C# URL Encode（開発者向けの動作方法）

URL Encoding in C#

When you encode a URL, you change its characters into a form that can be safely sent across the internet, avoiding any misunderstandings. This is because URLs can only be sent over the Internet using the ASCII character set. Characters that aren't part of this set, or have special meanings in URLs (like spaces, ampersands, and equals signs), need to be represented using percent-encoding (e.g., spaces become %20). C# provides built-in methods to accomplish this task.

URL Decoding in C#

URL decoding transforms encoded characters back to their original state upon arrival at their destination. This is essential for the receiving application to correctly understand and process the data as intended. Decoding turns the percent-encoded characters back into their original symbols, making the data readable and usable again.

Encoding Methods in C#

In C#, there are multiple ways to perform URL encoding, each suited for different scenarios. These methods are primarily found within the System.Web and System.Net namespaces, offering developers flexibility in how they encode URLs. Here's a brief overview of the methods available:

1. HttpUtility.UrlEncode Method (System.Web): This is perhaps the most commonly used method for URL encoding in a web application. It converts characters into a percent-encoded format, making the string safe for transmission over the URL. It's especially useful in ASP.NET projects for encoding query strings and form parameters.
2. HttpUtility.UrlPathEncode Method (System.Web): Unlike UrlEncode, UrlPathEncode is designed specifically for encoding the path portion of a URL, leaving the query string untouched. It's important to note that this method does not encode the entire URL but rather the path part, ensuring that the hierarchical structure of the URL is preserved.
3. Uri.EscapeUriString Method (System): This method is intended for escaping URI strings, turning all characters that are not allowed in a URI into their percent-encoded equivalents. However, it does not encode certain characters, such as the slash (/) and question mark (?), because they are considered valid URI characters.
4. Uri.EscapeDataString Method (System): This method is designed for encoding a string to be used in a query part of a URI. It encodes all characters except for the unreserved characters defined in RFC 3986. It's more aggressive than EscapeUriString, ensuring that the data is safely encoded for transmission within URLs.

Let's understand the first three encoding methods as described above, and their working by understanding their code examples.

using System;
using System.Web;

class Program
{
    static void Main()
    {
        string originalPath = "/api/search/Hello World!";
        string encodedPath = UrlEncode(originalPath);

        Console.WriteLine("Original Path: " + originalPath);
        Console.WriteLine("Encoded Path: " + encodedPath);
    }

    public static string UrlEncode(string originalString)
    {
        return HttpUtility.UrlEncode(originalString);
    }
}

using System;
using System.Web;

class Program
{
    static void Main()
    {
        string originalPath = "/api/search/Hello World!";
        string encodedPath = UrlEncode(originalPath);

        Console.WriteLine("Original Path: " + originalPath);
        Console.WriteLine("Encoded Path: " + encodedPath);
    }

    public static string UrlEncode(string originalString)
    {
        return HttpUtility.UrlEncode(originalString);
    }
}

Imports System
Imports System.Web

Friend Class Program
	Shared Sub Main()
		Dim originalPath As String = "/api/search/Hello World!"
		Dim encodedPath As String = UrlEncode(originalPath)

		Console.WriteLine("Original Path: " & originalPath)
		Console.WriteLine("Encoded Path: " & encodedPath)
	End Sub

	Public Shared Function UrlEncode(ByVal originalString As String) As String
		Return HttpUtility.UrlEncode(originalString)
	End Function
End Class

using System;
using System.Web;

class Program
{
    static void Main()
    {
        // Define the original URL path, which includes spaces.
        string originalPath = "/api/search/Hello World!";

        // Use the HttpUtility.UrlPathEncode method to encode the path.
        string encodedPath = HttpUtility.UrlPathEncode(originalPath);

        // Output the original and encoded paths to the console.
        Console.WriteLine("Original Path: " + originalPath);
        Console.WriteLine("Encoded Path: " + encodedPath);
    }
}

using System;
using System.Web;

class Program
{
    static void Main()
    {
        // Define the original URL path, which includes spaces.
        string originalPath = "/api/search/Hello World!";

        // Use the HttpUtility.UrlPathEncode method to encode the path.
        string encodedPath = HttpUtility.UrlPathEncode(originalPath);

        // Output the original and encoded paths to the console.
        Console.WriteLine("Original Path: " + originalPath);
        Console.WriteLine("Encoded Path: " + encodedPath);
    }
}

Imports System
Imports System.Web

Friend Class Program
	Shared Sub Main()
		' Define the original URL path, which includes spaces.
		Dim originalPath As String = "/api/search/Hello World!"

