I want check that that provided Rss feed Link Is valid or not and is it working right now?
Just load the URL and check that it is actually an RSS feed.
try {
var feedDoc = XDocument.Load(url);
return ValidateRss(feedDoc); // implementation left as an exercise for the reader.
}
catch(HttpException) { // perhaps others
return false;
}
Use below code to check RSS URL:
using System.ServiceModel.Syndication;
public static bool IsValidFeedUrl(string url)
{
bool isValid = true;
try
{
XmlReader reader = XmlReader.Create(url);
Rss20FeedFormatter formatter = new Rss20FeedFormatter();
formatter.ReadFrom(reader);
reader.Close();
}
catch
{
isValid = false;
}
return isValid;
}
Related
I'm using Xamarin.Forms and I am trying to convert an html string to a pdf file using EvoPdfConverter, but the problem is that when I try to do so, on the line htmlToPdfConverter.ConvertHtmlToFile(htmlData, "", myDir.ToString()); in the code snippet below, the app just freezes and does nothing, seems like it wants to connect to the given IP, but it can't, however I don't get any errors or exceptions! not even catch!! does anybody know what I should do to resolve this issue? and here is my code for this:
public void ConvertHtmlToPfd(string htmlData)
{
ServerSocket s = new ServerSocket(0);
HtmlToPdfConverter htmlToPdfConverter = new
HtmlToPdfConverter(GetLocalIPAddress(),(uint)s.LocalPort);
htmlToPdfConverter.TriggeringMode = TriggeringMode.Auto;
htmlToPdfConverter.PdfDocumentOptions.CompressCrossReference = true;
htmlToPdfConverter.PdfDocumentOptions.PdfCompressionLevel = PdfCompressionLevel.Best;
if (ContextCompat.CheckSelfPermission(Android.App.Application.Context, Manifest.Permission.WriteExternalStorage) != Permission.Granted)
{
ActivityCompat.RequestPermissions((Android.App.Activity)Android.App.Application.Context, new String[] { Manifest.Permission.WriteExternalStorage }, 1);
}
if (ContextCompat.CheckSelfPermission(Android.App.Application.Context, Manifest.Permission.ReadExternalStorage) != Permission.Granted)
{
ActivityCompat.RequestPermissions((Android.App.Activity)Android.App.Application.Context, new String[] { Manifest.Permission.ReadExternalStorage }, 1);
}
try
{
// create the HTML to PDF converter object
if (Android.OS.Environment.IsExternalStorageEmulated)
{
root = Android.OS.Environment.ExternalStorageDirectory.ToString();
}
htmlToPdfConverter.LicenseKey = "4W9+bn19bn5ue2B+bn1/YH98YHd3d3c=";
htmlToPdfConverter.PdfDocumentOptions.PdfPageSize = PdfPageSize.A4;
htmlToPdfConverter.PdfDocumentOptions.PdfPageOrientation = PdfPageOrientation.Portrait;
Java.IO.File myDir = new Java.IO.File(root + "/Reports");
try
{
myDir.Mkdir();
}
catch (Exception e)
{
string message = e.Message;
}
Java.IO.File file = new Java.IO.File(myDir, filename);
if (file.Exists()) file.Delete();
htmlToPdfConverter.ConvertHtmlToFile(htmlData, "", myDir.ToString());
}
catch (Exception ex)
{
string message = ex.Message;
}
}
Could you try to set a base URL to ConvertHtmlToFile call as the second parameter? You passed an empty string. That helps to resolve the relative URLs found in HTML to full URLs. The converter might have delays when trying to retrieve content from invalid resources URLs.
I have been looking into phantomJS and looks like it could be a great tool to use generating PDFs. I wonder if anyone have successfully used it for their .NET applications.
My specific question is: how would you use modules like rasterize.js on the server, receive requests and send back generated pdfs as a response.
My general question is: is there any best practice for using phantomJS with .NET Applications. What would be the best way to achieve it?
