C# HttpClient (How It Works For Developers)
The HttpClient class, part of the .NET framework, provides methods to send HTTP requests and receive HTTP responses from a resource identified by a URI. It simplifies making HTTP request calls, whether you're performing GET, POST, PUT, or DELETE requests. This guide will cover the essential usage of HttpClient in practical scenarios and introduce the IronPDF library.
Creating a New HttpClient Instance
The HttpClient class is used to send HTTP requests. You can create a new instance of it as follows:
using System;
using System.Net.Http;
using System.Threading.Tasks;
class Program
{
static async Task Main(string[] args)
{
using var client = new HttpClient(); // Create a new instance of HttpClient
// Send a GET request to the specified URI and store the HTTP response
var response = await client.GetAsync("https://api.weatherapi.com/v1/current.json?key=YOUR_API_KEY&q=London");
// Retrieve the response content as a string
var responseBody = await response.Content.ReadAsStringAsync();
// Print the response content to the console
Console.WriteLine(responseBody);
}
}
using System;
using System.Net.Http;
using System.Threading.Tasks;
class Program
{
static async Task Main(string[] args)
{
using var client = new HttpClient(); // Create a new instance of HttpClient
// Send a GET request to the specified URI and store the HTTP response
var response = await client.GetAsync("https://api.weatherapi.com/v1/current.json?key=YOUR_API_KEY&q=London");
// Retrieve the response content as a string
var responseBody = await response.Content.ReadAsStringAsync();
// Print the response content to the console
Console.WriteLine(responseBody);
}
}
Imports System
Imports System.Net.Http
Imports System.Threading.Tasks
Friend Class Program
Shared Async Function Main(ByVal args() As String) As Task
Dim client = New HttpClient() ' Create a new instance of HttpClient
' Send a GET request to the specified URI and store the HTTP response
Dim response = Await client.GetAsync("https://api.weatherapi.com/v1/current.json?key=YOUR_API_KEY&q=London")
' Retrieve the response content as a string
Dim responseBody = Await response.Content.ReadAsStringAsync()
' Print the response content to the console
Console.WriteLine(responseBody)
End Function
End Class
In this example:
- A new HttpClient instance is created using
var client = new HttpClient()
. - An HTTP GET request is sent using the
GetAsync
method. - The
HttpResponseMessage
is stored invar response
. - The content of the response is retrieved using
response.Content.ReadAsStringAsync()
.
Sending HTTP Requests
HTTP GET Request
To make an HTTP GET request and handle the response:
using System;
using System.Net.Http;
using System.Threading.Tasks;
class Example
{
static async Task Main(string[] args)
{
var client = new HttpClient();
var response = await client.GetAsync("https://api.weatherapi.com/v1/current.json?key=YOUR_API_KEY&q=Paris");
// Check if the request was successful
if (response.IsSuccessStatusCode)
{
var responseBody = await response.Content.ReadAsStringAsync();
Console.WriteLine(responseBody);
}
}
}
using System;
using System.Net.Http;
using System.Threading.Tasks;
class Example
{
static async Task Main(string[] args)
{
var client = new HttpClient();
var response = await client.GetAsync("https://api.weatherapi.com/v1/current.json?key=YOUR_API_KEY&q=Paris");
// Check if the request was successful
if (response.IsSuccessStatusCode)
{
var responseBody = await response.Content.ReadAsStringAsync();
Console.WriteLine(responseBody);
}
}
}
Imports System
Imports System.Net.Http
Imports System.Threading.Tasks
Friend Class Example
Shared Async Function Main(ByVal args() As String) As Task
Dim client = New HttpClient()
Dim response = Await client.GetAsync("https://api.weatherapi.com/v1/current.json?key=YOUR_API_KEY&q=Paris")
' Check if the request was successful
If response.IsSuccessStatusCode Then
Dim responseBody = Await response.Content.ReadAsStringAsync()
Console.WriteLine(responseBody)
End If
End Function
End Class
- The
IsSuccessStatusCode
property ensures that the request was successful. - The response body is read asynchronously with
ReadAsStringAsync()
.
