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26 <div id="page-content">
27 <div id="preamble"><h1>Apache Module mod_proxy_ajp</h1>
29 <p><span>Available Languages: </span><a href="../en/mod/mod_proxy_ajp.html" title="English"> en </a> |
30 <a href="../fr/mod/mod_proxy_ajp.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
31 <a href="../ja/mod/mod_proxy_ajp.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a></p>
33 <table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>AJP support module for
34 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code></td></tr>
35 <tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr>
36 <tr><th><a href="module-dict.html#ModuleIdentifier">Module Identifier:</a></th><td>proxy_ajp_module</td></tr>
37 <tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>mod_proxy_ajp.c</td></tr></table>
40 <p>This module <em>requires</em> the service of <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>. It provides support for the
41 <code>Apache JServ Protocol version 1.3</code> (hereafter
44 <p>Thus, in order to get the ability of handling <code>AJP13</code>
45 protocol, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> and
46 <code class="module"><a href="../mod/mod_proxy_ajp.html">mod_proxy_ajp</a></code> have to be present in the server.</p>
48 <div class="warning"><h3>Warning</h3>
49 <p>Do not enable proxying until you have <a href="mod_proxy.html#access">secured your server</a>. Open proxy
50 servers are dangerous both to your network and to the Internet at
54 <div id="quickview"><h3>Topics</h3>
56 <li><img alt="" src="../images/down.gif" /> <a href="#usage">Usage</a></li>
57 <li><img alt="" src="../images/down.gif" /> <a href="#env">Environment Variables</a></li>
58 <li><img alt="" src="../images/down.gif" /> <a href="#overviewprotocol">Overview of the protocol</a></li>
59 <li><img alt="" src="../images/down.gif" /> <a href="#basppacketstruct">Basic Packet Structure</a></li>
60 <li><img alt="" src="../images/down.gif" /> <a href="#rpacetstruct">Request Packet Structure</a></li>
61 <li><img alt="" src="../images/down.gif" /> <a href="#resppacketstruct">Response Packet Structure</a></li>
62 </ul><h3 class="directives">Directives</h3>
63 <p>This module provides no
65 <h3>Bugfix checklist</h3><ul class="seealso"><li><a href="https://www.apache.org/dist/httpd/CHANGES_2.4">httpd changelog</a></li><li><a href="https://bz.apache.org/bugzilla/buglist.cgi?bug_status=__open__&list_id=144532&product=Apache%20httpd-2&query_format=specific&order=changeddate%20DESC%2Cpriority%2Cbug_severity&component=mod_proxy_ajp">Known issues</a></li><li><a href="https://bz.apache.org/bugzilla/enter_bug.cgi?product=Apache%20httpd-2&component=mod_proxy_ajp">Report a bug</a></li></ul><h3>See also</h3>
67 <li><code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code></li>
68 <li><a href="../env.html">Environment Variable documentation</a></li>
69 <li><a href="#comments_section">Comments</a></li></ul></div>
70 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
72 <h2><a name="usage" id="usage">Usage</a> <a title="Permanent link" href="#usage" class="permalink">¶</a></h2>
73 <p>This module is used to reverse proxy to a backend application server
74 (e.g. Apache Tomcat) using the AJP13 protocol. The usage is similar to
75 an HTTP reverse proxy, but uses the <code>ajp://</code> prefix:</p>
77 <div class="example"><h3>Simple Reverse Proxy</h3><pre class="prettyprint lang-config">ProxyPass "/app" "ajp://backend.example.com:8009/app"</pre>
80 <p>Balancers may also be used:</p>
81 <div class="example"><h3>Balancer Reverse Proxy</h3><pre class="prettyprint lang-config"><Proxy balancer://cluster>
82 BalancerMember ajp://app1.example.com:8009 loadfactor=1
83 BalancerMember ajp://app2.example.com:8009 loadfactor=2
84 ProxySet lbmethod=bytraffic
86 ProxyPass "/app" "balancer://cluster/app"</pre>
89 <p>Note that usually no
90 <code class="directive"><a href="../mod/mod_proxy.html#proxypassreverse">ProxyPassReverse</a></code>
91 directive is necessary. The AJP request includes the original host
92 header given to the proxy, and the application server can be expected
93 to generate self-referential headers relative to this host, so no
94 rewriting is necessary.</p>
96 <p>The main exception is when the URL path on the proxy differs from that
98 backend. In this case, a redirect header can be rewritten relative to the
99 original host URL (not the backend <code>ajp://</code> URL), for
101 <div class="example"><h3>Rewriting Proxied Path</h3><pre class="prettyprint lang-config">ProxyPass "/apps/foo" "ajp://backend.example.com:8009/foo"
102 ProxyPassReverse "/apps/foo" "http://www.example.com/foo"</pre>
104 <p>However, it is usually better to deploy the application on the backend
105 server at the same path as the proxy rather than to take this approach.
