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Updated HttpClient tutorial to 4.3 APIs (fundamentals, conn mgmt and state mgmt chapters) 

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@1513603 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Oleg Kalnichevski 2013-08-13 18:15:16 +00:00
parent 64ca74933b
commit 5e2c01472d
10 changed files with 494 additions and 1019 deletions
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9
httpclient/src/main/java/org/apache/http/client/config/CookieSpecs.java
View File

@ -49,14 +49,9 @@ public final class CookieSpecs {
public static final String NETSCAPE = "netscape";
/**
* The RFC 2109 compliant policy.
* The RFC 2965 compliant policy (standard).
*/
public static final String RFC_2109 = "rfc2109";
/**
* The RFC 2965 compliant policy.
*/
public static final String RFC_2965 = "rfc2965";
public static final String STANDARD = "standard";
/**
* The default 'best match' policy.

5
httpclient/src/main/java/org/apache/http/impl/client/HttpClientBuilder.java
View File

@ -690,11 +690,12 @@ public class HttpClientBuilder {
if (cookieSpecRegistry == null) {
cookieSpecRegistry = RegistryBuilder.<CookieSpecProvider>create()
.register(CookieSpecs.BEST_MATCH, new BestMatchSpecFactory())
.register(CookieSpecs.STANDARD, new RFC2965SpecFactory())
.register(CookieSpecs.BROWSER_COMPATIBILITY, new BrowserCompatSpecFactory())
.register(CookieSpecs.NETSCAPE, new NetscapeDraftSpecFactory())
.register(CookieSpecs.RFC_2109, new RFC2109SpecFactory())
.register(CookieSpecs.RFC_2965, new RFC2965SpecFactory())
.register(CookieSpecs.IGNORE_COOKIES, new IgnoreSpecFactory())
.register("rfc2109", new RFC2109SpecFactory())
.register("rfc2965", new RFC2965SpecFactory())
.build();
}

4
httpclient/src/main/java/org/apache/http/impl/conn/DefaultProxyRoutePlanner.java
View File

@ -51,6 +51,10 @@ public class DefaultProxyRoutePlanner extends DefaultRoutePlanner {
this.proxy = Args.notNull(proxy, "Proxy host");
}
public DefaultProxyRoutePlanner(final HttpHost proxy) {
this(proxy, null);
}
@Override
protected HttpHost determineProxy(
final HttpHost target,

4
httpclient/src/main/java/org/apache/http/impl/conn/SystemDefaultRoutePlanner.java
View File

@ -65,6 +65,10 @@ public class SystemDefaultRoutePlanner extends DefaultRoutePlanner {
this.proxySelector = proxySelector != null ? proxySelector : ProxySelector.getDefault();
}
public SystemDefaultRoutePlanner(final ProxySelector proxySelector) {
this(null, proxySelector);
}
@Override
protected HttpHost determineProxy(
final HttpHost target,

4
httpclient/src/test/java/org/apache/http/client/config/TestRequestConfig.java
View File

@ -75,7 +75,7 @@ public class TestRequestConfig {
.setRelativeRedirectsAllowed(false)
.setCircularRedirectsAllowed(true)
.setMaxRedirects(100)
.setCookieSpec(CookieSpecs.RFC_2965)
.setCookieSpec(CookieSpecs.STANDARD)
.setLocalAddress(InetAddress.getLocalHost())
.setProxy(new HttpHost("someproxy"))
.setTargetPreferredAuthSchemes(Arrays.asList(AuthSchemes.NTLM))
@ -92,7 +92,7 @@ public class TestRequestConfig {
Assert.assertEquals(false, config.isRelativeRedirectsAllowed());
Assert.assertEquals(true, config.isCircularRedirectsAllowed());
Assert.assertEquals(100, config.getMaxRedirects());
Assert.assertEquals(CookieSpecs.RFC_2965, config.getCookieSpec());
Assert.assertEquals(CookieSpecs.STANDARD, config.getCookieSpec());
Assert.assertEquals(InetAddress.getLocalHost(), config.getLocalAddress());
Assert.assertEquals(new HttpHost("someproxy"), config.getProxy());
Assert.assertEquals(Arrays.asList(AuthSchemes.NTLM), config.getTargetPreferredAuthSchemes());

4
httpclient/src/test/java/org/apache/http/client/protocol/TestRequestAddCookies.java
View File

@ -52,7 +52,6 @@ import org.apache.http.impl.cookie.BrowserCompatSpec;
import org.apache.http.impl.cookie.BrowserCompatSpecFactory;
import org.apache.http.impl.cookie.IgnoreSpecFactory;
import org.apache.http.impl.cookie.NetscapeDraftSpecFactory;
import org.apache.http.impl.cookie.RFC2109SpecFactory;
import org.apache.http.impl.cookie.RFC2965SpecFactory;
import org.apache.http.message.BasicHttpRequest;
import org.junit.Assert;
@ -82,10 +81,9 @@ public class TestRequestAddCookies {
this.cookieSpecRegistry = RegistryBuilder.<CookieSpecProvider>create()
.register(CookieSpecs.BEST_MATCH, new BestMatchSpecFactory())
.register(CookieSpecs.STANDARD, new RFC2965SpecFactory())
.register(CookieSpecs.BROWSER_COMPATIBILITY, new BrowserCompatSpecFactory())
.register(CookieSpecs.NETSCAPE, new NetscapeDraftSpecFactory())
.register(CookieSpecs.RFC_2109, new RFC2109SpecFactory())
.register(CookieSpecs.RFC_2965, new RFC2965SpecFactory())
.register(CookieSpecs.IGNORE_COOKIES, new IgnoreSpecFactory())
.build();
}