HTTP POST Request
Sending a POST request involves adding a request body:
using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
class Example
{
static async Task Main(string[] args)
{
var client = new HttpClient();
var requestBody = new StringContent("{ \"location\": \"New York\" }", Encoding.UTF8, "application/json");
// Send the POST request with the specified body
var response = await client.PostAsync("https://api.weatherapi.com/v1/forecast.json?key=YOUR_API_KEY", requestBody);
// Check if the request was successful
if (response.IsSuccessStatusCode)
{
var responseBody = await response.Content.ReadAsStringAsync();
Console.WriteLine(responseBody);
}
}
}
using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
class Example
{
static async Task Main(string[] args)
{
var client = new HttpClient();
var requestBody = new StringContent("{ \"location\": \"New York\" }", Encoding.UTF8, "application/json");
// Send the POST request with the specified body
var response = await client.PostAsync("https://api.weatherapi.com/v1/forecast.json?key=YOUR_API_KEY", requestBody);
// Check if the request was successful
if (response.IsSuccessStatusCode)
{
var responseBody = await response.Content.ReadAsStringAsync();
Console.WriteLine(responseBody);
}
}
}
Imports System
Imports System.Net.Http
Imports System.Text
Imports System.Threading.Tasks
Friend Class Example
Shared Async Function Main(ByVal args() As String) As Task
Dim client = New HttpClient()
Dim requestBody = New StringContent("{ ""location"": ""New York"" }", Encoding.UTF8, "application/json")
' Send the POST request with the specified body
Dim response = Await client.PostAsync("https://api.weatherapi.com/v1/forecast.json?key=YOUR_API_KEY", requestBody)
' Check if the request was successful
If response.IsSuccessStatusCode Then
Dim responseBody = Await response.Content.ReadAsStringAsync()
Console.WriteLine(responseBody)
End If
End Function
End Class
PostAsync
sends the request with the specified body (requestBody
).- The content type must be specified (application/json).
HTTP PUT Request
An HTTP PUT request updates resources:
using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
class Example
{
static async Task Main(string[] args)
{
var client = new HttpClient();
var requestBody = new StringContent("{ \"location\": \"Tokyo\", \"days\": 3 }", Encoding.UTF8, "application/json");
// Send a PUT request to update the resource
var response = await client.PutAsync("https://api.weatherapi.com/v1/forecast.json?key=YOUR_API_KEY", requestBody);
// Check if the request was successful
if (response.IsSuccessStatusCode)
{
var responseBody = await response.Content.ReadAsStringAsync();
Console.WriteLine(responseBody);
}
}
}
using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
class Example
{
static async Task Main(string[] args)
{
var client = new HttpClient();
var requestBody = new StringContent("{ \"location\": \"Tokyo\", \"days\": 3 }", Encoding.UTF8, "application/json");
// Send a PUT request to update the resource
var response = await client.PutAsync("https://api.weatherapi.com/v1/forecast.json?key=YOUR_API_KEY", requestBody);
// Check if the request was successful
if (response.IsSuccessStatusCode)
{
var responseBody = await response.Content.ReadAsStringAsync();
Console.WriteLine(responseBody);
}
}
}
Imports System
Imports System.Net.Http
Imports System.Text
Imports System.Threading.Tasks
Friend Class Example
Shared Async Function Main(ByVal args() As String) As Task
Dim client = New HttpClient()
Dim requestBody = New StringContent("{ ""location"": ""Tokyo"", ""days"": 3 }", Encoding.UTF8, "application/json")
' Send a PUT request to update the resource
Dim response = Await client.PutAsync("https://api.weatherapi.com/v1/forecast.json?key=YOUR_API_KEY", requestBody)
' Check if the request was successful
If response.IsSuccessStatusCode Then
Dim responseBody = Await response.Content.ReadAsStringAsync()
Console.WriteLine(responseBody)
End If
End Function
End Class
PutAsync
sends a PUT request to update the resource at the specified URI.- The request body typically contains the data to be updated.
