build-support/http-get.vbs: handle exceptions when making http request and writing file, set appropriate errorlevel

build-support/http-get.vbs

@@ -1,3 +1,5 @@
+on error resume next
+
 if WScript.Arguments.Count < 2 then
     WScript.Echo "usage: http-get.vbs source-url dest-file"
     WScript.Quit 1
@@ -7,23 +9,33 @@ else
 
     dim http, source_data
     set http = CreateObject("WinHttp.WinHttpRequest.5.1")
+
+    Err.Clear
     http.Open "GET", source_url, false
     http.Send
 
-    if http.Status = 200 then
-        dim dest_stream
-        set dest_stream = CreateObject("ADODB.Stream")
+    if Err.Number = 0 then
+        if http.Status = 200 then
+            dim dest_stream
+            set dest_stream = CreateObject("ADODB.Stream")
 
-        dest_stream.Type = 1 ' adTypeBinary
-        dest_stream.Open
-        dest_stream.Write http.ResponseBody
-        dest_stream.SaveToFile dest_filename, 2 ' adSaveCreateOverWrite
-
-        set dest_stream = nothing
+            Err.Clear
+            dest_stream.Type = 1 ' adTypeBinary
+            dest_stream.Open
+            dest_stream.Write http.ResponseBody
+            dest_stream.SaveToFile dest_filename, 2 ' adSaveCreateOverWrite
+            if Err.Number <> 0 then
+                WScript.Echo "Error " + CStr(Err.Number) + " when writing " + dest_filename + ":"
+                WScript.Echo Err.Description
+                WScript.Quit 1
+            end if
+        else
+            WScript.Echo CStr(http.Status) + " " + http.StatusText + " when fetching " + source_url
+            WScript.Quit 1
+        end if
     else
-        WScript.Echo CStr(http.Status) + " " + http.StatusText + " when fetching " + source_url
+        WScript.Echo "Error " + CStr(Err.Number) + " when fetching " + source_url + ":"
+        WScript.Echo Err.Description
         WScript.Quit 1
     end if
-
-    set http = nothing
 end if