grpc request without any request param - grpc

I have a grpc server with request of type:
service AbcService {
rpc GetInfo(GetInfoRequest) returns (GetInfoResponse) {}
}
message GetInfoRequest {}
message GetInfoResponse {
string hostname = 3;
}
And this is my client:
channel = grpc.insecure_channel('test.url:1025')
client = svc_pb2_grpc.AbcServiceStub(channel)
# get response
resp = client.GetInfo
I am facing issues with the client, since I am not able to get any response from it. grpcurl works simply fine using:
grpcurl -plaintext test.url:1025 AbcService/GetInfo
Is resp = client.GetInfo the right way in client to invoke this call (which is not expecting any request parameter)?

The "stub" encapsulates your server with a class, where the different API calls (requests/responses) are method calls.
So first of all:
resp = client.GetInfo()
However, GetInfo expects an GetInfoRequest, so you need:
resp = client.GetInfo(GetInfoRequest())

Related

GRPC call for a service which is inside a subdirectory? (Android grpc client)

This question is similar to below but my issue is with Android grpc client
How can I make a GRPC call for a service which is inside a subdirectory? (in .Net Framework)
I am getting 404 error while accessing the grpc streaming api :
UNIMPLEMENTED: HTTP status code 404
invalid content-type: text/html
headers: Metadata(:status=404,content-length=1245,content-type=text/html,server=Microsoft-IIS/10.0,request-id=5154500d-fb58-7903-65d6-3d3711129101,strict-transport-security=max-age=31536000; includeSubDomains; preload,alt-svc=h3=":443",h3-29=":443",x-preferredroutingkeydiagnostics=1,x-calculatedfetarget=PS2PR02CU003.internal.outlook.com,x-backendhttpstatus=404,x-calculatedbetarget=PUZP153MB0788.APCP153.PROD.OUTLOOK.COM,x-backendhttpstatus=404,x-rum-validated=1,x-proxy-routingcorrectness=1,x-proxy-backendserverstatus=404,x-feproxyinfo=MA0PR01CA0051.INDPRD01.PROD.OUTLOOK.COM,x-feefzinfo=MAA,ms-cv=DVBUUVj7A3ll1j03ERKRAQ.1.1,x-feserver=PS2PR02CA0054,x-firsthopcafeefz=MAA,x-powered-by=ASP.NET,x-feserver=MA0PR01CA0051,date=Tue, 11 Oct 2022 06:24:18 GMT)
The issue is that the /subdirectory_path is getting ignored by the service in the final outgoing call.
Here's the code I am using to create the grpc channel in android (gives 404)
val uri = Uri.parse("https://examplegrpcserver.com/subdirectory_path")
private val channel = let {
val builder = ManagedChannelBuilder.forTarget(uri.host+uri.path)
if (uri.scheme == "https") {
builder.useTransportSecurity()
} else {
builder.usePlaintext()
}
builder.executor(Dispatchers.IO.asExecutor()).build()
}
The uri is correct since it works with web client.
For web client the channel is defined like this (working)
var handler = new SubdirectoryHandler(httpHandler, "/subdirectory_path");
var userToken = "<token string>";
var grpcWebHandler = new GrpcWebHandler(handler);
using var channel = GrpcChannel.ForAddress("https://examplegrpcserver.com", new GrpcChannelOptions { HttpHandler = grpcWebHandler,
Credentials = ChannelCredentials.Create(new SslCredentials(), CallCredentials.FromInterceptor((context, metadata) =>
{
metadata.Add("Authorization", $"Bearer {userToken}");
return Task.CompletedTask;
}))
});
I tried to inject the subdirectory_path in the uri for my android client but unable to find appropriate api. grpc-kotlin doesn't expose the underlying http-client used in the channel.
Could someone please help me with this issue, how can I specify the subdirectory_path? (before the service and method name)
The path for an RPC is fixed by the .proto definition. Adding prefixes to the path is unsupported.
The URI passed to forTarget() points to the resource containing the addresses to connect to. So the fully-qualified form is normally of the form dns:///example.com. If you specified a host in the URI like dns://1.1.1.1/example.com, then that would mean "look up example.com at the DNS server 1.1.1.1." But there's no place to put a path prefix in the target string, as that path would only be used for address lookup, not actual RPCs.
If the web client supports path prefixes, that is a feature specific to it. It would also be using a tweaked grpc protocol that requires translation to normal backends.

