admin 发表于 2021-3-18 16:30:35

No Access-Control-Allow-Origin 跨域错误解决

No Access-Control-Allow-Origin 跨域错误解决

什么是跨域访问
在A网站中,我们希望使用Ajax来获得B网站中的特定内容。如果A网站与B网站不在同一个域中,那么就出现了跨域访问问题。你可以理解为两个域名之间不能跨过域名来发送请求或者请求数据,否则就是不安全的。跨域访问违反了同源策略,
同源策略规定,浏览器的ajax只能访问跟它的HTML页面同源(相同域名或IP)的资源。



如何确定是跨域请求

[*]A域名资源请求到B/C……域名
[*]你当前访问的域名是http的当请求的部分资源是https的
[*]当使用ajax访问远程服务器时,请求失败,浏览器报如上错误。这是出于安全的考虑,默认禁止跨域访问导致的。

如果是跨域访问,这时候就会报错

has been blocked by CORS policy: No 'Access-Control-Allow-Origin'

错误场景如:Fonts –No 'Access-Control-Allow-Origin',已经提示我字体文件请求http url跨域了,然后根据我用的服务环境设置如下就行:
跨域访问解决
Apache
<IfModule mod_headers.c>
<FilesMatch "\.(svg|ttf|otf|eot|woff|woff2)$">
    Header set Access-Control-Allow-Origin "*"
</FilesMatch>
</IfModule>
Nginx
location ~* \.(eot|ttf|woff)$ {
   add_header Access-Control-Allow-Origin '*';
}
Access-Control-Allow-Origin:* 表示允许任何域名跨域访问。

扩展
server {
listen      80;
server_name   uedbox.com;


location / {

    # Simple requests
    if ($request_method ~* "(GET|POST)") {
      add_header "Access-Control-Allow-Origin"*;
    }

    # Preflighted requests
    if ($request_method = OPTIONS ) {
      add_header "Access-Control-Allow-Origin"*;
      add_header "Access-Control-Allow-Methods" "GET, POST, OPTIONS, HEAD";
      add_header "Access-Control-Allow-Headers" "Authorization, Origin, X-Requested-With, Content-Type, Accept";
      return 200;
    }

    ....
    # Handle request
    ....
}
}
你还可以动态配置跨域方案
set $cors '';
if ($http_origin ~ '^https?://(localhost|www\.yourdomain\.com|www\.yourotherdomain\.com)') {
      set $cors 'true';
}

if ($cors = 'true') {
      add_header 'Access-Control-Allow-Origin' "$http_origin" always;
      add_header 'Access-Control-Allow-Credentials' 'true' always;
      add_header 'Access-Control-Allow-Methods' 'GET, POST, PUT, DELETE, OPTIONS' always;
      add_header 'Access-Control-Allow-Headers' 'Accept,Authorization,Cache-Control,Content-Type,DNT,If-Modified-Since,Keep-Alive,Origin,User-Agent,X-Requested-With' always;
      # required to be able to read Authorization header in frontend
      #add_header 'Access-Control-Expose-Headers' 'Authorization' always;
}

if ($request_method = 'OPTIONS') {
      # Tell client that this pre-flight info is valid for 20 days
      add_header 'Access-Control-Max-Age' 1728000;
      add_header 'Content-Type' 'text/plain charset=UTF-8';
      add_header 'Content-Length' 0;
      return 204;
}

不改动服务配置跨域解决

<?php
$ret = array(
    'name' => isset($_POST['name'])? $_POST['name'] : '',
    'gender' => isset($_POST['gender'])? $_POST['gender'] : ''
);

header('content-type:application:json;charset=utf8');
header('Access-Control-Allow-Origin:*');
header('Access-Control-Allow-Methods:POST');
header('Access-Control-Allow-Headers:x-requested-with,content-type');

echo json_encode($ret);
?>
如果需要指定某域名才允许跨域访问,只需把Access-Control-Allow-Origin:*改为Access-Control-Allow-Origin:允许的域名,例如:
header('Access-Control-Allow-Origin:https://www.phpin.net');
如果需要设置多个域名允许访问,那么把多个域名放在数组中就可以,例如:
<?php
$ret = array(
    'name' => isset($_POST['name'])? $_POST['name'] : '',
    'gender' => isset($_POST['gender'])? $_POST['gender'] : ''
);

header('content-type:application:json;charset=utf8');

$origin = isset($_SERVER['HTTP_ORIGIN'])? $_SERVER['HTTP_ORIGIN'] : '';

$allow_origin = array(
    'https://www.uedbox.com',
    'https://www.uedbox.com'
);

if(in_array($origin, $allow_origin)){
    header('Access-Control-Allow-Origin:'.$origin);
    header('Access-Control-Allow-Methods:POST');
    header('Access-Control-Allow-Headers:x-requested-with,content-type');
}

echo json_encode($ret);
?>
至此,No 'Access-Control-Allow-Origin'问题解决!
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