926
src/docbkx/connmgmt.xml
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439
src/docbkx/fundamentals.xml
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@ -34,17 +34,13 @@
interface that defines the contract described above. </para>
<para>Here is an example of request execution process in its simplest form:</para>
<programlisting><![CDATA[
HttpClient httpclient = new DefaultHttpClient();
CloseableHttpClient httpclient = HttpClients.createDefault();
HttpGet httpget = new HttpGet("http://localhost/");
HttpResponse response = httpclient.execute(httpget);
HttpEntity entity = response.getEntity();
if (entity != null) {
InputStream instream = entity.getContent();
CloseableHttpResponse response = httpclient.execute(httpget);
try {
// do something useful
} finally {
instream.close();
}
response.close();
}
]]></programlisting>
<section>
@ -69,13 +65,15 @@ HttpGet httpget = new HttpGet(
<para>HttpClient provides <classname>URIBuilder</classname> utility class to simplify
creation and modification of request URIs.</para>
<programlisting><![CDATA[
URIBuilder builder = new URIBuilder();
builder.setScheme("http").setHost("www.google.com").setPath("/search")
URI uri = new URIBuilder()
.setScheme("http")
.setHost("www.google.com")
.setPath("/search")
.setParameter("q", "httpclient")
.setParameter("btnG", "Google Search")
.setParameter("aq", "f")
.setParameter("oq", "");
URI uri = builder.build();
.setParameter("oq", "")
.build();
HttpGet httpget = new HttpGet(uri);
System.out.println(httpget.getURI());
]]></programlisting>
@ -282,10 +280,12 @@ important message
</section>
<section>
<title>Ensuring release of low level resources</title>
<para> In order to ensure proper release of system resources one must close the content
stream associated with the entity.</para>
<para> In order to ensure proper release of system resources one must close either
the content stream associated with the entity or the response itself</para>
<programlisting><![CDATA[
HttpResponse response;
CloseableHttpClient httpclient = <...>
CloseableHttpResponse response = httpclient.execute(httpget);
try {
HttpEntity entity = response.getEntity();
if (entity != null) {
InputStream instream = entity.getContent();
@ -295,7 +295,14 @@ if (entity != null) {
instream.close();
}
}
} finally {
response.close();
}
]]></programlisting>
<para>The difference between closing the content stream and closing the response
is that the former will attempt to keep the underlying connection alive
by consuming the entity content while the latter immediately shuts down
and discards the connection.</para>
<para>Please note that the <methodname>HttpEntity#writeTo(OutputStream)</methodname>
method is also required to ensure proper release of system resources once the
entity has been fully written out. If this method obtains an instance of
@ -309,19 +316,20 @@ if (entity != null) {
<para>There can be situations, however, when only a small portion of the entire response
content needs to be retrieved and the performance penalty for consuming the
remaining content and making the connection reusable is too high, in which case
one can simply
terminate the request by calling <methodname>HttpUriRequest#abort()</methodname>
method.</para>
one can terminate the content stream by closing the response.</para>
<programlisting><![CDATA[
HttpGet httpget = new HttpGet("http://localhost/");
HttpResponse response = httpclient.execute(httpget);
CloseableHttpClient httpclient = <...>
CloseableHttpResponse response = httpclient.execute(httpget);
try {
HttpEntity entity = response.getEntity();
if (entity != null) {
InputStream instream = entity.getContent();
int byteOne = instream.read();
int byteTwo = instream.read();
// Do not need the rest
httpget.abort();
}
} finally {
response.close();
}
]]></programlisting>
<para>The connection will not be reused, but all level resources held by it will be
@ -340,8 +348,9 @@ if (entity != null) {
strongly discouraged unless the response entities originate from a trusted HTTP
server and are known to be of limited length.</para>
<programlisting><![CDATA[
HttpGet httpget = new HttpGet("http://localhost/");
HttpResponse response = httpclient.execute(httpget);
CloseableHttpClient httpclient = <...>
CloseableHttpResponse response = httpclient.execute(httpget);
try {
HttpEntity entity = response.getEntity();
if (entity != null) {
long len = entity.getContentLength();
@ -351,6 +360,9 @@ if (entity != null) {
// Stream content out
}
}
} finally {
response.close();
}
]]></programlisting>
<para>In some situations it may be necessary to be able to read entity content more than
once. In this case entity content must be buffered in some way, either in memory or
