How to read XML file without .xml format - c#

so I've created a simple RESTful service with netbeans and produce an XML file in localhost http://localhost:8080/testXML/webresources/entities.categoryid
inside this page is only a simple xml file format:
<categoryids>
<categoryid>
<CategoryID>id1111</CategoryID>
<CategoryName>Study</CategoryName>
</categoryid>
</categoryids>
I'm using C# to read the xml files, put them into dataset and finally datagridview. how do I do this? it works locally (sample.xml) with
ds.ReadXml(Application.StartupPath + "\\XML\\sample.xml", XmlReadMode.Auto);
dv = ds.Tables[0].DefaultView;
however it doesn't work with localhost
ds.ReadXml("http://localhost:8080/testXML/webresources/entities.categoryid", XmlReadMode.Auto);
Are there any way to do this?
edit:
NullRferenceException: Object reference not set to an instance of an object.
indicating that the datagridview is null
edit2: sorry, it's supposed to be "ReadXml" not "WriteXml"

The problem is that your DataSet.ReadXml()-Method can not read from a URL, because you have to send a GET-Request (referring to http://msdn.microsoft.com/en-us/library/system.data.dataset.readxml%28v=vs.80%29.aspx). You need to send a Webrequest to speak with your RESTful-Service:
WebRequest request = WebRequest.Create ("http://localhost:8080/testXML/webresources/entities.categoryid");
request.Credentials = CredentialCache.DefaultCredentials;
HttpWebResponse response = (HttpWebResponse)request.GetResponse ();
Stream dataStream = response.GetResponseStream ();
ds.ReadXml(dataStream);
dataStream.Close();
response.Close();
...
I hope that will work for you.

Related

Getting link from pastebin and downloading from link

I'm trying to get a link from a pastebin. Where the link is the only text in the raw paste. Then I want to download a file from the link in pastebin.
WebRequest request = WebRequest.Create("http://pastebin.com/raw/Dtdf2qMp");
WebResponse response = request.GetResponse();
System.IO.StreamReader reader = new
System.IO.StreamReader(response.GetResponseStream());
Console.WriteLine(reader.ReadToEnd());
WebClient client = new WebClient();
client.DownloadFile (Link gotten from pastebin here, "c:\\File");
System.Threading.Thread.Sleep(5000);
Instead of dumping the text read to console output, you should assign it to a variable.
var pastebinOutput = reader.ReadToEnd();
Then just pass that as the link for the DownloadFile method. If you want to do verification that it's actually a URL you got from the original pastebin, you can look into System.Uri's TryCreate method.
I've got a solution - assuming you have your link in the raw pastebin link (mine is a .txt file saying 'it worked') I suggest you copy and paste the code below exactly - if you get an file saying 'it worked' then you can change the pastebin link & file names. If you don't want to open the file then remove Process.Start - if you want to change the delay just change the number (it's in milliseconds) Also, you can change the format from .txt to .exe or whatever your file is (or you can remove it so its the defualt name in the download link):
WebRequest request = WebRequest.Create("https://pastebin.com/raw/QAWufg1z");
WebResponse response = request.GetResponse();
System.IO.StreamReader reader = new
System.IO.StreamReader(response.GetResponseStream());
var pastebinOutput = reader.ReadToEnd();
WebClient client = new WebClient();
client.DownloadFile(pastebinOutput, #".\downloaded.txt");
MessageBox.Show("File should open automatically in the next minute. Please wait...");
await Task.Delay(3000); //3000 = 3 seconds
Process.Start(#".\downloaded.txt");

Getting JSON data from a response stream and reading it as a string?

I am trying to read a response from a server that I receive when I send a POST request. Viewing fiddler, it says it is a JSON response. How do I decode it to a normal string using C# Winforms with preferably no outside APIs. I can provide additional code/fiddler results if you need them.
The fiddler and gibberish images:
The gibberish came from my attempts to read the stream in the code below:
Stream sw = requirejs.GetRequestStream();
sw.Write(logBytes, 0, logBytes.Length);
sw.Close();
response = (HttpWebResponse)requirejs.GetResponse();
Stream stream = response.GetResponseStream();
StreamReader sr = new StreamReader(stream);
MessageBox.Show(sr.ReadToEnd());
As mentioned in the comments, Newtonsoft.Json is really a good library and worth using -- very lightweight.
If you really want to only use Microsoft's .NET libraries, also consider System.Web.Script.Serialization.JavaScriptSerializer.
var serializer = new System.Web.Script.Serialization.JavaScriptSerializer();
var jsonObject = serializer.DeserializeObject(sr.ReadToEnd());
Going to assume (you haven't clarified yet) that you need to actually decode the stream, since A) retrieving a remote stream of text is well documented, and B) you can't do anything much with a non-decoded JSON stream.
Your best course of action is to implement System.Web.Helpers.Json:
using System.Web.Helpers.Json
...
var jsonObj = Json.Decode(jsonStream);

