http: allow Endpoint to register custom error handler

The new field ErrorHandler on Endpoint allow the implementor to define
their own function to handler error from Endpoint.Call.

If the ErrorHandler is nil it will default to DefaultErrorHandler.

1 files changed, 62 insertions, 0 deletions

diff --git a/lib/http/endpoint_example_test.go b/lib/http/endpoint_example_test.go
new file mode 100644
index 00000000..b605a931
--- /dev/null
+++ b/lib/http/endpoint_example_test.go
@@ -0,0 +1,62 @@
+package http
+
+import (
+	"fmt"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+	"time"
+)
+
+func ExampleEndpoint_errorHandler() {
+	serverOpts := &ServerOptions{
+		Address: "127.0.0.1:8123",
+	}
+	server, _ := NewServer(serverOpts)
+
+	endpointError := &Endpoint{
+		Method:       RequestMethodGet,
+		Path:         "/",
+		RequestType:  RequestTypeQuery,
+		ResponseType: ResponseTypePlain,
+		Call: func(res http.ResponseWriter, req *http.Request, reqBody []byte) ([]byte, error) {
+			return nil, fmt.Errorf(req.Form.Get("error"))
+		},
+		ErrorHandler: func(res http.ResponseWriter, req *http.Request, err error) {
+			res.Header().Set(HeaderContentType, ContentTypePlain)
+
+			codeMsg := strings.Split(err.Error(), ":")
+			if len(codeMsg) != 2 {
+				res.WriteHeader(http.StatusInternalServerError)
+				res.Write([]byte(err.Error()))
+			} else {
+				code, _ := strconv.Atoi(codeMsg[0])
+				res.WriteHeader(code)
+				res.Write([]byte(codeMsg[1]))
+			}
+		},
+	}
+	_ = server.RegisterEndpoint(endpointError)
+
+	go func() {
+		_ = server.Start()
+	}()
+	defer server.Stop(1 * time.Second)
+	time.Sleep(1 * time.Second)
+
+	client := NewClient("http://"+serverOpts.Address, nil, false)
+
+	params := url.Values{}
+	params.Set("error", "400:error with status code")
+	httpres, resbody, _ := client.Get(nil, "/", params)
+	fmt.Printf("%d: %s\n", httpres.StatusCode, resbody)
+
+	params.Set("error", "error without status code")
+	httpres, resbody, _ = client.Get(nil, "/", params)
+	fmt.Printf("%d: %s\n", httpres.StatusCode, resbody)
+
+	// Output:
+	// 400: error with status code
+	// 500: error without status code
+}