I'm investigating using the gorilla web toolkit to create a simple RPC API. I'm using the example from their documentation and I'm testing using Advanced Rest Client in Chrome and use
http://localhost:1111/api/
and POST the following RAW JSON payload:
{"method":"HelloService.Say","params":[{"Who":"Test"}]}
This reaches the server, I know this as I'm logging it (see code below) and I get a 200 OK response. However I'm getting "Response does not contain any data"
I'm expecting the JSON reply message that is defined in the Say method below. Does anyone have any suggestions as to what the problem is?
package main
import (
"gorilla/mux"
"gorilla/rpc"
"gorilla/rpc/json"
"log"
"net/http"
)
type HelloArgs struct {
Who string
}
type HelloReply struct {
Message string
}
type HelloService struct{}
func (h *HelloService) Say(r *http.Request, args *HelloArgs, reply *HelloReply) error {
log.Printf(args.Who)
reply.Message = "Hello, " + args.Who + "!"
log.Printf(reply.Message)
return nil
}
func main() {
r := mux.NewRouter()
jsonRPC := rpc.NewServer()
jsonCodec := json.NewCodec()
jsonRPC.RegisterCodec(jsonCodec, "application/json")
jsonRPC.RegisterCodec(jsonCodec, "application/json; charset=UTF-8") // For firefox 11 and other browsers which append the charset=UTF-8
jsonRPC.RegisterService(new(HelloService), "")
r.Handle("/api/", jsonRPC)
http.ListenAndServe(":1111", r)
}
It's because gorilla/rpc/json implements JSON-RPC, which requires three parameters in the request: method, params and id.
Requests without id in JSON-RPC are called notifications and do not have responses.
Check specification for more details.
So, in your case, you need to use following JSON:
{"method":"HelloService.Say","params":[{"Who":"Test"}], "id":"1"}
Related
i have a question. Is it possible to extract via metadata path from user request.
Here i have my proto file with defined method.
rpc AllPath(google.protobuf.Empty) returns (google.protobuf.Empty) {
option (google.api.http) = {
get: "/*",
};
}
rpc Auth(google.protobuf.Empty) returns (TokenRender) {
option (google.api.http) = {
get: "/auth"
};
}
}
In AllPath function in my server file im using something like this, found on grpc-gateway ecosystem website.
path := make(map[string]string)
if pattern, ok := runtime.HTTPPathPattern(ctx); ok {
path["pattern"] = pattern // /v1/example/login
}
fmt.Printf("Current path is: %v", path["pattern"])
but my current pattern/path is like i defined in proto file: Current path is: /*
If anyone have idea how to deal with this thing i would appreciate it :)
Best, Kacper
gRPC-Gateway passes various bits of information from the originating HTTP request via gRPC metadata. I don't believe the raw path is supplied, however. It is still possible to get the path passed through by registering a metadata annotator.
When calling github.com/grpc-ecosystem/grpc-gateway/v2/runtime.NewServeMux(), leverage the WithMetadata option func:
mux := runtime.NewServeMux(runtime.WithMetadata(func(_ context.Context, req *http.Request) metadata.MD {
return metadata.New(map[string]string{
"grpcgateway-http-path": req.URL.Path,
})
}))
Then in your gRPC service implementation, you can retrieve the value via the incoming context:
func (s *server) AllPath(ctx context.Context, _ *emptypb.Empty) (*emptypb.Empty, error) {
md, _ := metadata.FromIncomingContext(ctx)
log.Printf("path: %s", md["grpcgateway-http-path"][0])
return &emptypb.Empty{}, nil
}
When hitting, e.g. /foo, this should log:
2022/10/25 15:31:42 path: /foo
I'm trying to implement a google cloud function to test Google Logging client library. below is my code
// Package p contains an HTTP Cloud Function.
package loggingclient
import (
"cloud.google.com/go/logging"
"net/http"
"context"
"fmt"
)
// HelloWorld prints the JSON encoded "message" field in the body
// of the request or "Hello, World!" if there isn't one.
func HelloWorld(w http.ResponseWriter, r *http.Request) {
label := map[string]string{"priority": "High"}
var projectName = "my-project-id"
ctx := context.Background()
client, err := logging.NewClient(ctx, projectName)
if err != nil {
fmt.Printf("client not created: %v", err)
}
lg := client.Logger("MY-LOGGER")
lg.Log(logging.Entry{
Payload: "Hello, This is error!!",
Severity: logging.Error,
Labels: label,
})
client.Close()
}
Here, I'm expecting a log entry with a message:"Hello, This is error!!" and with a lable:"priority": "High" and severirty "ERROR"
But actually, when I trigger this Cloud Function, I didn't get any new log entries. Therefore don't client logging libraries work inside cloud functions?, How to resolve this?
