Blame - user_guide/libraries/xmlrpc.html - code-igniter-v3-giggi

2006-10-21 19:44:22 +0000

[diff] [blame]

67

<p>Code Igniter's XML-RPC classes permit you to send requests to another server, or set up

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

68

your own XML-RPC server to receive requests.</p>

admin

2006-10-21 19:44:22 +0000

[diff] [blame]

73

<p>Quite simply it is a way for two computers to communicate over the internet using XML.

74

One computer, which we will call the <dfn>client</dfn>, sends an XML-RPC <strong>request</strong> to

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

75

another computer, which we will call the <dfn>server</dfn>. Once the server receives and processes the request it

76

will send back a <strong>response</strong> to the client.</p>

77

admin

2006-10-21 19:44:22 +0000

[diff] [blame]

78

<p>For example, using the MetaWeblog API, an XML-RPC Client (usually a desktop publishing tool) will

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

79

send a request to an XML-RPC Server running on your site. This request might be a new weblog entry

80

being sent for publication, or it could be a request for an existing entry for editing.

81

82

When the XML-RPC Server receives this request it will examine it to determine which class/method should be called to process the request.

83

Once processed, the server will then send back a response message.</p>

84

admin

e7e1dcd

2006-10-21 18:04:01 +0000

[diff] [blame]

85

<p>For detailed specifications, you can visit the <a href="http://www.xmlrpc.com/">XML-RPC</a> site.</p>

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

86

87

<h2>Initializing the Class</h2>

88

89

<p>Like most other classes in Code Igniter, the XML-RPC and XML-RPCS classes are initialized in your controller using the <dfn>$this->load->library</dfn> function:</p>

90

91

<p>To load the XML-RPC class you will use:

92

<code>$this->load->library('xmlrpc');</code>

93

<p>Once loaded, the xml-rpc library object will be available using: <dfn>$this->xmlrpc</dfn></p>

94

95

<p>To load the XML-RPC Server class you will use:

admin

2006-09-27 00:31:22 +0000

[diff] [blame]

96

<code>

97

$this->load->library('xmlrpc');<br />

98

$this->load->library('xmlrpcs');

99

</code>

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

100

<p>Once loaded, the xml-rpcs library object will be available using: <dfn>$this->xmlrpcs</dfn></p>

101

admin

2006-09-27 00:31:22 +0000

[diff] [blame]

102

<p class="important"><strong>Note:</strong>  When using the XML-RPC Sever class you must load BOTH the XML-RPC class and the XML-RPC Server class.</p>

103

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

104

105

106

<h2>Sending XML-RPC Requests</h2>

107

108

<p>To send a request to an XML-RPC server you must specify the following information:</p>

109

110

<ul>

111

<li>The URL of the server</li>

112

<li>The method on the server you wish to call</li>

113

<li>The <em>request</em> data (explained below).</li>

114

</ul>

115

116

<p>Here is a basic example that sends a simple Weblogs.com ping to the <a href="http://pingomatic.com/">Ping-o-Matic</a></p>

117

118

119

<code>$this->load->library('xmlrpc');<br />

120

<br />

121

$this->xmlrpc->server('http://rpc.pingomatic.com/', 80);<br />

122

$this->xmlrpc->method('weblogUpdates.ping');<br />

123

124

<br />

125

$request = array('My Photoblog', 'http://www.my-site.com/photoblog/');<br />

126

$this->xmlrpc->request($request);<br />

127

<br />

128

if ( ! $this->xmlrpc->send_request())<br />

129

{<br />

130

    echo $xmlrpc->display_error();<br />

}

</code>

<h3>Explanation</h3>

<p>The above code initializes the XML-RPC class, sets the server URL and method to be called (weblogUpdates.ping). The

137

request (in this case, the title and URL of your site) is placed into an array for transportation, and

138

compiled using the request() function.

139

Lastly, the full request is sent. If the <dfn>send_request()</dfn> method returns false we will display the error message

140

sent back from the XML-RPC Server.</p>

141

142

<h2>Anatomy of a Request</h2>

143

admin

2006-10-21 19:44:22 +0000

[diff] [blame]

144

<p>An XML-RPC <dfn>request</dfn> is simply the data you are sending to the XML-RPC server. Each piece of data in a request

145

is referred to as a <dfn>request parameter</dfn>. The above example has two parameters:

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

146

The URL and title of your site. When the XML-RPC server receives your request, it will look for parameters it requires.</p>

147

admin

e7e1dcd

2006-10-21 18:04:01 +0000

[diff] [blame]

