add error handler to middlewares

hawry · Jan 12, 2018 · 4826209 · 4826209
1 parent 67a1680
commit 4826209
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Showing 5 changed files with 54 additions and 41 deletions.
diff --git a/.gitignore b/.gitignore
@@ -0,0 +1 @@
+*.out
diff --git a/README.md b/README.md
@@ -7,3 +7,7 @@
 ## Usage
 
 Checkout the GoDoc page for the documentation: https://godoc.org/github.com/Hawry/middlewares
+
+## Testing
+To see the test coverage and which lines that are being tested, run:
+`go test -coverprofile=cp.out && go tool cover -html=cp.out`
diff --git a/error_handler.go b/error_handler.go
@@ -2,7 +2,6 @@ package middlewares
 
 import (
 	"html/template"
-	"log"
 	"net/http"
 )
 
@@ -12,54 +11,20 @@ type errorHandler struct {
 	body       []byte
 }
 
-const errBody = `<!doctype HTML>
-<html>
-<head>
-	<meta charset="utf-8"/>
-	<meta name="viewport" content="width=device-width, initial-scale=1.0">
-	<title>{{.StatusCode}} - {{.StatusText}}</title>
-	<style type="text/css">
-	h1 {
-		color:#666;
-	}
-	.content {
-		text-align:center;
-		margin-left: auto;
-		margin-right: auto;
-		max-width: 75%;
-		font-size: 1.5rem;
-	}
-	.error-text {
-		color:#666;
-	}
-	</style>
-</head>
-<body>
-
-	<div class="content">
-		<h1>{{.StatusCode}}</h1>
-		<p class="error-text">
-			{{.StatusMessage}}
-		</p>
-	</div>
-
-</body>
-</html>
-`
+const errBody = `<!doctype HTML><html><head><meta charset="utf-8"/><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>{{.StatusCode}} - {{.StatusText}}</title><style type="text/css">h1 {color:#666;}.content {text-align:center;margin-left: auto;margin-right: auto;max-width: 75%;font-size: 1.5rem;}.error-text {color:#666;}</style></head><body><div class="content"><h1>{{.StatusCode}}</h1><p class="error-text">{{.StatusMessage}}</p></div></body></html>`
 
 var errTemplate *template.Template
 
 func init() {
 	errTemplate = template.Must(template.New("err").Parse(errBody))
 }
 
-//ErrorHandler will inject a html response to any error status code
+//ErrorHandler will inject a html response to any error status code (400/500 range)
 func ErrorHandler(next http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		eh := &errorHandler{ResponseWriter: w, statusCode: http.StatusOK}
 		next.ServeHTTP(eh, r)
 		if eh.statusCode >= 400 && eh.statusCode <= 509 {
-			// do something
 			dval := map[string]interface{}{
 				"StatusCode":    eh.statusCode,
 				"StatusText":    http.StatusText(eh.statusCode),
@@ -70,16 +35,15 @@ func ErrorHandler(next http.Handler) http.Handler {
 	})
 }
 
-// WriteHeader shadows ResponseWriter.Write
+// WriteHeader shadows ResponseWriter.Write. If the code is in the 400 or 500 range, the error handler will be used to display the corresponding error page
 func (e *errorHandler) WriteHeader(code int) {
 	e.statusCode = code
 	e.ResponseWriter.WriteHeader(code)
 }
 
-//Write shadows http.ResponseWriter.Write
+//Write shadows http.ResponseWriter.Write and writes the body as the text message in the error page
 func (e *errorHandler) Write(b []byte) (n int, err error) {
 	if e.statusCode >= 400 && e.statusCode <= 509 {
-		log.Printf("err handler write called")
 		e.body = append(e.body, b...) // use any written text as the error message
 	} else {
 		e.ResponseWriter.Write(b)

diff --git a/error_handler_test.go b/error_handler_test.go
@@ -0,0 +1,45 @@
+package middlewares
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+var tNotFound = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	w.WriteHeader(http.StatusNotFound)
+	w.Write([]byte("the page could not be found"))
+})
+
+var tFound = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	w.Write([]byte("the page could be found"))
+})
+
+func TestErrorBody(t *testing.T) {
+	req, err := http.NewRequest("GET", "/notfound", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	rr := httptest.NewRecorder()
+	handler := ErrorHandler(tNotFound)
+	handler.ServeHTTP(rr, req)
+	assert.Contains(t, rr.Body.String(), "the page could not be found")
+	assert.Equal(t, http.StatusNotFound, rr.Code)
+}
+
+func TestPassthrough(t *testing.T) {
+	req, err := http.NewRequest("GET", "/found", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	rr := httptest.NewRecorder()
+	handler := ErrorHandler(tFound)
+	handler.ServeHTTP(rr, req)
+
+	assert.Contains(t, rr.Body.String(), "the page could be found")
+	assert.Equal(t, http.StatusOK, rr.Code)
+}
diff --git a/fp_handler.go b/fp_handler.go