107 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
108 <div class="section">
109 <h2><a name="env" id="env">Environment Variables</a> <a title="Permanent link" href="#env" class="permalink">¶</a></h2>
110 <p>Environment variables whose names have the prefix <code>AJP_</code>
111 are forwarded to the origin server as AJP request attributes
112 (with the AJP_ prefix removed from the name of the key).</p>
113 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
114 <div class="section">
115 <h2><a name="overviewprotocol" id="overviewprotocol">Overview of the protocol</a> <a title="Permanent link" href="#overviewprotocol" class="permalink">¶</a></h2>
116 <p>The <code>AJP13</code> protocol is packet-oriented. A binary format
117 was presumably chosen over the more readable plain text for reasons of
118 performance. The web server communicates with the servlet container over
119 TCP connections. To cut down on the expensive process of socket creation,
120 the web server will attempt to maintain persistent TCP connections to the
121 servlet container, and to reuse a connection for multiple request/response
123 <p>Once a connection is assigned to a particular request, it will not be
124 used for any others until the request-handling cycle has terminated. In
125 other words, requests are not multiplexed over connections. This makes
126 for much simpler code at either end of the connection, although it does
127 cause more connections to be open at once.</p>
128 <p>Once the web server has opened a connection to the servlet container,
129 the connection can be in one of the following states:</p>
131 <li> Idle <br /> No request is being handled over this connection. </li>
132 <li> Assigned <br /> The connection is handling a specific request.</li>
134 <p>Once a connection is assigned to handle a particular request, the basic
135 request information (e.g. HTTP headers, etc) is sent over the connection in
136 a highly condensed form (e.g. common strings are encoded as integers).
137 Details of that format are below in Request Packet Structure. If there is a
138 body to the request <code>(content-length > 0)</code>, that is sent in a
139 separate packet immediately after.</p>
140 <p>At this point, the servlet container is presumably ready to start
141 processing the request. As it does so, it can send the
142 following messages back to the web server:</p>
144 <li>SEND_HEADERS <br />Send a set of headers back to the browser.</li>
145 <li>SEND_BODY_CHUNK <br />Send a chunk of body data back to the browser.
147 <li>GET_BODY_CHUNK <br />Get further data from the request if it hasn't all
148 been transferred yet. This is necessary because the packets have a fixed
149 maximum size and arbitrary amounts of data can be included the body of a
150 request (for uploaded files, for example). (Note: this is unrelated to
151 HTTP chunked transfer).</li>
152 <li>END_RESPONSE <br /> Finish the request-handling cycle.</li>
154 <p>Each message is accompanied by a differently formatted packet of data.
155 See Response Packet Structures below for details.</p>
156 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
157 <div class="section">
158 <h2><a name="basppacketstruct" id="basppacketstruct">Basic Packet Structure</a> <a title="Permanent link" href="#basppacketstruct" class="permalink">¶</a></h2>
159 <p>There is a bit of an XDR heritage to this protocol, but it differs
160 in lots of ways (no 4 byte alignment, for example).</p>
161 <p>AJP13 uses network byte order for all data types.</p>
162 <p>There are four data types in the protocol: bytes, booleans,
163 integers and strings.</p>
165 <dt><strong>Byte</strong></dt><dd>A single byte.</dd>
166 <dt><strong>Boolean</strong></dt>
167 <dd>A single byte, <code>1 = true</code>, <code>0 = false</code>.