@ -359,8 +371,7 @@ if (entity != null) {
the original entity to be read into a in-memory buffer. In all other ways the entity
wrapper will be have the original one.</para>
<programlisting><![CDATA[
HttpGet httpget = new HttpGet("http://localhost/");
HttpResponse response = httpclient.execute(httpget);
CloseableHttpResponse response = <...>
HttpEntity entity = response.getEntity();
if (entity != null) {
entity = new BufferedHttpEntity(entity);
@ -401,7 +412,7 @@ httppost.setEntity(entity);
List<NameValuePair> formparams = new ArrayList<NameValuePair>();
formparams.add(new BasicNameValuePair("param1", "value1"));
formparams.add(new BasicNameValuePair("param2", "value2"));
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(formparams, "UTF-8");
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(formparams, Consts.UTF_8);
HttpPost httppost = new HttpPost("http://localhost/handler.do");
httppost.setEntity(entity);
]]></programlisting>
@ -423,7 +434,7 @@ param1=value1&param2=value2
HTTP/1.0.</para>
<programlisting><![CDATA[
StringEntity entity = new StringEntity("important message",
"text/plain; charset=\"UTF-8\"");
ContentType.create("plain/text", Consts.UTF_8));
entity.setChunked(true);
HttpPost httppost = new HttpPost("http://localhost/acrtion.do");
httppost.setEntity(entity);
@ -441,22 +452,32 @@ httppost.setEntity(entity);
take care of ensuring release of the connection back to the connection manager
regardless whether the request execution succeeds or causes an exception.</para>
<programlisting><![CDATA[
HttpClient httpclient = new DefaultHttpClient();
HttpGet httpget = new HttpGet("http://localhost/");
HttpClient httpclient = <...>
HttpRequest request = <...>
ResponseHandler<byte[]> handler = new ResponseHandler<byte[]>() {
public byte[] handleResponse(
HttpResponse response) throws ClientProtocolException, IOException {
ResponseHandler<MyJsonObject> rh = new ResponseHandler<MyJsonObject>() {
@Override
public JsonObject handleResponse(
final HttpResponse response) throws IOException {
StatusLine statusLine = response.getStatusLine();
HttpEntity entity = response.getEntity();
if (entity != null) {
return EntityUtils.toByteArray(entity);
} else {
return null;
if (statusLine.getStatusCode() >= 300) {
throw new HttpResponseException(
statusLine.getStatusCode(),
statusLine.getReasonPhrase());
}
if (entity == null) {
throw new ClientProtocolException("Response contains no content");
}
Gson gson = new GsonBuilder().create();
ContentType contentType = ContentType.getOrDefault(entity);
Charset charset = contentType.getCharset();
Reader reader = new InputStreamReader(entity.getContent(), charset);
return gson.fromJson(reader, MyJsonObject.class);
}
};
byte[] response = httpclient.execute(httpget, handler);
MyJsonObject myjson = client.execute(request, rh);
]]></programlisting>
</section>
</section>
@ -476,81 +497,45 @@ byte[] response = httpclient.execute(httpget, handler);
<para><interfacename>HttpContext</interfacename> can contain arbitrary objects and
therefore may be unsafe to share between multiple threads. It is recommended that
each thread of execution maintains its own context.</para>
<para>In the course of HTTP request execution HttpClient adds the following attributes to
the execution context:</para>
<itemizedlist>
<listitem>
<formalpara>
<title><constant>ExecutionContext.HTTP_CONNECTION</constant>='http.connection':</title>
<para><interfacename>HttpConnection</interfacename> instance representing the
actual connection to the target server.</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title><constant>ExecutionContext.HTTP_TARGET_HOST</constant>='http.target_host':</title>
<para><classname>HttpHost</classname> instance representing the connection
target.</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title><constant>ExecutionContext.HTTP_PROXY_HOST</constant>='http.proxy_host':</title>
<para><classname>HttpHost</classname> instance representing the connection
proxy, if used</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title><constant>ExecutionContext.HTTP_REQUEST</constant>='http.request':</title>
<para><interfacename>HttpRequest</interfacename> instance representing the
actual HTTP request.
The final HttpRequest object in the execution context always represents
the state of the message _exactly_ as it was sent to the target server.
Per default HTTP/1.0 and HTTP/1.1 use relative request URIs.
However if the request is sent via a proxy in a non-tunneling mode then
the URI will be absolute.</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title><constant>ExecutionContext.HTTP_RESPONSE</constant>='http.response':</title>