		' Use the HttpUtility.UrlPathEncode method to encode the path.
		Dim encodedPath As String = HttpUtility.UrlPathEncode(originalPath)

		' Output the original and encoded paths to the console.
		Console.WriteLine("Original Path: " & originalPath)
		Console.WriteLine("Encoded Path: " & encodedPath)
	End Sub
End Class

using System;

class Program
{
    static void Main()
    {
        string originalUri = "https://example.com/search?query=Hello World!";
        string escapedUri = Uri.EscapeUriString(originalUri);

        Console.WriteLine("Original URI: " + originalUri);
        Console.WriteLine("Escaped URI: " + escapedUri);
    }
}

using System;

class Program
{
    static void Main()
    {
        string originalUri = "https://example.com/search?query=Hello World!";
        string escapedUri = Uri.EscapeUriString(originalUri);

        Console.WriteLine("Original URI: " + originalUri);
        Console.WriteLine("Escaped URI: " + escapedUri);
    }
}

Imports System

Friend Class Program
	Shared Sub Main()
		Dim originalUri As String = "https://example.com/search?query=Hello World!"
		Dim escapedUri As String = Uri.EscapeUriString(originalUri)

		Console.WriteLine("Original URI: " & originalUri)
		Console.WriteLine("Escaped URI: " & escapedUri)
	End Sub
End Class

IronPDF: C# PDF Library

IronPDF is a PDF library that simplifies creating, editing, and manipulating PDF files within .NET applications. Designed to seamlessly integrate with C# and VB.NET, IronPDF offers developers the functions to generate PDFs from HTML or directly from text. Whether you need to automate invoice generation, create dynamic reports, or manage documents in a .NET environment, IronPDF stands out for its ease of use and comprehensive set of features.

The highlight of IronPDF is its HTML to PDF Conversion feature, maintaining your layouts and styles. This allows for PDF creation from web content, perfect for reports, invoices, and documentation. HTML files, URLs, and HTML strings can be converted to PDFs easily.

using IronPdf;

class Program
{
    static void Main(string[] args)
    {
        var renderer = new ChromePdfRenderer();

        // 1. Convert HTML String to PDF
        var htmlContent = "<h1>Hello, IronPDF!</h1><p>This is a PDF from an HTML string.</p>";
        var pdfFromHtmlString = renderer.RenderHtmlAsPdf(htmlContent);
        pdfFromHtmlString.SaveAs("HTMLStringToPDF.pdf");

        // 2. Convert HTML File to PDF
        var htmlFilePath = "path_to_your_html_file.html"; // Specify the path to your HTML file
        var pdfFromHtmlFile = renderer.RenderHtmlFileAsPdf(htmlFilePath);
        pdfFromHtmlFile.SaveAs("HTMLFileToPDF.pdf");

        // 3. Convert URL to PDF
        var url = "http://ironpdf.com"; // Specify the URL
        var pdfFromUrl = renderer.RenderUrlAsPdf(url);
        pdfFromUrl.SaveAs("URLToPDF.pdf");
    }
}

using IronPdf;

class Program
{
    static void Main(string[] args)
    {
        var renderer = new ChromePdfRenderer();

        // 1. Convert HTML String to PDF
        var htmlContent = "<h1>Hello, IronPDF!</h1><p>This is a PDF from an HTML string.</p>";
        var pdfFromHtmlString = renderer.RenderHtmlAsPdf(htmlContent);
        pdfFromHtmlString.SaveAs("HTMLStringToPDF.pdf");

        // 2. Convert HTML File to PDF
        var htmlFilePath = "path_to_your_html_file.html"; // Specify the path to your HTML file
        var pdfFromHtmlFile = renderer.RenderHtmlFileAsPdf(htmlFilePath);
        pdfFromHtmlFile.SaveAs("HTMLFileToPDF.pdf");

        // 3. Convert URL to PDF
        var url = "http://ironpdf.com"; // Specify the URL
        var pdfFromUrl = renderer.RenderUrlAsPdf(url);
        pdfFromUrl.SaveAs("URLToPDF.pdf");
    }
}

Imports IronPdf

Friend Class Program
	Shared Sub Main(ByVal args() As String)
		Dim renderer = New ChromePdfRenderer()

		' 1. Convert HTML String to PDF
		Dim htmlContent = "<h1>Hello, IronPDF!</h1><p>This is a PDF from an HTML string.</p>"
		Dim pdfFromHtmlString = renderer.RenderHtmlAsPdf(htmlContent)
		pdfFromHtmlString.SaveAs("HTMLStringToPDF.pdf")

