stellar#3710: capture client disconnects as different HTTP status cod…

…e of 499 rather than 503

services/horizon/internal/actions/submit_transaction.go

@@ -78,7 +78,7 @@ func (handler SubmitTransactionHandler) response(r *http.Request, info envelopeI
 	}
 
 	if result.Err == txsub.ErrCanceled {
-		return nil, &hProblem.Timeout
+		return nil, &hProblem.ClientDisconnected
 	}
 
 	switch err := result.Err.(type) {
@@ -153,6 +153,6 @@ func (handler SubmitTransactionHandler) GetResource(w HeaderWriter, r *http.Requ
 	case result := <-submission:
 		return handler.response(r, info, result)
 	case <-r.Context().Done():
-		return nil, &hProblem.Timeout
+		return nil, &hProblem.ClientDisconnected
 	}
 }

services/horizon/internal/actions_transaction_test.go

@@ -1,7 +1,9 @@
 package horizon
 
 import (
+	"context"
 	"encoding/json"
+	"net/http"
 	"net/url"
 	"testing"
 
@@ -289,6 +291,62 @@ func TestTransactionActions_Post(t *testing.T) {
 	ht.Assert.Equal(200, w.Code)
 }
 
+
+
+
+func TestTransactionActions_Post_ClientDisconnect(t *testing.T) {
+	ht := StartHTTPTest(t, "base")
+	defer ht.Finish()
+
+	// Pass Synced check
+	ht.App.coreState.SetState(corestate.State{Synced: true})
+
+	tx := xdr.TransactionEnvelope{
+		Type: xdr.EnvelopeTypeEnvelopeTypeTxV0,
+		V0: &xdr.TransactionV0Envelope{
+			Tx: xdr.TransactionV0{
+				SourceAccountEd25519: *xdr.MustAddress("GBRPYHIL2CI3FNQ4BXLFMNDLFJUNPU2HY3ZMFSHONUCEOASW7QC7OX2H").Ed25519,
+				Fee:                  100,
+				SeqNum:               1,
+				Operations: []xdr.Operation{
+					{
+						Body: xdr.OperationBody{
+							Type: xdr.OperationTypeCreateAccount,
+							CreateAccountOp: &xdr.CreateAccountOp{
+								Destination:     xdr.MustAddress("GCXKG6RN4ONIEPCMNFB732A436Z5PNDSRLGWK7GBLCMQLIFO4S7EYWVU"),
+								StartingBalance: 1000000000,
+							},
+						},
+					},
+				},
+			},
+			Signatures: []xdr.DecoratedSignature{
+				{
+					Hint:      xdr.SignatureHint{86, 252, 5, 247},
+					Signature: xdr.Signature{131, 206, 171, 228, 64, 20, 40, 52, 2, 98, 124, 244, 87, 14, 130, 225, 190, 220, 156, 79, 121, 69, 60, 36, 57, 214, 9, 29, 176, 81, 218, 4, 213, 176, 211, 148, 191, 86, 21, 180, 94, 9, 43, 208, 32, 79, 19, 131, 90, 21, 93, 138, 153, 203, 55, 103, 2, 230, 137, 190, 19, 70, 179, 11},
+				},
+			},
+		},
+	}
+
+	txStr, err := xdr.MarshalBase64(tx)
+	assert.NoError(t, err)
+	form := url.Values{"tx": []string{txStr}}
+
+	// existing transaction
+
+    w := ht.Post("/transactions", form, 
+		func (req *http.Request) (*http.Request){
+		   ctx, cancel := context.WithCancel(req.Context())
+           req = req.WithContext(ctx)
+           cancel()
+           return req
+		})
+
+	ht.Assert.Equal(499, w.Code)
+}
+
+
 func TestTransactionActions_PostSuccessful(t *testing.T) {
 	ht := StartHTTPTest(t, "failed_transactions")
 	defer ht.Finish()

services/horizon/internal/app_test.go

@@ -20,8 +20,9 @@ func TestGenericHTTPFeatures(t *testing.T) {
 		ht.Assert.Empty(w.HeaderMap.Get("Access-Control-Allow-Origin"))
 	}
 
