! The path cannot be found using fopen in Yii

Help! In Yii, fopen cannot find the path. my code is written in the PHP file in view. the code is $ file_url = Yii: app ()-& gt; request-& gt; baseUrl. & quot;/file/"{file_name={file_url.'test.txt '; help! The path cannot be found using fopen in Yii
My code is written in the PHP file in the view,
Code:
$ File_url = Yii: app ()-> request-> baseUrl. "/file /";
Using file_name1_1_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

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BaseUrl is the path of the website... fopen opens the path of the file system and cannot be confused.
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Add the domain name to the path.
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Discussion

BaseUrl is the path of the website... fopen opens the path of the file system and cannot be confused.