148

<p>Request parameters must be placed into an array for transportation, and each parameter can be one

admin

2006-10-21 19:44:22 +0000

[diff] [blame]

149

of seven data types (strings, numbers, dates, etc.). If your parameters are something other than strings

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

150

you will have to include the data type in the request array.</p>

151

152

<p>Here is an example of a simple array with three parameters:</p>

153

154

<code>$request = array('John', 'Doe', 'www.some-site.com');<br />

155

$this->xmlrpc->request($request);</code>

156

157

<p>If you use data types other than strings, or if you have several different data types, you will place

158

each parameter into its own array, with the data type in the second position:</p>

159

160

<code>

161

$request = array (<br />

162

                   array('John', 'string'),<br />

163

                   array('Doe', 'string'),<br />

164

                   array(FALSE, 'boolean'),<br />

165

                   array(12345, 'int')<br />

166

                 );

167

<br />

168

$this->xmlrpc->request($request);</code>

169

170

The <a href="#datatypes">Data Types</a> section below has a full list of data types.</p>

<h2>Creating an XML-RPC Server</h2>

175

admin

2006-10-21 19:44:22 +0000

[diff] [blame]

176

<p>An XML-RPC Server acts as a traffic cop of sorts, waiting for incoming requests and redirecting them to the

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

177

appropriate functions for processing.</p>

178

admin

2006-10-21 19:44:22 +0000

[diff] [blame]

179

<p>To create your own XML-RPC server involves initializing the XML-RPC Server class in your controller where you expect the incoming

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

180

request to appear, then setting up an array with mapping instructions so that incoming requests can be sent to the appropriate

181

class and method for processing.</p>

182

183

<p>Here is an example to illustrate:</p>

184

admin

2006-09-27 00:31:22 +0000

[diff] [blame]

185

<code>

186

$this->load->library('xmlrpcs');<br />

187

$this->load->library('xmlrpcs');<br />

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

188

<br />

189

$config['functions']['<var>new_post</var>'];  = array('function' => '<dfn>My_blog.new_entry</dfn>');<br />

190

$config['functions']['<var>update_post</var>'] = array('function' => '<dfn>My_blog.update_entry</dfn>');<br />

191

<br />

192

$this->xmlrpcs->initialize($config);<br />

193

$this->xmlrpcs->serve();</code>

194

admin

2006-10-21 19:44:22 +0000

[diff] [blame]

195

<p>The above example contains an array specifying two method requests that the Server allows.

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

196

The allowed methods are on the left side of the array. When either of those are received, they will be mapped to the class and method on the right.

197

admin

2006-10-21 19:44:22 +0000

[diff] [blame]

198

<p>In other words, if an XML-RPC Client sends a request for the <var>new_post</var> method, your

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

199

server will load the <dfn>My_blog</dfn> class and call the <dfn>new_entry</dfn> function.

admin

2006-10-21 19:44:22 +0000

[diff] [blame]

200

If the request is for the <var>update_post</var> method, your

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

201

server will load the <dfn>My_blog</dfn> class and call the <dfn>update_entry</dfn> function.</p>

202

admin

2006-10-21 19:44:22 +0000

[diff] [blame]

203

<p>The function names in the above example are arbitrary. You'll decide what they should be called on your server,

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

204

or if you are using standardized APIs, like the Blogger or MetaWeblog API, you'll use their function names.</p>

205

206

207

<h2>Processing Server Requests</h2>

208

209

<p>When the XML-RPC Server receives a request and loads the class/method for processing, it will pass

210

an object to that method containing the data sent by the client.</p>

211

212

<p>Using the above example, if the <var>new_post</var> method is requested, the server will expect a class

213

to exist with this prototype:</p>

214

215

<code>class <kbd>My_blog</kbd> extends Controller {<br />

216

<br />

217

    function <kbd>new_post</kbd>(<var>$request</var>)<br />

    {<br />

<br />

    }<br />

}

</code>

<p>The <var>$request</var> variable is an object compiled by the Server, which contains the data sent by the XML-RPC Client.

225

Using this object you will have access to the <em>request parameters</em> enabling you to process the request. When

226

you are done you will send a <dfn>Response</dfn> back to the Client.<p>

227

admin

2006-10-21 19:44:22 +0000

[diff] [blame]

228

<p>Below is a real-world example, using the Blogger API. One of the methods in the Blogger API is <dfn>getUserInfo()</dfn>.