How to get gRPC to properly serialize response

getting a strange error when trying simple gRPC implementation I.e. following the standard python example. Server seems to run OK, but get the error when I ping it with a client
grpc:
package pas;
// The PAS service definition
service PAS {
// analyze single file
rpc getPhotonRecords (PhotonRecordsRequest) returns (PhotonRecordsReply) {}
}
message PhotonRecordsRequest {
string fileName = 1;
}
message PhotonRecordsReply {
repeated uint32 PhotonRecords = 1;
}
client:
with grpc.insecure_channel("localhost:50051") as channel:
stub = pas_pb2_grpc.PASStub(channel)
msg = pas_pb2.PhotonRecordsRequest(fileName='testingFilename.flb')
response = stub.getPhotonRecords(msg)
server:
class PAS_GRPC(pas_pb2_grpc.PASServicer):
def getPhotonRecords(self, request: pas_pb2.PhotonRecordsRequest, context):
# check for required fields and error if not there or valid
# update any optional fields that the request has specified
PhotonRecordsReply = pas_pb2.PhotonRecordsReply()
PhotonRecordsReply.PhotonRecords.extend([1, 3, 7])
return pas_pb2.PhotonRecordsReply
client error:
<_InactiveRpcError of RPC that terminated with:
status = StatusCode.INTERNAL
details = "Failed to serialize response!"
server error:
TypeError: IsInitialized() missing 1 required positional argument: 'self'
Your server method getPhotonRecords returns the type:
return pas_pb2.PhotonRecordsReply
But it should return the variable you created:
return PhotonRecordsReply
You may want to use snake_case for variables to help differentiate from CamelCase class names, i.e.:
photon_records_reply = pas_pb2.PhotonRecordsReply()
...

How to invoke a SignalR Core hub method from Postman WebSocket

I have a SignalR Core 5.0 app that works in Visual Studio 2019. I will deploy the SignalR server to IIS but want to do some testing in Postman using the new WebSockets.
Taking one of my hub methods in my VS project, let's call it "SomeHubMethod" that returns some data, what is the proper syntax to invoke the hub method?
For instance, how would I translate this C# invoke for Postman WebSocket?
SomeHubMethod = The hub method
groupxyz = The name of the client originating the call to SignalR server, and so the response from the server should be sent to "groupxyz". Let's say the response is "Hello World!"
"1234" = Just some test data.
In my VS project...
private async void SendSomeHubMethod()
{
await connection.InvokeAsync("SomeHubMethod", "groupxyz", "1234");
}
Where the response would be received in my class...
connection.On<string>("TheHubResponse", (m) =>
{
_ = Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () => Debug.WriteLine(m));
// Hello World!
});
My assembled request that I found in link below for Postman WebSocket...
{"arguments":["groupxyz", "1234"],"invocationId":"0","target":"SomeHubMethod","type":1}
On Send, Postman shows Connected but "Hello World!" is not returned from my hub.
I found this post but it is not detailed on invoke.
reference example
You can but it's kinda problematic, so let's start from beginning..
When you have your defined SignalR hub endpoint (ie. wss://localhost:5005/hub/notifications) then
Make a POST request to following URL (notice the https, not the wss): https://localhost:5005/hub/notifications/negotiate?negotiateVersion=1.
In answer you will receive following information:
{
"negotiateVersion": 1,
"connectionId": "zJ1cqyAe4FRyLCGMzzC0Fw",
"connectionToken": "HYunLu0j0IHdBY4NNrkm0g",
"availableTransports": [
{
"transport": "WebSockets",
"transferFormats": [
"Text",
"Binary"
]
},
{
"transport": "ServerSentEvents",
"transferFormats": [
"Text"
]
},
{
"transport": "LongPolling",
"transferFormats": [
"Text",
"Binary"
]
}
]
}
Get the connectionToken from the step above and copy it. Now open a websocket connection with your hub like following:
wss://localhost:5005/hub/notifications?id={connectionToken} where connectionToken is the token from previous step. The url should look like: wss://localhost:5005/hub/notifications?id=HYunLu0j0IHdBY4NNrkm0g.
Now hold something.. according to the Microsoft documentation (https://github.com/dotnet/aspnetcore/blob/main/src/SignalR/docs/specs/HubProtocol.md#overview) we need to send a handshake request with following informations:
{
"protocol": "json",
"version": 1
}
It's hard to achieve by plain text because it needs to ends with a 0xE1 ASCII character, so we need to convert the handshake request with that character to base64 and send it. I did it for you and this string is:
eyJwcm90b2NvbCI6Impzb24iLCAidmVyc2lvbiI6MX0e
Now when we have all these info, let's deep dive into Postman:
Connect to the endpoint:
Just send a request with string I pasted above to this URL with content-type: Binary using Base64.
As you can see, we are receiving message {"type": 6} what means we are connected to the Hub and it's pinging us.
You can now send/receive any messages from your hub:
Now you can change the content-type to JSON and invoke your hub endpoints.
How to invoke a SignalR Core hub method from Postman WebSocket
Short answer, you can't.
Long answer, SignalR is a protocol that requires certain ceremony to start sending and receiving messages. For example, you need an ID in the query string that is generated by the server. Then you need to send the handshake request over the transport before you can start making invocations.

