当我们使用 curl 命令访问网站的时候，有时候可能会得到一个 SSL 证书错误：
这是因为在默认情况下，cURL 使用 SSL 证书进行连接，如果指定的网站配置错误或证书过期，则会引发错误。
下面我们看一下如何忽略其中的 SSL 证书错误。
使用 cURL 忽略 SSL 证书错误
一般来说，直接忽略错误然后继续连接故障网站是不推荐的。但是如果你信任该网站，那就可以。
使用 curl 的时候，附带 --insecure 选项可以忽略 ssl 证书错误，如下代码：
$ curl https://expired.badssl.com
curl: (60) SSL certificate problem: certificate has expired
More details here: https://curl.se/docs/sslcerts.html
curl failed to verify the legitimacy of the server and therefore could not
establish a secure connection to it. To learn more about this situation and
how to fix it, please visit the web page mentioned above.
另外，也可以使用 -k 选项，其与 --insecure 的效果是相同的：
$ curl --insecure https://expired.badssl.com
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="shortcut icon" href="/icons/favicon-red.ico"/>
<link rel="apple-touch-icon" href="/icons/icon-red.png"/>
<title>expired.badssl.com</title>
<link rel="stylesheet" href="/style.css">
<style>body { background: red; }</style>
</head>
<body>
<div id="content">
<h1 style="font-size: 12vw;">
expired.<br>badssl.com
</h1>
</div>
</body>
</html>
对所有 SSL 连接都使用 --insecure 选项
注意：除非在隔离或测试环境下可以执行此操作，否则不建议这样做。
你可以使用如下命令将 insecure 添加到 curl 配置文件中：
echo "insecure" >> ~/.curlrc
然后，在不使用 --insecure 选项的情况下，再次直接使用 curl 连接 html地址，也是可以成功的：
$ curl https://expired.badssl.com
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="shortcut icon" href="/icons/favicon-red.ico"/>
<link rel="apple-touch-icon" href="/icons/icon-red.png"/>
<title>expired.badssl.com</title>
<link rel="stylesheet" href="/style.css">
<style>body { background: red; }</style>
</head>
<body>
<div id="content">
<h1 style="font-size: 12vw;">
expired.<br>badssl.com
</h1>
</div>
</body>
</html>
忽略 wget 的 SSL 证书错误
如果某个指定的网站配置错误或证书过期，而使用 wget 命令下载该网站中的文件时，也会出现 SSL 证书错误：
$ wget https://expired.badssl.com
--2022-11-17 14:35:55-- https://expired.badssl.com/
Resolving expired.badssl.com (expired.badssl.com)... 104.154.89.105
Connecting to expired.badssl.com (expired.badssl.com)|104.154.89.105|:443... connected.
ERROR: cannot verify expired.badssl.com's certificate, issued by ‘CN=COMODO RSA Domain Validation Secure Server CA,O=COMODO CA Limited,L=Salford,ST=Greater Manchester,C=GB’:
Issued certificate has expired.
To connect to expired.badssl.com insecurely, use `--no-check-certificate'.
默认情况下，wget会检查有效的SSL证书，以便您可以建立可靠的连接，如果没有，则会抛出一个错误，表示颁发的证书已过期。
要忽略 ssl 错误，可以使用 --no-check-certificate 选项，让它不检查 ssl 证书：
$ wget --no-check-certificate https://expired.badssl.com
--2022-11-17 15:18:07-- https://expired.badssl.com/
Resolving expired.badssl.com (expired.badssl.com)... 104.154.89.105
Connecting to expired.badssl.com (expired.badssl.com)|104.154.89.105|:443... connected.
WARNING: cannot verify expired.badssl.com's certificate, issued by ‘CN=COMODO RSA Domain Validation Secure Server CA,O=COMODO CA Limited,L=Salford,ST=Greater Manchester,C=GB’:
Issued certificate has expired.
HTTP request sent, awaiting response... 200 OK
Length: 494 [text/html]
Saving to: ‘index.html.1’
index.html.1 100%[===================>] 494 --.-KB/s in 0s
2022-11-17 15:18:08 (209 MB/s) - ‘index.html.1’ saved [494/494]
跳过认证检查
要在每次访问损坏的 SSL 站点的时候跳过证书检查，只需要在 wget 配置文件中添加 check-certificate = off 即可，这样在访问的时候就可以不添加 --no-check-certificate 选项了：
$ wget https://expired.badssl.com
--2022-11-17 15:41:50-- https://expired.badssl.com/
Resolving expired.badssl.com (expired.badssl.com)... 104.154.89.105
Connecting to expired.badssl.com (expired.badssl.com)|104.154.89.105|:443... connected.
WARNING: cannot verify expired.badssl.com's certificate, issued by ‘CN=COMODO RSA Domain Validation Secure Server CA,O=COMODO CA Limited,L=Salford,ST=Greater Manchester,C=GB’:
Issued certificate has expired.
HTTP request sent, awaiting response... 200 OK
Length: 494 [text/html]
Saving to: ‘index.html.2’
index.html.2 100%[===================>] 494 --.-KB/s in 0s
2022-11-17 15:41:51 (191 MB/s) - ‘index.html.2’ saved [494/494]
