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WebView2Header.md

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336 lines (254 loc) · 9.5 KB
title Header
parent WebView2 Package
nav_order 15

WebView2Header Class

The WebView2Header class represents a single HTTP header information, containing header name and header value.

Class Information

Property Value
Class Name WebView2Header
COM Creatable No

Properties

Name

Public Name As String

The name of the HTTP header.

Type: String

Example:

Dim header As WebView2Header
header.Name = "Content-Type"

Value

Public Value As String

The value of the HTTP header.

Type: String

Example:

Dim header As WebView2Header
header.Value = "application/json"

Constructor

Public Sub New(ByVal Name As String, ByVal Value As String)

Creates a new WebView2Header object.

Parameters:

  • Name - Header name
  • Value - Header value

Example:

Dim header As New WebView2Header("Content-Type", "text/html")
Debug.Print header.Name & ": " & header.Value
' Output: Content-Type: text/html

Usage Scenarios

1. Create Custom Header Object

' Create single header object
Dim authHeader As New WebView2Header("Authorization", "Bearer token123")
Debug.Print authHeader.Name & ": " & authHeader.Value

' Create multiple headers
Dim headers() As WebView2Header
ReDim headers(2)
Set headers(0) = New WebView2Header("Content-Type", "application/json")
Set headers(1) = New WebView2Header("Accept", "application/json")
Set headers(2) = New WebView2Header("User-Agent", "MyApp/1.0")

Dim i As Long
For i = LBound(headers) To UBound(headers)
    Debug.Print headers(i).Name & ": " & headers(i).Value
Next

2. Access in Enumeration

Private Sub WebView21_NavigationStarting(ByVal Uri As String, _
    ByVal IsUserInitiated As Boolean, ByVal IsRedirected As Boolean, _
    ByVal RequestHeaders As WebView2RequestHeaders, ByRef Cancel As Boolean)

    Dim header As WebView2Header
    For Each header In RequestHeaders
        Debug.Print "Name: " & header.Name
        Debug.Print "Value: " & header.Value
        Debug.Print "---"
    Next
End Sub

3. Header Validation

Private Function ValidateHeader(ByVal header As WebView2Header) As Boolean
    ' Check if header name is valid
    If Len(header.Name) = 0 Then
        Debug.Print "Error: Header name is empty"
        ValidateHeader = False
        Exit Function
    End If

    ' Check if header name contains illegal characters
    Dim invalidChars As String
    invalidChars = "()<>@,;:\""/[]?={} \t"

    Dim i As Long
    For i = 1 To Len(invalidChars)
        If InStr(header.Name, Mid(invalidChars, i, 1)) > 0 Then
            Debug.Print "Error: Header name contains illegal characters"
            ValidateHeader = False
            Exit Function
        End If
    Next

    ValidateHeader = True
End Function

' Usage example
Dim testHeader As New WebView2Header("Invalid-Name()", "value")
If Not ValidateHeader(testHeader) Then
    Debug.Print "Header validation failed"
End If

4. Header Conversion

' Convert header object to string
Function HeaderToString(ByVal header As WebView2Header) As String
    HeaderToString = header.Name & ": " & header.Value
End Function

' Usage example
Dim header As New WebView2Header("Content-Type", "application/json")
Debug.Print HeaderToString(header)
' Output: Content-Type: application/json

' Convert header object array to string
Function HeadersToString(headers() As WebView2Header) As String
    Dim result As String
    Dim i As Long

    For i = LBound(headers) To UBound(headers)
        result = result & headers(i).Name & ": " & headers(i).Value & vbCrLf
    Next

    HeadersToString = result
End Function

5. Header Filtering

' Filter specific headers
Private Sub FilterHeaders(ByVal RequestHeaders As WebView2RequestHeaders)
    Dim header As WebView2Header

    For Each header In RequestHeaders
        Select Case LCase(header.Name)
            Case "authorization"
                Debug.Print "Found authorization header: " & Left(header.Value, 10) & "..."
            Case "cookie"
                Debug.Print "Found Cookie header"
            Case "user-agent"
                Debug.Print "User Agent: " & header.Value
        End Select
    Next
End Sub

6. Header Cloning

' Clone header object
Function CloneHeader(ByVal header As WebView2Header) As WebView2Header
    Set CloneHeader = New WebView2Header(header.Name, header.Value)
End Function

' Clone header object array
Function CloneHeaders(headers() As WebView2Header) As WebView2Header()
    Dim result() As WebView2Header
    ReDim result(UBound(headers))

    Dim i As Long
    For i = LBound(headers) To UBound(headers)
        Set result(i) = CloneHeader(headers(i))
    Next

