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# API

API -- Class documentation of the package

## XML_RPC_Client

This is the basic class used to represent a client of an XML-RPC server.

### Creation

The constructor has the following syntax:

``$client = new XML_RPC_Client` (string $path, string $server [, integer $port [, string $proxy [, integer $proxy_port [, string $proxy_user [, string $proxy_pass]]]]])`

string `$path`

  the path and name of the RPC server script you want the request to go to

string `$server`

  the URL of the remote server to connect to. If this parameter doesn't specify a protocol and $port is 443, ssl:// is assumed.

integer `$port`

  a port for connecting to the remote server. Defaults to 80 for http:// connections and 443 for https:// and ssl:// connections.

string `$proxy`

  the URL of the proxy server to use, if any. If this parameter doesn't specify a protocol and $port is 443, ssl:// is assumed.

integer `$proxy_port`

  a port for connecting to the remote server. Defaults to 8080 for http:// connections and 443 for https:// and ssl:// connections.

string `$proxy_user`

  a user name for accessing the proxy server

string `$proxy_pass`

  a password for accessing the proxy server

> Note: In order to use SSL connections, your PHP installation must have the `openssl` extension enabled.

Here's an example client set up to query Userland's XML-RPC server at betty.userland.com:

    $client = new XML_RPC_Client('/RPC2', 'betty.userland.com');

### Methods

This class supports the following methods.

#### send()

This method takes the form:

``$response = $client->send` ($xmlrpc_message [, $timeout])`

Where `$xmlrpc_message` is an instance of XML_RPC_Message and `$response` is an instance of XML_RPC_Response (see XML_RPC_Response).

The `$timeout` is optional, and will be set to `0` (wait forever) if omitted. This timeout value is passed to fsockopen().

If the value of `$response` is `0` rather than an XML_RPC_Response object, then this signifies an I/O error has occured. You can find out what the I/O error was from the values `$client->errno` and `$client->errstring`.

In addition to low-level errors, the XML-RPC server you were querying may return an error in the XML_RPC_Response object. See XML_RPC_Response for details of how to handle these errors.

#### setCredentials()

``$client->setCredentials` ($username, $password)`

This method sets the username and password for authorizing the client to a server. With the default (HTTP) transport, this information is used for HTTP Basic authorization.

#### setCertificate()

``$client->setCertificate` ($certificate, $passphrase)`

This method sets the optional certificate and passphrase used in SSL-enabled communication with a remote server.

The `certificate` parameter must be the filename of a PEM formatted certificate. The `passphrase` parameter must contain the password required to use the certificate.

This requires the `openssl` extensions to be compiled into your installation of PHP.

#### setDebug()

``$client->setDebug` ($debugOn)`

`$debugOn` is either `0` or `1` depending on whether you require the client to print debugging information to the browser. The default is not to output this information.

The debugging information includes the raw data returned from the XML-RPC server it was querying, and the PHP value the client attempts to create to represent the value returned by the server. This option can be very useful when debugging servers as it allows you to see exactly what the server returns.

## XML_RPC_Message

This class provides a representation for a request to an XML-RPC server. A client sends an XML_RPC_Message to a server, and receives back an XML_RPC_Response.

### Creation

The constructor takes the following form:

``$msg = new XML_RPC_Message` ($methodName, $parameterArray)`

Where `$methodName` is a string indicating the name of the method you wish to invoke, and `$parameterArray` is a simple Array of XML_RPC_Value objects. Here's an example message to the US state name server:

    require_once "XML/RPC.php";
    $msg = new XML_RPC_Message("examples.getStateName", array(new XML_RPC_Value(23, "int")));

This example requests the name of state number 23. For more information on XML_RPC_Value objects, see XML_RPC_Value.

### Methods

#### serialize()

``$outString = $msg->serialize` ()`

Returns the an XML string representing the XML-RPC message.

#### addParam()

``$msg->addParam` ($xmlrpcVal)`

Adds the XML_RPC_Value `$xmlrpcVal` to the parameter list for this method call.

#### getParam()

``$xmlrpcVal = $msg->getParam` ($n)`

Gets the `$n`th parameter in the message. Use this method in server implementations. Returns the `undef` value if no such parameter exists.

#### getNumParams()

``$n = $msg->getNumParams` ()`

Returns the number of parameters attached to this message.

