How to call a WebService which has a querystring data? - asp.net

I have a webservice which i need to call in .net application. The link looks like this.
http://www.contoso.com/student?id=12345
This will work only when its called like this. For rest of the this i dont have access. ie if i call it on a browser without the querystring it will not work. but with querystring it will return an XML data.
Now, when i call this in the .net application its not working?
How can I call this in a .NET application?
The Normal Webservice Importing methods are not working since it needs a querystring with value and we dont have access to the links which doesnt have the querystring.

How are you currently trying to download it?
A very simple way to do this is to use the HttpWebRequest and HttpWebResponse classes;
public XmlDocument GetStudentXml(int studentId)
{
XmlDocument targetXml = new XmlDocument();
HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(String.Format("http://www.contoso.com/student?id={0}", studentId));
webRequest.Credentials = System.Net.CredentialCache.DefaultCredentials;
webRequest.Accept = "text/xml";
HttpWebResponse webResponse = (HttpWebResponse)webRequest.GetResponse();
using (Stream responseStream = webResponse.GetResponseStream())
{
XmlTextReader reader = new XmlTextReader(responseStream);
targetXml.Load(reader);
reader.Close();
}
webResponse.Close();
return targetXml;
}
This method simply creates a HttpWebRequest, initializes it with the URL (via String.Format so as to append the student id), some windows credentials and the expected content type.
It then calls the remote address via the GetResponse method. The response is then loaded into a stream, and an XmlTextReader is used to load the Xml data from the response stream into the XmlDocument, which is then returned to the caller.
You can also use WebClient and XDocument to achieve the same thing:
string url = String.Format("http://www.contoso.com/student?id={0}", studentId);
string remoteXml;
using (var webClient = new WebClient())
{
remoteXml = webClient.DownloadString(url);
}
XDocument doc = XDocument.Parse(remoteXml);

Related

can a MVC 3 app execute an Action in a different app on the same server

I have two asp.net applications running on one server, one is MVC-3, the other is not. the MVC application has a POST action which sends an email and returns a JSON object. Can the plain asp.net application somehow execute the action (from server) and receive the JSON object? I guess it just needs to execute a POST somehow?
Found the answer: It is the method HttpWebRequest, used as follows.
string data = "data to post";
HttpWebRequest request = (HttpWebRequest)WebRequest.Create("put URL here");
// set post headers
request.Method = "POST";
request.KeepAlive = true;
request.ContentLength = data.Length;
request.ContentType = "application/x-www-form-urlencoded";
System.IO.StreamWriter writer = new System.IO.StreamWriter(request.GetRequestStream());
writer.Write(data);
writer.Close();
writer.Dispose();
// next line posts the data to the URL
HttpWebResponse response = (HttpWebResponse)request.GetResponse();

How to do httpPost to a webservice which accepts a byte array of a file using c#

I am working on an API kind of project,
I have wrote a WebMethod (not exactly. I am using MVC to create REST like API)
public UploadFileImage(string employeeId, byte[] imageBytes, string imageName)
{
// saves the imagebyte as an image to a folder
}
the web service would be consumed by a web app, or windows or even iphone or such portable stuffs. I am testing my web service using a web app, by simple httpPost.
string Post(Uri RequestUri, string Data)
{
try
{
HttpWebRequest request = HttpWebRequest.Create(RequestUri) as HttpWebRequest;
request.Method = "POST";
request.ContentType = IsXml.Checked ? "text/xml" : "application/x-www-form-urlencoded";
byte[] bytes = Encoding.ASCII.GetBytes(Data);
Stream os = null; // send the Post
request.ContentLength = bytes.Length; //Count bytes to send
os = request.GetRequestStream();
os.Write(bytes, 0, bytes.Length);
HttpWebResponse httpWebResponse = (HttpWebResponse)request.GetResponse();
StreamReader streamReader = new StreamReader(request.GetResponse().GetResponseStream());
return streamReader.ReadToEnd();
}
catch (Exception ex)
{
return ex.Message;
}
}
This code works fine for evey method like, AddEmployee, DeleteEmployee etc. THe parameter Data is of form "Id=123&name=abcdefgh&desig=Developer",
How I call any other function is
Post(new Uri("http://localhost/addemployee"),"name=abcd&password=efgh")
where post is the function i wrote.
All good for all functions. Except that I dont know how to consume the above mentioned function UploadFileImage to upload an image?
Thanks
Try encoding the imageBytes as Base64.
From your code snippet is not too clear how you call UploadFileImage, that is how you convert its parameters tripplet into Data.
That is why my answer is quite generic:
In general, you'd better transfer your image file by
request.ContentType = "multipart/form-data; boundary=----------------------------" + DateTime.Now.Ticks.ToString("x");
Please allow me to refer you to a sample at StackOverflow on how to format a multipart request. I am sure that if you google, you shall find a lots of detailed examples and explanations as well.
I hope this helps :-)

