в 15:31, 26 мая 2010

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2010-05-26T12:20:37Z

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==MiniCrawler: A skeletal Web crawler.==

<source lang="csharp">//Code revised from
//C# 2.0 The Complete Reference
//
using System;
using System.Net;
using System.IO;

class MiniCrawler {

static string FindLink(string htmlstr, ref int startloc) {
int i;
int start, end;
string uri = null;
string lowcasestr = htmlstr.ToLower();

i = lowcasestr.IndexOf("href=\"http", startloc);
if(i != -1) {
start = htmlstr.IndexOf(""", i) + 1;
end = htmlstr.IndexOf(""", start);
uri = htmlstr.Substring(start, end-start);
startloc = end;
}

return uri;
}

public static void Main(string[] args) {
string link = null;
string str;
string answer;

int curloc; // holds current location in response

if(args.Length != 1) {
Console.WriteLine("Usage: MiniCrawler <uri>");
return ;
}

string uristr = args[0]; // holds current URI

try {

do {
Console.WriteLine("Linking to " + uristr);

// Create a WebRequest to the specified URI.
HttpWebRequest req = (HttpWebRequest) WebRequest.Create(uristr);

uristr = null; // disallow further use of this URI

// Send that request and return the response.
HttpWebResponse resp = (HttpWebResponse) req.GetResponse();

// From the response, obtain an input stream.
Stream istrm = resp.GetResponseStream();

// Wrap the input stream in a StreamReader.
StreamReader rdr = new StreamReader(istrm);

// Read in the entire page.
str = rdr.ReadToEnd();

curloc = 0;

do {
// Find the next URI to link to.
link = FindLink(str, ref curloc);

if(link != null) {
Console.WriteLine("Link found: " + link);

Console.Write("Link, More, Quit?");
answer = Console.ReadLine();

if(string.rupare(answer, "L", true) == 0) {
uristr = string.Copy(link);
break;
} else if(string.rupare(answer, "Q", true) == 0) {
break;
} else if(string.rupare(answer, "M", true) == 0) {
Console.WriteLine("Searching for another link.");
}
} else {
Console.WriteLine("No link found.");
break;
}

} while(link.Length > 0);

// Close the Response.
resp.Close();
} while(uristr != null);

} catch(WebException exc) {
Console.WriteLine("Network Error: " + exc.Message +
"\nStatus code: " + exc.Status);
} catch(ProtocolViolationException exc) {
Console.WriteLine("Protocol Error: " + exc.Message);
} catch(UriFormatException exc) {
Console.WriteLine("URI Format Error: " + exc.Message);
} catch(NotSupportedException exc) {
Console.WriteLine("Unknown Protocol: " + exc.Message);
} catch(IOException exc) {
Console.WriteLine("I/O Error: " + exc.Message);
}

Console.WriteLine("Terminating MiniCrawler.");
}
}</source>

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в 15:31, 26 мая 2010

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