168 Using other non-zero values as true (i.e. C-style) may work in some places,
169 but it won't in others.</dd>
170 <dt><strong>Integer</strong></dt>
171 <dd>A number in the range of <code>0 to 2^16 (32768)</code>. Stored in
172 2 bytes with the high-order byte first.</dd>
173 <dt><strong>String</strong></dt>
174 <dd>A variable-sized string (length bounded by 2^16). Encoded with
175 the length packed into two bytes first, followed by the string
176 (including the terminating '\0'). Note that the encoded length does
177 <strong>not</strong> include the trailing '\0' -- it is like
178 <code>strlen</code>. This is a touch confusing on the Java side, which
179 is littered with odd autoincrement statements to skip over these
180 terminators. I believe the reason this was done was to allow the C
181 code to be extra efficient when reading strings which the servlet
182 container is sending back -- with the terminating \0 character, the
183 C code can pass around references into a single buffer, without copying.
184 if the \0 was missing, the C code would have to copy things out in order
185 to get its notion of a string.</dd>
189 <p>According to much of the code, the max packet size is <code>
190 8 * 1024 bytes (8K)</code>. The actual length of the packet is encoded in
193 <h3>Packet Headers</h3>
194 <p>Packets sent from the server to the container begin with
195 <code>0x1234</code>. Packets sent from the container to the server
196 begin with <code>AB</code> (that's the ASCII code for A followed by the
197 ASCII code for B). After those first two bytes, there is an integer
198 (encoded as above) with the length of the payload. Although this might
199 suggest that the maximum payload could be as large as 2^16, in fact, the
200 code sets the maximum to be 8K.</p>
204 <th colspan="6"><em>Packet Format (Server->Container)</em></th>
218 <td colspan="2">Data Length (n)</td>
225 <th colspan="6"><em>Packet Format (Container->Server)</em></th>
239 <td colspan="2">Data Length (n)</td>
243 <p>For most packets, the first byte of the payload encodes the type of
244 message. The exception is for request body packets sent from the server to
245 the container -- they are sent with a standard packet header (<code>
246 0x1234</code> and then length of the packet), but without any prefix code
248 <p>The web server can send the following messages to the servlet
254 <td>Type of Packet</td>
259 <td>Forward Request</td>
260 <td>Begin the request-processing cycle with the following data</td>
265 <td>The web server asks the container to shut itself down.</td>
270 <td>The web server asks the container to take control
271 (secure login phase).</td>
276 <td>The web server asks the container to respond quickly with a CPong.
282 <td>Size (2 bytes) and corresponding body data.</td>
285 <p>To ensure some basic security, the container will only actually do the
286 <code>Shutdown</code> if the request comes from the same machine on which
288 <p>The first <code>Data</code> packet is send immediately after the
289 <code>Forward Request</code> by the web server.</p>
290 <p>The servlet container can send the following types of messages to the
296 <td>Type of Packet</td>
301 <td>Send Body Chunk</td>
302 <td>Send a chunk of the body from the servlet container to the web
303 server (and presumably, onto the browser). </td>
307 <td>Send Headers</td>
308 <td>Send the response headers from the servlet container to the web
309 server (and presumably, onto the browser).</td>
313 <td>End Response</td>
314 <td>Marks the end of the response (and thus the request-handling cycle).