<para><interfacename>HttpResponse</interfacename> instance representing the
actual HTTP response.</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title><constant>ExecutionContext.HTTP_REQ_SENT</constant>='http.request_sent':</title>
<para><classname>java.lang.Boolean</classname> object representing the flag
indicating whether the actual request has been fully transmitted to the
connection target.</para>
</formalpara>
</listitem>
</itemizedlist>
<para>For instance, in order to determine the final redirect target, one can examine the
value of the <literal>http.target_host</literal> attribute after the request
execution:</para>
<para>One can use <classname>HttpClientContext</classname> adaptor class to simplify
interractions with the context state.</para>
<programlisting><![CDATA[
DefaultHttpClient httpclient = new DefaultHttpClient();
HttpContext localContext = new BasicHttpContext();
HttpGet httpget = new HttpGet("http://www.google.com/");
HttpResponse response = httpclient.execute(httpget, localContext);
HttpHost target = (HttpHost) localContext.getAttribute(
ExecutionContext.HTTP_TARGET_HOST);
System.out.println("Final target: " + target);
HttpEntity entity = response.getEntity();
EntityUtils.consume(entity);
}
HttpContext context = <...>
HttpClientContext clientContext = HttpClientContext.adapt(context);
HttpHost target = clientContext.getTargetHost();
HttpRequest request = clientContext.getRequest();
HttpResponse response = clientContext.getResponse();
]]></programlisting>
<para>stdout &gt;</para>
<para>Multiple request sequences that represent a logically related session should be
executed with the same <interfacename>HttpContext</interfacename> instance to ensure
automatic propagation of conversation context and state information between
requests.</para>
<para>In the following example the request configuration set by the initial request will be
kept in the execution context and get propagatd to the consecutive requests sharing
the same context.</para>
<programlisting><![CDATA[
Final target: http://www.google.ch
CloseableHttpClient httpclient = <...>
RequestConfig requestConfig = RequestConfig.custom()
.setSocketTimeout(1000)
.setConnectTimeout(1000)
.build();
HttpGet httpget1 = new HttpGet("http://localhost/1");
httpget1.setConfig(requestConfig);
CloseableHttpResponse response1 = httpclient.execute(httpget1, context);
try {
HttpEntity entity1 = response1.getEntity();
} finally {
response1.close();
}
HttpGet httpget2 = new HttpGet("http://localhost/2");
CloseableHttpResponse response2 = httpclient.execute(httpget2, context);
try {
HttpEntity entity2 = response2.getEntity();
} finally {
response2.close();
}
]]></programlisting>
</section>
<section>
@ -628,8 +613,6 @@ Final target: http://www.google.ch
implementation of the <interfacename>HttpRequestRetryHandler</interfacename>
interface.</para>
<programlisting><![CDATA[
DefaultHttpClient httpclient = new DefaultHttpClient();
HttpRequestRetryHandler myRetryHandler = new HttpRequestRetryHandler() {
public boolean retryRequest(
@ -648,7 +631,7 @@ HttpRequestRetryHandler myRetryHandler = new HttpRequestRetryHandler() {
// Unknown host
return false;
}
if (exception instanceof ConnectException) {
if (exception instanceof ConnectTimeoutException) {
// Connection refused
return false;
}
@ -656,8 +639,8 @@ HttpRequestRetryHandler myRetryHandler = new HttpRequestRetryHandler() {
// SSL handshake exception
return false;
}
HttpRequest request = (HttpRequest) context.getAttribute(
ExecutionContext.HTTP_REQUEST);
HttpClientContext clientContext = HttpClientContext.adapt(context);
HttpRequest request = clientContext.getRequest();
boolean idempotent = !(request instanceof HttpEntityEnclosingRequest);
if (idempotent) {
// Retry if the request is considered idempotent
@ -667,8 +650,9 @@ HttpRequestRetryHandler myRetryHandler = new HttpRequestRetryHandler() {
}
};
httpclient.setHttpRequestRetryHandler(myRetryHandler);
CloseableHttpClient httpclient = HttpClients.custom()
.setRetryHandler(myRetryHandler)
.build();
]]></programlisting>
</section>
</section>
@ -708,15 +692,8 @@ httpclient.setHttpRequestRetryHandler(myRetryHandler);
<para>This is an example of how local context can be used to persist a processing state
between consecutive requests:</para>
<programlisting><![CDATA[
DefaultHttpClient httpclient = new DefaultHttpClient();
HttpContext localContext = new BasicHttpContext();
AtomicInteger count = new AtomicInteger(1);
localContext.setAttribute("count", count);
httpclient.addRequestInterceptor(new HttpRequestInterceptor() {
CloseableHttpClient httpclient = HttpClients.custom()
.addInterceptorLast(new HttpRequestInterceptor() {
public void process(
final HttpRequest request,