Thanks
It works on cloud functions. I have done the exact same thing in a cloud function before. You can use google's official documenation with cloud function logging here
Also ensure that the service account have necessary permissions for logging
https://cloud.google.com/logging/docs/access-control
I'm creating an endpoint using Go's Gin web framework. I need full server URL in my handler function. For example, if server is running on http://localhost:8080 and my endpoint is /foo then I need http://localhost:8080/foo when my handler is called.
If anyone is familiar with Python's fast API, the Request object has a method url_for(<endpoint_name>) which has the exact same functionality: https://stackoverflow.com/a/63682957/5353128
In Go, I've tried accessing context.FullPath() but that only returns my endpoint /foo and not the full URL. Other than this, I can't find appropriate method in docs: https://pkg.go.dev/github.com/gin-gonic/gin#Context
So is this possible via gin.Context object itself or are there other ways as well? I'm completely new to Go.
c.Request.Host+c.Request.URL.Path should work but the scheme has to be determined.
package main
import (
"fmt"
"github.com/gin-gonic/gin"
)
func main() {
r := gin.Default()
r.GET("/foo", func(c *gin.Context) {
fmt.Println("The URL: ", c.Request.Host+c.Request.URL.Path)
})
r.Run(":8080")
}
You can determine scheme which also you may know already. But you can check as follows:
scheme := "http"
if c.Request.TLS != nil {
scheme = "https"
}
If your server is behind the proxy, you can get the scheme by c.Request.Header.Get("X-Forwarded-Proto")
You can get host part localhost:8080 from context.Request.Host and path part /foo from context.Request.URL.String().
package main
import (
"fmt"
"net/http"
"github.com/gin-gonic/gin"
)
func main() {
r := gin.Default()
r.GET("/foo", func(c *gin.Context) {
c.String(http.StatusOK, "bar")
fmt.Println(c.Request.Host+c.Request.URL.String())
})
// Listen and Server in 0.0.0.0:8080
r.Run(":8080")
}
And you can get http protocol version by context.Request.Proto, But it will not determine http or https. you need to get it from your service specifications.
I am processing a GET request in Go using fasthttp.
The query parameter test in this request is .%2A%2Ftoday%2F.%2A.
I am using POSTMAN to create the request, and the URL generated is:
http://localhost:3000/apiname/?test=.%252A%252Ftoday%252F.%252A
ctx.QueryArgs().Peek("test") gives me .*/today/.* instead of the original .%2A%2Ftoday%2F.%2A
I know I cannot partially encode/decode the request URL. Is there any way to get the original param as is?
Are you sure? I've just tested it and I'm getting the result you want.
This is the minimal working example:
package main
import (
"fmt"
"log"
"github.com/fasthttp/router"
"github.com/valyala/fasthttp"
)
func Test(ctx *fasthttp.RequestCtx) {
ctx.Response.SetBodyString(string(ctx.QueryArgs().Peek("test")))
fmt.Println(string(ctx.QueryArgs().Peek("test")))
}
func main() {
r := router.New()
r.GET("/test", Test)
log.Fatal(fasthttp.ListenAndServe("127.0.0.1:8080", r.Handler))
}
This is the command line output after the GET request:
$ go run main.go
.%2A%2Ftoday%2F.%2A
and this is the response in Postman:
I'm trying to write a twitter reader that resolves the final URLs of link shorteners etc, but gives me a URL along the way for a list of manually defined host patterns. The reason to do this is that i don't want to end up with the paywall URL but the one before.
As far as i can tell the way to do this is write my own client based on the default RoundTripper because returning an error from a custom CheckRedirect function aborts the client without yielding a response.
Is there a way to use the default client and record a list of URLs/specific URL from a custom checkRedirect function?
The client request will actually still return the last valid Response in cases where your custom CheckResponse yields an error (As mentioned in the comments).
http://golang.org/pkg/net/http/#Client
If CheckRedirect returns an error, the Client's Get method returns both the previous Response and CheckRedirect's error (wrapped in a url.Error) instead of issuing the Request req.
If you maintain a list of "known" paywall-urls, you can abort the paywall-redirect in your CheckResponse with a custom error type (Paywalled in the example below).
Your error handling code later has to consider that error type as a special (non-erroneous) case.
Example:
package main
import (
"errors"
"fmt"
"net/http"
"net/url"
)
var Paywalled = errors.New("next redirect would hit a paywall")
var badHosts = map[string]error{
"registration.ft.com": Paywalled,
}
var client = &http.Client{
CheckRedirect: func(req *http.Request, via []*http.Request) error {
// N.B.: when used in production, also check for redirect loops
return badHosts[req.URL.Host]
},
}
func main() {
resp, err := client.Get("http://on.ft.com/14pQBYE")
// ignore non-nil err if it's a `Paywalled` wrapped in url.Error
if e, ok := err.(*url.Error); (ok && e.Err != Paywalled) || (!ok && err != nil) {
fmt.Println("error: ", err)
return
}
resp.Body.Close()
fmt.Println(resp.Request.URL)
}