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

229

Using this method, an XML-RPC Client can send the Server a username and password, in return the Server sends

230

back information about that particular user (nickname, user ID, email address, etc.). Here is how the processing

231

function might look:</p>

232

233

234

<code>class <kbd>My_blog</kbd> extends Controller {<br />

235

<br />

236

    function <kbd>getUserInfo</kbd>(<var>$request</var>)<br />

237

    {<br />

238

239

        $username = 'smitty';<br />

240

        $password = 'secretsmittypass';<br /><br />

241

242

        $this->load->library('xmlrpc');<br />

243

    <br />

244

        $parameters = $request->output_parameters();<br />

245

    <br />

246

        if ($parameters['1'] != $username AND $parameters['2'] != $password)<br />

247

        {<br />

248

            return $this->xmlrpc->send_error_message('100', 'Invalid Access');<br />

249

        }<br />

250

    <br />

251

        $response = array(array('nickname'  => array('Smitty','string'),<br />

252

                                'userid'    => array('99','string'),<br />

253

                                'url'       => array('http://yoursite.com','string'),<br />

254

                                'email'     => array('jsmith@yoursite.com','string'),<br />

255

                                'lastname'  => array('Smith','string'),<br />

256

                                'firstname' => array('John','string')<br />

257

                                ),<br />

258

                         'struct');<br />

259

<br />

260

        $this->xmlrpc->send_response($response);<br />

    }<br />

}

</code>

<h3>Notes:</h3>

<p>The <dfn>output_parameters()</dfn> function retrieves an indexed array corresponding to the request parameters sent by the client.

267

In the above example, the output parameters will be the username and password.</p>

268

269

<p>If the username and password sent by the client were not valid, and error message is returned using <dfn>send_error_message()</dfn>.</p>

270

271

<p>If the operation was successful, the client will be sent back a response array containing the user's info.</p>

272

273

274

<h2>Formatting a Response</h2>

275

276

<p>Similar to <em>Requests</em>, <em>Responses</em> must be formatted as an array. However, unlike requests, a response is an array

277

<strong>that contains a single item</strong>. This item can be an array with several additional arrays, but there

278

can be only one primary array index. In other words, the basic prototype is this:</p>

279

280

<code>$request = array('Response data', 'array');</code>

281

admin

2006-10-21 19:44:22 +0000

[diff] [blame]

282

<p>Responses, however, usually contain multiple pieces of information. In order to accomplish this we must put the response into its own

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

283

array so that the primary array continues to contain a single piece of data. Here's an example showing how this might be accomplished:</p>

284

285

<code>

286

$request = array (<br />

287

                   array(<br />

288

                         'first_name' => array('John', 'string'),<br />

289

                         'last_name' => array('Doe', 'string'),<br />

290

                         'member_id' => array(123435, 'int'),<br />

291

                         'todo_list' => array(array('clean house', 'call mom', 'water plants'), 'array'),<br />

292

                        ),<br />

293

                 'struct'<br />

                 );

</code>

<p class="important">Notice that the above array is formatted as a <dfn>struct</dfn>. This is the most common data type for responses.</p>

298

299

<p>As with Requests, a response can be on of the seven data types listed in the <a href="#datatypes">Data Types</a> section.</p>

300

301

302

<h2>Sending an Error Response</h2>

303

304

<p>If you need to send the client an error response you will use the following:</p>

305

306

<code>return $this->xmlrpc->send_error_message('123', 'Requested data not available');</code>

307

308

<p>The first parameter is the error number while the second parameter is the error message.</p>

<h2>Creating Your Own Client and Server</h2>

316

admin

2006-10-21 19:44:22 +0000

[diff] [blame]

317

<p>To help you understand everything we've covered thus far, let's create a couple controllers that act as

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

318

XML-RPC Client and Server. You'll use the Client to send a request to the Server and receive a response.</p>

<h3>The Client</h3>

admin

2006-10-21 19:44:22 +0000

[diff] [blame]

322

<p>Using a text editor, create a controller called <dfn>xmlrpc_client.php</dfn>.

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

323

In it, place this code and save it to your <samp>applications/controllers/</samp> folder:</p>

324

325

<textarea class="textarea" style="width:100%" cols="50" rows="32"><?php

326

327

class Xmlrpc_client extends Controller {

function index()

{

$this->load->helper('url');

332

$server_url = site_url('xmlrpc_server');

333

334

$this->load->library('xmlrpc');

335

336

$this->xmlrpc->server($server_url, 80);

337

$this->xmlrpc->method('Greetings');

338

339

$request = array('How is it going?');

340

$this->xmlrpc->request($request);

341

342

if ( ! $this->xmlrpc->send_request())

343

{

344

echo $this->xmlrpc->display_error();

}

else

{

echo '<pre>';

print_r($this->xmlrpc->display_response());

echo '</pre>';

}

}

}

?></textarea>

<p>Note: In the above code we are using a "url helper". You can find more information in the <a href="../general/helpers.html">Helpers Functions</a> page.</p>

<h3>The Server</h3>

admin

2006-10-21 19:44:22 +0000

[diff] [blame]

360

<p>Using a text editor, create a controller called <dfn>xmlrpc_server.php</dfn>.