    CloneHeaders = result
End Function

' Usage example
Dim originalHeader As New WebView2Header("X-Custom", "value1")
Dim clonedHeader As WebView2Header
Set clonedHeader = CloneHeader(originalHeader)

' Modifying clone doesn't affect original object
clonedHeader.Value = "value2"
Debug.Print originalHeader.Value  ' Output: value1
Debug.Print clonedHeader.Value   ' Output: value2

7. Header Comparison

' Compare two header objects
Function HeadersEqual(ByVal header1 As WebView2Header, _
                      ByVal header2 As WebView2Header) As Boolean
    HeadersEqual = (LCase(header1.Name) = LCase(header2.Name) And _
                    header1.Value = header2.Value)
End Function

' Usage example
Dim header1 As New WebView2Header("Content-Type", "application/json")
Dim header2 As New WebView2Header("Content-Type", "application/json")
Dim header3 As New WebView2Header("content-type", "application/json")  ' Different case

Debug.Print HeadersEqual(header1, header2)  ' Output: True
Debug.Print HeadersEqual(header1, header3)  ' Output: True (case-insensitive name)

8. Header Collection Operations

' Find header
Function FindHeader(headers() As WebView2Header, ByVal name As String) As WebView2Header
    Dim i As Long
    For i = LBound(headers) To UBound(headers)
        If LCase(headers(i).Name) = LCase(name) Then
            Set FindHeader = headers(i)
            Exit Function
        End If
    Next
    Set FindHeader = Nothing
End Function

' Add header (if doesn't exist)
Sub AddHeaderIfNotExists(headers() As WebView2Header, _
                          ByVal name As String, ByVal value As String)
    If FindHeader(headers, name) Is Nothing Then
        Dim newSize As Long
        newSize = UBound(headers) + 1
        ReDim Preserve headers(newSize)
        Set headers(newSize) = New WebView2Header(name, value)
    End If
End Sub

' Usage example
Dim headers() As WebView2Header
ReDim headers(0)
Set headers(0) = New WebView2Header("Content-Type", "text/html")

AddHeaderIfNotExists headers, "Content-Type", "application/json"
AddHeaderIfNotExists headers, "Authorization", "Bearer token"

Debug.Print "Header count: " & UBound(headers) + 1  ' Output: 2

Common HTTP Header Types

Request Headers

Dim userAgent As New WebView2Header("User-Agent", "MyApp/1.0")
Dim accept As New WebView2Header("Accept", "application/json")
Dim contentType As New WebView2Header("Content-Type", "application/json")
Dim authorization As New WebView2Header("Authorization", "Bearer token123")
Dim cookie As New WebView2Header("Cookie", "session_id=abc123")

Response Headers

Dim contentType As New WebView2Header("Content-Type", "text/html; charset=utf-8")
Dim contentLength As New WebView2Header("Content-Length", "1024")
Dim cacheControl As New WebView2Header("Cache-Control", "no-cache")
Dim setCookie As New WebView2Header("Set-Cookie", "session_id=xyz789; Path=/; HttpOnly")
Dim server As New WebView2Header("Server", "MyServer/1.0")

Security Headers

Dim xContentTypeOptions As New WebView2Header("X-Content-Type-Options", "nosniff")
Dim xFrameOptions As New WebView2Header("X-Frame-Options", "DENY")
Dim xXssProtection As New WebView2Header("X-XSS-Protection", "1; mode=block")
Dim strictTransportSecurity As New WebView2Header("Strict-Transport-Security", "max-age=31536000")

CORS Headers

Dim accessControlAllowOrigin As New WebView2Header("Access-Control-Allow-Origin", "*")
Dim accessControlAllowMethods As New WebView2Header("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE")
Dim accessControlAllowHeaders As New WebView2Header("Access-Control-Allow-Headers", "Content-Type, Authorization")

Notes

  1. Case Sensitivity: HTTP header names are case-insensitive, use LCase or UCase functions when comparing.

  2. Space Handling: Spaces in header names and values are significant, don't trim them arbitrarily.

  3. Multi-value Headers: Some headers may have multiple values (such as Set-Cookie), WebView2Header only stores a single value, multiple values need multiple WebView2Header objects.

  4. Special Characters: Header names should avoid containing special characters, some characters are illegal.

  5. Length Limits: HTTP headers have length limits (usually 8KB or more), overly long headers may cause issues.

  6. Encoding Issues: Header values are typically ASCII characters, non-ASCII characters may need encoding.

  7. Read-only Properties: WebView2Header objects obtained in WebResourceRequested event are read-only, modifications won't affect the actual request. To modify headers, use RequestHeaders or ResponseHeaders object methods.

  8. Object Lifecycle: WebView2Header objects are typically created and managed by WebView2HeadersCollection, no need for manual creation and destruction.