用C++ ulxmlrpcpp 做服务端，PHP xmlrpc 做客户端，实现前后xml通信
前一阵，想在fedora下用C++服务程序，PHP前台程序，实现一个系统。选择封装完整HTTP协议通信，且实现多线程的程序库：ulxmlrpcpp。但是这个库只封装c++的客户端和服务端，所以决定在客户端使用PHP xml-rpc。然而两个库并不能完全通信，需要修改一些源码（只修改ulxmlrpcpp代码，所以需要重新编译ulxmlrpcpp，而phpxmlrpc不需要修改）。
1.程序下载：（linux）
ulxmlrpcpp-1.7.5：http://download.csdn.net/detail/liuzhengjian123/4497109
expat-2.1.0：http://download.csdn.net/detail/liuzhengjian123/4497115
phpxmlrpc-3.0.0:http://download.csdn.net/detail/liuzhengjian123/4497119
2.程序安装：（linux）
ulxmlrpcpp和expat的安装都是使用命令：
./confingure
make
make install
注意：安装ulxmlrpcpp前需要先安装expat，还要修改部分代码（详细参考后面）。
phpxmlrpc无需安装，只要将lib目录下的三个文件xmlrpc.inc、xmlrpcs.inc和xmlrpc_wrappers.inc放到php包含目录下即可。如果只编写客户端程序，那么只需要xmlrpc.inc就够了。
3.ulxmlrpcpp代码修改：
1）ulxr_config.h文件：添加如下宏定义，或注释部分宏
#define ULXR_VERSION "1.7.5" #define ULXR_DATADIR "./" //#define ULXR_UNICODE 12）ulxmlrpcpp.h文件：取消下面宏定义的注释
#define ULXR_ENFORCE_NON_PERSISTENT3）ulxr_http_protocol.cpp文件：注释掉573和574行
//else
//setPersistent(true);
4.修改原因：
1.修改之前可能会根本无法通信，首先要编写好ulxmlrpcpp后台程序，添加调用函数。编写PHP前台程序，注意调用相应的函数，主机名 和端口：ulxmlrpcpp配置文件如下：
# IP for xmlrpc server xmlrpc_ip = localhost # Port for xmlrpc server xmlrpc_port = 32005 wbxml = 0 ssl = 0 secure = 0 chunked = 0 shutdown = 0 persistent = 0代码调试成功后可能还是无法通信的原因可能是SELinux的问题，前台会提示错误信息：
(13)Permission denied这个是SELinux的访问控制权限的问题，执行下面命令就可以解决：
# setsebool -P httpd_can_network_connect 1
2.代码调试正确之后，可能会出现服务端可以收到调用请求，但是而且回答也正常发送，但是前台PHP无法解析回答的xml，而求PHP页面一直在等待，超时后才结束。错误代码：
Code: 2 Reason: 'Invalid return payload: enable debugging to examine incoming payload (XML error: Invalid document end at line 2, column 1)'而且打开PHP调试信息函数： $c->setDebug(1); 会发现PHP页面会显示收到两个http回复包：
---GOT---
HTTP/1.1 200 OK ------------------（第一个回复包，看上去正常）
Proxy-Connection: Keep-Alive
Content-Type: text/xml
Content-Length: 130
X-Powered-By: ulxmlrpcpp/1.7.5
Server: localhost
Date: Mon Aug 13 20:15:57 2012
<?xml version="1.0" encoding="utf-8"?><methodResponse><params><param><value><i4>23</i4></value></param></params></methodResponse>
HTTP/1.1 200 OK --------------------（第二个回复包，超时错误提示）
Connection: Keep-Alive
Content-Type: text/xml
Content-Length: 306
X-Powered-By: ulxmlrpcpp/1.7.5
Server: localhost
Date: Mon Aug 13 20:16:07 2012
<?xml version="1.0" encoding="utf-8"?><methodResponse><fault><value><struct><member><name>faultCode</name><value><i4>500</i4></value></member><member><name>faultString</name><value><string>Timeout while attempting to read (using select).</string></value></member></struct></value></fault></methodResponse>
---END---
为什么会返回两个包呢，经过分析，服务端采用了连续通信方式，发送回复包后，并不断开TCP连接，一直等待前台回复，而前台PHP端并没有采用这种策略，并不会再次向客户端请求断开。所以服务端一直等到超时才主动断开连接，断开连接还向前台发送了一个超时错误提示的包（就是第二个包）。所以我们要让后台ulxmlrpcpp发送回复后就断开连接，及采用不连续的方式，所以要修改上面标题3 中的 2）和3），使其强制断开。
5.代码：
1）前台php示例代码：client.php
<html>
<head><title>xmlrpc</title></head>
<body>
<h1>Getstatename demo</h1>
<h2>Send a U.S. state number to the server and get back the state name</h2>
<h3>The code demonstrates usage of the php_xmlrpc_encode function</h3>
<?php
include("xmlrpc.inc");
// Play nice to PHP 5 installations with REGISTER_LONG_ARRAYS off
if(!isset($HTTP_POST_VARS) && isset($_POST))
{
$HTTP_POST_VARS = $_POST;
}
if(isset($HTTP_POST_VARS["stateno"]) && $HTTP_POST_VARS["stateno"]!="")
{
$stateno=(integer)$HTTP_POST_VARS["stateno"];
$f=new xmlrpcmsg('testcall_in_class_dynamic',
array(php_xmlrpc_encode($stateno))
);
print "<pre>Sending the following request:\n\n" . htmlentities($f->serialize()) . "\n\nDebug info of server data follows...\n\n";
$c=new xmlrpc_client("./RPC2", "localhost", 32005);
$c->setDebug(1);
$r=&$c->send($f);
echo htmlentities($r->serialize());
if(!$r->faultCode())
{
$v=$r->value();
print "</pre><br/>State number " . $stateno . " is "
. htmlspecialchars($v->scalarval()) . "<br/>";
// print "<HR>I got this value back<BR><PRE>" .