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

361

In it, place this code and save it to your <samp>applications/controllers/</samp> folder:</p>

362

363

<textarea class="textarea" style="width:100%" cols="50" rows="30"><?php

364

365

class Xmlrpc_server extends Controller {

366

367

function index()

368

{

admin

2006-09-27 00:31:22 +0000

[diff] [blame]

369

370

$this->load->library('xmlrpc');

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

371

$this->load->library('xmlrpcs');

372

373

$config['functions']['Greetings'] = array('function' => 'Xmlrpc_server.process');

374

375

$this->xmlrpcs->initialize($config);

376

$this->xmlrpcs->serve();

}

function process($request)

381

{

382

$parameters = $request->output_parameters();

$response = array(

array(

'you_said' => $parameters['0'],

387

'i_respond' => 'Not bad at all.'),

388

'struct');

admin

2006-10-21 19:44:22 +0000

[diff] [blame]

389

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

390

return $this->xmlrpc->send_response($response);

}

}

?></textarea>

<p>Now visit the your site using a URL similar to this:</p>

398

<code>www.your-site.com/index.php/<var>xmlrpc_client</var>/</code>

399

400

<p>You should now see the message you sent to the server, and its response back to you.</p>

401

402

<p>The client you created sends a message ("How's is going?") to the server, along with a reqest for the "Greetings" method.

403

The Server receives the request and maps it to the "process" function, where a response is sent back.</p>

<h1>XML-RPC Function Reference</h1>

409

410

<h2>$this->xmlrpc->server()</h2>

411

<p>Sets the URL and port number of the server to which a request is to be sent:</p>

412

<code>$this->xmlrpc->server('http://www.sometimes.com/pings.php', 80);</code>

413

414

<h2>$this->xmlrpc->timeout()</h2>

415

<p>Set a time out period (in seconds) after which the request will be canceled:</p>

416

<code>$this->xmlrpc->timeout(6);</code>

417

418

<h2>$this->xmlrpc->method()</h2>

419

<p>Sets the method that will be requested from the XML-RPC server:</p>

420

<code>$this->xmlrpc->method('<var>method</var>');</code>

421

422

<p>Where <var>method</var> is the name of the method.</p>

423

424

<h2>$this->xmlrpc->request()</h2>

425

<p>Takes an array of data and builds request to be sent to XML-RPC server:</p>

426

<code>$request = array(array('My Photoblog', 'string'), 'http://www.yoursite.com/photoblog/');<br />

427

$this->xmlrpc->request($request);</code>

428

429

<h2>$this->xmlrpc->send_request()</h2>

430

<p>The request sending function. Returns boolean TRUE or FALSE based on success for failure, enabling it to be used conditionally.</p>

431

432

<h2>$this->xmlrpc->set_debug(TRUE);</h2>

433

<p>Enables debugging, which will display a variety of information and error data helpful during development.</p>

434

435

436

<h2>$this->xmlrpc->display_error()</h2>

437

<p>Returns an error message as a string if your request failed for some reason.</p>

438

<code>echo $this->xmlrpc->display_error();</code>

439

440

<h2>$this->xmlrpc->display_response()</h2>

441

<p>Returns the response from the remote server once request is received. The response will typically be an associative array.</p>

442

<code>$this->xmlrpc->display_response();</code>

443

444

<h2>$this->xmlrpc->send_error_message()</h2>

admin

2006-10-21 19:44:22 +0000

[diff] [blame]

445

<p>This function lets you send an error message from your server to the client. First parameter is the error number while the second parameter

admin

2006-08-25 17:25:49 +0000

[diff] [blame]

446

is the error message.</p>

447

<code>return $this->xmlrpc->send_error_message('123', 'Requested data not available');</code>

448

449

<h2>$this->xmlrpc->send_response()</h2>

admin

e7e1dcd

2006-10-21 18:04:01 +0000

[diff] [blame]

450

<p>Lets you send the response from your server to the client. An array of valid data values must be sent with this method.</p>

admin