internal virtual void ApplyConditionals(URLConnection urlConnection)
{
if (lastModified != 0L)
{
urlConnection.SetIfModifiedSince(lastModified);
}
if (entityTags != null && entityTags.Length > 0)
{
urlConnection.AddRequestProperty("If-None-Match", entityTags);
}
}
/// <summary>
/// Decrypt an input stream from
/// <see cref="Get(string, string)">Get(string, string)</see>
/// .
/// </summary>
/// <param name="u">
/// connection previously created by
/// <see cref="Get(string, string)">Get(string, string)</see>
/// }.
/// </param>
/// <returns>stream to read plain text from.</returns>
/// <exception cref="System.IO.IOException">decryption could not be configured.</exception>
public virtual InputStream Decrypt(URLConnection u)
{
return encryption.Decrypt(u.GetInputStream());
}
private long CalculateExpiry(URLConnection urlConnection, long request_time, UrlConnectionExpiryCalculator urlConnectionExpiryCalculator)
{
if ("no-cache".Equals(urlConnection.GetHeaderField("Pragma")))
{
return 0L;
}
string cacheControl = urlConnection.GetHeaderField("Cache-Control");
if (cacheControl != null)
{
if (cacheControl.IndexOf("no-cache") != -1)
{
return 0L;
}
int max_age = GetMaxAge(cacheControl);
if (-1 != max_age)
{
long response_time = Runtime.CurrentTimeMillis();
long apparent_age = Math.Max(0, response_time - urlConnection.GetDate());
long corrected_received_age = Math.Max(apparent_age, urlConnection.GetHeaderFieldInt("Age", 0) * 1000L);
long response_delay = response_time - request_time;
long corrected_initial_age = corrected_received_age + response_delay;
long creation_time = response_time - corrected_initial_age;
return max_age * 1000L + creation_time;
}
}
long explicitExpiry = urlConnection.GetHeaderFieldDate("Expires", -1L);
if (explicitExpiry != -1L)
{
return explicitExpiry;
}
return urlConnectionExpiryCalculator == null ? 0L : urlConnectionExpiryCalculator.CalculateExpiry(urlConnection);
}
private string GetEntityTags(URLConnection urlConnection)
{
IList<string> etags = urlConnection.GetHeaderFields().Get("ETag");
if (etags == null || etags.IsEmpty())
{
return null;
}
StringBuilder b = new StringBuilder();
IEnumerator<string> it = etags.GetEnumerator();
b.Append(it.Next());
while (it.HasNext())
{
b.Append(", ").Append(it.Next());
}
return b.ToString();
}
/// <exception cref="System.IO.IOException"></exception>
internal virtual bool UpdateValidator(URLConnection urlConnection, long request_time, UrlConnectionExpiryCalculator urlConnectionExpiryCalculator)
{
bool isResourceChanged = IsResourceChanged(urlConnection);
if (!isResourceChanged)
{
expiry = CalculateExpiry(urlConnection, request_time, urlConnectionExpiryCalculator);
}
return isResourceChanged;
}
/// <exception cref="System.IO.IOException"></exception>
private bool IsResourceChanged(URLConnection urlConnection)
{
if (urlConnection is HttpURLConnection)
{
return ((HttpURLConnection)urlConnection).GetResponseCode() == HttpURLConnection.HTTP_NOT_MODIFIED;
}
return lastModified == urlConnection.GetLastModified();
}
/// <summary>
/// Override if you want to get notified if the URL connection fails to
/// close.
/// </summary>
/// <remarks>
/// Override if you want to get notified if the URL connection fails to
/// close. Does nothing by default.
/// </remarks>
/// <param name="urlConnection">the connection</param>
/// <param name="cause">the cause it failed to close.</param>
protected internal virtual void OnFailedClosingUrlConnection(URLConnection urlConnection, IOException cause)
{
}
public URLValidator(Uri uri, URLConnection urlConnection, long request_time, UrlConnectionExpiryCalculator urlConnectionExpiryCalculator)
{
this.uri = uri;
this.lastModified = urlConnection.GetLastModified();
this.entityTags = GetEntityTags(urlConnection);
expiry = CalculateExpiry(urlConnection, request_time, urlConnectionExpiryCalculator);
}
private void Close(URLConnection urlConnection)
{
try
{
urlConnection.GetInputStream().Close();
}
catch (IOException e)
{
OnFailedClosingUrlConnection(urlConnection, e);
}
}
private object GetSecurityDomain(URLConnection urlConnection)
{
return urlConnectionSecurityDomainProvider == null ? null : urlConnectionSecurityDomainProvider.GetSecurityDomain(urlConnection);
}
private static string GetCharacterEncoding(URLConnection urlConnection)
{
ParsedContentType pct = new ParsedContentType(urlConnection.GetContentType());
string encoding = pct.GetEncoding();
if (encoding != null)
{
return encoding;
}
string contentType = pct.GetContentType();
if (contentType != null && contentType.StartsWith("text/"))
{
return "8859_1";
}
else
{
return "utf-8";
}
}
/// <exception cref="System.IO.IOException"></exception>
private static TextReader GetReader(URLConnection urlConnection)
{
return new StreamReader(urlConnection.GetInputStream(), GetCharacterEncoding(urlConnection));
}
public virtual long CalculateExpiry(URLConnection urlConnection)
{
return Runtime.CurrentTimeMillis() + relativeExpiry;
}