HTTP DELETE Request
To send an HTTP DELETE request:
using System;
using System.Net.Http;
using System.Threading.Tasks;
class Example
{
static async Task Main(string[] args)
{
var client = new HttpClient();
// Send a DELETE request to remove the resource
var response = await client.DeleteAsync("https://api.weatherapi.com/v1/locations/1?key=YOUR_API_KEY");
// Check if the request was successful
if (response.IsSuccessStatusCode)
{
Console.WriteLine("Resource deleted successfully");
}
}
}
using System;
using System.Net.Http;
using System.Threading.Tasks;
class Example
{
static async Task Main(string[] args)
{
var client = new HttpClient();
// Send a DELETE request to remove the resource
var response = await client.DeleteAsync("https://api.weatherapi.com/v1/locations/1?key=YOUR_API_KEY");
// Check if the request was successful
if (response.IsSuccessStatusCode)
{
Console.WriteLine("Resource deleted successfully");
}
}
}
Imports System
Imports System.Net.Http
Imports System.Threading.Tasks
Friend Class Example
Shared Async Function Main(ByVal args() As String) As Task
Dim client = New HttpClient()
' Send a DELETE request to remove the resource
Dim response = Await client.DeleteAsync("https://api.weatherapi.com/v1/locations/1?key=YOUR_API_KEY")
' Check if the request was successful
If response.IsSuccessStatusCode Then
Console.WriteLine("Resource deleted successfully")
End If
End Function
End Class
DeleteAsync
sends a DELETE request to remove the resource.
Handling HTTP Responses
Each HTTP request returns an HttpResponseMessage object, which includes the response body, headers, and status code. For example:
using System;
using System.Net.Http;
using System.Threading.Tasks;
class Example
{
static async Task Main(string[] args)
{
var client = new HttpClient();
var response = await client.GetAsync("https://api.weatherapi.com/v1/current.json?key=YOUR_API_KEY&q=Sydney");
// Check if the request was successful
if (response.IsSuccessStatusCode)
{
var responseBody = await response.Content.ReadAsStringAsync();
Console.WriteLine(responseBody);
}
else
{
Console.WriteLine($"Error: {response.StatusCode}");
}
}
}
using System;
using System.Net.Http;
using System.Threading.Tasks;
class Example
{
static async Task Main(string[] args)
{
var client = new HttpClient();
var response = await client.GetAsync("https://api.weatherapi.com/v1/current.json?key=YOUR_API_KEY&q=Sydney");
// Check if the request was successful
if (response.IsSuccessStatusCode)
{
var responseBody = await response.Content.ReadAsStringAsync();
Console.WriteLine(responseBody);
}
else
{
Console.WriteLine($"Error: {response.StatusCode}");
}
}
}
Imports System
Imports System.Net.Http
Imports System.Threading.Tasks
Friend Class Example
Shared Async Function Main(ByVal args() As String) As Task
Dim client = New HttpClient()
Dim response = Await client.GetAsync("https://api.weatherapi.com/v1/current.json?key=YOUR_API_KEY&q=Sydney")
' Check if the request was successful
If response.IsSuccessStatusCode Then
Dim responseBody = Await response.Content.ReadAsStringAsync()
Console.WriteLine(responseBody)
Else
Console.WriteLine($"Error: {response.StatusCode}")
End If
End Function
End Class
Response.StatusCode
provides the status code (e.g., 200, 404).response.Content
contains the response body, which can be read asynchronously usingReadAsStringAsync()
.
Efficient Usage of HttpClient
HttpClient instances should be reused to exploit connection pooling and avoid exhausting system resources. A typical pattern is to create a single HttpClient instance for the lifetime of your application or service. This can be done using a static variable or dependency injection for web applications.
