Replace existing headers in WebRequest.Prepare

Fixes #80

Author: timhall

specs/Specs_WebHelpers.bas

@@ -371,6 +371,29 @@ Public Function Specs() As SpecSuite
         .Expect(WebHelpers.FindInKeyValues(KeyValues, "d")).ToBeEmpty
     End With
 
+    ' AddOrReplaceInKeyValues
+    ' --------------------------------------------- '
+    With Specs.It("should add or replace (with retained order) in Key-Values")
+        Set KeyValues = New Collection
+        KeyValues.Add WebHelpers.CreateKeyValue("a", 123)
+        KeyValues.Add WebHelpers.CreateKeyValue("b", 456)
+        KeyValues.Add WebHelpers.CreateKeyValue("c", 789)
+        
+        WebHelpers.AddOrReplaceInKeyValues KeyValues, "a", "abc"
+        WebHelpers.AddOrReplaceInKeyValues KeyValues, "b", "def"
+        WebHelpers.AddOrReplaceInKeyValues KeyValues, "c", "ghi"
+        WebHelpers.AddOrReplaceInKeyValues KeyValues, "d", "jkl"
+        
+        .Expect(KeyValues.Count).ToEqual 4
+        .Expect(KeyValues(1)("Key")).ToEqual "a"
+        .Expect(KeyValues(2)("Key")).ToEqual "b"
+        .Expect(KeyValues(3)("Key")).ToEqual "c"
+        .Expect(KeyValues(4)("Key")).ToEqual "d"
+        
+        .Expect(KeyValues(2)("Value")).ToEqual "def"
+        .Expect(KeyValues(4)("Value")).ToEqual "jkl"
+    End With
+    
     ' ============================================= '
     ' 5. Request preparation / handling
     ' ============================================= '

specs/Specs_WebRequest.bas

@@ -16,6 +16,7 @@ Public Function Specs() As SpecSuite
     Dim Request As WebRequest
     Dim Body As Object
     Dim Cloned As WebRequest
+    Dim NumHeaders As Long
 
     WebHelpers.RegisterConverter "csv", "text/csv", "Specs_WebHelpers.SimpleConverter", "Specs_WebHelpers.SimpleParser"
 
@@ -474,7 +475,7 @@ Public Function Specs() As SpecSuite
         Request.ContentLength = 100
 
         .Expect(Request.Headers.Count).ToEqual 0
-        
+         
         Request.Prepare
 
         .Expect(Request.Headers.Count).ToBeGTE 3
@@ -483,6 +484,22 @@ Public Function Specs() As SpecSuite
         .Expect(WebHelpers.FindInKeyValues(Request.Headers, "Content-Length")).ToEqual "100"
     End With
 
+    With Specs.It("Prepare should only add headers once")
+        Set Request = New WebRequest
+        
+        Request.ContentType = "text/plain"
+        Request.Accept = "text/csv"
+        Request.ContentLength = 100
+         
+        Request.Prepare
+        
+        NumHeaders = Request.Headers.Count
+        
+        Request.Prepare
+        
+        .Expect(Request.Headers.Count).ToEqual NumHeaders
+    End With
+    
     ' ============================================= '
     ' Errors
     ' ============================================= '

src/WebHelpers.bas

@@ -960,6 +960,43 @@ Public Function FindInKeyValues(KeyValues As Collection, Key As Variant) As Vari
     Next web_KeyValue
 End Function
 
+''
+' Helper for adding/replacing key-value in Collection of key-value
+' - Add if key not found
+' - Replace if key is found
+'
+' @param {Collection} KeyValues
+' @param {String} Key to find
+' @return {Variant}
+' --------------------------------------------- '
+Public Sub AddOrReplaceInKeyValues(KeyValues As Collection, Key As Variant, Value As Variant)
+    Dim web_KeyValue As Dictionary
+    Dim web_Index As Long
+    Dim web_NewKeyValue As Dictionary
+    
+    Set web_NewKeyValue = CreateKeyValue(CStr(Key), Value)
+    
+    web_Index = 1
+    For Each web_KeyValue In KeyValues
+        If web_KeyValue("Key") = Key Then
+            ' Replace existing
+            KeyValues.Remove web_Index
+            
+            If web_Index > KeyValues.Count Then
+                KeyValues.Add web_NewKeyValue, After:=web_Index - 1
+            Else
+                KeyValues.Add web_NewKeyValue, Before:=web_Index
+            End If
+            Exit Sub
+        End If
+        
+        web_Index = web_Index + 1
+    Next web_KeyValue
+    
+    ' Add
+    KeyValues.Add web_NewKeyValue
+End Sub
+
 ' ============================================= '
 ' 5. Request preparation / handling
 ' ============================================= '

src/WebRequest.cls

@@ -248,11 +248,11 @@ End Sub
 ' Prepare request for execution
 ' --------------------------------------------- '
 Public Sub Prepare()
-    ' Add general headers to request
-    Me.AddHeader "User-Agent", WebUserAgent
-    Me.AddHeader "Content-Type", Me.ContentType
-    Me.AddHeader "Accept", Me.Accept
-    Me.AddHeader "Content-Length", VBA.CStr(Me.ContentLength)
+    ' Add/replace general headers for request
+    WebHelpers.AddOrReplaceInKeyValues Me.Headers, "User-Agent", WebUserAgent
+    WebHelpers.AddOrReplaceInKeyValues Me.Headers, "Content-Type", Me.ContentType
+    WebHelpers.AddOrReplaceInKeyValues Me.Headers, "Accept", Me.Accept
+    WebHelpers.AddOrReplaceInKeyValues Me.Headers, "Content-Length", VBA.CStr(Me.ContentLength)
 End Sub
 
 ''