#### method()

``$methName=$msg->method` ()`

``$msg->method` ($methName)`

Gets or sets the method contained in the XML-RPC message.

#### parseResponse()

``$response = $msg->parseResponse` ($xmlString)`

Given an incoming XML-RPC server response contained in the string `$xmlString`, this method constructs an XML_RPC_Response response object and returns it, setting error codes as appropriate.

This method processes any HTTP/MIME headers it finds.

#### parseResponseFile()

``$response = $msg->parseResponseFile` ($fileHandle)`

Given an incoming XML-RPC server response on the file handle `$fileHandle`, this method reads the data and passes it to parseResponse().

This method is useful to construct responses from pre-prepared files. It processes any HTTP headers it finds.

## XML_RPC_Response

This class is used to contain responses to XML-RPC requests. A server method handler will construct an XML_RPC_Response and pass it as a return value. This same value will be returned by the result of an invocation of the send() method of the XML_RPC_Client class.

### Creation

``$resp = new XML_RPC_Response` ($xmlrpcval)`

``$resp = new XML_RPC_Response` (0, $errcode, $errstring)`

The first instance is used when execution has happened without difficulty: `$xmlrpcval` is an XML_RPC_Value value with the result of the method execution contained in it.

The second type of constructor is used in case of failure. `$errcode` and `$errstring` are used to provide indication of what has gone wrong. See XML_RPC_Server for more information on passing error codes.

### Methods

#### faultCode()

``$fn = $resp->faultCode` ()`

Returns the integer fault code return from the XML-RPC response `$resp`. A zero value indicates success, any other value indicates a failure response.

#### faultString()

``$fs = $resp->faultString` ()`

Returns the human readable explanation of the fault indicated by `$resp->faultCode`.

#### value()

``$xmlrpcVal = $resp->value` ()`

Returns an XML_RPC_Value object containing the return value sent by the server. If the response's `faultCode` is non-zero then the value returned by this method should not be used (it may not even be an object).

#### serialize()

``$outString = $resp->serialize` ()`

Returns an XML string representation of the response.

## XML_RPC_Value

This is where a lot of the hard work gets done. This class enables the creation and encapsulation of values for XML-RPC.

Ensure you've read the XML-RPC spec at http://www.xmlrpc.com/stories/storyReader$7 before reading on as it will make things clearer.

The XML_RPC_Value class can store arbitrarily complicated values using the following types: `i4`, `int`, `boolean`, `string`, `double`, `dateTime.iso8601`, `base64`, `array` or `struct`. You should refer to the spec for more information on what each of these types mean.

### Notes on types

#### int

The type i4 is accepted as a synonym for int. The value parsing code will always convert i4 to int: int is regarded by this implementation as the canonical name for this type.

#### base64

Base 64 encoding is performed transparently to the caller when using this type. Therefore you ought to consider it as a binary data type, for use when you want to pass none 7-bit clean data. Decoding is also transparent.

#### boolean

The values `true` and `1` map to `true`. All other values (including the empty string) are converted to `false`.

#### string

The characters `<`, `>`, `"` and `&` are converted to their entity equivalents `&lt;`, `&gt;`, `&quot;` and `&amp;` for transport through XML-RPC. The current XML-RPC spec recommends only encoding `<` and `&` but this implementation goes further, for reasons explained by the XML 1.0 recommendation.

TODO: `&apos;` entity is not yet supported

### Creation

The constructor is the normal way to create an XML_RPC_Value. The constructor can take these forms:

``$myVal = new XML_RPC_Value` ()`

``$myVal = new XML_RPC_Value` ($stringVal)`

``$myVal = new XML_RPC_Value` ($scalarVal, 'int' | 'boolean' | 'string' | 'double' | 'dateTime.iso8601' | 'base64')`

``$myVal = new XML_RPC_Value` ($arrayVal, 'array' | 'struct')`

The first constructor creates an empty value, which must be altered using the methods addScalar(), addArray() or addStruct() before it can be used.

The second constructor creates a simple string value.