Static HttpClient Example
public static class HttpClientProvider
{
private static readonly HttpClient client = new HttpClient();
public static HttpClient Client => client;
}
public static class HttpClientProvider
{
private static readonly HttpClient client = new HttpClient();
public static HttpClient Client => client;
}
Public Module HttpClientProvider
'INSTANT VB NOTE: The field client was renamed since Visual Basic does not allow fields to have the same name as other class members:
Private ReadOnly client_Conflict As New HttpClient()
Public ReadOnly Property Client() As HttpClient
Get
Return client_Conflict
End Get
End Property
End Module
The HttpClient instance is reused across the application, reducing the overhead of creating new HTTP connections.
Using HttpClient with Dependency Injection
In a web application, the recommended approach is to register HttpClient as a singleton service:
public void ConfigureServices(IServiceCollection services)
{
services.AddHttpClient();
}
public void ConfigureServices(IServiceCollection services)
{
services.AddHttpClient();
}
Public Sub ConfigureServices(ByVal services As IServiceCollection)
services.AddHttpClient()
End Sub
You can also create named clients and typed clients for more specific configurations.
Connection Pooling and Proxy Settings
By reusing HttpClient instances, you benefit from connection pooling, which improves the performance of multiple requests to the same server. You can also configure proxy settings using the HttpClientHandler class:
using System.Net;
using System.Net.Http;
var handler = new HttpClientHandler
{
Proxy = new WebProxy("http://proxyserver:port"), // Set the proxy server
UseProxy = true
};
var client = new HttpClient(handler);
using System.Net;
using System.Net.Http;
var handler = new HttpClientHandler
{
Proxy = new WebProxy("http://proxyserver:port"), // Set the proxy server
UseProxy = true
};
var client = new HttpClient(handler);
Imports System.Net
Imports System.Net.Http
Private handler = New HttpClientHandler With {
.Proxy = New WebProxy("http://proxyserver:port"),
.UseProxy = True
}
Private client = New HttpClient(handler)
Error Handling and Status Codes
To handle different HTTP status codes, check the HttpResponseMessage.StatusCode property:
using System;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
async Task MakeRequestAsync()
{
try
{
using var client = new HttpClient();
var response = await client.GetAsync("https://api.weatherapi.com/v1/current.json?key=YOUR_API_KEY&q=Berlin");
// Handle the response based on the status code
switch (response.StatusCode)
{
case HttpStatusCode.OK:
Console.WriteLine("Success");
var content = await response.Content.ReadAsStringAsync();
Console.WriteLine($"Response content: {content}");
break;
case HttpStatusCode.NotFound:
Console.WriteLine("Resource not found");
break;
case HttpStatusCode.Unauthorized:
Console.WriteLine("Unauthorized access");
break;
case HttpStatusCode.InternalServerError:
Console.WriteLine("Server error occurred");
break;
default:
Console.WriteLine($"Unexpected status code: {response.StatusCode}");
break;
}
}
catch (HttpRequestException e)
{
Console.WriteLine($"Request error: {e.Message}");
}
catch (Exception e)
{
Console.WriteLine($"An error occurred: {e.Message}");
}
}
using System;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
async Task MakeRequestAsync()
{
try
{
using var client = new HttpClient();
var response = await client.GetAsync("https://api.weatherapi.com/v1/current.json?key=YOUR_API_KEY&q=Berlin");
// Handle the response based on the status code
switch (response.StatusCode)
{
case HttpStatusCode.OK:
Console.WriteLine("Success");
var content = await response.Content.ReadAsStringAsync();
Console.WriteLine($"Response content: {content}");
break;
case HttpStatusCode.NotFound:
Console.WriteLine("Resource not found");
break;
case HttpStatusCode.Unauthorized:
Console.WriteLine("Unauthorized access");
break;
case HttpStatusCode.InternalServerError:
Console.WriteLine("Server error occurred");
break;
default:
Console.WriteLine($"Unexpected status code: {response.StatusCode}");
