Zend_XmlRpc_Client
Introdución
Zend Framework provee soporte para consumo remoto para servicios
XML-RPC
como un cliente en el paquete
Zend_XmlRpc_Client
. Su mejor
característica es la conversión automática de tipos entre
PHP
y
XML-RPC
, un servidor
de objeto proxy, y acceso a capacidades de instrospección del
servidor.
Method Calls
El constructor de
Zend_XmlRpc_Client
recibe la
URL
del servidor
XML-RPC
como su primer parámetro. La nueva
instacia devuelta puede ser usada para llamar
cualquier número de
métodos remotos en el punto final.
Para llamar un método remoto con el cliente
XML-RPC
, instáncealo y usa el método de
instancia
call()
. El código de ejemplo a
continuación utiliza una demostración en el servidor
XML-RPC
en el sitio web de Zend Framework .
Puede utilizarlo para probar o explorar los
componentes
Zend_XmlRpc
.
XML-RPC Method Call
call('test.sayHello');
// hello
]]>
El valor
XML-RPC
devuelto desde la llamada al
método remoto automáticamente será convertida al tipo nativo
PHP
equivalente . En el ejemplo anterior, es
devuelto un
string
PHP
y está listo para ser usado inmediatamente.
El primer parámetro del método
call()
recibe el nombre del método remoto que llamar. Si el método remoto
requiere algún
parámetro, éste puede ser enviado por el suministro
de un segundo, parámetro opcional a
call()
con un
array
de valores para pasar el
método remoto:
XML-RPC Method Call with Parameters
call('test.sayHello', array($arg1, $arg2));
// $result es un tipo nativo PHP
]]>
si el método remoto no requiere parámetros, este parámetro
opcional podrá ser excluido o
se puede pasar un
array()
vacío. El array de parámeters
para el método repoto puede contener tipos nativos
PHP
s, objetos
Zend_XmlRpc_Value
, o una combinación
de estos.
El método
call()
convertirá
automáticamente la respuesta
XML-RPC
y devolverá
su tipo nativo
PHP
equivalente. Un objeto
Zend_XmlRpc_Response
para el valor
devuelto también estará disponible para llamar el método
getLastResponse()
después de la
llamada.
Tipos y Conversiones
Algunas llamadas a métodos remoto requieren parámetros. Éstos son
dados al método
call()
de
Zend_XmlRpc_Client
como un array en el
segundo parámetro. Cada parámetro puede ser dado como un tipo nativo
PHP
, que será convertido automáticamente, o
como un objeto que representa un tipo específico
de
XML-RPC
(uno de los objetos
Zend_XmlRpc_Value
).
Tipos Nativos PHP como Parámetro
Los parámetros pueden ser pasados a
call()
como variables
PHP
nativas, ya sea un
string
,
integer
,
float
,
boolean
,
array
, o un
object
. En este caso, cada tipo
PHP
nativo será autodetectado y convertido en uno de los tipos
XML-RPC
de acuerdo con esta tabla:
Tipos de Conversión entre PHP y
XML-RPC
Tipo Nativo
PHP
Tipo
XML-RPC
integer
int
Zend_Crypt_Math_BigInteger
i8
double
double
boolean
boolean
string
string
null
nil
array
array
array asociativo
struct
object
array
Zend_Date
dateTime.iso8601
DateTime
dateTime.iso8601
¿A qué tipo se convierten los arrays Vacios?
Passing an empty array to an
XML-RPC
method is problematic,
as it could represent either an array or a struct.
Zend_XmlRpc_Client
detects such conditions and
makes a request to the server's
system.methodSignature
method to determine the
appropriate
XML-RPC
type to cast to.
However, this in itself can lead to issues. First off,
servers that do not
support
system.methodSignature
will log failed
requests, and
Zend_XmlRpc_Client
will resort to
casting the value to an
XML-RPC
array type. Additionally,
this means that any call with array arguments will
result in
an additional call to the remote server.
