org.openid4java.discovery.yadis
Class YadisResolver

java.lang.Object
  org.openid4java.discovery.yadis.YadisResolver

public class YadisResolver
extends java.lang.Object

Yadis discovery protocol implementation.

Yadis discovery protocol returns a Yadis Resource Descriptor (XRDS) document associated with a Yadis Identifier (YadisID)

YadisIDs can be any type of identifiers that are resolvable to a URL form, and in addition the URL form uses a HTTP or a HTTPS schema. Such an URL is defined by the Yadis speficification as a YadisURL. This functionality is implemented by the YadisURL helper class.

The discovery of the XRDS document is performed by the discover method on a YadisUrl.

Internal parameters used during the discovery process :

• max redirects (default 10): maximum number of redirects to be followed for YadisURL
• max HTML size (default 100,000 bytes): maximum size (in bytes) that will be retrived and parsed while trying to extract the XRDS location from the tag
• max XML size (default 100,000 bytes): maximum size (in bytes) that will be accepted for XRDS document
• HTTP connect timeout (default 3 seconds)
• HTTP read timeout (default 5 seconds)

Author:

Marius Scurtescu, Johnny Bufu

Field Summary

private int	_connTimeout HTTP connect timeout, in milliseconds.
private static org.apache.commons.logging.Log	_log
private int	_maxHtmlSize Maximum length (in bytes) to read when parsing a HTML response.
private int	_maxRedirects Maximum number of redirects to be followed for the HTTP calls.
private int	_maxXmlSize Maximum size in bytes for the XRDS document.
private int	_socketTimeout HTTP socket (read) timeout, in milliseconds.
private static boolean	DEBUG
private static java.lang.String	YADIS_ACCEPT_HEADER
private static java.lang.String	YADIS_CONTENT_TYPE
private static java.lang.String	YADIS_XRDS_LOCATION

Constructor Summary

YadisResolver()
Instantiates a YadisResolver with default values for the internal parameters.

Method Summary

YadisResult	discover(java.lang.String url) Performs Yadis discovery on the YadisURL.
YadisResult	discover(java.lang.String url, int maxRedirects) Performs Yadis discovery on the YadisURL.
int	getConnTimeout() Gets the HTTP connect timeout, in milliseconds.
private java.lang.String	getHtmlMeta(java.io.InputStream input) Parses the HTML input stream and scans for the Yadis XRDS location in the HTML HEAD Meta tags.
int	getMaxHtmlSize() Gets the aximum length (in bytes) to read when parsing a HTML response.
int	getMaxRedirects() Gets the internal limit configured for the maximum number of redirects to be followed for the HTTP calls.
int	getMaxXmlSize() Gets the maximum size in bytes for the XRDS document.
int	getSocketTimeout() Gets the HTTP socket (read) timeout, in milliseconds.
private void	getXrds(org.apache.commons.httpclient.HttpClient client, YadisResult result, boolean secondCall) Tries to retrieve the XRDS document via a GET call on the provided URL.
private void	headXrdsUrl(org.apache.commons.httpclient.HttpClient client, YadisUrl url, YadisResult result) Tries to retrieve the XRDS location url by performing a cheap HEAD call on the YadisURL.
private org.openxri.xml.XRDS	parseXrds(java.io.InputStream input) Parses the input stream and build a XRDS document from it.
void	setConnTimeout(int connTimeout) Sets the HTTP connect timeout, in milliseconds.
void	setMaxHtmlSize(int maxHtmlSize) Sets maximum length (in bytes) to read when parsing a HTML response.
void	setMaxRedirects(int maxRedirects) Sets the maximum number of redirects to be followed for the HTTP calls.
void	setMaxXmlSize(int maxXmlSize) Sets the maximum size in bytes for the XRDS document.
void	setSocketTimeout(int socketTimeout) Sets HTTP socket (read) timeout, in milliseconds.

Methods inherited from class java.lang.Object

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

Field Detail

_log

private static org.apache.commons.logging.Log _log

DEBUG

private static final boolean DEBUG

YADIS_XRDS_LOCATION

private static final java.lang.String YADIS_XRDS_LOCATION

See Also:

Constant Field Values

YADIS_CONTENT_TYPE

private static final java.lang.String YADIS_CONTENT_TYPE

See Also:

Constant Field Values

YADIS_ACCEPT_HEADER

private static final java.lang.String YADIS_ACCEPT_HEADER

See Also:

Constant Field Values

_maxRedirects

private int _maxRedirects

Maximum number of redirects to be followed for the HTTP calls. Defalut 10.

_maxHtmlSize

private int _maxHtmlSize

Maximum length (in bytes) to read when parsing a HTML response.

_maxXmlSize

private int _maxXmlSize

Maximum size in bytes for the XRDS document.