break;
}
}
catch (HttpRequestException e)
{
Console.WriteLine($"Request error: {e.Message}");
}
catch (Exception e)
{
Console.WriteLine($"An error occurred: {e.Message}");
}
}
Imports System
Imports System.Net
Imports System.Net.Http
Imports System.Threading.Tasks
Async Function MakeRequestAsync() As Task
Try
Dim client = New HttpClient()
Dim response = Await client.GetAsync("https://api.weatherapi.com/v1/current.json?key=YOUR_API_KEY&q=Berlin")
' Handle the response based on the status code
Select Case response.StatusCode
Case HttpStatusCode.OK
Console.WriteLine("Success")
Dim content = Await response.Content.ReadAsStringAsync()
Console.WriteLine($"Response content: {content}")
Case HttpStatusCode.NotFound
Console.WriteLine("Resource not found")
Case HttpStatusCode.Unauthorized
Console.WriteLine("Unauthorized access")
Case HttpStatusCode.InternalServerError
Console.WriteLine("Server error occurred")
Case Else
Console.WriteLine($"Unexpected status code: {response.StatusCode}")
End Select
Catch e As HttpRequestException
Console.WriteLine($"Request error: {e.Message}")
Catch e As Exception
Console.WriteLine($"An error occurred: {e.Message}")
End Try
End Function
JSON Response Body Handling
You often work with JSON responses. You can deserialize the response content into a strongly typed object:
using System;
using System.Net.Http;
using System.Text.Json;
using System.Threading.Tasks;
class Example
{
static async Task Main(string[] args)
{
var client = new HttpClient();
var response = await client.GetAsync("https://api.weatherapi.com/v1/current.json?key=YOUR_API_KEY&q=London");
var jsonString = await response.Content.ReadAsStringAsync();
// Deserialize the JSON response into a WeatherResponse object
var weatherResponse = JsonSerializer.Deserialize<WeatherResponse>(jsonString);
Console.WriteLine($"Location: {weatherResponse.Location}, Temperature: {weatherResponse.Temperature}");
}
}
public class WeatherResponse
{
public string Location { get; set; }
public double Temperature { get; set; }
}
using System;
using System.Net.Http;
using System.Text.Json;
using System.Threading.Tasks;
class Example
{
static async Task Main(string[] args)
{
var client = new HttpClient();
var response = await client.GetAsync("https://api.weatherapi.com/v1/current.json?key=YOUR_API_KEY&q=London");
var jsonString = await response.Content.ReadAsStringAsync();
// Deserialize the JSON response into a WeatherResponse object
var weatherResponse = JsonSerializer.Deserialize<WeatherResponse>(jsonString);
Console.WriteLine($"Location: {weatherResponse.Location}, Temperature: {weatherResponse.Temperature}");
}
}
public class WeatherResponse
{
public string Location { get; set; }
public double Temperature { get; set; }
}
Imports System
Imports System.Net.Http
Imports System.Text.Json
Imports System.Threading.Tasks
Friend Class Example
Shared Async Function Main(ByVal args() As String) As Task
Dim client = New HttpClient()
Dim response = Await client.GetAsync("https://api.weatherapi.com/v1/current.json?key=YOUR_API_KEY&q=London")
Dim jsonString = Await response.Content.ReadAsStringAsync()
' Deserialize the JSON response into a WeatherResponse object
Dim weatherResponse = JsonSerializer.Deserialize(Of WeatherResponse)(jsonString)
Console.WriteLine($"Location: {weatherResponse.Location}, Temperature: {weatherResponse.Temperature}")
End Function
End Class
Public Class WeatherResponse
Public Property Location() As String
Public Property Temperature() As Double
End Class
The ReadAsStringAsync()
method simplifies reading JSON content directly into C# objects.
Introducing IronPDF
IronPDF is a .NET PDF library designed to create, manipulate, and convert PDF files in C#. It is widely used for generating high-quality PDFs from HTML, CSS, JavaScript, and other formats. IronPDF offers features such as HTML to PDF conversion, PDF merging, watermarking, and even advanced operations like digital signatures and PDF encryption. It's compatible with various platforms, including Windows, Linux, and macOS, making it a versatile solution for cross-platform development.