@ -725,210 +702,22 @@ httpclient.addRequestInterceptor(new HttpRequestInterceptor() {
request.addHeader("Count", Integer.toString(count.getAndIncrement()));
}
});
})
.build();
AtomicInteger count = new AtomicInteger(1);
HttpClientContext localContext = HttpClientContext.create();
localContext.setAttribute("count", count);
HttpGet httpget = new HttpGet("http://localhost/");
for (int i = 0; i < 10; i++) {
HttpResponse response = httpclient.execute(httpget, localContext);
CloseableHttpResponse response = httpclient.execute(httpget, localContext);
try {
HttpEntity entity = response.getEntity();
EntityUtils.consume(entity);
} finally {
response.close();
}
}
]]></programlisting>
</section>
<section>
<title>HTTP parameters</title>
<para>The HttpParams interface represents a collection of immutable values that define a runtime
behavior of a component. In many ways <interfacename>HttpParams</interfacename> is
similar to <interfacename>HttpContext</interfacename>. The main distinction between the
two lies in their use at runtime. Both interfaces represent a collection of objects that
are organized as a map of keys to object values, but serve distinct purposes:</para>
<itemizedlist>
<listitem>
<para><interfacename>HttpParams</interfacename> is intended to contain simple
objects: integers, doubles, strings, collections and objects that remain
immutable at runtime.</para>
</listitem>
<listitem>
<para>
<interfacename>HttpParams</interfacename> is expected to be used in the 'write
once - ready many' mode. <interfacename>HttpContext</interfacename> is intended
to contain complex objects that are very likely to mutate in the course of HTTP
message processing. </para>
</listitem>
<listitem>
<para>The purpose of <interfacename>HttpParams</interfacename> is to define a
behavior of other components. Usually each complex component has its own
<interfacename>HttpParams</interfacename> object. The purpose of
<interfacename>HttpContext</interfacename> is to represent an execution
state of an HTTP process. Usually the same execution context is shared among
many collaborating objects.</para>
</listitem>
</itemizedlist>
<section>
<title>Parameter hierarchies</title>
<para>In the course of HTTP request execution <interfacename>HttpParams</interfacename>
of the <interfacename>HttpRequest</interfacename> object are linked together with
<interfacename>HttpParams</interfacename> of the
<interfacename>HttpClient</interfacename> instance used to execute the request.
This enables parameters set at the HTTP request level to take precedence over
<interfacename>HttpParams</interfacename> set at the HTTP client level. The
recommended practice is to set common parameters shared by all HTTP requests at the
HTTP client level and selectively override specific parameters at the HTTP request
level.</para>
<programlisting><![CDATA[
DefaultHttpClient httpclient = new DefaultHttpClient();
httpclient.getParams().setParameter(CoreProtocolPNames.PROTOCOL_VERSION,
HttpVersion.HTTP_1_0); // Default to HTTP 1.0
httpclient.getParams().setParameter(CoreProtocolPNames.HTTP_CONTENT_CHARSET,
"UTF-8");
HttpGet httpget = new HttpGet("http://www.google.com/");
httpget.getParams().setParameter(CoreProtocolPNames.PROTOCOL_VERSION,
HttpVersion.HTTP_1_1); // Use HTTP 1.1 for this request only
httpget.getParams().setParameter(CoreProtocolPNames.USE_EXPECT_CONTINUE,
Boolean.FALSE);
httpclient.addRequestInterceptor(new HttpRequestInterceptor() {
public void process(
final HttpRequest request,
final HttpContext context) throws HttpException, IOException {
System.out.println(request.getParams().getParameter(
CoreProtocolPNames.PROTOCOL_VERSION));
System.out.println(request.getParams().getParameter(
CoreProtocolPNames.HTTP_CONTENT_CHARSET));
System.out.println(request.getParams().getParameter(
CoreProtocolPNames.USE_EXPECT_CONTINUE));
System.out.println(request.getParams().getParameter(
CoreProtocolPNames.STRICT_TRANSFER_ENCODING));
}
});
]]></programlisting>
<para>stdout &gt;</para>
<programlisting><![CDATA[
HTTP/1.1
UTF-8
false
null
]]></programlisting>
</section>
<section>
<title>HTTP parameters beans</title>
<para>The <interfacename>HttpParams</interfacename> interface allows for a great deal of
flexibility in handling configuration of components. Most importantly, new
parameters can be introduced without affecting binary compatibility with older
versions. However, <interfacename>HttpParams</interfacename> also has a certain
disadvantage compared to regular Java beans:
<interfacename>HttpParams</interfacename> cannot be assembled using a DI
framework. To mitigate the limitation, HttpClient includes a number of bean classes
