一个"/"引发的血案

问题背景：最进在解决在线升级应用与服务器端对接的问题，升级应用客户端中通过http的post方法向服务器端发送json数据，服务器端在接收到json数据后，将返回升级所需的数据以json格式下发给到客户端。服务器端采用apache+PHP5.6.31版本搭建。

问题现象：在进行对接的过程中发现服务器端没有收到客户端通过post提交的json数据，客户端代码如下：

public HttpClient getHttpClient()
{
if( mHttpClient == null )
{
HttpParams params = new BasicHttpParams( );
HttpConnectionParams.setConnectionTimeout( params , HttpSessionConstant.CONNECTION_TIMEOUT );
HttpConnectionParams.setSoTimeout( params , HttpSessionConstant.SO_TIMEOUT );
HttpConnectionParams.setSocketBufferSize( params , HttpSessionConstant.SOCKET_BUFFER_SIZE );

HttpClientParams.setRedirecting( params , true );

mHttpClient = new DefaultHttpClient();
mHttpClient.getParams( ).setParameter( "http.useragent" , HttpSessionConstant.getUserAgent( ) );

Log.d(Tag,"not direct proxy here");
boolean useProxy = APNUtil.hasProxy( App.getAppContext( ) );
if( useProxy )
{
Log.d( Tag , "need getApnProxy = " + APNUtil.getApnProxy( App.getAppContext( ) ) );
Log.d( Tag , "need getApnPortInt = " + APNUtil.getApnPortInt( App.getAppContext( ) ) );

HttpHost proxy = new HttpHost( APNUtil.getApnProxy( App.getAppContext( ) ) , APNUtil.getApnPortInt( App
.getAppContext( ) ) );
mHttpClient.getParams( ).setParameter( ConnRoutePNames.DEFAULT_PROXY , proxy );
}
}

try {
HttpClient httpClient = getHttpClient( );
mHttpPost = new HttpPost( mUrl[mHasRetry] );
// 构造消息头
mHttpPost.setHeader("Content-type", "application/json; charset=utf-8");
if (null != mJsonParam) {
StringEntity entity = new StringEntity(mJsonParam.toString());
mHttpPost.setEntity(entity);

//LogUtils.e( "-------------------entity = " + mJsonParam.toString());
}

mResponse = httpClient.execute(mHttpPost);
int statusCode = mResponse.getStatusLine( ).getStatusCode( );
//LogUtils.e( "-------------------statusCode = " + statusCode);
if( statusCode == HttpStatus.SC_OK )
{
HttpEntity httpEntity = mResponse.getEntity( );
if( httpEntity != null )
{
String byteData = EntityUtils.toString( httpEntity );
//LogUtils.e( "-------------------byteData = " + byteData);
if( mCallBack != null )
mCallBack.onSucceed( byteData );
}

release( );
return;
}

String strStatus = mResponse.getStatusLine( ).toString( );
release( );
if( mCallBack != null )
mCallBack.onError( statusCode , strStatus );

continue;
}
catch ( Exception excp )
{
}
finally
{
}

服务器端PHP代码如下：（现学的PHP）

<?php
$params = file_get_contents('php://input','r');
echo $params;
if(!empty($params))
{
$obj=json_decode($params);
$action = $obj->action;
if ($action == "ReqUpdate")
{
$updateType = 0;
$oldRomVersion = $obj->RomVersion;
$oldRomType = $obj->RomType;
$newRomVersion = "20170728";

if ($oldRomVersion < $newRomVersion){
$updateType = 1;
}

$rspupdate_filename = "./rspupdate.json";
$rspupdate = json_decode(file_get_contents($rspupdate_filename,FILE_USE_INCLUDE_PATH));
$rspupdate->updateType = $updateType;
$rspupdate->oldRomType = $oldRomType;
$rspupdate->oldRomVersion = $oldRomVersion;

echo json_encode($rspupdate);
}
else if ($action == "ReqReported")
{
$rspreport_filename = "./rspreport.json";
$rspreport = json_decode(file_get_contents($rspreport_filename,FILE_USE_INCLUDE_PATH));
echo json_encode($rspreport);
}
}
else
{
echo file_get_contents("./rspreport.json",FILE_USE_INCLUDE_PATH);
}

升级服务器地址（搭建的apache 文件服务器）

private static final String PUBLIC_OTA_URL_A = "http://192.168.1.106/allwinner_update";

每次执行升级操作时，服务器端返回的值都是“$params”为null，通过wireshark抓包发现，客户端通过post发送的json数据已经被服务器端收到，如下图：



如上图，服务器IP为192.168.1.106，客户端IP为192.168.1.118。服务器端收到了json数据，同时也对客户端下发了数据，但是为什么$params为null？

同时也注意到POST操作完成之后，客户端又做了一次处理301的重定向，会不会是这里引起的呢？

问题原因：过程就不再废话了，反正是浪费了半天的时间，才注意到301的问题原来是由于服务器地址引起的，由于客户端设置的服务器地址是“http://192.168.1.106/allwinner_update”，所以301的重定向又定位到“http://192.168.1.106/allwinner_update/”,原来就是一个“/”符号引起的。

谨记谨记，勿重蹈覆辙！