The third constructor is used to create a scalar value. The second parameter must be a name of an XML-RPC type. Examples:

    $myInt = new XML_RPC_Value(1267, "int");
    $myString= new XML_RPC_Value("Hello, World!", "string");
    $myBool = new XML_RPC_Value(1, "boolean");

The fourth constructor form can be used to compose complex XML-RPC values. The first argument is either a simple array in the case of an XML-RPC array or an associative array in the case of a struct. The elements of the array must be XML_RPC_Value objects themselves. Examples:

    $myArray = new XML_RPC_Value(array(
        new XML_RPC_Value("Tom"), new XML_RPC_Value("Dick"),
        new XML_RPC_Value("Harry")), "array");

    $myStruct = new XML_RPC_Value(array(
        "name" => new XML_RPC_Value("Tom"),
        "age" => new XML_RPC_Value(34, "int"),
        "geek" => new XML_RPC_Value(1, "boolean")), "struct");

### Methods

#### addScalar()

``$ok = $val->addScalar` ($stringVal)`

``$ok = $val->addScalar` ($scalarVal, 'int' | 'boolean' | 'string' | 'double' | 'dateTime.iso8601' | 'base64')`

If `$val` is an empty XML_RPC_Value this method makes it a scalar value, and sets that value. If `$val` is already a scalar value, then no more scalars can be added and `0` is returned. If all went OK, `1` is returned.

There is a special case if `$val` is an array: the scalar value passedis appended to the array.

#### addArray()

``$ok = $val->addArray` ($arrayVal)`

Turns an empty XML_RPC_Value into an array with contents as specified by `$arrayVal`. See the fourth constructor form for more information.

#### addStruct()

``$ok = $val->addArray` ($assocArrayVal)`

Turns an empty XML_RPC_Value into a struct with contents as specified by `$assocArrayVal`. See the fourth constructor form for more information.

#### kindOf()

``$kind = $val->kindOf` ()`

Returns a string containing `struct`, `array` or `scalar` describing the base type of the value. If it returns `undef` it means that the value hasn't been initialised.

#### serialize()

``$outString = $val->serialize` ()`

Returns a string containing the XML-RPC representation of this value.

#### scalarval()

``$scalarVal = $val->scalarval` ()`

If $val->kindOf() == 'scalar', this method returns the actual PHP-language value of the scalar (base 64 decoding is automatically handled here).

#### scalartyp()

``$typeName = $val->scalartyp` ()`

If $val->kindOf() == 'scalar', this method returns a string denoting the type of the scalar. As mentioned before, `i4` is always coerced to `int`.

#### arraymem()

``$xmlrpcVal = $val->arraymem` ($n)`

Returns the `$n`th element in the array represented by the value `$val`. The value returned is an XML_RPC_Value object.

#### arraysize()

``$len = $val->arraysize` ()`

If `$val` is an array, returns the number of elements in that array.

#### structmem()

``$xmlrpcVal = $val->structmem` ($memberName)`

Returns the element called `$memberName` from the struct represented by the value `$val`. The value returned is an XML_RPC_Value object.

#### structeach()

``list($key,$value) = $val->structeach` ()`

Returns the next (key,value) pair from the struct, when `$val` is a struct. See also structreset().

#### structreset()

``$val->structreset` ()`

Resets the internal pointer for structeach() to the beginning of the struct, where `$val` is a struct.

## XML_RPC_Server

The current implementation of this class has been kept as simple as possible. The constructor for the server basically does all the work. Here's a minimal example:

    function foo ($params) {
       ...
    }

    $s = new XML_RPC_Server(array("examples.myFunc" => array("function" => "foo")));

This performs everything you need to do with a server. The single argument is an associative array from method names to function names. The request is parsed and despatched to the relevant function, which is reponsible for returning a XML_RPC_Response object, which gets serialized back to the caller.

Here is a more detailed look at what the handler function foo() may do:

    function foo ($params) {
        global $XML_RPC_erruser; // import user errcode value

        // $params is the received XML_RPC_Message object.
        if ($err) {
            // this is an error condition
            return new XML_RPC_Response(0, $XML_RPC_erruser+1, // user error 1
               "There's a problem, Captain");
        } else {
            // this is a successful value being returned
            return new XML_RPC_Response(new XML_RPC_Value("All's fine!", "string"));
        }
    }

### The dispatch map

The first argument to the XML_RPC_Server() constructor is an array, called the dispatch map. In this array is the information the server needs to service the XML-RPC methods you define.

The dispatch map takes the form of an associative array of associative arrays: the outer array has one entry for each method, the key being the method name. The corresponding value is another associative array, which can have the following members:

- `function` - this entry is mandatory. It must be a name of a function in the global scope which services the XML-RPC method.

