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Posted to dev@commons.apache.org by ad...@apache.org on 2003/06/13 00:24:21 UTC
cvs commit: jakarta-commons/httpclient/xdocs sslguide.xml
adrian 2003/06/12 15:24:21
Modified: httpclient/xdocs sslguide.xml
Log:
Minor clean-ups and rewording for clarity.
Contributed by Adrian Sutton
Reviewed by Oleg Kalnichevski
Revision Changes Path
1.2 +127 -105 jakarta-commons/httpclient/xdocs/sslguide.xml
Index: sslguide.xml
===================================================================
RCS file: /home/cvs/jakarta-commons/httpclient/xdocs/sslguide.xml,v
retrieving revision 1.1
retrieving revision 1.2
diff -u -r1.1 -r1.2
--- sslguide.xml 12 Jun 2003 03:31:50 -0000 1.1
+++ sslguide.xml 12 Jun 2003 22:24:21 -0000 1.2
@@ -5,6 +5,7 @@
<properties>
<title>HttpClient SSL Guide</title>
<author email="oleg@ural.ru">Oleg Kalnichevski</author>
+ <author email="adrian@intencha.com">Adrian Sutton</author>
<revision>$Id$</revision>
</properties>
@@ -16,7 +17,7 @@
HttpClient provides full support for HTTP over Secure Sockets Layer (SSL) or IETF Transport Layer
Security (TLS) protocols by leveraging the <a href="http://java.sun.com/products/jsse/index.html">
Java Secure Socket Extension (JSSE)</a>. JSSE has been integrated into the Java 2 platform as of
- version 1.4 and usually should work with HttpClient out of the box. On older Java 2 versions JSSE
+ version 1.4 and works with HttpClient out of the box. On older Java 2 versions JSSE
needs to be manually installed and configured. Installation instructions can be found
<a href="http://java.sun.com/products/jsse/doc/guide/API_users_guide.html#Installation">here</a>
</p>
@@ -25,7 +26,7 @@
<section name="Standard SSL in HttpClient">
<p>
- With SSL properly set up and configured, secure HTTP communication over SSL should be as simple
+ Once you have JSSE correctly installed, secure HTTP communication over SSL should be as simple
as plain HTTP communication.
</p>
<source><![CDATA[
@@ -37,8 +38,8 @@
<p>
HTTPS communication via an authenticating proxy server is also no different from plain HTTP
- communication. All the low-level details of establishing a tunneled SSL connection are abstracted
- away by HttpClient:
+ communication. All the low-level details of establishing a tunneled SSL connection are handled
+ by HttpClient:
</p>
<source><![CDATA[
@@ -57,105 +58,120 @@
<section name="Customizing SSL in HttpClient">
<p>
- Per default HTTP client does not perform any custom certificate or certificate chain validation.
- The default HTTPS protocol implementation is completely reliant upon the standard functionality
- of the JSSE that comes with the JVM. If your application requires some additional processing of
- credentials such certificate verification or certificate chain validation, or you want to be using
- a third party SSL library, you can augment HttpClient to meet your specific requirements by providing
- a custom protocol implementation.
- </p>
+ The default behaviour of HttpClient is suitable for most uses, however
+ there are some aspects which you may want to configure. The most common
+ requirements for customizing SSL are:</p>
+
+ <ul>
+ <li>Ability to accept self-signed or untrusted SSL certificates. This
+ is highlighted by an <code>SSLException</code> with the message
+ <i>Unrecognized SSL handshake</i> (or similar) being thrown when a
+ connection attempt is made.</li>
+
+ <li>You want to use a third party SSL library instead of Sun's default
+ implementation.</li>
+ </ul>
+
+ <p>
+ Implementation of a custom protocol involves the following steps:
+ </p>
- <p>
- Implementation of a custom protocol involves the following steps:
- </p>
+ <ol>
- <ul>
+ <li>
+ <p>
+ Provide a custom socket factory that implements
+ <a href="apidocs/org/apache/commons/httpclient/protocol/SecureProtocolSocketFactory.html">
+ org.apache.commons.httpclient.protocol.SecureProtocolSocketFactory</a> interface. The socket
+ factory is responsible for opening a socket to the target server
+ using either the standard or a third party SSL library and
+ performing any required initialization such as performing the
+ connection handshake. Generally the initialization is performed
+ automatically when the socket is created.
+ </p>
+ </li>
- <li>
- <p>
- Provide a custom socket factory that implements
- <a href="apidocs/org/apache/commons/httpclient/protocol/SecureProtocolSocketFactory.html">
- org.apache.commons.httpclient.protocol.SecureProtocolSocketFactory</a> interface. The socket
- factory should encapsulate application specific aspects of opening a socket to the target server
- using either standard or third party SSL library.
