HttpWebRequest.Headers.Add("Cookie",value) vs HttpWebRequest.CookieContainer

Question

When I get response from HttpWebRequest with HttpWebRequest.Headers.Add("Cookie",value) vs HttpWebRequest.CookieContainer, and results are difference.

So, What is the difference between they are, and when to use them.

Answer 1

From my experience, I have had some issues with using HttpWebRequest.CookieContainer for managing cookies. It can work to a degree, but sometimes cookies are not RFC compliant and they don't get parsed into the CookieContainer correctly. If you manage your cookies manually by adding them to the Cookie header on the request, you will have better success with certain websites that aren't RFC compliant. One of the issues with CookieContainer is that if there is a date with a comma in the date such as "September 26, 2013", it will parse that as a separate cookie entirely and break the parsing. Another issue is that cookies set on a HTTP 302 redirect will not be picked up by the CookieContainer.

It's up to you on what is the best for your specific requirements, but if the issues with the CookieContainer are providing different results than manually setting the cookie header, I would recommend that you stick to manually setting the cookie header. Hopefully Microsoft will update this in the future so that we can go back to using the nice .NET classes for managing cookies.

Edit:
I came across some code that properly parses a "Set-Cookie" header. It handles cookies separated by commas and extracts the name, expiration, path, value, and domain of each cookie.

This code works better than Microsoft's own cookie parser and this is really what the official cookie parser should be doing. I don't have any clue why Microsoft hasn't fixed this yet since it's a very common issue.

Here is the original code: http://snipplr.com/view/4427/

I'm posting it here in case the link goes down at some point:

public static CookieCollection GetAllCookiesFromHeader(string strHeader, string strHost)
{
    ArrayList al = new ArrayList();
    CookieCollection cc = new CookieCollection();
    if (strHeader != string.Empty)
    {
        al = ConvertCookieHeaderToArrayList(strHeader);
        cc = ConvertCookieArraysToCookieCollection(al, strHost);
    }
    return cc;
}


private static ArrayList ConvertCookieHeaderToArrayList(string strCookHeader)
{
    strCookHeader = strCookHeader.Replace("\r", "");
    strCookHeader = strCookHeader.Replace("\n", "");
    string[] strCookTemp = strCookHeader.Split(',');
    ArrayList al = new ArrayList();
    int i = 0;
    int n = strCookTemp.Length;
    while (i < n)
    {
        if (strCookTemp[i].IndexOf("expires=", StringComparison.OrdinalIgnoreCase) > 0)
        {
            al.Add(strCookTemp[i] + "," + strCookTemp[i + 1]);
            i = i + 1;
        }
        else
        {
            al.Add(strCookTemp[i]);
        }
        i = i + 1;
    }
    return al;
}


private static CookieCollection ConvertCookieArraysToCookieCollection(ArrayList al, string strHost)
{
    CookieCollection cc = new CookieCollection();

    int alcount = al.Count;
    string strEachCook;
    string[] strEachCookParts;
    for (int i = 0; i < alcount; i++)
    {
        strEachCook = al[i].ToString();
        strEachCookParts = strEachCook.Split(';');
        int intEachCookPartsCount = strEachCookParts.Length;
        string strCNameAndCValue = string.Empty;
        string strPNameAndPValue = string.Empty;
        string strDNameAndDValue = string.Empty;
        string[] NameValuePairTemp;
        Cookie cookTemp = new Cookie();

        for (int j = 0; j < intEachCookPartsCount; j++)
        {
            if (j == 0)
            {
                strCNameAndCValue = strEachCookParts[j];
                if (strCNameAndCValue != string.Empty)
                {
                    int firstEqual = strCNameAndCValue.IndexOf("=");
                    string firstName = strCNameAndCValue.Substring(0, firstEqual);
                    string allValue = strCNameAndCValue.Substring(firstEqual + 1, strCNameAndCValue.Length - (firstEqual + 1));
                    cookTemp.Name = firstName;
                    cookTemp.Value = allValue;
                }
                continue;
            }
            if (strEachCookParts[j].IndexOf("path", StringComparison.OrdinalIgnoreCase) >= 0)
            {
                strPNameAndPValue = strEachCookParts[j];
                if (strPNameAndPValue != string.Empty)
                {
                    NameValuePairTemp = strPNameAndPValue.Split('=');
                    if (NameValuePairTemp[1] != string.Empty)
                    {
                        cookTemp.Path = NameValuePairTemp[1];
                    }
                    else
                    {
                        cookTemp.Path = "/";
                    }
                }
                continue;
            }

            if (strEachCookParts[j].IndexOf("domain", StringComparison.OrdinalIgnoreCase) >= 0)
            {
                strPNameAndPValue = strEachCookParts[j];
                if (strPNameAndPValue != string.Empty)
                {
                    NameValuePairTemp = strPNameAndPValue.Split('=');

                    if (NameValuePairTemp[1] != string.Empty)
                    {
                        cookTemp.Domain = NameValuePairTemp[1];
                    }
                    else
                    {
                        cookTemp.Domain = strHost;
                    }
                }
                continue;
            }
        }

        if (cookTemp.Path == string.Empty)
        {
            cookTemp.Path = "/";
        }
        if (cookTemp.Domain == string.Empty)
        {
            cookTemp.Domain = strHost;
        }
        cc.Add(cookTemp);
    }
    return cc;
}