Sending headers to post request

I have this python code that does not work as expected.
import requests
import json
API_ENDPOINT = "https://lkokpdvhc4.execute-api.us-east-1.amazonaws.com/mycall"
data = {'mnumber':'9819838466'}
r = requests.post(url = API_ENDPOINT, data = json.dumps(data))
print (r.text)
This will return an error:
{"stackTrace": [["/var/task/index.py", 5, "handler", "return
mydic[code]"]], "errorType": "KeyError", "errorMessage": "''"}
When I test the API using Amazon console's gateway, I get the expected output (i.e. string like "mumbai"). It means this is client side issue. I have confirmed this by using "postman" as well that returns the same error as mentioned above. How do I send correct headers to post request?
You can create a dictionary with the headers such as
headers = {
"Authorization": "Bearer 12345",
"Content-Type": "application/json",
"key" : "value"
}
Then at the point of making the request pass it as a keyword argument to the request method i.e .post() or .get() or .put
This will be
response = requests.post(API_ENDPOINT, data=json.dumps(data), headers=headers)

Using HTTPBuilder to execute a HTTP DELETE request

I'm trying to use the Groovy HTTPBuilder library to delete some data from Firebase via a HTTP DELETE request. If I use curl, the following works
curl -X DELETE https://my.firebase.io/users/bob.json?auth=my-secret
Using the RESTClient class from HTTPBuilder works if I use it like this:
def client = new RESTClient('https://my.firebase.io/users/bob.json?auth=my-secret')
def response = client.delete(requestContentType: ContentType.ANY)
However, when I tried breaking down the URL into it's constituent parts, it doesn't work
def client = new RESTClient('https://my.firebase.io')
def response = client.delete(
requestContentType: ContentType.ANY,
path: '/users/bob.json',
query: [auth: 'my-secret']
)
I also tried using the HTTPBuilder class instead of RESTClient
def http = new HTTPBuilder('https://my.firebase.io')
// perform a POST request, expecting TEXT response
http.request(Method.DELETE, ContentType.ANY) {
uri.path = '/users/bob.json'
uri.query = [auth: 'my-secret']
// response handler for a success response code
response.success = { resp, reader ->
println "response status: ${resp.statusLine}"
}
}
But this also didn't work. Surely there's a more elegant approach than stuffing everything into a single string?
There's an example of using HttpURLClient in the tests to do a delete, which in its simplest form looks like:
def http = new HttpURLClient(url:'https://some/path/')
resp = http.request(method:DELETE, contentType:JSON, path: "destroy/somewhere.json")
def json = resp.data
assert json.id != null
assert resp.statusLine.statusCode == 200
Your example is very close to the test for the delete in a HTTPBuilder.
A few differences I see are:
Your path is absolute and not relative
Your http url path doesn't end with trailing slash
You're using content type ANY where test uses JSON. Does the target need the content type to be correct? (Probably not as you're not setting it in curl example unless it's doing some voodoo on your behalf)
Alternatively you could use apache's HttpDelete but requires more boiler plate. For a HTTP connection this is some code I've got that works. You'll have to fix it for HTTPS though.
def createClient() {
HttpParams params = new BasicHttpParams()
HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1)
HttpProtocolParams.setContentCharset(params, "UTF-8")
params.setBooleanParameter(ClientPNames.HANDLE_REDIRECTS, true)
SchemeRegistry registry = new SchemeRegistry()
registry.register(new Scheme("http", PlainSocketFactory.getSocketFactory(), 80))
ClientConnectionManager ccm = new PoolingClientConnectionManager(registry)
HttpConnectionParams.setConnectionTimeout(params, 8000)
HttpConnectionParams.setSoTimeout(params, 5400000)
HttpClient client = new DefaultHttpClient(ccm, params)
return client
}
HttpClient client = createClient()
def url = new URL("http", host, Integer.parseInt(port), "/dyn/admin/nucleus$component/")
HttpDelete delete = new HttpDelete(url.toURI())
// if you have any basic auth, you can plug it in here
def auth="USER:PASS"
delete.setHeader("Authorization", "Basic ${auth.getBytes().encodeBase64().toString()}")
// convert a data map to NVPs
def data = [:]
List<NameValuePair> nvps = new ArrayList<NameValuePair>(data.size())
data.each { name, value ->
nvps.add(new BasicNameValuePair(name, value))
}
delete.setEntity(new UrlEncodedFormEntity(nvps))
HttpResponse response = client.execute(delete)
def status = response.statusLine.statusCode
def content = response.entity.content
I adopted the code above from a POST version, but the principle is the same.

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