-	w = ht.Get("/", func(r *http.Request) {
+	w = ht.Get("/", func(r *http.Request) (*http.Request){
 		r.Header.Set("Origin", "somewhere.com")
+		return r
 	})
 
 	if ht.Assert.Equal(200, w.Code) {

services/horizon/internal/httpt_test.go

@@ -68,7 +68,7 @@ func StartHTTPTestWithoutScenario(t *testing.T) *HTTPT {
 // Get delegates to the test's request helper
 func (ht *HTTPT) Get(
 	path string,
-	fn ...func(*http.Request),
+	fn ...func(*http.Request)(*http.Request),
 ) *httptest.ResponseRecorder {
 	return ht.RH.Get(path, fn...)
 }
@@ -77,7 +77,7 @@ func (ht *HTTPT) Get(
 func (ht *HTTPT) GetWithParams(
 	path string,
 	queryParams url.Values,
-	fn ...func(*http.Request),
+	fn ...func(*http.Request)(*http.Request),
 ) *httptest.ResponseRecorder {
 	return ht.RH.Get(path+"?"+queryParams.Encode(), fn...)
 }
@@ -93,7 +93,7 @@ func (ht *HTTPT) Finish() {
 func (ht *HTTPT) Post(
 	path string,
 	form url.Values,
-	mods ...func(*http.Request),
+	mods ...func(*http.Request)(*http.Request),
 ) *httptest.ResponseRecorder {
 	return ht.RH.Post(path, form, mods...)
 }

services/horizon/internal/httpx/server.go

@@ -55,7 +55,7 @@ func init() {
 	problem.RegisterError(db2.ErrInvalidOrder, problem.BadRequest)
 	problem.RegisterError(sse.ErrRateLimited, hProblem.RateLimitExceeded)
 	problem.RegisterError(context.DeadlineExceeded, hProblem.Timeout)
-	problem.RegisterError(context.Canceled, hProblem.ServiceUnavailable)
+	problem.RegisterError(context.Canceled, hProblem.ClientDisconnected)
 	problem.RegisterError(db.ErrCancelled, hProblem.ServiceUnavailable)
 	problem.RegisterError(db.ErrConflictWithRecovery, hProblem.ServiceUnavailable)
 	problem.RegisterError(db.ErrBadConnection, hProblem.ServiceUnavailable)

services/horizon/internal/middleware_test.go

@@ -27,15 +27,17 @@ import (
 	"github.com/stellar/go/xdr"
 )
 
-func requestHelperRemoteAddr(ip string) func(r *http.Request) {
-	return func(r *http.Request) {
+func requestHelperRemoteAddr(ip string) func(r *http.Request)(*http.Request) {
+	return func(r *http.Request) (*http.Request) {
 		r.RemoteAddr = ip
+		return r
 	}
 }
 
-func requestHelperXFF(xff string) func(r *http.Request) {
-	return func(r *http.Request) {
+func requestHelperXFF(xff string) func(r *http.Request) (*http.Request) {
+	return func(r *http.Request) (*http.Request) {
 		r.Header.Set("X-Forwarded-For", xff)
+		return r
 	}
 }
 
@@ -306,6 +308,35 @@ func TestStateMiddleware(t *testing.T) {
 	}
 }
 
+func TestClientDisconnect(t *testing.T) {
+	tt := test.Start(t)
+	defer tt.Finish()
+	test.ResetHorizonDB(t, tt.HorizonDB)
+
+	request, err := http.NewRequest("GET", "http://localhost/", nil)
+	tt.Assert.NoError(err)
+
+	endpoint := func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+	}
+
+	stateMiddleware := &httpx.StateMiddleware{
+		HorizonSession: tt.HorizonSession(),
+		NoStateVerification: true,
+	}
+	handler := chi.NewRouter()
+	handler.With(stateMiddleware.Wrap).MethodFunc("GET", "/", endpoint)
+    w := httptest.NewRecorder()
+
+    ctx, cancel := context.WithCancel(request.Context())
+    request = request.WithContext(ctx)
+	// cancel invocation simulates client disconnect in the context
+    cancel()    
+
+	handler.ServeHTTP(w, request)
+	tt.Assert.Equal(499, w.Code)
+}
+
 func TestCheckHistoryStaleMiddleware(t *testing.T) {
 	tt := test.Start(t)
 	defer tt.Finish()

