I am getting "HTTP/2 client preface string missing or corrupt."
My thoughts are that it has to do with the headers not being set correctly. It is likely the implementation of WifiClient/WifiSecureClient. I've been thinking about this for over several weeks and I'm stuck. Any advice?
[Updated: Answer below]
The client was generated using the nanopb protocol buffer compiler:
protoc --plugin=protoc-gen-nanopb=~/grpc/nanopb/generator/protoc-gen-nanopb --nanopb_out=. helloworld.proto
Arduino client:
DHT dht(DHTPIN, DHTTYPE);
WiFiClient client;
//WiFiClientSecure client;
void setup() {
Serial.setDebugOutput(true);
Serial.begin(115200);
delay(10);
WiFi.begin("<SSID>", "<My Password>");
delay(3000);
while (WiFi.status() != WL_CONNECTED) {
Serial.println("WIFI connection failed, reconnecting...");
delay(2000);
}
Serial.print("WiFi connected, ");
Serial.print("IP address: ");
Serial.println(WiFi.localIP());
Serial.println("Starting DHT11 sensor...");
dht.begin();
}
void loop() {
Serial.print("connecting to ");
Serial.println(addr);
// client.setInsecure();
if (!client.connect(addr, port)) {
Serial.println(addr);
Serial.println(port);
Serial.println("connection failed");
Serial.println("wait 5 sec to reconnect...");
delay(5000);
return;
}
Serial.println("reading humidity/temp...");
float hum = dht.readHumidity();
float tmp = dht.readTemperature(true);
Serial.println(hum);
Serial.println(tmp);
if (isnan(hum) || isnan(tmp)) {
Serial.println("failed to read sensor data");
delay(2000);
return;
}
float hiCel = dht.computeHeatIndex(tmp, hum, true);
helloworld_TempEvent temp = helloworld_TempEvent_init_zero;
temp.deviceId = 1;
temp.eventId = 0;
temp.humidity = hum;
temp.tempCel = tmp;
temp.heatIdxCel = hiCel;
sendTemp(temp);
delay(1000);
}
void sendTemp(helloworld_TempEvent e) {
uint8_t buffer[128];
pb_ostream_t stream = pb_ostream_from_buffer(buffer, sizeof(buffer));
if (!pb_encode(&stream, helloworld_TempEvent_fields, &e)) {
Serial.println("failed to encode temp proto");
Serial.println(PB_GET_ERROR(&stream));
return;
}
Serial.print("sending temp... ");
Serial.println(e.tempCel);
client.write(buffer, stream.bytes_written);
}
The server was generated using the standard java protocol buffer compiler. The only thing I changed was adding a TempEvent (below).
... (helloworld template stuff) ...
// The request message containing temperatures
message TempEvent {
int32 deviceId = 1;
int32 eventId = 2;
float humidity = 3;
float tempCel = 4;
float heatIdxCel = 5;
}
The sample java client works without any issues. Where my problem lies is the simple client using nanopb on an ESP8266-01 wifi module which is sending the data using gRPC.
public class Server {
// Doesn't work
public static void main(String[] args) throws IOException, InterruptedException {
io.grpc.Server server = ServerBuilder
.forPort(8080)
.addService(new HelloServiceImpl()).build();
server.start();
server.awaitTermination();
}
// Works just fine
public static void main(String[] args) throws IOException, InterruptedException {
try (ServerSocket server = new ServerSocket(8080)) {
System.out.println("Server accepting connections on port " + server.getLocalPort());
TemperatureClient tempClient = new TemperatureClient();
while(true) {
Socket client = server.accept();
System.out.println("Client connected using remote port " + client.getPort());
final Thread t = new Thread(() -> {
try {
TempEvent p = TempEvent.parseFrom(client.getInputStream());
float i = p.getTempCel();
System.out.println("TEMP " + i);
} catch (IOException ioe) {
ioe.printStackTrace();
}
});
t.start();
}
}
}
The client is able to hit the server:
Nov 29, 2021 5:49:30 PM io.grpc.netty.shaded.io.grpc.netty.NettyServerTransport notifyTerminated
INFO: Transport failed
io.grpc.netty.shaded.io.netty.handler.codec.http2.Http2Exception: HTTP/2 client preface string missing or corrupt. Hex dump for received bytes: 080c10641d0000d84125e17aa0422de4459e42
at io.grpc.netty.shaded.io.netty.handler.codec.http2.Http2Exception.connectionError(Http2Exception.java:108)
at io.grpc.netty.shaded.io.netty.handler.codec.http2.Http2ConnectionHandler$PrefaceDecoder.readClientPrefaceString(Http2ConnectionHandler.java:306)
