更新时间:2022-09-29 19:10:38
概念:
WEB服务的风格,从***上查了一下,有不下十几种,但是比较常用的就是REST和RPC。其中,基于SOAP协议的Webservice就是RPC风格的。
REST全称Representational State Transfer。它是基于无状态的,cs结构的,可以缓存的通信协议。事实上,它是使用 HTTP协议的。某些观点来看,互联网本身就是基于HTTP的,因此也可以认为是一种基于REST风格的Webservice。REST风格的Webservice对于SOAP,CORBA(一种和SOAP互相竞争的协议)来说,属于轻量级。请求较之于也比较简单。比如,用SOAP的Webservice的请求可能是如下这样的一个XML,有用的信息都被包括在冗余的信息中:
<?xml version="1.0"?>
<soap:Envelope
xmlns:soap="http://www.w3.org/2001/12/soap-envelope"
soap:encodingStyle="http://www.w3.org/2001/12/soap-encoding">
<soap:body pb="http://www.acme.com/phonebook">
<pb:GetUserDetails>
<pb:UserID>12345</pb:UserID>
</pb:GetUserDetails>
</soap:Body>
</soap:Envelope>
而使用REST的请求就很简单,只是一个URL地址:http://www.acme.com/phonebook/UserDetails/12345,只需要使用浏览器就能验证这个REST的Webservice是否正常。HTTP的请求方式有多种,GET,POST,PUT,PATCH,DELETE。REST同样可以利用这些请求方式。REST的Webservice的响应通常是一个XML文件,但是和SOAP不同的是,REST并不一定需要响应返回XML文件,它也可以是CSV格式或者Json格式。
很多公司都采用REST风格的Webservice,比如 Google Glass API,Twitter,Yahoo,Flickr,Amazon等。比如Google有一个Webservice,Google Maps API,它提供2种输出格式,JSON和XML。地址分别是http://maps.googleapis.com/maps/api/geocode/json?parameters和http://maps.googleapis.com/maps/api/geocode/xml?parameters
该服务的具体使用方法和参数满可以查阅https://developers.google.com/maps/documentation/geocoding/?hl=zh-CN&csw=1#XML
演示:
下面演示一个基于PHP语言开发的REST风格的webservice。
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<?php switch ( $_SERVER [ 'REQUEST_METHOD' ])
{ case 'GET' :
$id = $_GET [ "id" ];
$arrayid = explode ( "," , $id );
search( $arrayid );
break ;
case 'POST' :
$id = $_POST [ "id" ];
$username = $_POST [ "username" ];
$sex = $_POST [ "sex" ];
$age = $_POST [ "age" ];
add( $id , $username , $sex , $age );
break ;
default :
exit ();
} function search( $arrayid )
{ $users =getCsvFile( "example.csv" );
$string = "" ;
foreach ( $users as $a )
{
$id = $a [0];
if (in_array( $id , $arrayid ))
{
$string .= <<<EOF
<user id= "$a[0]" >
<name> $a [1]</name>
<sex> $a [2]</sex>
<age> $a [3]</age>
</user>
EOF; }
}
$string = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\r\n"
. "<data>\r\n"
. $string
. "</data>" ;
header( "Content-type:application/xml" );
print ( $string );
} function add( $id , $username , $sex , $age )
{ $users =getCsvFile( "example.csv" );
$string = "$id,$username,$sex,$age" ;
WriteLinetxt( $string , "example.csv" );
$string = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\r\n"
. "<return>\r\n"
. " <status>0</status>\r\n"
. "</return>\r\n" ;
header( "Content-type:application/xml" );
print ( $string );
} function getCsvFile( $filepath )
{
$handle =null;
$returnvalue = array ();
try
{
$handle = fopen ( $filepath , "r" );
while ( $data = fgetcsv ( $handle , 1000, "," ))
{
array_push ( $returnvalue , $data );
}
fclose( $handle );
}
catch (Exception $e )
{
fclose( $handle );
$handle =null;
die ( "Error!: " . $e ->getMessage(). "<br/>" );
}
return $returnvalue ;
}
function WriteLinetxt( $content , $filename )
{ file_put_contents ( $filename , $content . "\r\n" ,FILE_APPEND);
} ?> |
代码说明:
上述代码,根据请求的方式是POST还是GET来区分,如果是GET的话,则需带上查询的ID。服务会返回一个Content-type为application/xml的一份xm文档。如果是POST的话,则会把相应的POST进来的值写入到数据库。
本例中,数据库只是简单的采用CSV文件,即用逗号分割数据的文本文件。数据文件如下:
由于REST风格的web服务可以通过浏览器验证,因此可以输入url地址测试。本例中没有采用url重写,如果使用url重写的话,服务地址会更友好。
服务部署好之后,就可以调用了。在PHP中,可以通过simplexml_load_file方法,get到这个xml文件。
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<?php $url = "http://localhost:8080/b.php?id=1001,1003,1004" ;
$response =simplexml_load_file( $url );