- </p>
- </li>
+ <li>
+ <p>
+ Instantiate an object of type <a href="apidocs/org/apache/commons/httpclient/protocol/Protocol.html">
+ org.apache.commons.httpclient.protocol.Protocol</a>. The new instance
+ would be created with a valid URI protocol scheme (https in this
+ case), the custom socket factory (discussed above) and a default port
+ number (typically 443 for https). For example:
+ </p>
- <li>
- <p>
- Instantiate an object of type <a href="apidocs/org/apache/commons/httpclient/protocol/Protocol.html">
- org.apache.commons.httpclient.protocol.Protocol</a>. The new instance would be initialized with the
- following parameters: valid URI protocol scheme (https in this case), custom socket factory discussed
- above, and a default port number.
- </p>
+ <source><![CDATA[
+Protocol myhttps = new Protocol("https", new MySSLSocketFactory(), 443);
+ ]]></source>
- <source><![CDATA[
- Protocol myhttps = new Protocol("https", new MySSLSocketFactory(), 443);
- ]]></source>
+ <p>
+ The new instance of protocol can then be set as the protocol handler
+ for a HostConfiguration. For example to configure the default host and
+ protocol handler for a HttpClient instance use:
+ </p>
- <p>
- The resultant protocol object then can be used as a default protocol for a host.
- </p>
+ <source><![CDATA[
+HttpClient httpclient = new HttpClient();
+httpclient.getHostConfiguration().setHost("www.whatever.com", 443, myhttps);
+GetMethod httpget = new GetMethod("/");
+httpclient.executeMethod(httpget);
+ ]]></source>
- <source><![CDATA[
- HttpClient httpclient = new HttpClient();
- httpclient.getHostConfiguration().setHost("www.whatever.com", 443, myhttps);
- GetMethod httpget = new GetMethod("/");
- httpclient.executeMethod(httpget);
- ]]></source>
+ </li>
- </li>
+ <li>
+ <p>
+ Finally, you can register your custom protocol as the default handler
+ for a specific protocol designator (eg: https) by calling the
+ Protocol.registerProtocol method. You can specify your own protocol
+ designator (such as 'myhttps') if you need to use your custom
+ protocol as well as the default SSL protocol implementation.
+ </p>
- <li>
- <p>
- Optionally register the custom protocol by calling Protocol.registerProtocol method. You can
- specify your own protocol designator (such as 'myhttps') if you are going to be using this protocol
- along with the default SSL protocol implementation.
- </p>
+ <source><![CDATA[
+Protocol.registerProtocol("myhttps",
+new Protocol("https", new MySSLSocketFactory(), 9443));
+ ]]></source>
- <source><![CDATA[
- Protocol.registerProtocol("myhttps",
- new Protocol("https", new MySSLSocketFactory(), 9443));
- ]]></source>
+ <p>
+ Once registered the protocol be used as a 'virtual' scheme inside target URIs.
+ </p>
- <p>
- Once registered the protocol be used as a 'virtual' scheme inside target URIs.
- </p>
+ <source><![CDATA[
+HttpClient httpclient = new HttpClient();
+GetMethod httpget = new GetMethod("myhttps://www.whatever.com/");
+httpclient.executeMethod(httpget);
+ ]]></source>
- <source><![CDATA[
- HttpClient httpclient = new HttpClient();
- GetMethod httpget = new GetMethod("myhttps://www.whatever.com/");
- httpclient.executeMethod(httpget);
- ]]></source>
+ <p>
+ If you want this protocol to represent the default SSL protocol implementation, simply register
+ it under 'https' designator, which will make the protocol object take place of the existing one
+ </p>
- <p>
- If you want this protocol to represent the default SSL protocol implementation, simply register
- it under 'https' designator, which will make the protocol object take place of the existing one
- </p>
-
- <source><![CDATA[
- Protocol.registerProtocol("https",
- new Protocol("https", new MySSLSocketFactory(), 443));
- HttpClient httpclient = new HttpClient();
- GetMethod httpget = new GetMethod("https://www.whatever.com/");
- httpclient.executeMethod(httpget);
- ]]></source>
+ <source><![CDATA[
+Protocol.registerProtocol("https",
+new Protocol("https", new MySSLSocketFactory(), 443));
+HttpClient httpclient = new HttpClient();
+GetMethod httpget = new GetMethod("https://www.whatever.com/");
+httpclient.executeMethod(httpget);
+ ]]></source>
- </li>
+ </li>
- </ul>
+ </ol>
- </section>
+ </section>
- <section name="Examples of SSL customization in HttpClient">
-
- <p>
- There are several custom socket factories available in our contribution package. They can
- be a good start for those who seek to tailor the behavior of the HTTPS protocol to the specific
- needs of their application:
- </p>
+ <section name="Examples of SSL customization in HttpClient">
