Add WithHost Option

v2/alias.go

@@ -173,6 +173,7 @@ var (
 
 	WithTarget          = http.WithTarget
 	WithHeader          = http.WithHeader
+	WithHost            = http.WithHost
 	WithShutdownTimeout = http.WithShutdownTimeout
 	//WithEncoding           = http.WithEncoding
 	//WithStructuredEncoding = http.WithStructuredEncoding // TODO: expose new way

v2/protocol/http/options.go

@@ -72,6 +72,26 @@ func WithHeader(key, value string) Option {
 	}
 }
 
+// WithHost sets the outbound host header for all cloud events when using an HTTP request
+func WithHost(value string) Option {
+	return func(p *Protocol) error {
+		if p == nil {
+			return fmt.Errorf("http host option can not set nil protocol")
+		}
+		value = strings.TrimSpace(value)
+		if value != "" {
+			if p.RequestTemplate == nil {
+				p.RequestTemplate = &nethttp.Request{
+					Method: nethttp.MethodPost,
+				}
+			}
+			p.RequestTemplate.Host = value
+			return nil
+		}
+		return fmt.Errorf("http host option was empty string")
+	}
+}
+
 // WithShutdownTimeout sets the shutdown timeout when the http server is being shutdown.
 func WithShutdownTimeout(timeout time.Duration) Option {
 	return func(p *Protocol) error {

v2/protocol/http/options_test.go

@@ -271,6 +271,77 @@ func TestWithHeader(t *testing.T) {
 	}
 }
 
+func TestWithHost(t *testing.T) {
+	testCases := map[string]struct {
+		t       *Protocol
+		value   string
+		want    *Protocol
+		wantErr string
+	}{
+		"valid host": {
+			t: &Protocol{
+				RequestTemplate: &http.Request{},
+			},
+			value: "test",
+			want: &Protocol{
+				RequestTemplate: &http.Request{
+					Host: "test",
+				},
+			},
+		},
+		"valid host, unset req": {
+			t:     &Protocol{},
+			value: "test",
+			want: &Protocol{
+				RequestTemplate: &http.Request{
+					Method: http.MethodPost,
+					Host:   "test",
+				},
+			},
+		},
+		"empty host value": {
+			t: &Protocol{
+				RequestTemplate: &http.Request{},
+			},
+			wantErr: `http host option was empty string`,
+		},
+		"whitespace key": {
+			t: &Protocol{
+				RequestTemplate: &http.Request{},
+			},
+			value:   " \t\n",
+			wantErr: `http host option was empty string`,
+		},
+		"nil protocol": {
+			wantErr: `http host option can not set nil protocol`,
+		},
+	}
+	for n, tc := range testCases {
+		t.Run(n, func(t *testing.T) {
+
+			err := tc.t.applyOptions(WithHost(tc.value))
+
+			if tc.wantErr != "" || err != nil {
+				var gotErr string
+				if err != nil {
+					gotErr = err.Error()
+				}
+				if diff := cmp.Diff(tc.wantErr, gotErr); diff != "" {
+					t.Errorf("unexpected error (-want, +got) = %v", diff)
+				}
+				return
+			}
+
+			got := tc.t
+
+			if diff := cmp.Diff(tc.want, got,
+				cmpopts.IgnoreUnexported(Protocol{}), cmpopts.IgnoreUnexported(http.Request{})); diff != "" {
+				t.Errorf("unexpected (-want, +got) = %v", diff)
+			}
+		})
+	}
+}
+
 func TestWithShutdownTimeout(t *testing.T) {
 	testCases := map[string]struct {
 		t       *Protocol