at io.grpc.netty.shaded.io.netty.handler.codec.http2.Http2ConnectionHandler$PrefaceDecoder.decode(Http2ConnectionHandler.java:239)
at io.grpc.netty.shaded.io.netty.handler.codec.http2.Http2ConnectionHandler.decode(Http2ConnectionHandler.java:438)
at io.grpc.netty.shaded.io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:508)
at io.grpc.netty.shaded.io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:447)
at io.grpc.netty.shaded.io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:276)
at io.grpc.netty.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.grpc.netty.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.grpc.netty.shaded.io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at io.grpc.netty.shaded.io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
at io.grpc.netty.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.grpc.netty.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.grpc.netty.shaded.io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
at io.grpc.netty.shaded.io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:166)
at io.grpc.netty.shaded.io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:719)
at io.grpc.netty.shaded.io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:655)
at io.grpc.netty.shaded.io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:581)
at io.grpc.netty.shaded.io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:493)
at io.grpc.netty.shaded.io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
at io.grpc.netty.shaded.io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at io.grpc.netty.shaded.io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.base/java.lang.Thread.run(Thread.java:831)
To debug this, I wanted to first see if I could use grpcurl, but I get this:
localhost#pro ~ % grpcurl -plaintext localhost:50051 list
Failed to list services: server does not support the reflection API
localhost#pro ~ % grpcurl -insecure localhost:50051 list
Failed to dial target host "localhost:50051": tls: first record does not look like a TLS handshake
I started looking into the implementation for WifiClient.h used in my implementation code, but does anyone have any ideas on a simple way to test this without digging into everything? I was thinking this should be super simple... but it is turning out to be much more entailed to generate a simple client than I thought. I feel like I am missing something here.
From other forums on here: "The client and server aren't agreeing. Typically this is because one is plaintext and the other using TLS. But it can also be due to HTTP/1 vs HTTP/2 in certain environments."
After looking at the Go Lang implementation, I just tried using WiFiClientSecure client.setInsecure(); // didn't work and the hex dump is below.
17:36:33.030 [grpc-nio-worker-ELG-3-1] DEBUG io.grpc.netty.shaded.io.grpc.netty.NettyServerHandler - [id: 0x41b96938, L:/192.168.0.23:8080 - R:/192.168.0.24:61587] OUTBOUND SETTINGS: ack=false settings={MAX_CONCURRENT_STREAMS=2147483647, INITIAL_WINDOW_SIZE=1048576, MAX_HEADER_LIST_SIZE=8192}
17:36:33.031 [grpc-nio-worker-ELG-3-1] DEBUG io.grpc.netty.shaded.io.grpc.netty.NettyServerHandler - [id: 0x41b96938, L:/192.168.0.23:8080 - R:/192.168.0.24:61587] OUTBOUND WINDOW_UPDATE: streamId=0 windowSizeIncrement=983041
17:36:33.063 [grpc-nio-worker-ELG-3-1] DEBUG io.grpc.netty.shaded.io.grpc.netty.NettyServerHandler - [id: 0x41b96938, L:/192.168.0.23:8080 - R:/192.168.0.24:61587] OUTBOUND GO_AWAY: lastStreamId=2147483647 errorCode=1 length=126 bytes=485454502f3220636c69656e74207072656661636520737472696e67206d697373696e67206f7220636f72727570742e204865782064756d7020666f72207265...
17:36:33.064 [grpc-nio-worker-ELG-3-1] DEBUG io.grpc.netty.shaded.io.netty.handler.codec.http2.Http2ConnectionHandler - [id: 0x41b96938, L:/192.168.0.23:8080 - R:/192.168.0.24:61587] Sent GOAWAY: lastStreamId '2147483647', errorCode '1', debugData 'HTTP/2 client preface string missing or corrupt. Hex dump for received bytes: 16030100d4010000d00303000000005c2f03aae7147c5f36'. Forcing shutdown of the connection.