		' 2. Convert HTML File to PDF
		Dim htmlFilePath = "path_to_your_html_file.html" ' Specify the path to your HTML file
		Dim pdfFromHtmlFile = renderer.RenderHtmlFileAsPdf(htmlFilePath)
		pdfFromHtmlFile.SaveAs("HTMLFileToPDF.pdf")

		' 3. Convert URL to PDF
		Dim url = "http://ironpdf.com" ' Specify the URL
		Dim pdfFromUrl = renderer.RenderUrlAsPdf(url)
		pdfFromUrl.SaveAs("URLToPDF.pdf")
	End Sub
End Class

Install-Package IronPdf

using System.Web;
using IronPdf;

class Program
{
    static void Main(string[] args)
    {
        License.LicenseKey = "License-Key"; // Set your IronPDF license key
        string baseUrl = "https://example.com/search";

        // The query parameter with spaces that needs to be encoded
        string query = "Hello World!";

        // Encoding the query parameter to ensure the URL is correctly formatted
        string encodedQuery = HttpUtility.UrlEncode(query);

        // Constructing the full URL with the encoded query parameter
        string fullUrl = $"{baseUrl}?query={encodedQuery}";

        // Initialize the IronPDF HtmlToPdf renderer
        var renderer = new ChromePdfRenderer();

        // Convert the web page at the encoded URL to a PDF document
        var pdf = renderer.RenderUrlAsPdf(fullUrl);

        // Save the PDF to a file
        string filePath = "webpage.pdf";
        pdf.SaveAs(filePath);

        Console.WriteLine($"PDF successfully created from: {fullUrl}");
        Console.WriteLine($"Saved to: {filePath}");
    }
}

using System.Web;
using IronPdf;

class Program
{
    static void Main(string[] args)
    {
        License.LicenseKey = "License-Key"; // Set your IronPDF license key
        string baseUrl = "https://example.com/search";

        // The query parameter with spaces that needs to be encoded
        string query = "Hello World!";

        // Encoding the query parameter to ensure the URL is correctly formatted
        string encodedQuery = HttpUtility.UrlEncode(query);

        // Constructing the full URL with the encoded query parameter
        string fullUrl = $"{baseUrl}?query={encodedQuery}";

        // Initialize the IronPDF HtmlToPdf renderer
        var renderer = new ChromePdfRenderer();

        // Convert the web page at the encoded URL to a PDF document
        var pdf = renderer.RenderUrlAsPdf(fullUrl);

        // Save the PDF to a file
        string filePath = "webpage.pdf";
        pdf.SaveAs(filePath);

        Console.WriteLine($"PDF successfully created from: {fullUrl}");
        Console.WriteLine($"Saved to: {filePath}");
    }
}

Imports System.Web
Imports IronPdf

Friend Class Program
	Shared Sub Main(ByVal args() As String)
		License.LicenseKey = "License-Key" ' Set your IronPDF license key
		Dim baseUrl As String = "https://example.com/search"

		' The query parameter with spaces that needs to be encoded
		Dim query As String = "Hello World!"

		' Encoding the query parameter to ensure the URL is correctly formatted
		Dim encodedQuery As String = HttpUtility.UrlEncode(query)

		' Constructing the full URL with the encoded query parameter
		Dim fullUrl As String = $"{baseUrl}?query={encodedQuery}"

		' Initialize the IronPDF HtmlToPdf renderer
		Dim renderer = New ChromePdfRenderer()

		' Convert the web page at the encoded URL to a PDF document
		Dim pdf = renderer.RenderUrlAsPdf(fullUrl)

		' Save the PDF to a file
		Dim filePath As String = "webpage.pdf"
		pdf.SaveAs(filePath)

		Console.WriteLine($"PDF successfully created from: {fullUrl}")
		Console.WriteLine($"Saved to: {filePath}")
	End Sub
End Class

結論

To wrap up, C# provides powerful capabilities for URL encoding and decoding, ensuring data can be securely and efficiently transmitted over the internet. Through the built-in methods within the System.Web and System.Net namespaces, developers can encode URLs to prevent issues with special characters and decode them to their original form for accurate data interpretation.

For those interested in exploring the IronPDF Trial License Offerings, they provide an opportunity to evaluate its functionality firsthand. Should you decide to integrate IronPDF into your projects, licenses start at $799, offering a comprehensive suite of features to meet your PDF manipulation needs within the .NET framework.