While getting the permanent access token I followed above 5 steps as Donut mentioned. However in the 5th step while generating permanent access token its returning the long lived access token(Which is valid for 2 months) not permanent access token(which never expires). what I noticed is the current version of Graph API is V2.5. If you trying to get the permanent access token with V2.5 its giving long lived access token.Try to make API call with V2.2(if you are not able to change version in the graph api explorer,hit the API call https://graph.facebook.com/v2.2/{account_id}/accounts?access_token={long_lived_access_token} in the new tab with V2.2) then you will get the permanent access token(Which never expires)

如果只请求页数据，则可以使用页访问令牌。您只需授权用户一次即可获得用户访问令牌;将有效期延长到两个月，然后请求该页的令牌。这在场景5中都有解释。请注意，获取的页面访问令牌仅在用户访问令牌有效期间有效。

我找到了这个答案，它指的是这个工具，它真的很有用。

我希望当你读到这篇文章时，这个答案仍然有效。

我根据donut的回答创建了一个小的NodeJS脚本。将以下文件存储在名为get-facebook-access-token.js的文件中:

const fetch = require('node-fetch');
const open = require('open');

const api_version = 'v9.0';
const app_id = '';
const app_secret = '';
const short_lived_token = '';
const page_name = '';

const getPermanentAccessToken = async () => {
  try {
    const long_lived_access_token = await getLongLivedAccessToken();
    const account_id = await getAccountId(long_lived_access_token);
    const permanent_page_access_token = await getPermanentPageAccessToken(
      long_lived_access_token,
      account_id
    );
    checkExpiration(permanent_page_access_token);
  } catch (reason) {
    console.error(reason);
  }
};

const getLongLivedAccessToken = async () => {
  const response = await fetch(
    `https://graph.facebook.com/${api_version}/oauth/access_token?grant_type=fb_exchange_token&client_id=${app_id}&client_secret=${app_secret}&fb_exchange_token=${short_lived_token}`
  );
  const body = await response.json();
  return body.access_token;
};

const getAccountId = async (long_lived_access_token) => {
  const response = await fetch(
    `https://graph.facebook.com/${api_version}/me?access_token=${long_lived_access_token}`
  );
  const body = await response.json();
  return body.id;
};

const getPermanentPageAccessToken = async (
  long_lived_access_token,
  account_id
) => {
  const response = await fetch(
    `https://graph.facebook.com/${api_version}/${account_id}/accounts?access_token=${long_lived_access_token}`
  );
  const body = await response.json();
  const page_item = body.data.find(item => item.name === page_name);  
  return page_item.access_token;
};

const checkExpiration = (access_token) => {
  open(`https://developers.facebook.com/tools/debug/accesstoken/?access_token=${access_token}&version=${api_version}`);
}

getPermanentAccessToken();

填入常量，然后运行:

npm install node-fetch
npm install open
node get-facebook-access-token.js

运行脚本后，浏览器中会打开一个页面，显示令牌及其有效期。

我做了一个PHP脚本，使它更容易。创建一个应用程序。在Graph API资源管理器中选择你的应用程序，并获得具有manage_pages和publish_pages权限的用户令牌。在关于页面的底部找到页面的ID。填写配置变量并运行脚本。

<?php
$args=[
    'usertoken'=>'',
    'appid'=>'',
    'appsecret'=>'',
    'pageid'=>''
];

echo generate_token($args);

function generate_token($args){
    $r=json_decode(file_get_contents("https://graph.facebook.com/v2.8/oauth/access_token?grant_type=fb_exchange_token&client_id={$args['appid']}&client_secret={$args['appsecret']}&fb_exchange_token={$args['usertoken']}")); // get long-lived token
    $longtoken=$r->access_token;
    $r=json_decode(file_get_contents("https://graph.facebook.com/v2.8/me?access_token={$longtoken}")); // get user id
    $userid=$r->id;
    $r=json_decode(file_get_contents("https://graph.facebook.com/v2.8/{$userid}/accounts?access_token={$longtoken}")); // get permanent token
    foreach($r->data as $d) if($d->id==$args['pageid']) return $d->access_token;
}

另一个PHP答案使生活更简单。更新为Facebook Graph API 2.9。把它装满，装上。

<?php
$args=[
/*-- Permanent access token generator for Facebook Graph API version 2.9 --*/
//Instructions: Fill Input Area below and then run this php file
/*-- INPUT AREA START --*/
    'usertoken'=>'',
    'appid'=>'',
    'appsecret'=>'',
    'pageid'=>''
/*-- INPUT AREA END --*/
];
echo 'Permanent access token is: <input type="text" value="'.generate_token($args).'"></input>';
function generate_token($args){
    $r=json_decode(file_get_contents("https://graph.facebook.com/v2.9/oauth/access_token?grant_type=fb_exchange_token&client_id={$args['appid']}&client_secret={$args['appsecret']}&fb_exchange_token={$args['usertoken']}")); // get long-lived token
    $longtoken=$r->access_token;
    $r=json_decode(file_get_contents("https://graph.facebook.com/v2.9/me?access_token={$longtoken}")); // get user id
    $userid=$r->id;
    $r=json_decode(file_get_contents("https://graph.facebook.com/v2.9/{$userid}?fields=access_token&access_token={$longtoken}")); // get permanent token
    if($r->id==$args['pageid']) $finaltoken=$r->access_token;
    return $finaltoken;
}
?>

附录(备选):

从图2.9开始，在调试了短访问令牌之后，只需单击访问令牌调试器工具底部的扩展访问令牌，就可以跳过获取长访问令牌的许多麻烦。掌握了pageid和longlivetoken的信息后，运行下面的php以获得永久访问令牌。

<?php
$args=[
/*-- Permanent access token generator for Facebook Graph API version 2.9 --*/
//Instructions: Fill Input Area below and then run this php file
/*-- INPUT AREA START --*/
    'longlivedtoken'=>'',
    'pageid'=>''
/*-- INPUT AREA END --*/
];
echo 'Permanent access token is: <input type="text" value="'.generate_token($args).'"></input>';
function generate_token($args){
$r=json_decode(file_get_contents("https://graph.facebook.com/v2.9/{$args['pageid']}?fields=access_token&access_token={$args['longlivedtoken']}"));
return $r->access_token;
}
?>

尽管第二个代码为您节省了很多麻烦，但我建议运行第一个php代码，除非您非常着急，因为它会交叉检查pageid和userid。如果您错误地选择了user令牌，则第二个代码将无法工作。

感谢dw1和Rob