The path is not found in Yii using fopen

Help! Using fopen in Yii cannot find a path
My code is written in the view PHP file,
Specific code:
$file _url=yii::app ()->request->baseurl. " /file/";
$file _name= $file _url. ' Test.txt ';
if ($file =fopen ($file _name, "W")) {
Fwrite ($file, ' This is test content 1 ');
Fclose ($file);
}

Display Error:
fopen (/yiitest/file/test.txt) [function.fopen]: failed to open stream:no such file or directory

------Solution--------------------
BASEURL is the path to the Web site ... fopen open the path of the filesystem and cannot be confused.
------Solution--------------------
The path plus the domain name will do.
------Solution--------------------
Explore

BASEURL is the path to the Web site ... fopen open the path of the filesystem and cannot be confused.