_connTimeout

private int _connTimeout

HTTP connect timeout, in milliseconds.

_socketTimeout

private int _socketTimeout

HTTP socket (read) timeout, in milliseconds.

Constructor Detail

YadisResolver

public YadisResolver()

Instantiates a YadisResolver with default values for the internal parameters.

Method Detail

getMaxRedirects

public int getMaxRedirects()

Gets the internal limit configured for the maximum number of redirects to be followed for the HTTP calls.

setMaxRedirects

public void setMaxRedirects(int maxRedirects)

Sets the maximum number of redirects to be followed for the HTTP calls.

getMaxHtmlSize

public int getMaxHtmlSize()

Gets the aximum length (in bytes) to read when parsing a HTML response.

setMaxHtmlSize

public void setMaxHtmlSize(int maxHtmlSize)

Sets maximum length (in bytes) to read when parsing a HTML response.

getMaxXmlSize

public int getMaxXmlSize()

Gets the maximum size in bytes for the XRDS document.

setMaxXmlSize

public void setMaxXmlSize(int maxXmlSize)

Sets the maximum size in bytes for the XRDS document.

getConnTimeout

public int getConnTimeout()

Gets the HTTP connect timeout, in milliseconds.

setConnTimeout

public void setConnTimeout(int connTimeout)

Sets the HTTP connect timeout, in milliseconds.

getSocketTimeout

public int getSocketTimeout()

Gets the HTTP socket (read) timeout, in milliseconds.

setSocketTimeout

public void setSocketTimeout(int socketTimeout)

Sets HTTP socket (read) timeout, in milliseconds.

discover

public YadisResult discover(java.lang.String url)
                     throws YadisException

Performs Yadis discovery on the YadisURL.

• tries to retrieve the XRDS location via a HEAD call on the Yadis URL
• retrieves the XRDS document with a GET on the above if available, or through a GET on the YadisURL otherwise

The maximum number of redirects that are followed is determined by the #_maxRedirects member field.

Parameters:

url - YadisURL on which discovery will be performed

Returns:

YadisResult containing discovered information, which includes the XRDS document associated with the Yadis URL and additional meta-information

Throws:

YadisException

See Also:

YadisResult, #discover(String, int)

discover

public YadisResult discover(java.lang.String url,
                            int maxRedirects)
                     throws YadisException

Performs Yadis discovery on the YadisURL.

• tries to retrieve the XRDS location via a HEAD call on the Yadis URL
• retrieves the XRDS document with a GET on the above if available, or through a GET on the YadisURL otherwise

Parameters:

url - YadisURL on which discovery will be performed

maxRedirects - The maximum number of redirects to be followed.

Returns:

YadisResult containing discovered information, which includes the XRDS document associated with the Yadis URL and additional meta-information

Throws:

YadisException

See Also:

YadisResult

getXrds

private void getXrds(org.apache.commons.httpclient.HttpClient client,
                     YadisResult result,
                     boolean secondCall)
              throws YadisException

Tries to retrieve the XRDS document via a GET call on the provided URL.

Parameters:

client - The HttpClient object to use for placing the call

result - The YadisResult object where discovery results will be stored

secondCall - true on the second (recursive) call

Throws:

YadisException - (hard-fail) if:

• there's a transport error
• the returned status code is different than SC_OK

getHtmlMeta

private java.lang.String getHtmlMeta(java.io.InputStream input)
                              throws YadisException

Parses the HTML input stream and scans for the Yadis XRDS location in the HTML HEAD Meta tags.

Parameters:

input - input data stream

Returns:

String the XRDS location URL, or null if not found

Throws:

YadisException - on parsing errors or Yadis protocal violations

parseXrds

private org.openxri.xml.XRDS parseXrds(java.io.InputStream input)
                                throws YadisException

Parses the input stream and build a XRDS document from it.

Parameters:

input - input data stream

Returns:

XRDS Yadis Resource Descriptor (XRDS) document

Throws:

YadisException - if the input stream does not contain a valid XRDS

headXrdsUrl

private void headXrdsUrl(org.apache.commons.httpclient.HttpClient client,
                         YadisUrl url,
                         YadisResult result)
                  throws YadisException

Tries to retrieve the XRDS location url by performing a cheap HEAD call on the YadisURL.

The returned string should be validated before being used as a XRDS-Location URL.

Parameters:

client - The HttpClient object to use for placing the call

url - The YadisURL

result - The location of the XRDS document and the normalized Url will be returned in the YadisResult object.

The location of the XRDS document will be null if:

• the returned status code is different than SC_OK
• the Yadis header is not present
• there was an HTTP-level error (allows fallback to GET + HTML response)

Throws:

YadisException - if:

• there's a (lower level) transport error
• there are more than one Yadis headers present