// htmlentities($r->serialize()). "</PRE><HR>\n";
}
else
{
print "An error occurred: ";
print "Code: " . htmlspecialchars($r->faultCode())
. " Reason: '" . htmlspecialchars($r->faultString()) . "'</pre><br/>";
}
}
else
{
$stateno = "";
}
print "<form action=\"test.php\" method=\"POST\">
<input name=\"stateno\" value=\"" . $stateno . "\"><input type=\"submit\" value=\"go\" name=\"submit\"></form>
<p>Enter a state number to query its name</p>";
?>
<hr/>
<em>$Id: client.php 2 2009-03-16 20:22:51Z ggiunta $</em>
</body>
</html>
2）后台C++示例代码：server.cpp
#include <ulxmlrpcpp/ulxmlrpcpp.h> // always first header
#include <cstring>
#include <cstdlib>
#include <ulxmlrpcpp/ulxr_tcpip_connection.h> // first, don't move: msvc #include bug
#include <ulxmlrpcpp/ulxr_ssl_connection.h>
#include <ulxmlrpcpp/ulxr_http_protocol.h>
#ifdef __WIN32__
#include <process.h>
#endif
#include "util.c"
#ifdef ULXR_MULTITHREADED
#ifdef __unix__
#include <pthread.h>
#endif
#endif
#include <iostream>
#include <cstring>
#include <memory>
#include <ulxmlrpcpp/ulxr_except.h>
#include <ulxmlrpcpp/ulxr_signature.h>
#include <ulxmlrpcpp/ulxr_mtrpc_server.h>
#ifdef __WIN32__
const unsigned num_threads = 10;
#else
const unsigned num_threads = 100;
#endif
////////////////////////////////////////////////////////////////////////
#ifdef ULXR_MULTITHREADED
ulxr::MultiThreadRpcServer *mtServer = 0;
class TestWorker
{
public:
TestWorker ()
{
}
ulxr::MethodResponse numThreads (const ulxr::MethodCall &/*calldata*/)
{
ulxr::MethodResponse resp;
resp.setResult(ulxr::Integer(mtServer->numThreads()));
return resp;
}
ulxr::MethodResponse shutdown (const ulxr::MethodCall &/*calldata*/)
{
ULXR_COUT << ULXR_PCHAR("TestWorker got signal to shut down\n");
ulxr::MethodResponse resp;
resp.setResult(ulxr::Boolean(true));
ULXR_COUT << ULXR_PCHAR(" Terminating..\n");
mtServer->terminateAllThreads();
ULXR_COUT << ULXR_PCHAR(" Returning..\n");
return resp;
}
ulxr::MethodResponse testcall (const ulxr::MethodCall &calldata)
{
ulxr::Integer I = calldata.getParam(0);
int p1 = I.getInteger();
ULXR_COUT << ULXR_PCHAR("TestWorker got call(") << p1 << ULXR_PCHAR(") \n");
ulxr::MethodResponse resp;
resp.setResult(I);
return resp;
}
};
#endif // ULXR_MULTITHREADED
////////////////////////////////////////////////////////////////////////
int main(int argc, char **argv)
{
#ifdef ULXR_MULTITHREADED
try
{
ulxr::intializeLog4J(argv[0]);
ulxr::getLogger4J()->send(ULXR_PCHAR("DEBUG"),
ULXR_PCHAR("mt_server started"),
ULXR_GET_STRING(__FILE__),
__LINE__);
ulxr::CppString host = ULXR_PCHAR("localhost");
if (argc > 1)
host = ULXR_GET_STRING(argv[1]);
unsigned port = 32005;
if (argc > 2)
port = ulxr_atoi(argv[2]);
bool wbxml = haveOption(argc, argv, "wbxml");
bool secure = haveOption(argc, argv, "ssl");
bool chunked = haveOption(argc, argv, "chunked");
bool shutme = haveOption(argc, argv, "shutdown");
bool persistent = haveOption(argc, argv, "persistent");