How can I read in C# XML from another page while logged in to the site

I have logged in to the site with my webbrowser and whenever I try to call
WebClient myWebClient = new WebClient();
string str = myWebClient.DownloadString("http://localhost/myxml.aspx");
Response.Write(str.ToString());
Or
XmlTextReader reader = new XmlTextReader(url);
while (reader.Read()) {
Response.Write(reader.ReadOuterXml());
}
Response.Write returns me the login page.
Is there away to attach user SessionId to WebClient or XmlTextReader or how can I request another page in C# with current logged user?
You'll need to use an object that can handle storing cookies. In this case, you'll need the HttpWebRequest class. You'll also need a CookieContainer to manage authentication cookies.
To do this you would:
Create a CookieContainer object (a cookie jar) that you can keep track of throughout the scope of every request you make.
Create an HttpWebRequest that logs into the site you're accessing.
Use the CookieContainer you created in step 1 for every subsequent request.
Below is an example of how to use the HttpWebRequest, HttpWebResponse, and CookieContainer classes together to make a simple request that will set some cookies, and then using those cookies on a subsequent request. The rest should be easy assuming everything is well formed markup ;)
CookieContainer cookieJar = new CookieContainer();
var webRequest = (HttpWebRequest)HttpWebRequest.Create("http://www.google.com");
webRequest.CookieContainer = cookieJar;
var webResponse = webRequest.GetResponse();
using (var reader = new StreamReader(webResponse.GetResponseStream()))
{
Response.Write(reader.ReadToEnd());
}
var anotherWebRequest = (HttpWebRequest)HttpWebRequest.Create("http://www.google.com/search?q=stackoverflow.com");
anotherWebRequest.CookieContainer = cookieJar;
webResponse = anotherWebRequest.GetResponse();
Another option (if you really want to use the WebClient class) would be to parse out the ResponseHeaders property of the class once you've made your request and include the appropriate cookies in your next request. This is a little more involved though since it requires you to manage your cookies manually.
Since I'm assuming that you want to be able to traverse your web responses as XML, I suggest you look into the open source library, HtmlAgilityPack. It allows you to send in markup from a web site that is (most likely) not well-formed, or has some sort of invalid markup in it, and then fixes the invalid parts so that you can traverse it like XML.
While doing some screen scraping, I had the same issue. I was requesting a Classic ASP app on an IIS server (I could tell by some of the headers that the server reponded with). The way I supported an ongoing session was by enabling Cookies on the WebClient. Theres no toggle for it, you have to subclass WebClient to get it to work.
public class CookieAwareWebClient : WebClient
{
protected CookieContainer _container = new CookieContainer();
public CookieContainer Cookies
{
get { return _container; }
set { _container = value; }
}
protected override WebRequest GetWebRequest(Uri address)
{
HttpWebRequest httpRequest = base.GetWebRequest(address) as HttpWebRequest;
if (httpRequest.CookieContainer != null)
{
if (httpRequest != null)
{
CookieCollection newCookies =
GetUniqueCookies(
address
,httpRequest.CookieContainer.GetCookies(address)
);
foreach (Cookie c in newCookies)
httpRequest.CookieContainer.Add(c);
}
}
else
httpRequest.CookieContainer = this.Cookies;
return (WebRequest)httpRequest;
}
Note: this isn't a unique solution, I found this out there on the web myself, but I've implemented the solution and it works really well.

How do I make a simple post to Twitter via ASP.NET (VB, preferably)?