that can used in order to initialize <interfacename>HttpParams</interfacename>
objects using standard Java bean conventions.</para>
<programlisting><![CDATA[
HttpParams params = new BasicHttpParams();
HttpProtocolParamBean paramsBean = new HttpProtocolParamBean(params);
paramsBean.setVersion(HttpVersion.HTTP_1_1);
paramsBean.setContentCharset("UTF-8");
paramsBean.setUseExpectContinue(true);
System.out.println(params.getParameter(
CoreProtocolPNames.PROTOCOL_VERSION));
System.out.println(params.getParameter(
CoreProtocolPNames.HTTP_CONTENT_CHARSET));
System.out.println(params.getParameter(
CoreProtocolPNames.USE_EXPECT_CONTINUE));
System.out.println(params.getParameter(
CoreProtocolPNames.USER_AGENT));
]]></programlisting>
<para>stdout &gt;</para>
<programlisting><![CDATA[
HTTP/1.1
UTF-8
false
null
]]></programlisting>
</section>
</section>
<section>
<title>HTTP request execution parameters</title>
<para>These are parameters that can impact the process of request execution:</para>
<itemizedlist>
<listitem>
<formalpara>
<title><constant>CoreProtocolPNames.PROTOCOL_VERSION</constant>='http.protocol.version':</title>
<para>defines HTTP protocol version used if not set explicitly on the request
object. This parameter expects a value of type
<interfacename>ProtocolVersion</interfacename>. If this parameter is not
set HTTP/1.1 will be used.</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title><constant>CoreProtocolPNames.HTTP_ELEMENT_CHARSET</constant>='http.protocol.element-charset':</title>
<para>defines the charset to be used for encoding HTTP protocol elements. This
parameter expects a value of type <classname>java.lang.String</classname>.
If this parameter is not set <literal>US-ASCII</literal> will be
used.</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title><constant>CoreProtocolPNames.HTTP_CONTENT_CHARSET</constant>='http.protocol.content-charset':</title>
<para>defines the charset to be used per default for content body coding. This
parameter expects a value of type <classname>java.lang.String</classname>.
If this parameter is not set <literal>ISO-8859-1</literal> will be
used.</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title><constant>CoreProtocolPNames.USER_AGENT</constant>='http.useragent':</title>
<para>defines the content of the <literal>User-Agent</literal> header. This
parameter expects a value of type <classname>java.lang.String</classname>.
If this parameter is not set, HttpClient will automatically generate a value
for it.</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title><constant>CoreProtocolPNames.STRICT_TRANSFER_ENCODING</constant>='http.protocol.strict-transfer-encoding':</title>
<para>defines whether responses with an invalid
<literal>Transfer-Encoding</literal> header should be rejected. This
parameter expects a value of type <classname>java.lang.Boolean</classname>.
If this parameter is not set, invalid <literal>Transfer-Encoding</literal>
values will be ignored.</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title><constant>CoreProtocolPNames.USE_EXPECT_CONTINUE</constant>='http.protocol.expect-continue':</title>
<para>activates the <literal>Expect: 100-Continue</literal> handshake for the entity
enclosing methods. The purpose of the <literal>Expect:
100-Continue</literal> handshake is to allow the client that is sending
a request message with a request body to determine if the origin server is
willing to accept the request (based on the request headers) before the
client sends the request body. The use of the <literal>Expect:
100-continue</literal> handshake can result in a noticeable performance
improvement for entity enclosing requests (such as <literal>POST</literal>
and <literal>PUT</literal>) that require the target server's authentication.
The <literal>Expect: 100-continue</literal> handshake should be used with
caution, as it may cause problems with HTTP servers and proxies that do not
support HTTP/1.1 protocol. This parameter expects a value of type
<classname>java.lang.Boolean</classname>. If this parameter is not set,
HttpClient will not attempt to use the handshake.</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title><constant>CoreProtocolPNames.WAIT_FOR_CONTINUE</constant>='http.protocol.wait-for-continue':</title>
<para>defines the maximum period of time in milliseconds the client should spend
waiting for a <literal>100-continue</literal> response. This parameter
expects a value of type <classname>java.lang.Integer</classname>. If this
parameter is not set HttpClient will wait 3 seconds for a confirmation
before resuming the transmission of the request body.</para>
</formalpara>
</listitem>
</itemizedlist>
</section>
</chapter>