ulxr::CppString sec = ULXR_PCHAR("unsecured");
if (secure)
sec = ULXR_PCHAR("secured");
ULXR_COUT << ULXR_PCHAR("Serving ") << sec << ULXR_PCHAR(" rpc requests at ") << host << ULXR_PCHAR(":") << port << std::endl;
ULXR_COUT << ULXR_PCHAR("WBXML: ") << wbxml << std::endl
<< ULXR_PCHAR("Chunked transfer: ") << chunked << std::endl;
std::auto_ptr<ulxr::TcpIpConnection> conn;
#ifdef ULXR_INCLUDE_SSL_STUFF
if (secure)
{
ulxr::SSLConnection *ssl = new ulxr::SSLConnection (true, host, port);
ssl->setCryptographyData("password", "foo-cert.pem", "foo-cert.pem");
conn.reset(ssl);
}
else
#endif
#ifdef _MSC_VER
{
std::auto_ptr<ulxr::TcpIpConnection> temp(new ulxr::TcpIpConnection (true, host, port));
conn = temp;
}
#else
conn.reset(new ulxr::TcpIpConnection (true, host, port));
#endif
std::auto_ptr<ulxr::HttpProtocol> prot(new ulxr::HttpProtocol(conn.get()));
prot->setChunkedTransfer(chunked);
prot->setPersistent(persistent);
if (persistent)
conn->setTcpNoDelay(true);
if (prot->isPersistent())
ULXR_COUT << ULXR_PCHAR("Using persistent connections\n") ;
else
ULXR_COUT << ULXR_PCHAR("Using non-persistent connections\n") ;
ulxr::MultiThreadRpcServer server(prot.get(), num_threads, wbxml);
mtServer = &server;
TestWorker worker;
server.addMethod(ulxr::make_method(worker, &TestWorker::testcall),
ulxr::Signature(ulxr::Struct()),
ULXR_PCHAR("testcall_in_class_dynamic"),
ulxr::Signature(ulxr::Integer()),
ULXR_PCHAR("Testcase with a dynamic method in a class"));
server.addMethod(ulxr::make_method(worker, &TestWorker::shutdown),
ulxr::Signature(ulxr::Boolean()),
ULXR_PCHAR("testcall_shutdown"),
ulxr::Signature(),
ULXR_PCHAR("Testcase with a dynamic method in a class, shut down server, return old state"));
server.addMethod(ulxr::make_method(worker, &TestWorker::numThreads),
ulxr::Signature(ulxr::Integer()),
ULXR_PCHAR("testcall_numthreads"),
ulxr::Signature(),
ULXR_PCHAR("Returns number of installed threads at startup"));
unsigned started = server.dispatchAsync();
ULXR_COUT << ULXR_PCHAR("Started ") << started << ULXR_PCHAR(" threads for dispatching rpc requests\n");
if (shutme)
{
ULXR_COUT << ULXR_CHAR("sleep before shutting down\n");
#ifdef __unix__
usleep(5 * 1000 * 1000);
#elif defined(__WIN32__)
Sleep(5 * 1000);
#else
#error platform not supported
#endif
ULXR_COUT << ULXR_CHAR("shutdownAllThreads\n");
server.shutdownAllThreads();
}
server.waitAsync(false, true);
ULXR_COUT << ULXR_PCHAR("Done.\n");
}
catch(ulxr::Exception& ex)
{
ULXR_COUT << ULXR_PCHAR("Error occured: ") << ULXR_GET_STRING(ex.why()) << std::endl;
return 1;
}
catch(...)
{
ULXR_COUT << ULXR_PCHAR("Unknown error occured\n");
return 1;
}
ULXR_COUT << ULXR_PCHAR("Ready.") << std::endl;
#else // ULXR_MULTITHREADED
ULXR_COUT << ULXR_PCHAR("Multithreaded support disabled.");
#endif
return 0;
}
6.总结
本文重点就是第3点的代码修改，虽然需要修改的地方并不是很多，但是也让我花了好长时间去分析ulxmlrpcpp源代码，才找出错误原因的，希望能给大家带来一些帮助。