319 <td>Get Body Chunk</td>
320 <td>Get further data from the request if it hasn't all been
321 transferred yet.</td>
326 <td>The reply to a CPing request</td>
329 <p>Each of the above messages has a different internal structure, detailed
332 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
333 <div class="section">
334 <h2><a name="rpacetstruct" id="rpacetstruct">Request Packet Structure</a> <a title="Permanent link" href="#rpacetstruct" class="permalink">¶</a></h2>
335 <p>For messages from the server to the container of type
336 <em>Forward Request</em>:</p>
337 <div class="example"><pre>AJP13_FORWARD_REQUEST :=
338 prefix_code (byte) 0x02 = JK_AJP13_FORWARD_REQUEST
345 server_port (integer)
347 num_headers (integer)
348 request_headers *(req_header_name req_header_value)
349 attributes *(attribut_name attribute_value)
350 request_terminator (byte) OxFF</pre></div>
351 <p>The <code>request_headers</code> have the following structure:
352 </p><div class="example"><pre>req_header_name :=
353 sc_req_header_name | (string) [see below for how this is parsed]
355 sc_req_header_name := 0xA0xx (integer)
357 req_header_value := (string)</pre></div>
358 <p>The <code>attributes</code> are optional and have the following
360 <div class="example"><pre>attribute_name := sc_a_name | (sc_a_req_attribute string)
362 attribute_value := (string)</pre></div>
363 <p>Not that the all-important header is <code>content-length</code>,
364 because it determines whether or not the container looks for another
365 packet immediately.</p>
366 <h3>Detailed description of the elements of Forward Request
368 <h3>Request prefix</h3>
369 <p>For all requests, this will be 2. See above for details on other Prefix
373 <p>The HTTP method, encoded as a single byte:</p>
375 <tr><td>Command Name</td><td>Code</td></tr>
376 <tr><td>OPTIONS</td><td>1</td></tr>
377 <tr><td>GET</td><td>2</td></tr>
378 <tr><td>HEAD</td><td>3</td></tr>
379 <tr><td>POST</td><td>4</td></tr>
380 <tr><td>PUT</td><td>5</td></tr>
381 <tr><td>DELETE</td><td>6</td></tr>
382 <tr><td>TRACE</td><td>7</td></tr>
383 <tr><td>PROPFIND</td><td>8</td></tr>
384 <tr><td>PROPPATCH</td><td>9</td></tr>
385 <tr><td>MKCOL</td><td>10</td></tr>
386 <tr><td>COPY</td><td>11</td></tr>
387 <tr><td>MOVE</td><td>12</td></tr>
388 <tr><td>LOCK</td><td>13</td></tr>
389 <tr><td>UNLOCK</td><td>14</td></tr>
390 <tr><td>ACL</td><td>15</td></tr>
391 <tr><td>REPORT</td><td>16</td></tr>
392 <tr><td>VERSION-CONTROL</td><td>17</td></tr>
393 <tr><td>CHECKIN</td><td>18</td></tr>
394 <tr><td>CHECKOUT</td><td>19</td></tr>
395 <tr><td>UNCHECKOUT</td><td>20</td></tr>
396 <tr><td>SEARCH</td><td>21</td></tr>
397 <tr><td>MKWORKSPACE</td><td>22</td></tr>
398 <tr><td>UPDATE</td><td>23</td></tr>
399 <tr><td>LABEL</td><td>24</td></tr>
400 <tr><td>MERGE</td><td>25</td></tr>
401 <tr><td>BASELINE_CONTROL</td><td>26</td></tr>
402 <tr><td>MKACTIVITY</td><td>27</td></tr>
404 <p>Later version of ajp13, will transport
405 additional methods, even if they are not in this list.</p>
407 <h3>protocol, req_uri, remote_addr, remote_host, server_name,
408 server_port, is_ssl</h3>
409 <p>These are all fairly self-explanatory. Each of these is required, and
410 will be sent for every request.</p>
413 <p>The structure of <code>request_headers</code> is the following:
414 First, the number of headers <code>num_headers</code> is encoded.
415 Then, a series of header name <code>req_header_name</code> / value
416 <code>req_header_value</code> pairs follows.
417 Common header names are encoded as integers,
418 to save space. If the header name is not in the list of basic headers,
419 it is encoded normally (as a string, with prefixed length). The list of
420 common headers <code>sc_req_header_name</code>and their codes
421 is as follows (all are case-sensitive):</p>
423 <tr><td>Name</td><td>Code value</td><td>Code name</td></tr>
424 <tr><td>accept</td><td>0xA001</td><td>SC_REQ_ACCEPT</td></tr>
425 <tr><td>accept-charset</td><td>0xA002</td><td>SC_REQ_ACCEPT_CHARSET
427 <tr><td>accept-encoding</td><td>0xA003</td><td>SC_REQ_ACCEPT_ENCODING
429 <tr><td>accept-language</td><td>0xA004</td><td>SC_REQ_ACCEPT_LANGUAGE
431 <tr><td>authorization</td><td>0xA005</td><td>SC_REQ_AUTHORIZATION</td>