6
src/docbkx/preface.xml
View File

@ -70,9 +70,9 @@
<para>
HttpClient is NOT a browser. It is a client side HTTP transport library.
HttpClient's purpose is to transmit and receive HTTP messages. HttpClient will not
attempt to cache content, execute javascript embedded in HTML pages, try to guess
content type, or reformat request / redirect location URIs, or other functionality
unrelated to the HTTP transport.
attempt to process content, execute javascript embedded in HTML pages, try to guess
content type, if not explicitly set, or reformat request / redirect location URIs,
or other functionality unrelated to the HTTP transport.
</para>
</listitem>
</itemizedlist>

208
src/docbkx/statemgmt.xml
View File

@ -133,15 +133,8 @@ stdCookie.setAttribute(ClientCookie.PORT_ATTR, "80,8080");
</listitem>
<listitem>
<formalpara>
<title>RFC 2109:</title>
<para>Older version of the official HTTP state management specification
superseded by RFC 2965.</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title>RFC 2965:</title>
<para>The official HTTP state management specification.</para>
<title>Standard:</title>
<para>RFC 2965 HTTP state management specification.</para>
</formalpara>
</listitem>
<listitem>
@ -171,123 +164,37 @@ stdCookie.setAttribute(ClientCookie.PORT_ATTR, "80,8080");
HttpClient pick up an appropriate compliance level at runtime based on the execution
context.</para>
</section>
<section>
<title>HTTP cookie and state management parameters</title>
<para>These are parameters that be used to customize HTTP state management and the behaviour of
individual cookie specifications:</para>
<itemizedlist>
<listitem>
<formalpara>
<title><constant>CookieSpecPNames.DATE_PATTERNS</constant>='http.protocol.cookie-datepatterns':</title>
<para>defines valid date patterns to be used for parsing non-standard
<literal>expires</literal> attribute. Only required for compatibility
with non-compliant servers that still use <literal>expires</literal> defined
in the Netscape draft instead of the standard <literal>max-age</literal>
attribute. This parameter expects a value of type
<interfacename>java.util.Collection</interfacename>. The collection
elements must be of type <classname>java.lang.String</classname> compatible
with the syntax of <classname>java.text.SimpleDateFormat</classname>. If
this parameter is not set the choice of a default value is
<interfacename>CookieSpec</interfacename> implementation specific.</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title><constant>CookieSpecPNames.SINGLE_COOKIE_HEADER</constant>='http.protocol.single-cookie-header':</title>
<para>defines whether cookies should be forced into a single
<literal>Cookie</literal> request header. Otherwise, each cookie is
formatted as a separate <literal>Cookie</literal> header. This parameter
expects a value of type <classname>java.lang.Boolean</classname>. If this
parameter is not set, the choice of a default value is CookieSpec
implementation specific. Please note this parameter applies to strict cookie
specifications (RFC 2109 and RFC 2965) only. Browser compatibility and
netscape draft policies will always put all cookies into one request
header.</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title><constant>ClientPNames.COOKIE_POLICY</constant>='http.protocol.cookie-policy':</title>
<para>defines the name of a cookie specification to be used for HTTP state
management. This parameter expects a value of type
<classname>java.lang.String</classname>. If this parameter is not set,
valid date patterns are <interfacename>CookieSpec</interfacename>
implementation specific.</para>
</formalpara>
</listitem>
</itemizedlist>
</section>
<section>
<title>Cookie specification registry</title>
<para>HttpClient maintains a registry of available cookie specifications using
the <classname>CookieSpecRegistry</classname> class. The following specifications are
registered per default:</para>
<itemizedlist>
<listitem>
<formalpara>
<title>compatibility:</title>
<para> Browser compatibility (lenient policy).</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title>netscape:</title>
<para>Netscape draft.</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title>rfc2109:</title>
<para>RFC 2109 (outdated strict policy).</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title>rfc2965:</title>
<para>RFC 2965 (standard conformant strict policy).</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title>best-match:</title>
<para>Best match meta-policy.</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title>ignoreCookies:</title>
<para>All cookies are ignored.</para>
</formalpara>
</listitem>
</itemizedlist>
</section>
<section>
<title>Choosing cookie policy</title>
<para>Cookie policy can be set at the HTTP client and overridden on the HTTP request level
if required.</para>
<programlisting><![CDATA[
HttpClient httpclient = new DefaultHttpClient();
// force strict cookie policy per default
httpclient.getParams().setParameter(
ClientPNames.COOKIE_POLICY, CookiePolicy.RFC_2965);
HttpGet httpget = new HttpGet("http://www.broken-server.com/");
// Override the default policy for this request
httpget.getParams().setParameter(
ClientPNames.COOKIE_POLICY, CookiePolicy.BROWSER_COMPATIBILITY);
RequestConfig globalConfig = RequestConfig.custom()
.setCookieSpec(CookieSpecs.BEST_MATCH)
.build();
CloseableHttpClient httpclient = HttpClients.custom()
.setDefaultRequestConfig(globalConfig)
.build();
RequestConfig localConfig = RequestConfig.copy(globalConfig)
.setCookieSpec(CookieSpecs.BROWSER_COMPATIBILITY)
.build();
HttpGet httpGet = new HttpGet("/");
httpGet.setConfig(localConfig);
]]></programlisting>
</section>
<section>
<title>Custom cookie policy</title>
<para>In order to implement a custom cookie policy one should create a custom implementation
of the <interfacename>CookieSpec</interfacename> interface, create a
<interfacename>CookieSpecFactory</interfacename> implementation to create and
<interfacename>CookieSpecProvider</interfacename> implementation to create and
