get a mysterious problem,when i use HttpWebRequest in unity c# script.

in script,i use HttpWebRequest to get service from network.but it comes a mysterious problem.
the source code:

            string url = "http://apis.baidu.com/apistore/vop/baiduvopjson";
		HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
		print(request.Address);
		request.Method = "get";
		HttpWebResponse response = (HttpWebResponse)request.GetResponse();
		Stream s = response.GetResponseStream();
		StreamReader Reader = new StreamReader(s, Encoding.UTF8);
		string strValue = "";
		strValue = Reader.ReadToEnd();
		print (strValue);

the result is like(i have copy the html to a html file):

but the mysterious problem comes.when i use this code in Visual studio c# project,here is the source code:

            string url = "http://apis.baidu.com/apistore/vop/baiduvopjson";
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Method = "get";
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            Stream s = response.GetResponseStream();
            StreamReader Reader = new StreamReader(s, Encoding.UTF8);
            string strValue = "";
            strValue = Reader.ReadToEnd();
            Console.WriteLine(strValue);

the result which is true in fact is as follows:

{"errNum":300202,"errMsg":"Missing apikey"}

do some one know what mistake do i make in unity project? why can i get the ture httpweb response?

the problem is not your use of HTTPWebRequest, the problem is your use of the remote service.
if you use command-line “curl” with the same URL, you get the same response:

curl http://apis.baidu.com/apistore/vop/baiduvopjson
{"errNum":300202,"errMsg":"Missing apikey"}

or even just visit http://apis.baidu.com/apistore/vop/baiduvopjson in a browser - same response.

it seems like you should be providing an API key somehow. maybe as a form parameter, maybe as a URL parameter, header param, etc, etc. you should look up the docs for whatever service that is.