433 <tr><td>connection</td><td>0xA006</td><td>SC_REQ_CONNECTION</td></tr>
434 <tr><td>content-type</td><td>0xA007</td><td>SC_REQ_CONTENT_TYPE</td>
436 <tr><td>content-length</td><td>0xA008</td><td>SC_REQ_CONTENT_LENGTH</td>
438 <tr><td>cookie</td><td>0xA009</td><td>SC_REQ_COOKIE</td></tr>
439 <tr><td>cookie2</td><td>0xA00A</td><td>SC_REQ_COOKIE2</td></tr>
440 <tr><td>host</td><td>0xA00B</td><td>SC_REQ_HOST</td></tr>
441 <tr><td>pragma</td><td>0xA00C</td><td>SC_REQ_PRAGMA</td></tr>
442 <tr><td>referer</td><td>0xA00D</td><td>SC_REQ_REFERER</td></tr>
443 <tr><td>user-agent</td><td>0xA00E</td><td>SC_REQ_USER_AGENT</td></tr>
445 <p>The Java code that reads this grabs the first two-byte integer and if
446 it sees an <code>'0xA0'</code> in the most significant
447 byte, it uses the integer in the second byte as an index into an array of
448 header names. If the first byte is not <code>0xA0</code>, it assumes that
449 the two-byte integer is the length of a string, which is then read in.</p>
450 <p>This works on the assumption that no header names will have length
451 greater than <code>0x9FFF (==0xA000 - 1)</code>, which is perfectly
452 reasonable, though somewhat arbitrary.</p>
453 <div class="note"><h3>Note:</h3>
454 The <code>content-length</code> header is extremely
455 important. If it is present and non-zero, the container assumes that
456 the request has a body (a POST request, for example), and immediately
457 reads a separate packet off the input stream to get that body.
461 <p>The attributes prefixed with a <code>?</code>
462 (e.g. <code>?context</code>) are all optional. For each, there is a
463 single byte code to indicate the type of attribute, and then its value
464 (string or integer). They can be sent in any order (though the C code
465 always sends them in the order listed below). A special terminating code
466 is sent to signal the end of the list of optional attributes. The list of
469 <tr><td>Information</td><td>Code Value</td><td>Type Of Value</td><td>Note</td></tr>
470 <tr><td>?context</td><td>0x01</td><td>-</td><td>Not currently implemented
472 <tr><td>?servlet_path</td><td>0x02</td><td>-</td><td>Not currently implemented
474 <tr><td>?remote_user</td><td>0x03</td><td>String</td><td /></tr>
475 <tr><td>?auth_type</td><td>0x04</td><td>String</td><td /></tr>
476 <tr><td>?query_string</td><td>0x05</td><td>String</td><td /></tr>
477 <tr><td>?jvm_route</td><td>0x06</td><td>String</td><td /></tr>
478 <tr><td>?ssl_cert</td><td>0x07</td><td>String</td><td /></tr>
479 <tr><td>?ssl_cipher</td><td>0x08</td><td>String</td><td /></tr>
480 <tr><td>?ssl_session</td><td>0x09</td><td>String</td><td /></tr>
481 <tr><td>?req_attribute</td><td>0x0A</td><td>String</td><td>Name (the name of the
482 attribute follows)</td></tr>
483 <tr><td>?ssl_key_size</td><td>0x0B</td><td>Integer</td><td /></tr>
484 <tr><td>?secret</td><td>0x0C</td><td>String</td><td>Sent if secret is configured</td></tr>
485 <tr><td>are_done</td><td>0xFF</td><td>-</td><td>request_terminator</td></tr>
487 <p>The <code>context</code> and <code>servlet_path</code> are not
488 currently set by the C code, and most of the Java code completely ignores
489 whatever is sent over for those fields (and some of it will actually break
490 if a string is sent along after one of those codes). I don't know if this
491 is a bug or an unimplemented feature or just vestigial code, but it's
492 missing from both sides of the connection.</p>
493 <p>The <code>remote_user</code> and <code>auth_type</code> presumably
494 refer to HTTP-level authentication, and communicate the remote user's
495 username and the type of authentication used to establish their identity
496 (e.g. Basic, Digest).</p>
497 <p>The <code>query_string</code>, <code>ssl_cert</code>,
498 <code>ssl_cipher</code>, <code>ssl_session</code> and
499 <code>ssl_key_size</code> refer to the
500 corresponding pieces of HTTP and HTTPS.</p>
501 <p>The <code>jvm_route</code>, is used to support sticky
502 sessions -- associating a user's sesson with a particular Tomcat instance
503 in the presence of multiple, load-balancing servers.</p>
504 <p>Beyond this list of basic attributes, any number of other attributes
505 can be sent via the <code>req_attribute</code> code <code>0x0A</code>.