+
+ <p>
+ There are several custom socket factories available in our contribution
+ package. They can be a good start for those who seek to tailor the
+ behavior of the HTTPS protocol to the specific needs of their
+ application:
+ </p>
- <ul>
+ <ul>
<li>
<a href="http://cvs.apache.org/viewcvs/jakarta-commons/httpclient/src/contrib/org/apache/commons/httpclient/contrib/ssl/EasySSLProtocolSocketFactory.java?rev=HEAD">
@@ -185,19 +201,20 @@
Due to what appears to be a bug in Sun's older (below 1.4) implementation of
Java Virtual Machines or JSSE there's no reliable way of telling if an SSL connection
is 'stale' or not. For example, the HTTP 1.1 specification permits HTTP servers in
- 'keep-alive' mode to drop connection to the client after a given period inactivity
+ 'keep-alive' mode to drop the connection to the client after a given period inactivity
without having to notify the client, effectively rendering such connection unusable or
- 'stale'. For the HTTP agent written in Java there's no reliable way known to us to test
- if a connection is 'stale' other than attempting to perform a read on it. If you happen
- to know a better way we would be delighted to hear about it. Rather unfortunately, a read
+ 'stale'. For the HTTP agent written in Java there's no reliable way to test
+ if a connection is 'stale' other than attempting to perform a read on it.
+ However, a read
operation on an idle SSL connection on Sun JVM older than 1.4 returns 'end of stream'
instead of an expected read timeout. That effectively makes the connection appear 'stale'
- to the HttpClient, which leaves it with no other way but to drop the connection and to
+ to HttpClient, which leaves it with no other way but to drop the connection and to
open a new one, thus defeating HTTP 1.1 keep-alive mechanism and resulting in significant
- performance degradation (SSL authentication is a highly time consuming operation). Sun's
- Java 1.4 SSL implementation does not exhibit this kind of problem. Plain sockets on all
- JVMs are not subject to the problem either.
+ performance degradation (SSL authentication is a highly time consuming operation). The problem appears to have been fixed in Sun's
+ Java 1.4 SSL implementation. Sockets which are not using HTTPS are
+ unaffected on any JVM.
</p>
+
<p>
<strong>Workaround:</strong> If persistent SSL connections support is an issue for your
application we strongly advise you to upgrade to Java 1.4.
@@ -214,9 +231,12 @@
breaking the existing APIs. The problem will be addressed in HttpClient release 2.1.
</p>
<p>
- <strong>Workaround:</strong> Use preemptive server authentication. Please note that only
- BASIC authentication can be used preemptively. For more detailed information please refer
- to the <a href="authentication.html">Authentication Guide</a>.
+ <strong>Workaround:</strong> Use preemptive server authentication or
+ configure the server to keep the connection alive when returning an
+ authorization challenge. Please note that only
+ BASIC authentication can be used preemptively. For more detailed
+ information please refer to the
+ <a href="authentication.html">Authentication Guide</a>.
</p>
</li>
@@ -227,17 +247,19 @@
<section name="Troubleshooting">
<p>
- If you are unlucky and HTTPS with HttpClient does not work for you, it may be a bit premature
- to blame it squarely on HttpClient. The JSSE is highly prone to configuration problems, especially
- on older JVMs, which it is not an integral part of.
+ JSSE is prone to configuration problems, especially on older JVMs,
+ which it is not an integral part of. As such, if you do encounter
+ problems with SSL and HttpClient it is important to check that JSSE is
+ correctly installed.
</p>
<p>
- The application below can be used as an ultimate test that can reliably tell if SSL configured
- properly, as it relies on a plain socket in order to communicate with the target server. If you
- get an exception while executing this code, most certainly SSL is not functioning properly with
- your JVM. Please refer to Sun's official resources for support or additional details on JSSE
- configuration.
+ The application below can be used as an ultimate test that can reliably
+ tell if SSL configured properly, as it relies on a plain socket in
+ order to communicate with the target server. If an exception is thrown
+ when executing this code, SSL is not correctly installed and configured.
+ Please refer to Sun's official resources for support or additional
+ details on JSSE configuration.
</p>
<source><![CDATA[
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