- `signature` - this entry is an array containg the possible signatures (see Signatures) for the method. If this entry is present then the server will check that the correct number and type of parameters have been sent for this method before dispatching it.

- `docstring` - this entry is a string containing documentation for the method. The documentation may contain HTML markup.

### Method signatures

A signature is a description of a method's return type and its parameter types. A method may have more than one signature.

Within a server's dispatch map, each method has an array of possible signatures. Each signature is an array of types. The first entry is the return type.

Let's run through an example. Imagine you wanted to write a regular PHP function like this:

    function is_8($input, $strict = false) {
        if ($strict) {
           return ($input === 8);
        } else {
           return ($input == 8);
        }
    }

To get it to work in an XML_RPC server, you would have to write it like this:

    function is_8($params) {
        // This parameter is required.
        $param = $params->getParam(0);
        if (!XML_RPC_Value::isValue($param)) {
            return $param;
        }
        $input = $param->scalarval();

        // This parameter is optional.
        $param = $params->getParam(1);
        if (!XML_RPC_Value::isValue($param)) {
            $strict = false;
        } else {
            $strict = $param->scalarval();
        }

        if ($strict) {
           $answer = ($input === 8);
        } else {
           $answer = ($input == 8);
        }

        $val = new XML_RPC_Value($answer, 'boolean');
        return new XML_RPC_Response($val);
    }

Here is a signature covering all of the possible permutations:

    array(
        array('boolean', 'int'),
        array('boolean', 'int', 'boolean'),
        array('boolean', 'string'),
        array('boolean', 'string', 'boolean'),
    )

The server could be instatiated like this:

    $server = new XML_RPC_Server(
        array(
            'isan8' =>
                array(
                    'function' => 'is_8',
                    'signature' =>
                         array(
                             array('boolean', 'int'),
                             array('boolean', 'int', 'boolean'),
                             array('boolean', 'string'),
                             array('boolean', 'string', 'boolean'),
                         ),
                    'docstring' => 'Is the value an 8?'
                ),
        ),
        1,
        0
    );

The strings representing the XML-RPC types have been encoded as global variables for your convenience:

    $XML_RPC_I4       = 'i4';
    $XML_RPC_Int      = 'int';
    $XML_RPC_Boolean  = 'boolean';
    $XML_RPC_Double   = 'double';
    $XML_RPC_String   = 'string';
    $XML_RPC_DateTime = 'dateTime.iso8601';
    $XML_RPC_Base64   = 'base64';
    $XML_RPC_Array    = 'array';
    $XML_RPC_Struct   = 'struct';

### Delaying the server response

You may want to construct the server, but for some reason not fulfill the request immediately (security verification, for instance). If you pass the constructor a second argument of `0` this will have the desired effect. You can then use the service() method of the server class to service the request. For example:

    $s = new XML_RPC_Server($myDispMap, 0);

    // ... some code that does other stuff here

    $s->service();

### Fault reporting

Fault codes for your servers should start at the value indicated by the global `$xmlrpcerruser` + 1.

Standard errors returned by the server include:

`1` Unknown method

  Returned if the server was asked to dispatch a method it didn't know about

`2` Invalid return payload

  This error is actually generated by the client, not server, code, but signifies that a server returned something it couldn't understand.

`3` Incorrect parameters

  This error is generated when the server has signature(s) defined for a method, and the parameters passed by the client do not match any of signatures.

`4` Can't introspect: method unknown

  This error is generated by the builtin system.*() methods when any kind of introspection is attempted on a method undefined by the server.

`5` Didn't receive 200 OK from remote server

  This error is generated by the client when a remote server doesn't return HTTP/1.1 200 OK in response to a request. A more detailed error report is added onto the end of the phrase above.

`100-` XML parse errors

  Returns 100 plus the XML parser error code for the fault that occurred. The `faultString` returned explains where the parse error was in the incoming XML stream.

## XML_RPC_Dump

This class generates string representations of the data in XML_RPC_Value objects.

## Other Functions

Below are functions that lay outside the various XML_RPC objects.

### XML_RPC_encode()

``$rpc = XML_RPC_encode` ($php_val)`

Takes native php types and encodes them into XML_RPC PHP object format.

### XML_RPC_decode()

``$values = XML_RPC_decode` ($XML_RPC_val)`

Takes a message in PHP XML_RPC object format and translates it into native PHP types.

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