
responses = append(
responses,
types.RPCInvalidParamsError(request.ID, fmt.Errorf("error converting json params to arguments: %w", err)),
)
continue
}
args = append(args, fnArgs...)
}
returns := rpcFunc.f.Call(args)
logger.Debug("HTTPJSONRPC", "method", request.Method, "args", args, "returns", returns)
result, err := unreflectResult(returns)
switch e := err.(type) {
// if no error then return a success response
case nil:
responses = append(responses, types.NewRPCSuccessResponse(request.ID, result))
// if this already of type RPC error then forward that error
case *types.RPCError:
responses = append(responses, types.NewRPCErrorResponse(request.ID, e.Code, e.Message, e.Data))
default: // we need to unwrap the error and parse it accordingly
switch errors.Unwrap(err) {
// check if the error was due to an invald request
case ctypes.ErrZeroOrNegativeHeight, ctypes.ErrZeroOrNegativePerPage,
ctypes.ErrPageOutOfRange, ctypes.ErrInvalidRequest:
responses = append(responses, types.RPCInvalidRequestError(request.ID, err))
// lastly default all remaining errors as internal errors
default: // includes ctypes.ErrHeightNotAvailable and ctypes.ErrHeightExceedsChainHead
responses = append(responses, types.RPCInternalError(request.ID, err))
}
}
}
if len(responses) > 0 {
if wErr := WriteRPCResponseHTTP(w, responses...); wErr != nil {
logger.Error("failed to write responses", "res", responses, "err", wErr)
}
}
}
}
func handleInvalidJSONRPCPaths(next http.HandlerFunc) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
// Since the pattern "/" matches all paths not matched by other registered patterns,
// we check whether the path is indeed "/", otherwise return a 404 error
if r.URL.Path != "/" {
http.NotFound(w, r)
return
}
next(w, r)
}
}
func mapParamsToArgs(
rpcFunc *RPCFunc,
params map[string]json.RawMessage,
argsOffset int,
) ([]reflect.Value, error) {
values := make([]reflect.Value, len(rpcFunc.argNames))
for i, argName := range rpcFunc.argNames {
argType := rpcFunc.args[i+argsOffset]
if p, ok := params[argName]; ok && p != nil && len(p) > 0 {
val := reflect.New(argType)
err := tmjson.Unmarshal(p, val.Interface())
if err != nil {
return nil, err
}
values[i] = val.Elem()
} else { // use default for that type
values[i] = reflect.Zero(argType)
}
}
return values, nil
}
func arrayParamsToArgs(
rpcFunc *RPCFunc,
params []json.RawMessage,
argsOffset int,
) ([]reflect.Value, error) {
if len(rpcFunc.argNames) != len(params) {
return nil, fmt.Errorf("expected %v parameters (%v), got %v (%v)",
len(rpcFunc.argNames), rpcFunc.argNames, len(params), params)
}
values := make([]reflect.Value, len(params))
for i, p := range params {
argType := rpcFunc.args[i+argsOffset]
val := reflect.New(argType)
err := tmjson.Unmarshal(p, val.Interface())
if err != nil {
return nil, err
}
values[i] = val.Elem()
}
return values, nil
}
// raw is unparsed json (from json.RawMessage) encoding either a map or an
// array.
//
// Example:
// rpcFunc.args = [rpctypes.Context string]
// rpcFunc.argNames = ["arg"]
func jsonParamsToArgs(rpcFunc *RPCFunc, raw []byte) ([]reflect.Value, error) {
const argsOffset = 1
// TODO: Make more efficient, perhaps by checking the first character for '{' or '['?
// First, try to get the map.
var m map[string]json.RawMessage
err := json.Unmarshal(raw, &m)
if err == nil {
return mapParamsToArgs(rpcFunc, m, argsOffset)
}
// Otherwise, try an array.
var a []json.RawMessage
err = json.Unmarshal(raw, &a)
if err == nil {
return arrayParamsToArgs(rpcFunc, a, argsOffset)
}
// Otherwise, bad format, we cannot parse
return nil, fmt.Errorf("unknown type for JSON params: %v. Expected map or array", err)
}
// writes a list of available rpc endpoints as an html page
func writeListOfEndpoints(w http.ResponseWriter, r *http.Request, funcMap map[string]*RPCFunc) {
noArgNames := []string{}
argNames := []string{}
for name, funcData := range funcMap {
if len(funcData.args) == 0 {
noArgNames = append(noArgNames, name)
} else {
argNames = append(argNames, name)
}
}
sort.Strings(noArgNames)
sort.Strings(argNames)
buf := new(bytes.Buffer)
buf.WriteString("<html><body>")
buf.WriteString("<br>Available endpoints:<br>")
for _, name := range noArgNames {
link := fmt.Sprintf("//%s/%s", r.Host, name)
buf.WriteString(fmt.Sprintf("<a href=\"%s\">%s</a></br>", link, link))
}
buf.WriteString("<br>Endpoints that require arguments:<br>")
for _, name := range argNames {
link := fmt.Sprintf("//%s/%s?", r.Host, name)
funcData := funcMap[name]
for i, argName := range funcData.argNames {
link += argName + "=_"
if i < len(funcData.argNames)-1 {
link += "&"
}
}
buf.WriteString(fmt.Sprintf("<a href=\"%s\">%s</a></br>", link, link))
}
buf.WriteString("</body></html>")
w.Header().Set("Content-Type", "text/html")
w.WriteHeader(200)
w.Write(buf.Bytes()) // nolint: errcheck
}