Dec 10, 2021 5:36:33 PM io.grpc.netty.shaded.io.grpc.netty.NettyServerTransport notifyTerminated
INFO: Transport failed
io.grpc.netty.shaded.io.netty.handler.codec.http2.Http2Exception: HTTP/2 client preface string missing or corrupt. Hex dump for received bytes: 16030100d4010000d00303000000005c2f03aae7147c5f36
at io.grpc.netty.shaded.io.netty.handler.codec.http2.Http2Exception.connectionError(Http2Exception.java:108)
at io.grpc.netty.shaded.io.netty.handler.codec.http2.Http2ConnectionHandler$PrefaceDecoder.readClientPrefaceString(Http2ConnectionHandler.java:306)
at io.grpc.netty.shaded.io.netty.handler.codec.http2.Http2ConnectionHandler$PrefaceDecoder.decode(Http2ConnectionHandler.java:239)
at io.grpc.netty.shaded.io.netty.handler.codec.http2.Http2ConnectionHandler.decode(Http2ConnectionHandler.java:438)
at io.grpc.netty.shaded.io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:508)
at io.grpc.netty.shaded.io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:447)
at io.grpc.netty.shaded.io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:276)
at io.grpc.netty.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.grpc.netty.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.grpc.netty.shaded.io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at io.grpc.netty.shaded.io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
at io.grpc.netty.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.grpc.netty.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.grpc.netty.shaded.io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
at io.grpc.netty.shaded.io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:166)
at io.grpc.netty.shaded.io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:719)
at io.grpc.netty.shaded.io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:655)
at io.grpc.netty.shaded.io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:581)
at io.grpc.netty.shaded.io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:493)
at io.grpc.netty.shaded.io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
at io.grpc.netty.shaded.io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at io.grpc.netty.shaded.io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.base/java.lang.Thread.run(Thread.java:831)
WiFiClient client;
if (!client.connect(addr, port)) {
This forms a basic TCP connection. However, gRPC is a complex protocol based on HTTP/2. Currently you are just writing raw protobuf messages to a TCP socket, which can work for communication but is certainly not what a gRPC server is expecting.
Nanopb does not have gRPC support in itself. There is a third-party project adding it, but it is currently unmaintained.
I am facing problems while connecting to my SocketIo server through my ESP8266.
I have my ESP connected to my Wifi and my Node Server is running on localhost.
I have the following code in ESP8266
#include <ESP8266HTTPClient.h>
#include <ESP8266WiFi.h>
#include <SocketIoClient.h>
//192.168.1.37 --My IP Address
SocketIoClient webSocket;
const char* ssid = "ssid"; // SSID
const char* password = "pass"; // Password
const char* host = "192.168.1.37"; // Server IP (localhost)
const int port = 8080; // Server Port
const char* url = "http://localhost:8080/test";
void event(const char * payload, size_t length) {
Serial.println("Message");
}
void setup() {
Serial.begin(115200);
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500); // 5ms Delay
Serial.print(".");
}
Serial.print("");
Serial.println("WiFi connected");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
Serial.println("Connecting To Socket");
webSocket.on("event", event);
webSocket.begin("192.168.1.37", 8080);
}
void loop() {
if (WiFi.status() == WL_CONNECTED) { //Check WiFi connection status
delay(3000); //Send a request every 3 seconds
webSocket.loop();
Serial.println("Retrying ....");
}
Also my Server side code is in JavaScript.
var io = socket(server);
io.on('connection', (socket) => {
console.log('made socket connection', socket.id);
socket.on("ESP", function(data){
socket.emit('Hi ESP, ESP called', data);
console.log("Socket Working !");
});
console.log('made socket connection', socket.id);
socket.on("connect", function(data){
socket.emit('Hi ESP connect called', data);
console.log("Socket Working !");
});
});
But i keep on receiving this output in the Serial Monitor.
Also there is no request received on my server.
11:37:09.729 -> ..........WiFi connected
11:37:14.129 -> IP address:
11:37:14.129 -> 192.168.1.13
11:37:14.129 -> Connecting To Socket
11:37:17.245 -> Retrying ....
11:37:17.245 -> [SIoC] Disconnected!
11:37:17.245 -> [SIoC] event disconnected not found. 1 events available
11:37:20.230 -> Retrying ....
11:37:20.230 -> [SIoC] Disconnected!
11:37:20.230 -> [SIoC] event disconnected not found. 1 events available
i have same issue
[SIoC] Disconnected!
[SIoC] Connected to url: /socket.io/?transport=websocket
[SIoC] Disconnected!
[SIoC] Disconnected!
[SIoC] Disconnected!
i change server side socket io config to this :
const io = require("socket.io")(server, {
cors: {
origin: "*",
methods: ["GET", "POST"],
transports: ["websocket", "polling"],
credentials: true,
},
allowEIO3: true,
});
and Fix !
I have faced the same issue. It is fixed when I changed the socket.io version to ^2.3.0
Change the socket io version to ^2.3.0 in package.json, delete node modules and reinstall the packages using npm install command
I had the same issue and changed:
WiFi.begin(ssid, password);
to
WiFiMulti.addAP(ssid, pass);
and it connects fine.
PS: I used <SocketIOclient.h>
I m a beginner programmer, I am developing an android application which process an image and generate its histogram. I am using AndroidPlot to draw different color channels of an image in the histogram, but I'm having some errors and exceptions.
