From: Chris Jaekl <chris@localhost>
Date: Wed, 11 Nov 2020 05:05:35 +0000 (-0500)
Subject: Rework error handling to use http.Error()
X-Git-Url: http://jaekl.net/gitweb/?p=quanweb.git;a=commitdiff_plain;h=508fafb1316cdc3a83a7b160a34b50017315977a

Rework error handling to use http.Error()
---

diff --git a/main/handler.go b/main/handler.go
index 599f5d5..d0771fa 100644
--- a/main/handler.go
+++ b/main/handler.go
@@ -17,7 +17,7 @@ const MAX_TERMS = 10
 // ============================================================================
 func bookMimeType(bookPath string) string {
   upper := strings.ToUpper(bookPath)
-  
+
   if strings.HasSuffix(upper, ".EPUB") {
     return "application/epub+zip"
   } else if strings.HasSuffix(upper, ".PDF") {
@@ -40,7 +40,7 @@ func efsPathForId(efsId int) string {
 func handler(w http.ResponseWriter, r *http.Request) {
   err := r.ParseForm()
   if nil != err {
-    fmt.Fprintln(w, "ERROR!", err)
+    handleError(w, err.Error())
     return
   }
 
@@ -56,32 +56,37 @@ func handler(w http.ResponseWriter, r *http.Request) {
   case "search":
     handleSearch(w, r)
   default:
-    fmt.Fprintf(w, "Unrecognized request:  %s\n", r.URL.Path[1:])
-    fmt.Fprintf(w, "id: %s\n", r.FormValue("id"))
-  
-    fmt.Fprintln(w, "URL: ", r.URL)
-    fmt.Fprintln(w, "Query: ", r.URL.Query())
+    handleError(
+      w,
+      fmt.Sprintf(
+        "Unrecognized request:  %s\nid: %s\nURL: %s\nQuery: %s\n",
+        r.URL.Path[1:],
+        r.FormValue("id"),
+        r.URL,
+        r.URL.Query()))
   }
 }
 
 // Download a book, based on the path stored in the DB
 func handleBook(w http.ResponseWriter, r *http.Request) {
+  fmt.Println("handleBook:", r.URL.Path)
   path := r.URL.Path[1:]
   tok := strings.Split(path, "/")
   if 2 != len(tok) {
-    fmt.Fprintln(w, "Unexpected path for book download:", path)
+    handleError(w, fmt.Sprintf("Unexpected path for book download: %s\n", path))
     return
   }
 
   bookId, err := strconv.Atoi(tok[1])
   if (nil != err) || (0 == bookId) {
-    fmt.Fprintln(w, "Invalid id for book download:", path, err)
+    msg := fmt.Sprintf("Invalid id for book download: \"%s\" (%s)\n", path, err.Error())
+    handleError(w, msg)
     return
   }
 
   bookPath := queryBookPathById(bookId)
   if 0 == len(bookPath) {
-    fmt.Fprintln(w, "No book for ID:", bookId)
+    handleError(w, fmt.Sprintf("No book for ID: %s\n", bookId))
     return
   }
 
@@ -89,22 +94,22 @@ func handleBook(w http.ResponseWriter, r *http.Request) {
 
   mimeType := bookMimeType(bookPath)
   if 0 == len(mimeType) {
-    fmt.Fprintln(w, "Failed to determine MIME type for book:", bookPath)
+    handleError(w, fmt.Sprintf("Failed to determine MIME type for book: %s\n", bookPath))
     return
   }
 
   var info os.FileInfo
   info, err = os.Stat(bookPath)
   if nil != err {
-    fmt.Fprintln(w, "Failed to read file metadata:", bookPath, err)
+    handleError(w, fmt.Sprintf("Failed to read file metadata: \"%s\" (%s)\n", bookPath, err.Error()))
     return
   }
   modTime := info.ModTime()
-  
+
   var fd *os.File
   fd, err = os.Open(bookPath)
   if nil != err {
-    fmt.Fprintln(w, "Failed to open file:", bookPath, err)
+    handleError(w, fmt.Sprintf("Failed to open file: \"%s\" (%s)\n", bookPath, err.Error()))
     return
   }
   defer fd.Close()
@@ -127,7 +132,7 @@ func handleDownload(w http.ResponseWriter, r *http.Request) {
     fmt.Fprintln(w, "Invalid id for download:", path, err)
     return
   }
-  
+
   mimeType := queryMimeTypeByEfsId(efsId)
   if 0 == len(mimeType) {
     fmt.Fprintln(w, "No MIME type found for id:", efsId)
@@ -148,12 +153,17 @@ func handleDownload(w http.ResponseWriter, r *http.Request) {
   io.Copy(w, fd)
 }
 
+func handleError(w http.ResponseWriter, msg string) {
+  fmt.Printf("ERROR: %s", msg)
+  http.Error(w, msg, http.StatusInternalServerError)
+}
+
 func handleInfo(w http.ResponseWriter, r *http.Request) {
   idParams := r.Form[PARAM_IDS]
   if 1 != len(idParams) {
-    fmt.Fprintln(w, "ERROR!  Detected either zero or multiple ids= parameters.  Exactly one expected.")
-    return 
-  } 
+    handleError(w, "ERROR!  Detected either zero or multiple ids= parameters.  Exactly one expected.")
+    return
+  }
 
   idParam := idParams[0]
   idStrings := strings.Split(idParam, ",")
@@ -171,7 +181,7 @@ func handleInfo(w http.ResponseWriter, r *http.Request) {
   var jsonValue []byte
   jsonValue, err = json.Marshal(books)
   if nil != err {
-    fmt.Fprintln(w, "ERROR!", err)
+    handleError(w, err.Error())
   } else {
     w.Write(jsonValue)
   }
@@ -204,7 +214,7 @@ func handleSearch(w http.ResponseWriter, r *http.Request) {
 
   jsonValue, err := json.Marshal(ids)
   if nil != err {
-    fmt.Fprintln(w, "ERROR!", err)
+    handleError(w, err.Error())
   } else {
     w.Write(jsonValue)
   }