simple question: I have an file online (txt). How to read it and check if its there? (C#.net 2.0)
7 Answers
I think the WebClient-class is appropriate for that:
WebClient client = new WebClient();
Stream stream = client.OpenRead("http://yoururl/test.txt");
StreamReader reader = new StreamReader(stream);
String content = reader.ReadToEnd();
http://msdn.microsoft.com/en-us/library/system.net.webclient.openread.aspx
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1Could you fill in the prerequisites for this? I'm getting
The type or namespace name 'WebClient' could not be found
– jbyrdCommented Feb 27, 2018 at 19:33 -
WebClient can be found in System.Net - a quick Google for "dotnet WebClient" usually turns up the Microsoft reference page which tells you the hierarchy. Commented Mar 22, 2021 at 8:50
from http://www.csharp-station.com/HowTo/HttpWebFetch.aspx
HttpWebRequest request = (HttpWebRequest)
WebRequest.Create("myurl");
// execute the request
HttpWebResponse response = (HttpWebResponse)
request.GetResponse();
// we will read data via the response stream
Stream resStream = response.GetResponseStream();
string tempString = null;
int count = 0;
do
{
// fill the buffer with data
count = resStream.Read(buf, 0, buf.Length);
// make sure we read some data
if (count != 0)
{
// translate from bytes to ASCII text
tempString = Encoding.ASCII.GetString(buf, 0, count);
// continue building the string
sb.Append(tempString);
}
}
while (count > 0); // any more data to read?
// print out page source
Console.WriteLine(sb.ToString());
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9Nowadays it's much simpler: just instantiate a
WebClient
and callDownloadString
on it. Commented Mar 20, 2016 at 19:34 -
1Where do the variables
sb
andbuf
come from? Also the link is dead now.– jbyrdCommented Feb 27, 2018 at 19:38 -
1
A little bit easier way:
string fileContent = new WebClient().DownloadString("yourURL");
First, you can download the binary file:
public byte[] GetFileViaHttp(string url)
{
using (WebClient client = new WebClient())
{
return client.DownloadData(url);
}
}
Then you can make array of strings for text file (assuming UTF-8 and that it is a text file):
var result = GetFileViaHttp(@"http://example.com/index.html");
string str = Encoding.UTF8.GetString(result);
string[] strArr = str.Split(new[] { "\r\n" }, StringSplitOptions.RemoveEmptyEntries);
You'll receive every (except empty) line of text in every array field.
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1This is for Windows line ending encoding. If you wish to split lines for Linux use "\n".– pbiesCommented Jul 28, 2016 at 16:40
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better to use new string[] { Environment.NewLine } for generic soltuion Commented Apr 17, 2022 at 22:43
an alternative to HttpWebRequest
is WebClient
// create a new instance of WebClient
WebClient client = new WebClient();
// set the user agent to IE6
client.Headers.Add("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.0.3705;)");
try
{
// actually execute the GET request
string ret = client.DownloadString("http://www.google.com/");
// ret now contains the contents of the webpage
Console.WriteLine("First 256 bytes of response: " + ret.Substring(0,265));
}
catch (WebException we)
{
// WebException.Status holds useful information
Console.WriteLine(we.Message + "\n" + we.Status.ToString());
}
catch (NotSupportedException ne)
{
// other errors
Console.WriteLine(ne.Message);
}
example from http://www.daveamenta.com/2008-05/c-webclient-usage/
This is too much easier:
using System.Net;
using System.IO;
...
using (WebClient client = new WebClient()) {
//... client.options
Stream stream = client.OpenRead("http://.........");
using (StreamReader reader = new StreamReader(stream)) {
string content = reader.ReadToEnd();
}
}
"WebClient" and "StreamReader" are disposables. The content of file will be into "content" var.
The client var contains several configuration options.
The default configuration could be called as:
string content = new WebClient().DownloadString("http://.........");
Look at System.Net.WebClient
, the docs even have an example of retrieving the file.
But testing if the file exists implies asking for the file and catching the exception if it's not there.