C++；HTTPS请求使用cURL 7.55.1失败

我只是想从页面上获取数据。在这个测试示例中，它应该返回一个数字。 在控制台中：

* STATE: INIT => CONNECT handle 0x7011c8; line 1654 (connection #-5000)
* Added connection 0. The cache now contains 1 members
* STATE: CONNECT => WAITRESOLVE handle 0x7011c8; line 1700 (connection #0)
* family0 == v4, family1 == v6
*   Trying 31.170.160.123:443...
* STATE: WAITRESOLVE => WAITCONNECT handle 0x7011c8; line 1782 (connection #0)
* Connected to www.atmaple.com (31.170.160.123) port 443 (#0)
* STATE: WAITCONNECT => SENDPROTOCONNECT handle 0x7011c8; line 1848 (connection #0)
* Marked for [keep alive]: HTTP default
* ALPN, offering http/1.1
* STATE: SENDPROTOCONNECT => PROTOCONNECT handle 0x7011c8; line 1866 (connection #0)
* SSL certificate problem: unable to get local issuer certificate
* Marked for [closure]: Failed HTTPS connection
* multi_done
* The cache now contains 0 members
* Closing connection 0
* Expire cleared (transfer 0x7011c8)

这是我使用的从vcpkg安装的版本：

curl --ssl https://www.atmaple.com/Test.txt
3,711,488

尝试添加SSL

curl --version
curl 7.55.1 (Windows) libcurl/7.55.1 WinSSL
Release-Date: 2017-11-14, security patched: 2019-11-05
Protocols: dict file ftp ftps http https imap imaps pop3 pop3s smtp smtps telnet tftp
Features: AsynchDNS IPv6 Largefile SSPI Kerberos SPNEGO NTLM SSL

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所以，我做了一些搜索，找到了这个网站：

有一个叫做LibCurl with SSL的部分，他从这个网站下载了一个CA证书：

我下载了cacert.pem并将其重命名为ca_bundle.crt（或任何您想命名的名称，并将其添加到我的代码中：

#include <openssl/ssl.h>
#include <openssl/err.h>
#include <openssl/bio.h>

并从链接返回正确的数据

curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 1);
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 1);
curl_easy_setopt(curl, CURLOPT_CAINFO, "ca-bundle.crt");

*状态：INIT=>连接句柄0x1174928；第1654行（连接#-5000）
*已添加连接0。缓存现在包含1个成员
*状态：CONNECT=>WAITRESOLVE句柄0x1174928；第1700行（连接#0）
*家族0==v4，家族1==v6
*正在尝试31.170.160.123:443。。。
*状态：WAITRESOLVE=>WAITCONNECT句柄0x1174928；第1782行（连接#0）
*已连接到www.atmaple.com（31.170.160.123）端口443（#0）
*状态：WAITCONNECT=>SENDPROTOCONNECT句柄0x1174928；第1848行（连接#0）
*标记为[保持活动]：HTTP默认值
*ALPN，提供http/1.1
*已成功设置证书验证位置：
*CAfile:ca-bundle.crt
*卡帕斯：没有
*状态：SENDPROTOCONNECT=>PROTOCONNECT句柄0x1174928；第1866行（连接#0）
*使用TLSv1.3/TLS_AES_256_GCM_SHA384的SSL连接
*ALPN，接受使用http/1.1的服务器
*服务器证书：
*主题：CN=atmaple.com
*开始日期：2月25日03:04:46格林尼治标准时间2021
*过期日期：5月26日03:04:46 2021 GMT
*主题名称：主机“www.atmaple.com”匹配证书的“www.atmaple.com”
*发卡机构：C=US；O=Let's Encrypt；CN=R3
*SSL证书验证正常。
*状态：PROTOCONNECT=>DO句柄0x1174928；第1885行（连接#0）
>GET/Test.txt HTTP/1.1
主持人：www.atmaple.com
接受：*/*
*状态：DO=>DO#u DONE句柄0x1174928；第1940行（连接#0）
*状态：DO#u DONE=>执行句柄0x1174928；第2061行（连接#0）
*将捆绑包标记为不支持多用途
*HTTP 1.1或更高版本，具有持久连接
DONE句柄0x1174928；第2251行（连接#0）
*多次完成
*0到主机www.atmaple.com的连接保持不变
*已清除过期（传输0x1174928）

---

3711488这并没有解决问题。尽管如此，我还是开始使用ca-bundle.crt，它从站点返回正确的数据。虽然，最初我不必这样做，这就是为什么我如此困惑的原因。

curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 1);
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 1);
curl_easy_setopt(curl, CURLOPT_CAINFO, "ca-bundle.crt");

* STATE: INIT => CONNECT handle 0x1174928; line 1654 (connection #-5000)
* Added connection 0. The cache now contains 1 members
* STATE: CONNECT => WAITRESOLVE handle 0x1174928; line 1700 (connection #0)
* family0 == v4, family1 == v6
*   Trying 31.170.160.123:443...
* STATE: WAITRESOLVE => WAITCONNECT handle 0x1174928; line 1782 (connection #0)
* Connected to www.atmaple.com (31.170.160.123) port 443 (#0)
* STATE: WAITCONNECT => SENDPROTOCONNECT handle 0x1174928; line 1848 (connection #0)
* Marked for [keep alive]: HTTP default
* ALPN, offering http/1.1
* successfully set certificate verify locations:
*  CAfile: ca-bundle.crt
*  CApath: none
* STATE: SENDPROTOCONNECT => PROTOCONNECT handle 0x1174928; line 1866 (connection #0)
* SSL connection using TLSv1.3 / TLS_AES_256_GCM_SHA384
* ALPN, server accepted to use http/1.1
* Server certificate:
*  subject: CN=atmaple.com
*  start date: Feb 25 03:04:46 2021 GMT
*  expire date: May 26 03:04:46 2021 GMT
*  subjectAltName: host "www.atmaple.com" matched cert's "www.atmaple.com"
*  issuer: C=US; O=Let's Encrypt; CN=R3
*  SSL certificate verify ok.
* STATE: PROTOCONNECT => DO handle 0x1174928; line 1885 (connection #0)
> GET /Test.txt HTTP/1.1
Host: www.atmaple.com
Accept: */*

* STATE: DO => DO_DONE handle 0x1174928; line 1940 (connection #0)
* STATE: DO_DONE => PERFORM handle 0x1174928; line 2061 (connection #0)
* Mark bundle as not supporting multiuse
* HTTP 1.1 or later with persistent connection
< HTTP/1.1 200 OK
< Connection: Keep-Alive
< Content-Type: text/plain
< Last-Modified: Tue, 27 Oct 2020 22:25:29 GMT
< Etag: "9-5f989e59-7aa76bf0011c68c2;;;"
< Accept-Ranges: bytes
< Content-Length: 9
< Date: Mon, 05 Apr 2021 23:39:30 GMT
< Server: LiteSpeed
< Content-Security-Policy: upgrade-insecure-requests
<
* STATE: PERFORM => DONE handle 0x1174928; line 2251 (connection #0)
* multi_done
* Connection #0 to host www.atmaple.com left intact
* Expire cleared (transfer 0x1174928)