Using IronPDF with HttpClient
Combining IronPDF with the HttpClient class in C# is an effective way to generate and manipulate PDF documents from web resources dynamically. For instance, you can retrieve HTML content from a URL via HttpClient and then convert this HTML into a PDF document using IronPDF. This is useful when generating reports, invoices, or any document dynamically based on live web content.
using System;
using System.Net.Http;
using System.Text.Json;
using System.Threading.Tasks;
using IronPdf;
class Program
{
static async Task Main(string[] args)
{
License.LicenseKey = "YOUR_LICENSE_KEY"; // Set your IronPDF license key
using var client = new HttpClient();
var response = await client.GetAsync("https://api.weatherapi.com/v1/forecast.json?key=YOUR_API_KEY&q=London&days=3");
// Check if the request was successful
if (response.IsSuccessStatusCode)
{
var jsonContent = await response.Content.ReadAsStringAsync();
var jsonElement = JsonSerializer.Deserialize<JsonElement>(jsonContent);
// Format the JSON content for pretty-printing
var formattedJson = JsonSerializer.Serialize(jsonElement, new JsonSerializerOptions { WriteIndented = true });
// Escape the JSON for HTML
formattedJson = System.Web.HttpUtility.HtmlEncode(formattedJson);
// Create an HTML string for PDF generation
var htmlContent = $@"
<html>
<head>
<style>
body {{ font-family: Arial, sans-serif; }}
pre {{ background-color: #f4f4f4; padding: 20px; border-radius: 5px; white-space: pre-wrap; word-wrap: break-word; }}
</style>
</head>
<body>
<h1>Weather Forecast (JSON Data)</h1>
<pre>{formattedJson}</pre>
</body>
</html>";
// Generate the PDF from the HTML content
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf(htmlContent);
// Save the PDF to a file
pdf.SaveAs("F://weather_report.pdf");
Console.WriteLine("PDF generated successfully!");
}
else
{
Console.WriteLine($"Failed to retrieve content. Status code: {response.StatusCode}");
}
}
}
using System;
using System.Net.Http;
using System.Text.Json;
using System.Threading.Tasks;
using IronPdf;
class Program
{
static async Task Main(string[] args)
{
License.LicenseKey = "YOUR_LICENSE_KEY"; // Set your IronPDF license key
using var client = new HttpClient();
var response = await client.GetAsync("https://api.weatherapi.com/v1/forecast.json?key=YOUR_API_KEY&q=London&days=3");
// Check if the request was successful
if (response.IsSuccessStatusCode)
{
var jsonContent = await response.Content.ReadAsStringAsync();
var jsonElement = JsonSerializer.Deserialize<JsonElement>(jsonContent);
// Format the JSON content for pretty-printing
var formattedJson = JsonSerializer.Serialize(jsonElement, new JsonSerializerOptions { WriteIndented = true });
// Escape the JSON for HTML
formattedJson = System.Web.HttpUtility.HtmlEncode(formattedJson);
// Create an HTML string for PDF generation
var htmlContent = $@"
<html>
<head>
<style>
body {{ font-family: Arial, sans-serif; }}
pre {{ background-color: #f4f4f4; padding: 20px; border-radius: 5px; white-space: pre-wrap; word-wrap: break-word; }}
</style>
</head>
<body>
<h1>Weather Forecast (JSON Data)</h1>
<pre>{formattedJson}</pre>
</body>
</html>";
// Generate the PDF from the HTML content
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf(htmlContent);
// Save the PDF to a file
pdf.SaveAs("F://weather_report.pdf");
Console.WriteLine("PDF generated successfully!");
}
else
{
Console.WriteLine($"Failed to retrieve content. Status code: {response.StatusCode}");
}
}
}
Imports System
Imports System.Net.Http
Imports System.Text.Json
Imports System.Threading.Tasks
Imports IronPdf
Friend Class Program
Shared Async Function Main(ByVal args() As String) As Task
License.LicenseKey = "YOUR_LICENSE_KEY" ' Set your IronPDF license key
Dim client = New HttpClient()
Dim response = Await client.GetAsync("https://api.weatherapi.com/v1/forecast.json?key=YOUR_API_KEY&q=London&days=3")
' Check if the request was successful
If response.IsSuccessStatusCode Then