This is my code :
public class ImgHistogram extends Activity {
ImageView ImageView;
LinearLayout ll;
ImageView imgView;
private Bitmap source ;
private XYPlot xyPlot;
public XYSeries rSerie;
int[] intensities={
0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,
101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,
201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255
} ;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.histo);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
imgView = (ImageView) findViewById(R.id.img);
Bundle bundle = this.getIntent().getExtras();
source=(Bitmap) bundle.getParcelable("img");
imgView.setImageBitmap(source);
// initialize our XYPlot reference:
xyPlot = (XYPlot) findViewById(R.id.xyplot);
Bitmap image = Bitmap.createBitmap(source.getWidth(),source.getHeight(), Bitmap.Config.ARGB_8888);
ArrayList<Integer> rVals = new ArrayList<Integer>();
for (int x = 0; x < image.getWidth(); x++) {
for (int y = 0; y < image.getHeight(); y++) {
int color = image.getPixel(x, y);
rVals.add((color >> 16) & 0xff); //red channel
}}
rSerie = new SimpleXYSeries(
rVals, SimpleXYSeries.ArrayFormat.Y_VALS_ONLY, "red channel");
// Create a formatter to format Line and Point of income series
LineAndPointFormatter format = new LineAndPointFormatter(
Color.rgb(0, 0, 255), // line color
Color.rgb(200, 200, 200), // point color
Color.rgb(10, 20, 20), // fill color (none)
null );
// add series to the xyplot:
xyPlot.addSeries(rSerie, format);
// Formatting the Domain Values ( X-Axis )
xyPlot.setDomainValueFormat(new Format() {
private static final long serialVersionUID = 1L;
#Override
public StringBuffer format(Object obj, StringBuffer toAppendTo, FieldPosition pos) {
return new StringBuffer( intensities[ ( (Number)obj).intValue() ] );
}
#Override
public Object parseObject(String source, ParsePosition pos) {
return null;
}
});
xyPlot.setDomainLabel("");
xyPlot.setRangeLabel("");
// Increment X-Axis by 1 value
xyPlot.setDomainStep(XYStepMode.INCREMENT_BY_VAL, 1);
xyPlot.getGraphWidget().setRangeLabelWidth(50);
// Reduce the number of range labels
xyPlot.setTicksPerRangeLabel(2);
// Reduce the number of domain labels
xyPlot.setTicksPerDomainLabel(2);
// Remove all the developer guides from the chart
// xyPlot.disableAllMarkup();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
and this is the stack trace:
05-23 23:52:21.731: E/AndroidRuntime(30404): FATAL EXCEPTION: main
05-23 23:52:21.731: E/AndroidRuntime(30404): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.dreamaker.magipixel/com.dreamaker.magipixel.processing.ImgHistogram}: java.lang.NullPointerException
05-23 23:52:21.731: E/AndroidRuntime(30404): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2295)
05-23 23:52:21.731: E/AndroidRuntime(30404): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2349)
05-23 23:52:21.731: E/AndroidRuntime(30404): at android.app.ActivityThread.access$700(ActivityThread.java:159)
05-23 23:52:21.731: E/AndroidRuntime(30404): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1316)
05-23 23:52:21.731: E/AndroidRuntime(30404): at android.os.Handler.dispatchMessage(Handler.java:99)
05-23 23:52:21.731: E/AndroidRuntime(30404): at android.os.Looper.loop(Looper.java:137)
05-23 23:52:21.731: E/AndroidRuntime(30404): at android.app.ActivityThread.main(ActivityThread.java:5419)
05-23 23:52:21.731: E/AndroidRuntime(30404): at java.lang.reflect.Method.invokeNative(Native Method)
05-23 23:52:21.731: E/AndroidRuntime(30404): at java.lang.reflect.Method.invoke(Method.java:525)
05-23 23:52:21.731: E/AndroidRuntime(30404): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1187)
05-23 23:52:21.731: E/AndroidRuntime(30404): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
05-23 23:52:21.731: E/AndroidRuntime(30404): at dalvik.system.NativeStart.main(Native Method)
05-23 23:52:21.731: E/AndroidRuntime(30404): Caused by: java.lang.NullPointerException
05-23 23:52:21.731: E/AndroidRuntime(30404): at com.dreamaker.magipixel.processing.ImgHistogram.onCreate(ImgHistogram.java:110)
05-23 23:52:21.731: E/AndroidRuntime(30404): at android.app.Activity.performCreate(Activity.java:5372)
05-23 23:52:21.731: E/AndroidRuntime(30404): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1104)
05-23 23:52:21.731: E/AndroidRuntime(30404): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2257)
05-23 23:52:21.731: E/AndroidRuntime(30404): ... 11 more
I hope that someone could help me!
Given the fact that in the line in question (ImgHistogram.java:110) you have only 1 object which could possibly cause the exception - xyPlot:
xyPlot.addSeries(rSerie, format);
This suggests that findViewByID returns null =< xyPlot is null. There is a question about this: findViewByID returns null the accepted answer should solve your problem:
Wait until onFinishInflate()