var_dump( $response );
?> |
通过var_dump,可以看到获得的直接是一个SimpleXMLElement对象,当然你也可以把它转换成string对象。
下面用php代码实现模拟POST数据。PHP常用的模拟POST动作的方法有3种,分别为Curl、socket、file_get_contents,这里还是采用file_get_contents方法。代码如下:
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<?php $url = "http://localhost:8080/b.php" ;
$data = array
( 'id' => '1990' ,
'username' => '小张' ,
'sex' => '男' ,
'age' => '20'
); $post_string =http_build_query( $data );
$context = array (
'http' => array (
'method' => 'POST' ,
'header' => 'content-type: application/x-www-form-urlencoded' ,
'content' => $post_string )
);
$stream_context = stream_context_create( $context );
$response = file_get_contents ( $url , false, $stream_context );
$xml =simplexml_load_string( $response );
var_dump( $xml );
?> |
代码中,模拟了POST提交,并且获得了返回的string,再把string转成了SimpleXMLElement对象。而且数据库中数据也已经写入。
C#版本访问:
C#也可以通过代码调用PHP写的REST风格的Webservice。代码如下:
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class Program
{
static void Main( string [] args)
{
string [] paramName = { "id" };
string [] paramVal = { "1001,1004" };
var p = HttpGet( "http://localhost:8080/b.php" , paramName, paramVal);
Console.WriteLine(p);
Console.WriteLine( "-------------------------------" );
string [] paramName1 = { "id" , "username" , "sex" , "age" };
string [] paramVal1 = { "1030" , "tom" , "男" , "23" };
var p1 = HttpPost( "http://localhost:8080/b.php" , paramName1, paramVal1);
Console.WriteLine(p1);
}
static string HttpGet( string url, string [] paramName, string [] paramVal)
{
StringBuilder paramz = new StringBuilder();
for ( int i = 0; i < paramName.Length; i++)
{
paramz.Append(paramName[i]);
paramz.Append( "=" );
paramz.Append(HttpUtility.UrlEncode(paramVal[i]));
paramz.Append( "&" );
}
url += "?" + paramz.ToString();
HttpWebRequest req = WebRequest.Create(url) as HttpWebRequest;
string result = null ;
using (HttpWebResponse resp = req.GetResponse() as HttpWebResponse)
{
StreamReader reader = new StreamReader(resp.GetResponseStream());
result = reader.ReadToEnd();
}
return result;
}
static string HttpPost( string url, string [] paramName, string [] paramVal)
{
HttpWebRequest req = WebRequest.Create( new Uri(url)) as HttpWebRequest;
req.Method = "POST" ;
req.ContentType = "application/x-www-form-urlencoded" ;
// Build a string with all the params, properly encoded.
// We assume that the arrays paramName and paramVal are
// of equal length:
StringBuilder paramz = new StringBuilder();
for ( int i = 0; i < paramName.Length; i++)
{
paramz.Append(paramName[i]);
paramz.Append( "=" );
paramz.Append(HttpUtility.UrlEncode(paramVal[i]));
paramz.Append( "&" );
}
// Encode the parameters as form data:
byte [] formData = UTF8Encoding.UTF8.GetBytes(paramz.ToString());
req.ContentLength = formData.Length;
// Send the request:
using (Stream post = req.GetRequestStream())
{
post.Write(formData, 0, formData.Length);
}
// Pick up the response:
string result = null ;
using (HttpWebResponse resp = req.GetResponse() as HttpWebResponse)
{
StreamReader reader = new StreamReader(resp.GetResponseStream());
result = reader.ReadToEnd();
}
return result;
}
}
|
参考文档:
http://geeknizer.com/rest-vs-soap-using-http-choosing-the-right-webservice-protocol/
http://msdn.microsoft.com/zh-cn/magazine/dd942839.aspx
http://www.gen-x-design.com/archives/create-a-rest-api-with-php/
http://rest.elkstein.org/2008/02/what-is-rest.html
本文转自cnn23711151CTO博客,原文链接: http://blog.51cto.com/cnn237111/1285298,如需转载请自行联系原作者