編輯用PHP給語法錯誤

Question

我試圖通過刪除所有額外的代碼只得到訪問令牌，但它總是給我的「」

這裏語法錯誤是我的代碼

$top = $_GET["user"]; 

$line = '$top'; 
$decoded = json_decode($line,true); 

$token2 = $decoded['access_token']; 

$頂部

{"session_key":"5.uDUKhUqs4_N0Ow.1492573795.34-100007001746590","uid":100007001746590,"secret":"a01298dab24aa3c62adea05c6a79392e","access_token":"EAAAAAYsX7TsBAKXNrDxZB5Wx9vYY4HO8ux38JNIdTmYxwr15SFVuk0BOBeKQdS9C8BE4CzmIgxmghonZAjQmAl0E5pygW7s3eZCGEE4PxeXXO5kV5a2zt27LHo80YiekAZBzN3zHA9kuIiYNquvDLdgNaLlTtTObUZC1BrCKepc9NY7a3ieXaOSM0gsQePO9tf8nSykNahAZDZD","machine_id":"Y972WDldq3SeEw4bTWfnVj9Z","confirmed":true,"identifier":"9431448548"} 

Answer 1

問題是在這裏$line = '$top'這裏使用的是單引號定義$line爲$top，而不是

{"session_key":"5.uDUKhUqs4_N0Ow.1492573795.34-100007001746590","uid":100007001746590,"secret":"a01298dab24aa3c62adea05c6a79392e","access_token":"EAAAAAYsX7TsBAKXNrDxZB5Wx9vYY4HO8ux38JNIdTmYxwr15SFVuk0BOBeKQdS9C8BE4CzmIgxmghonZAjQmAl0E5pygW7s3eZCGEE4PxeXXO5kV5a2zt27LHo80YiekAZBzN3zHA9kuIiYNquvDLdgNaLlTtTObUZC1BrCKepc9NY7a3ieXaOSM0gsQePO9tf8nSykNahAZDZD","machine_id":"Y972WDldq3SeEw4bTWfnVj9Z","confirmed":true,"identifier":"9431448548"} 

變化值這：

$top = $_GET["user"]; 

$line = '$top'; 
$decoded = json_decode($line,true); 

$token2 = $decoded['access_token']; 

此：

$top = $_GET["user"]; 
$decoded = json_decode($top,true); 
$token2 = $decoded['access_token'];