services/horizon/internal/render/problem/problem.go

@@ -8,6 +8,17 @@ import (
 
 // Well-known and reused problems below:
 var (
+
+    // ClientDisconnected, represented by a non-standard HTTP status code of 499, which was introduced by
+    // nginix.org(https://www.nginx.com/resources/wiki/extending/api/http/) as a way to capture this state.  Use it as a shortcut
+	// in your actions.
+	ClientDisconnected = problem.P{
+		Type:   "client_disconnected",
+		Title:  "Client Disconnected",
+		Status: 499,
+		Detail: "The client has closed the connection.",
+	}
+
 	// ServiceUnavailable is a well-known problem type.  Use it as a shortcut
 	// in your actions.
 	ServiceUnavailable = problem.P{

services/horizon/internal/render/problem/problem_test.go

@@ -25,6 +25,7 @@ func TestCommonProblems(t *testing.T) {
 	}{
 		{"NotFound", problem.NotFound, 404},
 		{"RateLimitExceeded", RateLimitExceeded, 429},
+		{"ClientDisconneted", ClientDisconnected, 499},
 	}
 
 	for _, tc := range testCases {

services/horizon/internal/test/http.go

@@ -10,20 +10,22 @@ import (
 )
 
 type RequestHelper interface {
-	Get(string, ...func(*http.Request)) *httptest.ResponseRecorder
-	Post(string, url.Values, ...func(*http.Request)) *httptest.ResponseRecorder
+	Get(string, ...func(*http.Request)(*http.Request)) *httptest.ResponseRecorder
+	Post(string, url.Values, ...func(*http.Request)(*http.Request)) *httptest.ResponseRecorder
 }
 
 type requestHelper struct {
 	router *chi.Mux
 }
 
-func RequestHelperRaw(r *http.Request) {
+func RequestHelperRaw(r *http.Request) (*http.Request) {
 	r.Header.Set("Accept", "application/octet-stream")
+	return r
 }
 
-func RequestHelperStreaming(r *http.Request) {
+func RequestHelperStreaming(r *http.Request) (*http.Request){
 	r.Header.Set("Accept", "text/event-stream")
+	return r
 }
 
 func NewRequestHelper(router *chi.Mux) RequestHelper {
@@ -32,7 +34,7 @@ func NewRequestHelper(router *chi.Mux) RequestHelper {
 
 func (rh *requestHelper) Get(
 	path string,
-	mods ...func(*http.Request),
+	mods ...func(*http.Request)(*http.Request),
 ) *httptest.ResponseRecorder {
 
 	req, _ := http.NewRequest("GET", path, nil)
@@ -42,7 +44,7 @@ func (rh *requestHelper) Get(
 func (rh *requestHelper) Post(
 	path string,
 	form url.Values,
-	mods ...func(*http.Request),
+	mods ...func(*http.Request)(*http.Request),
 ) *httptest.ResponseRecorder {
 
 	body := strings.NewReader(form.Encode())
@@ -53,13 +55,13 @@ func (rh *requestHelper) Post(
 
 func (rh *requestHelper) Execute(
 	req *http.Request,
-	requestModFns []func(*http.Request),
+	requestModFns []func(*http.Request)(*http.Request),
 ) *httptest.ResponseRecorder {
 
 	req.RemoteAddr = "127.0.0.1"
 	req.Host = "localhost"
 	for _, fn := range requestModFns {
-		fn(req)
+		req = fn(req)
 	}
 
 	w := httptest.NewRecorder()