Convertir HTML a PDF con autenticación de inicio de sesión en C

// Use this helper method to extract form fields
public Dictionary<string, string> ExtractFormFields(string loginPageHtml)
{
    var formData = new Dictionary<string, string>();
    var doc = new HtmlDocument();
    doc.LoadHtml(loginPageHtml);

    // Find all input fields
    var inputs = doc.DocumentNode.SelectNodes("//input");
    if (inputs != null)
    {
        foreach (var input in inputs)
        {
            string name = input.GetAttributeValue("name", "");
            string value = input.GetAttributeValue("value", "");
            string type = input.GetAttributeValue("type", "text");

            if (!string.IsNullOrEmpty(name))
            {
                // Handle different input types
                switch (type.ToLower())
                {
                    case "checkbox":
                        if (input.Attributes["checked"] != null)
                            formData[name] = "on";
                        break;
                    case "radio":
                        if (input.Attributes["checked"] != null)
                            formData[name] = value;
                        break;
                    default:
                        formData[name] = value;
                        break;
                }
            }
        }
    }

    // Don't forget select elements
    var selects = doc.DocumentNode.SelectNodes("//select");
    if (selects != null)
    {
        foreach (var select in selects)
        {
            string name = select.GetAttributeValue("name", "");
            var selected = select.SelectSingleNode(".//option[@selected]");
            if (selected != null && !string.IsNullOrEmpty(name))
            {
                formData[name] = selected.GetAttributeValue("value", "");
            }
        }
    }

    return formData;
}

Imports HtmlAgilityPack

Public Function ExtractFormFields(loginPageHtml As String) As Dictionary(Of String, String)
    Dim formData As New Dictionary(Of String, String)()
    Dim doc As New HtmlDocument()
    doc.LoadHtml(loginPageHtml)

    ' Find all input fields
    Dim inputs = doc.DocumentNode.SelectNodes("//input")
    If inputs IsNot Nothing Then
        For Each input In inputs
            Dim name As String = input.GetAttributeValue("name", "")
            Dim value As String = input.GetAttributeValue("value", "")
            Dim type As String = input.GetAttributeValue("type", "text")

            If Not String.IsNullOrEmpty(name) Then
                ' Handle different input types
                Select Case type.ToLower()
                    Case "checkbox"
                        If input.Attributes("checked") IsNot Nothing Then
                            formData(name) = "on"
                        End If
                    Case "radio"
                        If input.Attributes("checked") IsNot Nothing Then
                            formData(name) = value
                        End If
                    Case Else
                        formData(name) = value
                End Select
            End If
        Next
    End If

    ' Don't forget select elements
    Dim selects = doc.DocumentNode.SelectNodes("//select")
    If selects IsNot Nothing Then
        For Each selectNode In selects
            Dim name As String = selectNode.GetAttributeValue("name", "")
            Dim selected = selectNode.SelectSingleNode(".//option[@selected]")
            If selected IsNot Nothing AndAlso Not String.IsNullOrEmpty(name) Then
                formData(name) = selected.GetAttributeValue("value", "")
            End If
        Next
    End If

    Return formData
End Function

public string ExtractFormAction(string loginPageUrl, string loginPageHtml)
{
    var doc = new HtmlDocument();
    doc.LoadHtml(loginPageHtml);

    // Find the login form
    var form = doc.DocumentNode.SelectSingleNode("//form[contains(@action, 'login') or contains(@id, 'login') or contains(@class, 'login')]");

    if (form == null)
    {
        // Try finding any form with password field
        form = doc.DocumentNode.SelectSingleNode("//form[.//input[@type='password']]");
    }

    if (form != null)
    {
        string action = form.GetAttributeValue("action", "");

        // Resolve relative URLs
        if (!string.IsNullOrEmpty(action))
        {
            var baseUri = new Uri(loginPageUrl);
            var actionUri = new Uri(baseUri, action);
            return actionUri.ToString();
        }
    }

    // Default to the login page URL if no action found
    return loginPageUrl;
}

Imports System

Public Function ExtractFormAction(loginPageUrl As String, loginPageHtml As String) As String
    Dim doc As New HtmlDocument()
    doc.LoadHtml(loginPageHtml)

    ' Find the login form
    Dim form = doc.DocumentNode.SelectSingleNode("//form[contains(@action, 'login') or contains(@id, 'login') or contains(@class, 'login')]")

    If form Is Nothing Then
        ' Try finding any form with password field
        form = doc.DocumentNode.SelectSingleNode("//form[.//input[@type='password']]")
    End If

    If form IsNot Nothing Then
        Dim action As String = form.GetAttributeValue("action", "")

        ' Resolve relative URLs
        If Not String.IsNullOrEmpty(action) Then
            Dim baseUri As New Uri(loginPageUrl)
            Dim actionUri As New Uri(baseUri, action)
            Return actionUri.ToString()
        End If
    End If

    ' Default to the login page URL if no action found
    Return loginPageUrl
End Function

// Strategies for handling anti-bot measures
var renderer = new ChromePdfRenderer
{
    RenderingOptions = new ChromePdfRenderOptions
    {
        // Mimic real browser behavior
        ViewPortWidth = 1920,
        ViewPortHeight = 1080,
        EnableJavaScript = true,
        RenderDelay = 5000, // Wait for JavaScript

        // Set a real user agent
        CustomHttpHeaders = new Dictionary<string, string>
        {
            {"User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36"}
        }
    }
};

 // For sites with rate limiting, add delays between requests
 System.Threading.Thread.Sleep(2000);

' Strategies for handling anti-bot measures
Dim renderer = New ChromePdfRenderer With {
    .RenderingOptions = New ChromePdfRenderOptions With {
        ' Mimic real browser behavior
        .ViewPortWidth = 1920,
        .ViewPortHeight = 1080,
        .EnableJavaScript = True,
        .RenderDelay = 5000, ' Wait for JavaScript

        ' Set a real user agent
        .CustomHttpHeaders = New Dictionary(Of String, String) From {
            {"User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36"}
        }
    }
}

' For sites with rate limiting, add delays between requests
System.Threading.Thread.Sleep(2000)