Reading information from a website c#

In the project I have in mind I want to be able to look at a website, retrieve text from that website, and do something with that information later.
My question is what is the best way to retrieve the data(text) from the website. I am unsure about how to do this when dealing with a static page vs dealing with a dynamic page.
From some searching I found this:
WebRequest request = WebRequest.Create("anysite.com");
// If required by the server, set the credentials.
request.Credentials = CredentialCache.DefaultCredentials;
// Get the response.
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
// Display the status.
Console.WriteLine(response.StatusDescription);
Console.WriteLine();
// Get the stream containing content returned by the server.
using (Stream dataStream = response.GetResponseStream())
{
// Open the stream using a StreamReader for easy access.
StreamReader reader = new StreamReader(dataStream, Encoding.UTF8);
// Read the content.
string responseString = reader.ReadToEnd();
// Display the content.
Console.WriteLine(responseString);
reader.Close();
}
response.Close();
So from running this on my own I can see it returns the html code from a website, not exactly what I'm looking for. I eventually want to be able to type in a site (such as a news article), and return the contents of the article. Is this possible in c# or Java?
Thanks
I hate to brake this to you but that's how webpages looks, it's a long stream of html markup/content. This gets rendered by the browser as what you see on your screen. The only way I can think of is to parse to html by yourself.
After a quick search on google I found this stack overflow article.
What is the best way to parse html in C#?
but I'm betting you figured this would be a bit easier than you expected, but that's the fun in programming always challenging problems
You can just use a WebClient:
using(var webClient = new WebClient())
{
string htmlFromPage = webClient.DownloadString("http://myurl.com");
}
In the above example htmlFromPage will contain the HTML which you can then parse to find the data you're looking for.
What you are describing is called web scraping, and there are plenty of libraries that do just that for both Java and C#. It doesn't really matter if the target site is static or dynamic since both output HTML in the end. JavaScript or Flash heavy sites on the other hand tend to be problematic.
Please try this,
System.Net.WebClient wc = new System.Net.WebClient();
string webData = wc.DownloadString("anysite.com");

Get Size of Image File before downloading from web

I am downloading image files from web using the following code in my Console Application.
WebClient client = new WebClient();
client.DownloadFile(string address_of_image_file,string filename);
The code is running absolutely fine.
I want to know if there is a way i can get the size of this image file before I download it.
PS- Actually I have written code to make a crawler which moves around the site downloading image files. So I doesn't know its size beforehand. All I have is the complete path of file which has been extracted from the source of webpage.
Here is a simple example you can try
if you have files of different extensions like .GIF, .JPG, etc
you can create a variable or wrap the code within a Switch Case Statement
System.Net.WebClient client = new System.Net.WebClient();
client.OpenRead("http://someURL.com/Images/MyImage.jpg");
Int64 bytes_total= Convert.ToInt64(client.ResponseHeaders["Content-Length"])
MessageBox.Show(bytes_total.ToString() + " Bytes");
If the web-service gives you a Content-Length HTTP header then it will be the image file size. However, if the web-service wants to "stream" data to you (using Chunk encoding), then you won't know until the whole file is downloaded.
You can use this code:
using System.Net;
public long GetFileSize(string url)
{
long result = 0;
WebRequest req = WebRequest.Create(url);
req.Method = "HEAD";
using (WebResponse resp = req.GetResponse())
{
if (long.TryParse(resp.Headers.Get("Content-Length"), out long contentLength))
{
result = contentLength;
}
}
return result;
}
You can use an HttpWebRequest to query the HEAD Method of the file and check the Content-Length in the response
You should look at this answer: C# Get http:/…/File Size where your question is fully explained. It's using HEAD HTTP request to retrieve the file size, but you can also read "Content-Length" header during GET request before reading response stream.

FTP - Filename not allowed

I'm trying to upload a file to an FTP server using code based on this Microsoft Article
My code looks like this for testing purposes:
string ftpUrl = "ftp://" + ftpSite + ftpPath + "test.txt";
//string ftpUrl = ftpSite;
FtpWebRequest request = (FtpWebRequest)WebRequest.Create(ftpUrl);
request.Credentials = new NetworkCredential(ftpUsername, ftpPassword);
request.Method = WebRequestMethods.Ftp.UploadFile;
StreamReader srcStream = new StreamReader(filePath);
byte[] fileContents = Encoding.UTF8.GetBytes(srcStream.ReadToEnd());
request.ContentLength = fileContents.Length;
Stream requestStream = request.GetRequestStream();
requestStream.Write(fileContents, 0, fileContents.Length);
requestStream.Close();
FtpWebResponse response = (FtpWebResponse)request.GetResponse();
Every time I try to upload the file, I get a "Filename not allowed" error back from the FTP server. If I use an FTP client application like WS_FTP, I'm able to FTP the same file just fine.
Any thoughts on how to correct this? I've already tried setting active/passive FTP mode, keepalive, and binary modes without any luck.
EDIT
This is a winforms application - the filename comes in from an OpenFileDialog prompt and the FTP address is based on settings in App.Config.
Without seeing your full code, I will say there is a very good chance the constructed FTP URL / path is incorrect, in comparison to what you expect it to be when you manually connect to the FTP site through a FTP client.
If you post your app.config code and how you assign values to ftpSite and ftpPath, it would be helpful in answering this question.
You can get that particular error for many cases.
Most common issue is that the path you are accessing is not valid by the permissions allowed, and using a relative path or changing thew path might get it fixed.

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