Discuz x2.0 debugging important functions of Application Communication

Find the source of this information from "communication failed:

Open. /control/admin/app. in the PHP file, find the onping method, and you can see that when the $ status is equal to 1, the communication will be successful. In addition, the communication will fail, so that we can set the breakpoint to get the status information, find the problem. The source code is as follows:

Function onping () {$ IP = getgpc ('IP'); $ url = getgpc ('url'); $ appid = intval (getgpc ('appid ')); $ app =$ _ env ['app']-> get_app_by_appid ($ appid); $ status = ''; if ($ app ['extra '] ['apppath'] & @ include $ app ['extra'] ['apppath']. '. /API /'. $ app ['apifilename']) {$ uc_note = new uc_note (); $ status = $ uc_note-> test ($ note ['getdata'], $ note ['postdata']);} else {$ this-> load ('note '); $ url = $ _ env ['note']-> get_url_code ('test', '', $ appid ); $ status = $ _ env ['app']-> test_api ($ URL, $ IP);} if ($ status = '1') {echo 'document. getelementbyid (\ 'status _'. $ appid. '\'). innerhtml = " <SPAN class = \ 'green \'> '. $ this-> Lang ['app _ connent_ OK ']. '</span> "; testlink ();';} else {echo 'document. getelementbyid (\ 'status _'. $ appid. '\'). innerhtml = " <SPAN class = \ 'Red \'> '. $ this-> Lang ['app _ connent_false ']. '</span> "; testlink ();';}}

 when dealing with this problem, there is a small problem in the middle. When $ status is printed as 1, this is also a "communication failure". After searching for half a day, we found that it was a BOM problem. I would like to remind you of it here, if you encounter a similar problem, you can use the ultraedit tool to save it as a file (you can choose whether to add BOM through configuration when saving it)