org.das2.util.filesystem

Class HttpUtil

java.lang.Object

org.das2.util.filesystem.HttpUtil

public final class HttpUtil
extends java.lang.Object

Utilities for HTTP protocol, such as a cache for the HEAD metadata.

Field Summary

Fields

Modifier and Type	Field and Description
protected static java.util.logging.Logger	loggerUrl this logger is for opening connections to remote sites.

Constructor Summary

Constructors

Constructor and Description
HttpUtil()

Method Summary

Modifier and Type	Method and Description
static java.net.URLConnection	checkRedirect(java.net.URLConnection urlConnection) check for 301, 302 or 303 redirects, and return a new connection in this case.
static void	consumeStream(java.io.InputStream err) nice clients consume both the stderr and stdout coming from websites.
static java.util.Map<java.lang.String,java.lang.String>	getMetadata(java.net.URL url, java.util.Map<java.lang.String,java.lang.String> props) return the metadata about a URL.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

loggerUrl

protected static final java.util.logging.Logger loggerUrl

this logger is for opening connections to remote sites.

Constructor Detail

HttpUtil

public HttpUtil()

Method Detail

consumeStream

public static void consumeStream(java.io.InputStream err)
                          throws java.io.IOException

nice clients consume both the stderr and stdout coming from websites. This reads everything off of the stream and closes it. http://docs.oracle.com/javase/1.5.0/docs/guide/net/http-keepalive.html suggests that you "do not abandon connection"

Parameters:

err - the input stream

Throws:

java.io.IOException

getMetadata

public static java.util.Map<java.lang.String,java.lang.String> getMetadata(java.net.URL url,
                                                                           java.util.Map<java.lang.String,java.lang.String> props)
                                                                    throws java.io.IOException

return the metadata about a URL. This will support http, https, and ftp, and will check for redirects. This will allow caching of head requests.

Parameters:

url - ftp,https, or http URL

props - if non-null, may be a map containing cookie.

Returns:

the metadata

Throws:

java.io.IOException - when HEAD requests are made.

checkRedirect

public static java.net.URLConnection checkRedirect(java.net.URLConnection urlConnection)
                                            throws java.io.IOException

check for 301, 302 or 303 redirects, and return a new connection in this case. This should be called immediately before the urlConnection.connect call, as this must connect to get the response code.

Parameters:

urlConnection - if an HttpUrlConnection, check for 301 or 302; return connection otherwise.

Returns:

a connection, typically the same one as passed in.

Throws:

java.io.IOException