for digital animal test

main.go

@@ -0,0 +1,113 @@
+package main
+import (
+    "encoding/json"
+    "log"
+    "net/http"
+	"io/ioutil"    
+    "strconv"
+    "fmt"
+
+
+    "github.com/gorilla/mux"
+)
+
+
+//struct used to send the id of the message in json format
+type messageID struct {
+	Id int `json:"id"`
+}
+
+
+//Store for the Messages
+var msgStore = make(map[string]string)
+
+//int used as key into message store
+var idSeq int = 0
+
+//==============================================================================
+// Struct Error handling
+type ErrorMessage struct {
+	Status string `json:"status"`
+	Message string `json:"error_message"`
+}
+
+func genericErrorHandler(w http.ResponseWriter, r *http.Request) {
+	if p := recover(); p != nil {
+		s := fmt.Sprintf("internal error>> %s", p)
+        e := &ErrorMessage{Status:"error occured",Message: s}
+		writeErrorResponse(w, e,http.StatusInternalServerError)
+    }
+
+}
+func writeErrorResponse(w http.ResponseWriter,e *ErrorMessage, status int) {
+    j, err := json.Marshal(e)
+	if err != nil {
+			panic(err)
+	}
+	fmt.Printf(e.Status,e.Message)
+    w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	w.Write(j)
+}
+//==============================================================================
+
+
+//POST method handler
+func PostMsgHandler(w http.ResponseWriter, r *http.Request) {
+	defer genericErrorHandler(w,r)
+
+	msgReader := http.MaxBytesReader(w,r.Body,4096) //Limit the max number of chars in message
+	reqDump, err := ioutil.ReadAll(msgReader)
+
+	if err != nil {
+		panic (fmt.Sprintf("PostMsgHandler:[Max content length 4096] err[%s]", err))
+	}
+
+    msgContent := string(reqDump[:])
+    idSeq++
+    k := strconv.Itoa(idSeq)
+    msgStore[k] =msgContent
+
+    log.Printf("Received message %d => %s", idSeq, msgContent)
+    resp := &messageID{idSeq}
+    j, err := json.Marshal(resp)
+    if err != nil {
+        panic(err)
+    }
+    w.Header().Set("Content-Type", "application/json")
+    w.WriteHeader(http.StatusCreated)
+    w.Write(j)
+}
+
+
+//HTTP GET - /messages/{id}
+func GetMsgHandler(w http.ResponseWriter, r *http.Request) {
+	defer genericErrorHandler(w,r)
+    vars := mux.Vars(r)
+    k := vars["id"]
+    log.Printf("key %s",k)
+    if msgContent, ok := msgStore[k]; ok {
+    	log.Printf("Key found [%s]=>[%s]",k,msgContent)
+    	w.WriteHeader(http.StatusOK)
+        fmt.Fprintf(w, msgContent) // Escape HTML special chars
+    } else {
+    	log.Printf("Key Not found %s",k)
+        w.WriteHeader(http.StatusNotFound)
+    }
+
+}
+
+//Entry point of the program
+func main() {
+
+    r := mux.NewRouter().StrictSlash(false)
+    r.HandleFunc("/messages/{id}", GetMsgHandler).Methods("GET")
+    r.HandleFunc("/messages", PostMsgHandler).Methods("POST")
+
+    server := &http.Server{
+        Addr:    ":8080",
+        Handler: r,
+    }
+    log.Println("Listening...")
+    server.ListenAndServe()
+}

main_test.go

@@ -0,0 +1,114 @@
+package main
+import (
+        "net/http"
+        "net/http/httptest"
+        "strings"
+        "testing"
+
+        "github.com/gorilla/mux"
+)
+
+
+func TestStoreMsg(t *testing.T) {
+    r := mux.NewRouter()
+    r.HandleFunc("/messages", PostMsgHandler).Methods("POST")
+    req, err := http.NewRequest(
+            "POST",
+            "/messages",
+            strings.NewReader(`Hello World`),
+    )
+    if err != nil {
+            t.Error(err)
+    }
+
+    w := httptest.NewRecorder()
+    r.ServeHTTP(w, req)
+    if w.Code != 201 {
+            t.Errorf("HTTP Status expected: 201, got: %d", w.Code)
+    }
+}
+
+func TestStoreTooLongMsg(t *testing.T) {
+    r := mux.NewRouter()
+    r.HandleFunc("/messages", PostMsgHandler).Methods("POST")
+    byteSlice := []byte{0:'a',5000:'b'}
+    tooLongString:= string(byteSlice[:])
+
+    req, err := http.NewRequest(
+            "POST",
+            "/messages",
+            strings.NewReader(tooLongString),
+    )
+    if err != nil {
+            t.Error(err)
+    }
+
+    w := httptest.NewRecorder()
+    r.ServeHTTP(w, req)
+    if w.Code != 500 {
+            t.Errorf("HTTP Status expected: 500, got: %d", w.Code)
+    }
+}
+
+
+func TestGetMsgHandler(t *testing.T) {
+    r := mux.NewRouter()
+    r.HandleFunc("/messages/{id}", GetMsgHandler).Methods("GET")
+    req, err := http.NewRequest("GET", "/messages/1", nil)
+    if err != nil {
+            t.Error(err)
+    }
+    w := httptest.NewRecorder()
+
+    r.ServeHTTP(w, req)
+    if w.Code != 200 {
+            t.Errorf("HTTP Status expected: 200, got: %d", w.Code)
+    }
+}
+
+func TestGetNonExistentMsgHandler(t *testing.T) {
+    r := mux.NewRouter()
+    r.HandleFunc("/messages/{id}", GetMsgHandler).Methods("GET")
+    req, err := http.NewRequest("GET", "/messages/31", nil)
+    if err != nil {
+            t.Error(err)
+    }
+    w := httptest.NewRecorder()
+
+    r.ServeHTTP(w, req)
+    if w.Code != 404 {
+            t.Errorf("HTTP Status expected: 404, got: %d", w.Code)
+    }
+}
+
+
+/*
+func TestGetMsgHandlerWithServer(t *testing.T) {
+    log.SetPrefix("TestGetMsgHandlerWithServer:")
+    log.Println ("Testing message retrieval")
+    r := mux.NewRouter()
+    r.HandleFunc("/messages/{id}", GetMsgHandler).Methods("GET")
+    server := httptest.NewServer(r)
+    defer server.Close()
+    msgUrl := fmt.Sprintf("%s/messages/1", server.URL)
+    log.Printf ("msgUrl %s", msgUrl)
+    request, err := http.NewRequest("GET", msgUrl, nil)
+
+    res, err := http.DefaultClient.Do(request)
+    if err != nil {
+        t.Error(err)
+    }
+
+    resDump, err2 := ioutil.ReadAll(res.Body)
+    
+    
+    if err2 != nil {
+        t.Error(err2)
+    }
+
+
+    log.Printf("Response is [%s]",string(resDump[:]))
+    if res.StatusCode != 200 {
+        t.Errorf("HTTP Status expected: 200, got: %d", res.StatusCode)
+    }
+}*/