To disable the lookup entirely, you can call the
setSkipSystemLookup()
method prior to making
your
XML-RPC
call:
setSkipSystemLookup(true);
$result = $client->call('foo.bar', array(array()));
]]>
Zend_XmlRpc_Value Objects as Parameters
Parameters may also be created as
Zend_XmlRpc_Value
instances to specify an exact
XML-RPC
type. The primary reasons
for doing this are:
When you want to make sure the correct parameter
type is passed to the
procedure (i.e. the
procedure requires an integer and you may get it
from
a database as a string)
When the procedure requires
base64
or
dateTime.iso8601
type (which doesn't exists as a
PHP
native type)
When auto-conversion may fail (i.e. you want to
pass an empty
XML-RPC
struct as a parameter. Empty
structs are represented as empty arrays in
PHP
but, if you give an empty array as a parameter it
will be auto-converted
to an
XML-RPC
array since
it's not an associative array)
There are two ways to create a
Zend_XmlRpc_Value
object: instantiate one of the
Zend_XmlRpc_Value
subclasses directly, or use the static factory method
Zend_XmlRpc_Value::getXmlRpcValue()
.
Zend_XmlRpc_Value Objects for XML-RPC Types
XML-RPC
Type
Zend_XmlRpc_Value
Constant
Zend_XmlRpc_Value
Object
int
Zend_XmlRpc_Value::XMLRPC_TYPE_INTEGER
Zend_XmlRpc_Value_Integer
i8
Zend_XmlRpc_Value::XMLRPC_TYPE_I8
Zend_XmlRpc_Value_BigInteger
ex:i8
Zend_XmlRpc_Value::XMLRPC_TYPE_APACHEI8
Zend_XmlRpc_Value_BigInteger
double
Zend_XmlRpc_Value::XMLRPC_TYPE_DOUBLE
Zend_XmlRpc_Value_Double
boolean
Zend_XmlRpc_Value::XMLRPC_TYPE_BOOLEAN
Zend_XmlRpc_Value_Boolean
string
Zend_XmlRpc_Value::XMLRPC_TYPE_STRING
Zend_XmlRpc_Value_String
nil
Zend_XmlRpc_Value::XMLRPC_TYPE_NIL
Zend_XmlRpc_Value_Nil
ex:nil
Zend_XmlRpc_Value::XMLRPC_TYPE_APACHENIL
Zend_XmlRpc_Value_Nil
base64
Zend_XmlRpc_Value::XMLRPC_TYPE_BASE64
Zend_XmlRpc_Value_Base64
dateTime.iso8601
Zend_XmlRpc_Value::XMLRPC_TYPE_DATETIME
Zend_XmlRpc_Value_DateTime
array
Zend_XmlRpc_Value::XMLRPC_TYPE_ARRAY
Zend_XmlRpc_Value_Array
struct
Zend_XmlRpc_Value::XMLRPC_TYPE_STRUCT
Zend_XmlRpc_Value_Struct
Automatic Conversion
When building a new
Zend_XmlRpc_Value
object, its value is set by a
PHP
type. The
PHP
type will be converted to the specified type using
PHP
casting. For example, if a string is given as a
value to the
Zend_XmlRpc_Value_Integer
object, it will be converted using
(int)$value
.
Server Proxy Object
Another way to call remote methods with the
XML-RPC
client is to
use the server proxy. This is a
PHP
object that proxies a remote
XML-RPC
namespace, making it work as close to a native
PHP
object as possible.
To instantiate a server proxy, call the
getProxy()
instance method of
Zend_XmlRpc_Client
. This will
return an instance of
Zend_XmlRpc_Client_ServerProxy
.
Any method call on the server proxy object will be forwarded to
the remote, and
parameters may be passed like any other
PHP
method.
Proxy the Default Namespace
getProxy(); // Proxy the default namespace
$hello = $service->test->sayHello(1, 2); // test.Hello(1, 2) returns "hello"
]]>
The
getProxy()
method receives an optional argument
specifying which namespace of the remote server to
proxy. If it
does not receive a namespace, the default namespace will be
proxied. In the
next example, the 'test' namespace
will be proxied:
Proxy Any Namespace
getProxy('test'); // Proxy the "test" namespace
$hello = $test->sayHello(1, 2); // test.Hello(1,2) returns "hello"
]]>
If the remote server supports nested namespaces of any depth,
these can also be used
through the server proxy. For example, if
the server in the example above had a method
test.foo.bar()
, it could be called as
$test->foo->bar()
.
