Dart cannot access cloud endpoint API - dart

Question

It's frustrating and I'm stuck here for one week and no clue how to fix it ; (
Inspired by Gerwin Sturm's great work (https://github.com/Scarygami/gdg-endpoint-demo) and I like to build the java backend instead.
But unfortunately, every time when I'm trying to call the endpoints API, a NoSuchMethodError error arise.
Exception: NoSuchMethodError : method not found: '_client#0x296594a'
Receiver: Instance of 'Dbentryendpoint'
Arguments: []
Stack Trace: #0 Object.noSuchMethod (dart:core-patch:1737:25)
#1 Dbentryendpoint.listDBEntry (http://127.0.0.1:3030/C:/Users/VincentZhou/dart/dart_dbentryendpoint_v1_api_client/packages/google_dbentryendpoint_v1_api/src/browser/dbentryendpoint.dart:162:16)
#2 main.fetch (http://127.0.0.1:3030/C:/Users/VincentZhou/dart/dart_dbentryendpoint_v1_api_client/demo.dart:24:20)
#3 main (http://127.0.0.1:3030/C:/Users/VincentZhou/dart/dart_dbentryendpoint_v1_api_client/demo.dart:64:8)
Exception: NoSuchMethodError : method not found: '_client#0x296594a'
Receiver: Instance of 'Dbentryendpoint'
Arguments: []
Stack Trace: #0 Object.noSuchMethod (dart:core-patch:1737:25)
#1 Dbentryendpoint.insertDBEntry (http://127.0.0.1:3030/C:/Users/VincentZhou/dart/dart_dbentryendpoint_v1_api_client/packages/google_dbentryendpoint_v1_api/src/browser/dbentryendpoint.dart:124:16)
#2 main.<anonymous closure>.<anonymous closure>.<anonymous closure>.<anonymous closure> (http://127.0.0.1:3030/C:/Users/VincentZhou/dart/dart_dbentryendpoint_v1_api_client/demo.dart:56:28)
the source code of demo.dart is almost identical to the original one (https://github.com/Scarygami/gdg-endpoint-demo) and I only change the cloudendpint API and web client ID.
import "dart:html";
import 'packages/google_dbentryendpoint_v1_api/dbentryendpoint_v1_api_browser.dart' as gdglib;
import 'packages/google_plus_v1_api/plus_v1_api_browser.dart' as pluslib;
import 'packages/google_oauth2_client/google_oauth2_browser.dart';
final CLIENT_ID = "878766780041.apps.googleusercontent.com";
final SCOPES = ["https://www.googleapis.com/auth/userinfo.email", "https://www.googleapis.com/auth/plus.me"];
void main() {
var auth = new GoogleOAuth2(CLIENT_ID, SCOPES);
var gdg = new gdglib.Dbentryendpoint(auth);
var plus = new pluslib.Plus(auth);
var container = query("#entries");
var loginButton = query("#login");
var sendButton = query("#send");
InputElement textInput = query("#text");
var authorSpan = query("#author");
pluslib.Person me;
void fetch() {
//gdg.makeAuthRequests = false;
gdg.makeAuthRequests = true;
gdg.listDBEntry(limit:10).then((l) {
container.text = "";
if (l.items != null) {
l.items.forEach((e) {
var p = new ParagraphElement();
var date = e.date.replaceAll("T", " ");
p.text = "$date - ${e.author}: ${e.text}";
container.append(p);
});
}
});
}
loginButton.onClick.listen((Event e) {
auth.login().then((token) {
loginButton.style.display = "none";
plus.makeAuthRequests = true;
plus.people.get("me").then((p) {
me = p;
authorSpan.text = "${me.displayName}:";
authorSpan.style.display = "inline-block";
textInput.style.display = "inline-block";
sendButton.style.display = "inline-block";
sendButton.onClick.listen((Event e) {
var text = textInput.value;
textInput.value = "";
var entry = new gdglib.DBEntry.fromJson({
"author": me.displayName,
"text": text
});
gdg.makeAuthRequests = true;
gdg.insertDBEntry(entry).then((entry) {
fetch();
});
});
});
});
});
on the Google App Engine side, I generate the cloud endpoint class automatically by the GPE and then add the client ID related info:
#Api(name = "dbentryendpoint",
clientIds={Ids.WEB_CLIENT_ID,com.google.api.server.spi.Constant.API_EXPLORER_CLIENT_ID},
scopes={"https://www.googleapis.com/auth/userinfo.email"}
)
public class DBEntryEndpoint {
.....
Appreciate for any help!

Answer 1

I think I figure out the way to work around it but I don't know why:
the "generate cloud endpoints" of GPE doesn't generate the path,
for example it generate the method listEntities, not entities.list
the path is necessary to generate resource in
_ah/api/discovery/v1/apis/dbentryendpoint/v1/rest; without path ,there is only schemas and methods, not schemas and resources
without resources, the Dart client generator only export empty
resouces.dart under /commom folder. and the mothods will be inside
entityEndpoints.dart, which cannot correctly recognize the
_client(), which is defined in client.dart under /common.
So the demo.dart cannot find the method.
Question: why the path is ncessary? because GPE dont generate the path automatically, can we have a way to generate the correct dart client file without manually adding the path in google app engine file? Thanks.

Answer 2

The package import does not look correct, try this.
import 'packages:google_dbentryendpoint_v1_api/dbentryendpoint_v1_api_browser.dart' as gdglib;
import 'packages:google_plus_v1_api/plus_v1_api_browser.dart' as pluslib;
import 'packages:google_oauth2_client/google_oauth2_browser.dart';