initialize instances of the custom specification and register the factory with
HttpClient. Once the custom specification has been registered, it can be activated the
same way as a standard cookie specification.</para>
<programlisting><![CDATA[
CookieSpecFactory csf = new CookieSpecFactory() {
public CookieSpec newInstance(HttpParams params) {
CookieSpecProvider easySpecProvider = new CookieSpecProvider() {
public CookieSpec create(HttpContext context) {
return new BrowserCompatSpec() {
@Override
public void validate(Cookie cookie, CookieOrigin origin)
@ -296,12 +203,22 @@ CookieSpecFactory csf = new CookieSpecFactory() {
}
};
}
};
DefaultHttpClient httpclient = new DefaultHttpClient();
httpclient.getCookieSpecs().register("easy", csf);
httpclient.getParams().setParameter(
ClientPNames.COOKIE_POLICY, "easy");
};
Registry<CookieSpecProvider> cookieSpecReg = RegistryBuilder.<CookieSpecProvider>create()
.register(CookieSpecs.BEST_MATCH, new BestMatchSpecFactory())
.register(CookieSpecs.BROWSER_COMPATIBILITY, new BrowserCompatSpecFactory())
.register("easy", easySpecProvider)
.build();
RequestConfig requestConfig = RequestConfig.custom()
.setCookieSpec("easy")
.build();
CloseableHttpClient httpclient = HttpClients.custom()
.setDefaultCookieSpecRegistry(cookieSpecReg)
.setDefaultRequestConfig(requestConfig)
.build();
]]></programlisting>
</section>
<section>
@ -315,9 +232,8 @@ httpclient.getParams().setParameter(
get garbage collected. Users can provide more complex implementations if
necessary.</para>
<programlisting><![CDATA[
DefaultHttpClient httpclient = new DefaultHttpClient();
// Create a local instance of cookie store
CookieStore cookieStore = new MyCookieStore();
CookieStore cookieStore = new BasicCookieStore();
// Populate cookies if needed
BasicClientCookie cookie = new BasicClientCookie("name", "value");
cookie.setVersion(0);
@ -325,7 +241,9 @@ cookie.setDomain(".mycompany.com");
cookie.setPath("/");
cookieStore.addCookie(cookie);
// Set the store
httpclient.setCookieStore(cookieStore);
CloseableHttpClient httpclient = HttpClients.custom()
.setDefaultCookieStore(cookieStore)
.build();
]]></programlisting>
</section>
<section>
@ -335,7 +253,6 @@ httpclient.setCookieStore(cookieStore);
<itemizedlist>
<listitem>
<formalpara>
<title><constant>ClientContext.COOKIESPEC_REGISTRY</constant>='http.cookiespec-registry':</title>
<para><classname>CookieSpecRegistry</classname> instance representing the actual
cookie specification registry. The value of this attribute set in the local
context takes precedence over the default one.</para>
@ -343,21 +260,18 @@ httpclient.setCookieStore(cookieStore);
</listitem>
<listitem>
<formalpara>
<title><constant>ClientContext.COOKIE_SPEC</constant>='http.cookie-spec':</title>
<para><interfacename>CookieSpec</interfacename> instance representing the actual
cookie specification.</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title><constant>ClientContext.COOKIE_ORIGIN</constant>='http.cookie-origin':</title>
<para><classname>CookieOrigin</classname> instance representing the actual
details of the origin server.</para>
</formalpara>
</listitem>
<listitem>
<formalpara>
<title><constant>ClientContext.COOKIE_STORE</constant>='http.cookie-store':</title>
<para><interfacename>CookieStore</interfacename> instance representing the actual
cookie store. The value of this attribute set in the local context takes
precedence over the default one.</para>
@ -366,38 +280,26 @@ httpclient.setCookieStore(cookieStore);
</itemizedlist>
<para>The local <interfacename>HttpContext</interfacename> object can be used to customize
the HTTP state management context prior to request execution, or to examine its state after
the request has been executed:</para>
the request has been executed. One can also use separate execution contexts in order
to implement per user (or per thread) state management. A cookie specification registry
and cookie store defined in the local context will take precedence over the default
ones set at the HTTP client level</para>
<programlisting><![CDATA[
HttpClient httpclient = new DefaultHttpClient();
HttpContext localContext = new BasicHttpContext();
HttpGet httpget = new HttpGet("http://localhost:8080/");
HttpResponse response = httpclient.execute(httpget, localContext);
CloseableHttpClient httpclient = <...>
CookieOrigin cookieOrigin = (CookieOrigin) localContext.getAttribute(
ClientContext.COOKIE_ORIGIN);
System.out.println("Cookie origin: " + cookieOrigin);
CookieSpec cookieSpec = (CookieSpec) localContext.getAttribute(
ClientContext.COOKIE_SPEC);
System.out.println("Cookie spec used: " + cookieSpec);
]]></programlisting>
</section>
<section>
<title>Per user / thread state management</title>
<para>One can use an individual local execution context in order to implement per user (or
per thread) state management. A cookie specification registry and cookie store defined in
the local context will take precedence over the default ones set at the HTTP client
level.</para>
<programlisting><![CDATA[
HttpClient httpclient = new DefaultHttpClient();
// Create a local instance of cookie store
CookieStore cookieStore = new BasicCookieStore();
// Create local HTTP context
HttpContext localContext = new BasicHttpContext();
// Bind custom cookie store to the local context
localContext.setAttribute(ClientContext.COOKIE_STORE, cookieStore);
HttpGet httpget = new HttpGet("http://www.google.com/");
// Pass local context as a parameter
HttpResponse response = httpclient.execute(httpget, localContext);
Registry<CookieSpecProvider> cookieSpecReg = <...>
CookieStore cookieStore = <...>
HttpClientContext context = HttpClientContext.create();
context.setCookieSpecRegistry(cookieSpecReg);
context.setCookieStore(cookieStore);
HttpGet httpget = new HttpGet("http://localhost/1");
CloseableHttpResponse response1 = httpclient.execute(httpget, context);
<...>
// Cookie origin details
CookieOrigin cookieOrigin = context.getCookieOrigin();
// Cookie spec used
CookieSpec cookieSpec = context.getCookieSpec();
]]></programlisting>
</section>
</chapter>