I don't want to do anything fancy on Twitter except post to it via my site once a day. I have searched around a bit and there are all sorts of super-complex ways to do every little thing that Twitter does, but there seems to be little documentation on how to do the simplest thing, which is make a post!
Does anyone know how to do this? Or can you at least point me in the right direction? I don't need full wrappers or anything (http://apiwiki.twitter.com/Libraries#C/NET), just one simple function that will post to Twitter.
Thanks!
This is the easiest implementation ever. Up and running in under 2 minutes: Twitterizer
Its fairly simple; you just need to post an xml file to a web page using webrequest.create. This example is close (assumes you have the xml for the message in another place and just pass it into twitterxml variable as a string. The url might not be the right one; found it on this [page][1] which defines the interface
WebRequest req = null;
WebResponse rsp = null;
try
{
string twitterXML = "xml as string";
string uri = "http://twitter.com/statuses/update.format";
req = WebRequest.Create(uri);
//req.Proxy = WebProxy.GetDefaultProxy(); // Enable if using proxy
req.Method = "POST"; // Post method
req.ContentType = "text/xml"; // content type
// Wrap the request stream with a text-based writer
StreamWriter writer = new StreamWriter(req.GetRequestStream());
// Write the XML text into the stream
writer.WriteLine(twitterXML);
writer.Close();
// Send the data to the webserver
rsp = req.GetResponse();
}
[1]: http://apiwiki.twitter.com/Twitter-REST-API-Method%3A-statuses update
There are a couple different ways of doing this, they vary depending on the tools you want to use and have access to. Option 1 will work right out of the box, but the coding can be complicated. Option 3 you will have to download tools for, but once there installed and loaded you should be able to consume the twitter api very quickly.
Use WebRequest.Create to create/send messages to remote endpoints
Use WCF, create a mirror endpoint and access the twitter api using client only endpoint.
Use the WCF REST Starter Kit Preview 2, which has a new class called the HttpClient. I would have to recommend this technique if you can. Here is a great video Consuming a REST Twitter Feed in under 3 minutes.
Here is a sample of using the WCF REST Starter Kit's HttpClient:
public void CreateFriendship(string friend)
{
using (var client = new HttpClient())
{
var url = string.Format("http://www.twitter.com/friendships/create/{0}.xml?follow=true", friend);
client.Post(url)
.CheckForTwitterError()
.EnsureStatusIs(HttpStatusCode.OK);
}
}
Add a comment if you'd like more info about a particular method.
Update:
For Option #1 see this question: Remote HTTP Post with C#
There are a few ways of doing this, you can check out http://restfor.me/twitter and it will give you the code from RESTful documentation.
Essentially making any authenticated call you can follow this logic:
///
/// Executes an HTTP POST command and retrives the information.
/// This function will automatically include a "source" parameter if the "Source" property is set.
///
/// The URL to perform the POST operation
/// The username to use with the request
/// The password to use with the request
/// The data to post
/// The response of the request, or null if we got 404 or nothing.
protected string ExecutePostCommand(string url, string userName, string password, string data) {
WebRequest request = WebRequest.Create(url);
request.ContentType = "application/x-www-form-urlencoded";
request.Method = "POST";
if (!string.IsNullOrEmpty(userName) && !string.IsNullOrEmpty(password)) {
request.Credentials = new NetworkCredential(userName, password);
byte[] bytes = Encoding.UTF8.GetBytes(data);
request.ContentLength = bytes.Length;
using (Stream requestStream = request.GetRequestStream()) {
requestStream.Write(bytes, 0, bytes.Length);
using (WebResponse response = request.GetResponse()) {
using (StreamReader reader = new StreamReader(response.GetResponseStream())) {
return reader.ReadToEnd();
}
}
}
}
return null;
}

How to submit a form automatically using HttpWebResponse

I am looking for an application that can do the following
a) Programmatically auto login to a page(login.asxp) using HttpWebResponse by using already specified username and password.
b) Detect the redirect URL if the login is successful.
c) Submit another form (settings.aspx) to update certain fields in the database.
The required coding needs to be using asp.net
The application needs to complete this entire process in the same session cookie.
string sUrl = "login.aspx";
HttpWebRequest oRequest = (HttpWebRequest)WebRequest.Create(sUrl);
CookieContainer oMyCookies = new CookieContainer();
oRequest.CookieContainer = oMyCookies;
// encode postdata into byte array. the postdata string format will most likely be different and you'll have to examine the postdata going back and forth using some firefox addon like LiveHTTPHeaders
byte[] oPostData = System.Encoding.UTF8.GetBytes("username=" + HttpUtility.UrlEncode(sUser) + "&pass=" HttpUtility.UrlEncode(sPass));
using (Stream oStream = oRequest.GetRequestStream())
{
oStream.Write(oPostData, 0, oPostData.Length);
}
HttpWebResponse oResponse = oRequest.GetResponse();
// save response cookies in our cookie object for future sessions!
foreach (Cookie oCookie in oResponse.Cookies)
{
oMyCookies.SetCookies(sUrl, oCookie.ToString());
}
// maybe check response headers for location
string sResponseContents = null;
using (StreamReader oReader = new StreamReader(oResponse.GetResponseStream())
{
// store server response into string
sResponseContents = oReader.ReadToEnd();
}
...this is the basic code required for what you want to do.

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