Access a HTML Page Using GET and POST HTTP Methods

EVO HTML to PDF Converter allows you to access a HTML page using both GET and POST HTTP Methods. By default the GET method is used by converter to access the HTML page. When you access the page using GET method you can transmit the parameters in query string. When you access the page using the POST method you transmit the parameters in HTTP request form.

When you add one or more items to HtmlToPdfConverterHttpPostFields collection the converter will automatically use the POST HTTP method to access the HTML page to convert.

By default the converter automatically applies application/x-www-form-urlencoded encoding to the names and values in the HtmlToPdfConverterHttpPostFields collection when building the POST request body. If the names and values are already encoded by the caller, the automatic encoding can be disabled by setting the HtmlToPdfConverterEncodeHttpPostFields property to false. The parameters transmitted in query string when using the GET method must still be URL-encoded by the caller.

Code Sample - Access a HTML Page Using GET and POST HTTP Methods

C#
using System;
using System.ComponentModel.DataAnnotations;
using Microsoft.AspNetCore.Mvc;
using EvoPdf_Next_AspNetDemo.Models; 
using EvoPdf_Next_AspNetDemo.Models.HTML_to_PDF;

// Use EVO PDF Namespace
using EvoPdf.Next;

namespace EvoPdf_Next_AspNetDemo.Controllers.HTML_to_PDF
{
    public class GET_and_POST_HTTP_MethodsController : Controller
    {
        public IActionResult Index()
        {
            var model = new GET_and_POST_HTTP_Methods_ViewModel();
            return View(model);
        }

        [HttpPost]
        public ActionResult ConvertHtmlToPdf(GET_and_POST_HTTP_Methods_ViewModel model)
        {
            if (!ModelState.IsValid)
            {
                var errorMessage = ModelStateHelper.GetModelErrors(ModelState);
                throw new ValidationException(errorMessage);
            }

            // Set license key received after purchase to use the converter in licensed mode
            // Leave it not set to use the library in demo mode
            Licensing.LicenseKey = "3FJDU0ZDU0NTQkddQ1NAQl1CQV1KSkpKU0M=";

            // Create a HTML to PDF converter object with default settings
            HtmlToPdfConverter htmlToPdfConverter = new HtmlToPdfConverter();

            // The POST field names and values are automatically form-urlencoded by the converter
            // Set the EncodeHttpPostFields property to false if they are already encoded by the caller
            // The parameters transmitted in query string when using the GET method must be URL-encoded by the caller

            string param1Name = !string.IsNullOrEmpty(model.Param1Name) ? model.Param1Name : "param1";
            string param1Value = !string.IsNullOrEmpty(model.Param1Value) ? model.Param1Value : "Value1";

            string param2Name = !string.IsNullOrEmpty(model.Param2Name) ? model.Param2Name : "param2";
            string param2Value = !string.IsNullOrEmpty(model.Param2Value) ? model.Param2Value : "Value2";

            string param3Name = !string.IsNullOrEmpty(model.Param3Name) ? model.Param3Name : "param3";
            string param3Value = !string.IsNullOrEmpty(model.Param3Value) ? model.Param3Value : "Value3";

            string param4Name = !string.IsNullOrEmpty(model.Param4Name) ? model.Param4Name : "param4";
            string param4Value = !string.IsNullOrEmpty(model.Param4Value) ? model.Param4Value : "Value4";

            string param5Name = !string.IsNullOrEmpty(model.Param5Name) ? model.Param5Name : "param5";
            string param5Value = !string.IsNullOrEmpty(model.Param5Value) ? model.Param5Value : "Value5";

            string urlToConvert = model.Url;

            if (model.HttpMethod == "Post")
            {
                htmlToPdfConverter.HttpPostFields.Add(param1Name, param1Value);
                htmlToPdfConverter.HttpPostFields.Add(param2Name, param2Value);
                htmlToPdfConverter.HttpPostFields.Add(param3Name, param3Value);
                htmlToPdfConverter.HttpPostFields.Add(param4Name, param4Value);
                htmlToPdfConverter.HttpPostFields.Add(param5Name, param5Value);
            }
            else
            {
                Uri getMethodUri = new Uri(model.Url);

                string query = (getMethodUri.Query.Length > 0 ? "&" : "?") + String.Format("{0}={1}", param1Name, param1Value);
                query += String.Format("&{0}={1}", param2Name, param2Value);
                query += String.Format("&{0}={1}", param3Name, param3Value);
                query += String.Format("&{0}={1}", param4Name, param4Value);
                query += String.Format("&{0}={1}", param5Name, param5Value);

                urlToConvert = model.Url + query;
            }

            // Convert the HTML page to a PDF document in a memory buffer
            byte[] outPdfBuffer = htmlToPdfConverter.ConvertUrl(urlToConvert);

            // Send the PDF file to browser
            FileResult fileResult = new FileContentResult(outPdfBuffer, "application/pdf");
            fileResult.FileDownloadName = "GET_and_POST.pdf";

            return fileResult;
        }
    }
}

See Also