128

Given a URL in a string:

http://www.example.com/test.xml

What's the easiest/most succinct way to download the contents of the file from the server (pointed to by the url) into a string in C#?

The way I'm doing it at the moment is:

WebRequest request = WebRequest.Create("http://www.example.com/test.xml");
WebResponse response = request.GetResponse();
Stream dataStream = response.GetResponseStream();
StreamReader reader = new StreamReader(dataStream);
string responseFromServer = reader.ReadToEnd();

That's a lot of code that could essentially be one line:

string responseFromServer = ????.GetStringFromUrl("http://www.example.com/test.xml");

Note: I'm not worried about asynchronous calls - this is not production code.

rein
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3 Answers3

298

Important: this was correct when written, but in $current_year$, please see the HttpClient answer below

using(WebClient client = new WebClient()) {
   string s = client.DownloadString(url);
}
Marc Gravell
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  • Another one of those often-overlooked utility classes - but **so** useful. – Marc Gravell Jun 26 '09 at 09:31
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    Keep in mind that you should be putting it in a `try catch` block as well, in case something goes awry – mikeyq6 Aug 17 '15 at 16:02
  • @DanW yes it does, I've just tested it (with `string s = client.DownloadString("https://stackoverflow.com/questions/1048199/easiest-way-to-read-from-a-url-into-a-string-in-net/1048204");`) - works absolutely fine. Whatever is happening: it isn't https that is the immediate problem. Are you sure the site has a valid cert? – Marc Gravell May 13 '19 at 07:14
  • At this point in time, ```WebClient``` is **obsolete** and this is *not* a valid answer to the question any more. You probably have to use ```HttpClient``` to do this now, but it's no where near as succinct or simple, and doesn't give you a choice over asynchronous calls... – NetXpert Sep 17 '22 at 01:36
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    @NetXpert I added a note – Marc Gravell Sep 17 '22 at 06:46
9

The method in the above answer is now deprecated, the current recommendation is to use HttpClient:

using (HttpClient client = new HttpClient())
{
    string s = await client.GetStringAsync(url);
}
gunr2171
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Plasma
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  • Please provide a COMPLETE solution. What does your corresponding method declaration look like, and what is the valid ```Task``` value you put in the ```return``` statement? As is, this snippet generates the critical error: *CS4033: "The 'await' operator can only be used within an async method. Consider marking this method with the 'async' modifier and changing it's return type to 'Task'"* – NetXpert Sep 17 '22 at 01:28
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    @NetXpert the snippet works and satisfies the question, just like the accepted answer with 297 votes, but has current classes. If you are seeing that error then you have your method configured wrong and need to make it Async, no point in me creating a method around this as it wouldn't fit everyones requirements. – Plasma Oct 12 '22 at 12:28
1

Given that, at the time of this writing, HttpClient is the only remaining, valid .Net mechanism for performing this function, and, in any case where you're "not worried about asynchronous calls" (which appear to be unavoidable with HttpClient), I think that this function should get you what you're after:

public static class Http
{
    ///<remarks>NOTE: The <i>HttpCLient</i> class is <b>intended</b> to only ever be instantiated once in any application.</remarks>
    private static readonly HttpClient _client = new();

    /// <summary>Used to retrieve webserver data via simple <b>GET</b> requests.</summary>
    /// <param name="url">A string containing the complete web <b>URL</b> to submit.</param>
    /// <returns>Whatever <i>HttpClient</i> returns after attempting the supplied query (as a <i>Task&lt;string&gt;</i> value).</returns>
    /// <exception cref="InvalidOperationException">Returned if the supplied <i>url</i> string is null, empty or whitespace.</exception>
    private static async Task<string> HttpClientKludge( string url )
    {
        if ( string.IsNullOrWhiteSpace( url ) )
            throw new InvalidOperationException( "You must supply a url to interrogate for this function to work." );

        Uri uri;
        try { uri = new Uri( url ); }
        catch ( UriFormatException e ) { return $"{e.Message}\r\n{url}"; }

        return await _client.GetStringAsync( uri );
    }

    /// <summary>Attempts to interrogate a website via the supplied URL and stores the result in a <i>string</i>.</summary>
    /// <param name="url">A string containing a fully-formed, proper URL to retrieve.</param>
    /// <param name="captureExceptions">If <b>TRUE</b>, any Exceptions generated by the operation will be suppressed with their Message returned as the result string, otherwise they're thrown normally.</param>
    /// <returns>The result generated by submitting the request, as a <i>string</i>.</returns>
    public static string Get( string url, bool captureExceptions = true )
    {
        string result;
        try { result = HttpClientKludge( url ).Result; }
        catch (AggregateException e)
        {
            if (!captureExceptions) throw;
            result = e.InnerException is null ? e.Message : e.InnerException.Message;
        }
        return result;
    }
}

With that in place, anytime you want to interrogate a website with a simple URL+GET inquiry, you can simply do:

string query = "/search?q=Easiest+way+to+read+from+a+URL+into+a+string+in+.NET",
siteResponse = Http.Get( $"https://www.google.com{query}" );
// Now use 'siteResponse' in any way you want...
NetXpert
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