Yar拓展自带了一个Yar的PHP客户端，这一章先讲yar的同步客户端实现。
我们假设使用代码如下：
//demo.php
$client = new Yar_Client("http://www.demoserver.com/rpc/s.php");
$client->SetOpt(YAR_OPT_CONNECT_TIMEOUT, 1000);
echo $client->getOrderMoney(123456);
Client构造器
从Yar_Client类的构造器看起，Yar_Client的源码实现如下：
//yar_client.c
/* {{{ proto Yar_Client::__construct($uri[, array $options = NULL]) */
PHP_METHOD(yar_client, __construct) {
zend_string *url;
zval *options = NULL;
//使用url,option变量来接收构造器的两个参数，第一个为字符串，第二个为可选参数，可空，类型为数组
if (zend_parse_parameters_throw(ZEND_NUM_ARGS(), "S|a!", &url, &options) == FAILURE) {
return;
}
zend_update_property_str(yar_client_ce, getThis(), ZEND_STRL("_uri"), url);
if (strncasecmp(ZSTR_VAL(url), "http://", sizeof("http://") - 1) == 0
|| strncasecmp(ZSTR_VAL(url), "https://", sizeof("https://") - 1) == 0) {
//_protocol的默认值是 YAR_CLIENT_PROTOCOL_HTTP,无需处理
} else if (strncasecmp(ZSTR_VAL(url), "tcp://", sizeof("tcp://") - 1) == 0) {
zend_update_property_long(yar_client_ce, getThis(), ZEND_STRL("_protocol"), YAR_CLIENT_PROTOCOL_TCP);
} else if (strncasecmp(ZSTR_VAL(url), "unix://", sizeof("unix://") - 1) == 0) {
zend_update_property_long(yar_client_ce, getThis(), ZEND_STRL("_protocol"), YAR_CLIENT_PROTOCOL_UNIX);
} else {
php_yar_client_trigger_error(1, YAR_ERR_PROTOCOL, "unsupported protocol address %s", ZSTR_VAL(url));
return;
}
if (options) {
zend_update_property(yar_client_ce, getThis(), ZEND_STRL("_options"), options);
}
}
/* }}} */
Yar_Client的构造器就是将options参数，以及从$uri中解析出的通信协议写入成员变量而已。
万能的__call()
不像Java系的RpcClient实现，动不动来个动态代理设计，在PHP中一个__call()足以动态"生成"任意远程方法。
对Yar_Client实例的所有调用，都直接通过__call()魔术方法对远程Yar服务器执行远程调用。
/* {{{ proto Yar_Client::__call($method, $parameters = NULL) */
PHP_METHOD(yar_client, __call) {
zval *params, *protocol, rv;
zend_string *method;
if (zend_parse_parameters(ZEND_NUM_ARGS(), "Sa", &method, ¶ms) == FAILURE) {
return;
}
protocol = zend_read_property(yar_client_ce, getThis(), ZEND_STRL("_protocol"), 0, &rv);
//Yar拓展目前客户端支持UnixSocket Tcp Http三种协议，根据使用的uri隐式确认，不同的协议会使用不同的传输器
switch (Z_LVAL_P(protocol)) {
case YAR_CLIENT_PROTOCOL_TCP:
case YAR_CLIENT_PROTOCOL_UNIX:
case YAR_CLIENT_PROTOCOL_HTTP:
if ((php_yar_client_handle(Z_LVAL_P(protocol), getThis(), method, params, return_value))) {
return;
}
break;
default:
php_error_docref(NULL, E_WARNING, "unsupported protocol %ld", Z_LVAL_P(protocol));
break;
}
RETURN_FALSE;
}
/* }}} */
而Yar_Client->__call()的唯一有效操作是执行php_yar_client_handle()
static int php_yar_client_handle(int protocol, zval *client, zend_string *method, zval *params, zval *retval) /* {{{ */ {
char *msg;
zval *uri, *options;
zval rv;
const yar_transport_t *factory;
yar_transport_interface_t *transport;
yar_request_t *request;
yar_response_t *response;
int flags = 0;
uri = zend_read_property(yar_client_ce, client, ZEND_STRL("_uri"), 0, &rv);
//根据协议(from uri)获取传输器实例
if (protocol == YAR_CLIENT_PROTOCOL_HTTP) {
factory = php_yar_transport_get(ZEND_STRL("curl"));
} else if (protocol == YAR_CLIENT_PROTOCOL_TCP || protocol == YAR_CLIENT_PROTOCOL_UNIX) {
factory = php_yar_transport_get(ZEND_STRL("sock"));
} else {
return 0;
}
//传输器和传输器工厂的细节见传输器章节
transport = factory->init();
options = zend_read_property(yar_client_ce, client, ZEND_STRL("_options"), 1, &rv);
if (IS_ARRAY != Z_TYPE_P(options)) {
options = NULL;
}
//构造request
if (!(request = php_yar_request_instance(method, params, options))) {
transport->close(transport);
factory->destroy(transport);
return 0;
}
if (YAR_G(allow_persistent)) {
if (options) {
zval *flag = php_yar_client_get_opt(options, YAR_OPT_PERSISTENT);
if (flag && (Z_TYPE_P(flag) == IS_TRUE || (Z_TYPE_P(flag) == IS_LONG && Z_LVAL_P(flag)))) {
flags |= YAR_PROTOCOL_PERSISTENT;
}
}
}
/* This is tricky to pass options in, for custom headers*/
msg = (char*)options;
//调用传输器实例的open()接口方法 (具体内容见传输器章节)
if (!transport->open(transport, Z_STR_P(uri), flags, &msg)) {
php_yar_client_trigger_error(1, YAR_ERR_TRANSPORT, msg);
php_yar_request_destroy(request);
efree(msg);
transport->close(transport);
factory->destroy(transport);
return 0;
}
DEBUG_C(ZEND_ULONG_FMT": call api '%s' at (%c)'%s' with '%d' parameters",
request->id, ZSTR_VAL(request->method), (flags & YAR_PROTOCOL_PERSISTENT)? 'p' : 'r', Z_STRVAL_P(uri),
zend_hash_num_elements(Z_ARRVAL(request->parameters)));
//调用传输器实例的send()接口方法
if (!transport->send(transport, request, &msg)) {
php_yar_client_trigger_error(1, YAR_ERR_TRANSPORT, msg);
php_yar_request_destroy(request);
efree(msg);
transport->close(transport);
factory->destroy(transport);
return 0;
}
//调用传输器实例的exec()接口方法，获取响应对应的response变量
response = transport->exec(transport, request);
if (response->status != YAR_ERR_OKEY) {
php_yar_client_handle_error(1, response);
php_yar_request_destroy(request);
php_yar_response_destroy(response);
transport->close(transport);
factory->destroy(transport);
return 0;
} else {
//打印 远程服务器的（如）标准输出，事实上没有人会糟糕到直接利用远程服务的标准输出
//这个功能的主要使用场景有两个
//1个是代替远程服务器打印各种Notice，Warning信息
//2是将RPC服务文档从RPC Server的标准输出转移到RPC Client的标准输出上。
if (response->out && ZSTR_LEN(response->out)) {
PHPWRITE(ZSTR_VAL(response->out), ZSTR_LEN(response->out));
}
//从responce中获取远程RPC方法的返回值作为PHP方法的返回值返回
ZVAL_COPY(retval, &response->retval);
//相关资源释放
php_yar_request_destroy(request);
php_yar_response_destroy(response);
transport->close(transport);
factory->destroy(transport);
return 1;
}
} /* }}} */
整理来说还是比较容易理解的，传输细节在传输器章节中再讲。
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