I am fairly new in .NET World and I would appreciate the more detailed answers. Thanks everyone. :)
I don't know about best practices, but, I'm using phantomJS with no problems with the following code.
public ActionResult DownloadStatement(int id)
{
string serverPath = HttpContext.Server.MapPath("~/Phantomjs/");
string filename = DateTime.Now.ToString("ddMMyyyy_hhmmss") + ".pdf";
new Thread(new ParameterizedThreadStart(x =>
{
ExecuteCommand("cd " + serverPath + #" & phantomjs rasterize.js http://localhost:8080/filetopdf/" + id.ToString() + " " + filename + #" ""A4""");
})).Start();
var filePath = Path.Combine(HttpContext.Server.MapPath("~/Phantomjs/"), filename);
var stream = new MemoryStream();
byte[] bytes = DoWhile(filePath);
return File(bytes, "application/pdf", filename);
}
private void ExecuteCommand(string Command)
{
try
{
ProcessStartInfo ProcessInfo;
Process Process;
ProcessInfo = new ProcessStartInfo("cmd.exe", "/K " + Command);
ProcessInfo.CreateNoWindow = true;
ProcessInfo.UseShellExecute = false;
Process = Process.Start(ProcessInfo);
}
catch { }
}
public ViewResult FileToPDF(int id)
{
var viewModel = file.Get(id);
return View(viewModel);
}
private byte[] DoWhile(string filePath)
{
byte[] bytes = new byte[0];
bool fail = true;
while (fail)
{
try
{
using (FileStream file = new FileStream(filePath, FileMode.Open, FileAccess.Read))
{
bytes = new byte[file.Length];
file.Read(bytes, 0, (int)file.Length);
}
fail = false;
}
catch
{
Thread.Sleep(1000);
}
}
System.IO.File.Delete(filePath);
return bytes;
}
Here is the action flow:
The user clicks on a link to DownloadStatement Action. Inside there, a new Thread is created to call the ExecuteCommand method.
The ExecuteCommand method is responsible to call phantomJS. The string passed as an argument do the following.
Go to the location where the phantomJS app is and, after that, call rasterize.js with an URL, the filename to be created and a print format. (More about rasterize here).
In my case, what I really want to print is the content delivered by the action filetoupload. It's a simple action that returns a simple view. PhantomJS will call the URL passed as parameter and do all the magic.
While phantomJS is still creating the file, (I guess) I can not return the request made by the client. And that is why I used the DoWhile method. It will hold the request until the file is created by phantomJS and loaded by the app to the request.
If you're open to using NReco.PhantomJS, which provides a .NET wrapper for PhantomJS, you can do this very succinctly.
public async Task<ActionResult> DownloadPdf() {
var phantomJS = new PhantomJS();
try {
var temp = Path.Combine(Path.GetTempPath(),
Path.ChangeExtension(Path.GetRandomFileName(), "pdf")); //must end in .pdf
try {
await phantomJS.RunAsync(HttpContext.Server.MapPath("~/Scripts/rasterize.js"),
new[] { "https://www.google.com", temp });
return File(System.IO.File.ReadAllBytes(temp), "application/pdf");
}
finally {
System.IO.File.Delete(temp);
}
}
finally {
phantomJS.Abort();
}
}
Here's some very basic code to generate a PDF using Phantom.JS but you can find more information here: https://buttercms.com/blog/generating-pdfs-with-node
var webPage = require('webpage');
var page = webPage.create();
page.viewportSize = { width: 1920, height: 1080 };
page.open("http://www.google.com", function start(status) {
page.render('google_home.pdf, {format: 'pdf', quality: '100'});
phantom.exit();
});
i need to get the number of subscribers of a youtube channel in my asp.net website, i have searched the documentation (https://developers.google.com/youtube/2.0/developers_guide_protocol_activity_feeds) and i got that i have to put this:
http://gdata.youtube.com/feeds/api/users/PageName
but its not giving anything even when i open it in a browser it wont open any help would be much appreciated.
is there a special library or api i can use?
What you can do is the following:
System.Net.WebClient wb = new System.Net.WebClient();
string str = wb.DownloadString("http://gdata.youtube.com/feeds/api/users/TheNewYorkTimes");
Response.Write(getCount(str));
public static string getCount(string video)
{
if (video.Contains("="))
{
string str = "subscriberCount='";
string videoid = video.Substring(video.IndexOf("subscriberCount") + str.Length);
if (videoid.Contains("'"))
{
videoid = videoid.Remove(videoid.IndexOf("'"));
return videoid;
}
else
{
return "";
}
}
else
{
return "";
}
}
Is there a way how to convert the string to HttpFilePostedBase?