Error Handling
Two kinds of errors can occur during an
XML-RPC
method call:
HTTP
errors and
XML-RPC
faults. The
Zend_XmlRpc_Client
recognizes each and provides the ability
to detect and trap them independently.
HTTP Errors
If any
HTTP
error occurs, such as the remote
HTTP
server returns a
404 Not Found
, a
Zend_XmlRpc_Client_HttpException
will be thrown.
Handling HTTP Errors
call('bar', array($arg1, $arg2));
} catch (Zend_XmlRpc_Client_HttpException $e) {
// $e->getCode() returns 404
// $e->getMessage() returns "Not Found"
}
]]>
Regardless of how the
XML-RPC
client is used, the
Zend_XmlRpc_Client_HttpException
will be thrown
whenever an
HTTP
error occurs.
XML-RPC Faults
An
XML-RPC
fault is analogous to a
PHP
exception. It is a special type returned from an
XML-RPC
method
call that has both an error code and an error message.
XML-RPC
faults are handled differently depending on the context of how the
Zend_XmlRpc_Client
is used.
When the
call()
method or the server
proxy object is used, an
XML-RPC
fault will result in a
Zend_XmlRpc_Client_FaultException
being thrown.
The code and message of the exception will map directly to
their
respective values in the original
XML-RPC
fault
response.
Handling XML-RPC Faults
call('badMethod');
} catch (Zend_XmlRpc_Client_FaultException $e) {
// $e->getCode() returns 1
// $e->getMessage() returns "Unknown method"
}
]]>
Cuando el método
call()
es usado
para realizar la petición,
Zend_XmlRpc_Client_FaultException
será lanzado como error. Un objeto
Zend_XmlRpc_Response
conteniendo el
error estará disponible llamando a
getLastResponse()
.
Cuando el método
doRequest()
sea
usado para realizar una petición, no lanzará una excepción. En
vez de eso,
devolverá un objeto
Zend_XmlRpc_Response
que contendrá
el error. Esto puede comprobarse con
isFault()
método instancia de
Zend_XmlRpc_Response
.
Server Introspection
Some
XML-RPC
servers support the de facto introspection methods
under the
XML-RPC
system.
namespace.
Zend_XmlRpc_Client
provides special support for servers with
these capabilities.
A
Zend_XmlRpc_Client_ServerIntrospection
instance may be
retrieved by calling the
getIntrospector()
method of
Zend_XmlRpcClient
. It can then be used to perform introspection
operations on the server.
From Request to Response
Under the hood, the
call()
instance method of
Zend_XmlRpc_Client
builds a request object
(
Zend_XmlRpc_Request
) and sends it to another method,
doRequest()
, that returns a response object
(
Zend_XmlRpc_Response
).
The
doRequest()
method is also available for use directly:
Processing Request to Response
setMethod('test.sayHello');
$request->setParams(array('foo', 'bar'));
$client->doRequest($request);
// $client->getLastRequest() returns instanceof Zend_XmlRpc_Request
// $client->getLastResponse() returns instanceof Zend_XmlRpc_Response
]]>
Whenever an
XML-RPC
method call is made by the client through any
means, either the
call()
method,
doRequest()
method, or server proxy, the last request
object and its resultant response object will
always be available
through the methods
getLastRequest()
and
getLastResponse()
respectively.
HTTP Client and Testing
In all of the prior examples, an
HTTP
client was never specified.
When this is the case, a new instance of
Zend_Http_Client
will be created with its default
options and used by
Zend_XmlRpc_Client
automatically.
The
HTTP
client can be retrieved at any time with the
getHttpClient()
method. For most cases, the default
HTTP
client will be sufficient. However, the
setHttpClient()
method allows for a different
HTTP
client instance to be injected.
The
setHttpClient()
is particularly useful for unit testing.
When combined with the
Zend_Http_Client_Adapter_Test
, remote
services can be mocked out for testing. See the unit tests for
Zend_XmlRpc_Client
for examples of how to do this.