Dim jsonContent = Await response.Content.ReadAsStringAsync()
Dim jsonElement = JsonSerializer.Deserialize(Of JsonElement)(jsonContent)
' Format the JSON content for pretty-printing
Dim formattedJson = JsonSerializer.Serialize(jsonElement, New JsonSerializerOptions With {.WriteIndented = True})
' Escape the JSON for HTML
formattedJson = System.Web.HttpUtility.HtmlEncode(formattedJson)
' Create an HTML string for PDF generation
Dim htmlContent = $"
<html>
<head>
<style>
body {{ font-family: Arial, sans-serif; }}
pre {{ background-color: #f4f4f4; padding: 20px; border-radius: 5px; white-space: pre-wrap; word-wrap: break-word; }}
</style>
</head>
<body>
<h1>Weather Forecast (JSON Data)</h1>
<pre>{formattedJson}</pre>
</body>
</html>"
' Generate the PDF from the HTML content
Dim renderer = New ChromePdfRenderer()
Dim pdf = renderer.RenderHtmlAsPdf(htmlContent)
' Save the PDF to a file
pdf.SaveAs("F://weather_report.pdf")
Console.WriteLine("PDF generated successfully!")
Else
Console.WriteLine($"Failed to retrieve content. Status code: {response.StatusCode}")
End If
End Function
End Class
Remember to replace "YOUR_API_KEY" with an API key when using a real weather API.
Conclusion
This tutorial explored using the HttpClient class in C# to send HTTP requests and handle responses. We also introduced IronPDF, a powerful library for generating PDFs in .NET applications. We demonstrated how to combine these technologies by retrieving HTML content from a web service using HttpClient and converting it to PDF using IronPDF.
IronPDF offers a free trial, and its licenses start at $749, making it a valuable tool for developers seeking comprehensive PDF generation capabilities.
Frequently Asked Questions
How can I convert HTML content to PDF in C#?
You can use IronPDF to convert HTML content to PDF by utilizing its methods like RenderHtmlAsPdf
. This allows you to easily transform HTML strings, complete with CSS and JavaScript, into professional PDF documents.
How do I combine HttpClient with PDF generation in C#?
By integrating HttpClient with IronPDF, you can retrieve HTML content from web resources and then convert that content into PDF documents using IronPDF's conversion methods. This is particularly useful for creating reports or invoices from real-time data.
What is the importance of reusing HttpClient instances?
Reusing HttpClient instances is crucial for efficient resource management. It leverages connection pooling, minimizing the overhead of creating new connections for each request, which enhances the performance of applications.
How can I deserialize JSON responses in C#?
In C#, JSON responses can be deserialized using the JsonSerializer
class. After retrieving the response content as a string, you can use JsonSerializer.Deserialize
to convert it into a strongly typed C# object.
What are the best practices for handling HTTP status codes in C#?
Handling HTTP status codes in C# involves checking the StatusCode
property of the HttpResponseMessage
. Use conditional statements to manage specific codes, such as HttpStatusCode.OK
or HttpStatusCode.NotFound
, to implement appropriate error handling.
How does IronPDF enhance .NET applications with PDF capabilities?
IronPDF enhances .NET applications by providing robust tools for creating, manipulating, and converting PDF files. It supports high-quality PDF generation from HTML, CSS, and JavaScript, offering developers the ability to produce dynamic documents with ease.
Can I use HttpClient to fetch HTML content for PDF conversion?
Yes, HttpClient can fetch HTML content from web resources, which can then be converted into a PDF using IronPDF. This approach is excellent for generating PDFs from live web data or dynamic content.
How do I configure proxy settings for HttpClient in C#?
To configure proxy settings for HttpClient, you can use the HttpClientHandler
class. Set the Proxy
property to a WebProxy
instance and enable the UseProxy
option when creating the HttpClient instance.