I'm currently using the Ajax File upload . But the value that it return is string. But my method is requesting for HttpFilePostedBase is there a way how to cast or convert it to HttpFilePostedBase?
here's my sample method in uploading files.
public bool uploadfiles(HttpPostedFileBase filedata)
{
bool status = false;
//code for uploading goes here
return status;
}
How can i call this method if the ajax file upload is passing a string?
Are you using IE or Chrome/Firefox? cause, different browsers upload files in a different manner. IE uploads the files through Requres.Files but others use qqfile in the query string.
Take a look here on how to use valums with mvc for different browsers
EDIT: Okay then, how about this. This is an example which worked for me:
public void ControllerUploadHandler()
{
// Set the response return data type
this.Response.ContentType = "text/html";
try
{
// get just the original filename
byte[] buffer = new byte[Request.ContentLength];
if (Request.QueryString["qqfile"] != null)
{
using (BinaryReader br = new BinaryReader(this.Request.InputStream))
br.Read(buffer, 0, buffer.Length);
}
else if (Request.Files.Count > 0)
{
HttpPostedFileBase httpPostedFileBase = Request.Files[0] as HttpPostedFileBase;
using (BinaryReader br = new BinaryReader(httpPostedFileBase.InputStream))
br.Read(buffer, 0, buffer.Length);
}
else
this.Response.Write(" {'success': false }");
// return the json object as successful
this.Response.Write("{ 'success': true }");
this.Response.End();
return;
}
catch (Exception)
{
// return the json object as unsuccessful
this.Response.Write("{ 'success': false }");
this.Response.End();
}
}
You can't. You can access files posted to an aspx page via the HttpContext.Request.Files property.
Ok i have been working non stop on this and doing a lot of searching. I cannot get my images to display when pulling them from the database. If i try going to the handler link manually i get a message saying "The image [Image] cannot be displayed because it contains errors". I had some old images in the database from before and it first displayed those correctly. But now if i update images it will give me this error when trying to view them.
Upload code.
if (fileuploadImage.HasFile)
{
if (IsValidImage(fileuploadImage))
{
int length = fileuploadImage.PostedFile.ContentLength;
byte[] imgbyte = new byte[length];
HttpPostedFile img = fileuploadImage.PostedFile;
img.InputStream.Read(imgbyte, 0, length);
if (mainImage == null)
{
ProfileImage image = new ProfileImage();
image.ImageName = txtImageName.Text;
image.ImageData = imgbyte;
image.ImageType = img.ContentType;
image.MainImage = true;
image.PersonID = personID;
if (image.CreateImage() <= 0)
{
SetError("There was an error uploading this image.");
}
}
else
{
mainImage.ImageName = txtImageName.Text;
mainImage.ImageType = img.ContentType;
mainImage.ImageData = imgbyte;
mainImage.MainImage = true;
mainImage.PersonID = personID;
if (!mainImage.UpdateImage())
{
SetError("There was an error uploading this image.");
}
}
}
else
{
SetError("Not a valid image type.");
}
Here is my image handler:
public class ImageHandler : IHttpHandler
{
public bool IsReusable
{
get
{
return false;
}
}
public void ProcessRequest(HttpContext context)
{
int imageid = Parser.GetInt(context.Request.QueryString["ImID"]);
ProfileImage image = new ProfileImage(Parser.GetInt(imageid));
context.Response.ContentType = image.ImageType;
context.Response.Clear();
context.Response.BinaryWrite(image.ImageData);
context.Response.End();
}
And this is how i'm calling it "~/ImageHandler.ashx?ImID=" + Parser.GetString(image.ImageID)
I'm using the data type Image in sql server to store this.
Edit:
I also found out that if i put a try catch around context.Response.end() it is erroring out saying the "Unable to evaluate the code because the native frame..."
I found my problem. I was checking the header of the actual file to make sure it was valid. Somehow that was altering the data and making it bad.