506 A pair of strings to represent the attribute name and value are sent
507 immediately after each instance of that code. Environment values are passed
508 in via this method.</p>
509 <p>The <code>secret</code> is sent when the <code>secret=secret_keyword</code> parameter is
511 <code class="directive"><a href="../mod/mod_proxy.html#proxypass">ProxyPass</a></code> or
512 <code class="directive"><a href="../mod/mod_proxy.html#balancermember">BalancerMember</a></code> directives.
513 The backend needs to support secret and the values must match.
514 <code>request.secret</code> or <code>requiredSecret</code> are documented in the AJP
515 configuration of the Apache Tomcat.</p>
516 <p>Finally, after all the attributes have been sent, the attribute
517 terminator, <code>0xFF</code>, is sent. This signals both the end of the
518 list of attributes and also then end of the Request Packet.</p>
520 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
521 <div class="section">
522 <h2><a name="resppacketstruct" id="resppacketstruct">Response Packet Structure</a> <a title="Permanent link" href="#resppacketstruct" class="permalink">¶</a></h2>
523 <p>for messages which the container can send back to the server.</p>
524 <div class="example"><pre>AJP13_SEND_BODY_CHUNK :=
526 chunk_length (integer)
528 chunk_terminator (byte) Ox00
531 AJP13_SEND_HEADERS :=
533 http_status_code (integer)
534 http_status_msg (string)
535 num_headers (integer)
536 response_headers *(res_header_name header_value)
539 sc_res_header_name | (string) [see below for how this is parsed]
541 sc_res_header_name := 0xA0 (byte)
543 header_value := (string)
545 AJP13_END_RESPONSE :=
550 AJP13_GET_BODY_CHUNK :=
552 requested_length (integer)</pre></div>
554 <h3>Send Body Chunk</h3>
555 <p>The chunk is basically binary data, and is sent directly back to the
558 <h3>Send Headers</h3>
559 <p>The status code and message are the usual HTTP things
560 (e.g. <code>200</code> and <code>OK</code>). The response header names are
561 encoded the same way the request header names are. See header_encoding above
562 for details about how the codes are distinguished from the strings.<br />
563 The codes for common headers are:</p>
565 <tr><td>Name</td><td>Code value</td></tr>
566 <tr><td>Content-Type</td><td>0xA001</td></tr>
567 <tr><td>Content-Language</td><td>0xA002</td></tr>
568 <tr><td>Content-Length</td><td>0xA003</td></tr>
569 <tr><td>Date</td><td>0xA004</td></tr>
570 <tr><td>Last-Modified</td><td>0xA005</td></tr>
571 <tr><td>Location</td><td>0xA006</td></tr>
572 <tr><td>Set-Cookie</td><td>0xA007</td></tr>
573 <tr><td>Set-Cookie2</td><td>0xA008</td></tr>
574 <tr><td>Servlet-Engine</td><td>0xA009</td></tr>
575 <tr><td>Status</td><td>0xA00A</td></tr>
576 <tr><td>WWW-Authenticate</td><td>0xA00B</td></tr>
578 <p> After the code or the string header name, the header value is
579 immediately encoded.</p>
581 <h3>End Response</h3>
582 <p>Signals the end of this request-handling cycle. If the
583 <code>reuse</code> flag is true <code>(anything other than 0 in the actual
584 C code)</code>, this TCP connection can now be used to handle new incoming
585 requests. If <code>reuse</code> is false (==0), the connection should
588 <h3>Get Body Chunk</h3>
589 <p>The container asks for more data from the request (If the body was
590 too large to fit in the first packet sent over or when the request is
591 chunked). The server will send a body packet back with an amount of data
592 which is the minimum of the <code>request_length</code>, the maximum send
593 body size <code>(8186 (8 Kbytes - 6))</code>, and the number of bytes
594 actually left to send from the request body.<br />
595 If there is no more data in the body (i.e. the servlet container is
596 trying to read past the end of the body), the server will send back an
597 <em>empty</em> packet, which is a body packet with a payload length of 0.
598 <code>(0x12,0x34,0x00,0x00)</code></p>
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