How to Programmatically Log In to a Website Using C#?

Write website login script using C#

Problem: My web scraper requires a logged in user to access specific source code on the website. How can I implement login functionality in my program to bypass this restriction?

Answer: To log in to the specified website (mmoinn.com/index.do?PageModule=UsersLogin), you can follow the steps below:

1. Send a POST request to the login form

Format your login credentials into form POST:

<code class="language-csharp">string formUrl = "http://www.mmoinn.com/index.do?PageModule=UsersAction&Action=UsersLogin";
string formParams = string.Format("email_address={0}&password={1}", "您的邮箱地址", "您的密码");

WebRequest req = WebRequest.Create(formUrl);
req.ContentType = "application/x-www-form-urlencoded";
req.Method = "POST";

byte[] bytes = Encoding.ASCII.GetBytes(formParams);
req.ContentLength = bytes.Length;

using (Stream os = req.GetRequestStream())
{
    os.Write(bytes, 0, bytes.Length);
}

WebResponse resp = req.GetResponse();
string cookieHeader = resp.Headers["Set-cookie"];</code>

2. Get the login page

Create a GET request to the desired page containing the cookie header you retrieved from the login form:

<code class="language-csharp">string getUrl = "登录后页面的URL";
WebRequest getRequest = WebRequest.Create(getUrl);
getRequest.Headers.Add("Cookie", cookieHeader);
WebResponse getResponse = getRequest.GetResponse();

using (StreamReader sr = new StreamReader(getResponse.GetResponseStream()))
{
    string pageSource = sr.ReadToEnd();
}</code>

Additional notes:

If you want to verify the response of the login POST, you can add the following lines of code:

<code class="language-csharp">using (StreamReader sr = new StreamReader(resp.GetResponseStream()))
{
    string pageSource = sr.ReadToEnd();
}</code>

Check the pageSource string to check the server's response.

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