基于 WSS 的 MQTT
功能概述
这个示例使用 MQTT WSS 连接到指定的 URI，并演示如何订阅/取消订阅主题和发送消息。 (请注意，所使用的公共 URI 可能不是永远可用的，详情请参阅此免责声明)
这个示例的 PEM 证书可以从连接到 mqtt.eclipseprojects.io 的 openssl s_client 命令中提取。 如果主机操作系统安装了 openssl 和 sed，则可以执行以下命令下载根证书并保存到文件中 (Windows 系统中需使用类似 Linux shell 的环境)。
echo "" | openssl s_client -showcerts -connect mqtt.eclipseprojects.io:443 | sed -n "1,/Root/d; /BEGIN/,/END/p" | openssl x509 -outform PEM >mqtt_eclipseprojects_io.pem
需注意，这不是为任意主机下载根证书的通用命令，这个命令只对 mqtt.eclipseprojects.io 主机起作用。
环境要求
需要有一个能正常连接的 AP。
在 menuconfig 中配置 WiFi SSID 和 WiFi Password。
在 menuconfig 中配置 Broker URL。
需要一个 PEM 证书，默认位于 mian/src/mqtt_eclipseprojects_io.pem，mian/src/mqtt_eclipseprojects_io.crt，mian/src/mqtt_eclipseprojects_io.key。
编译和烧录
示例位置：examples/network/mqtt/wss
编译、烧录等操作请参考：快速入门
运行结果
成功运行将输出如下日志
I/wm_nm_core [5.488] got ip: 192.168.3.208
D/wm_nm_core [5.492] WM_NM_EV post event 4 success
I/mqtt example [5.996] wifi station start success, network is ready!
D/mqtt [6.004] uri: wss://mqtt.eclipseprojects.io:443
D/mqtt [6.012] mqtt_config mode: 3
D/mqtt [6.016] mode: MQTT_AUTH_MODE_MUTUAL_AUTH
D/mqtt [6.862] ======================================
D/mqtt [6.868] Trace Output
D/mqtt [6.872] se Paho Synchronous MQTT C Client Library
D/mqtt [6.878] se Paho Synchronous MQTT C Client Library
D/mqtt [6.884] 55
D/mqtt [6.886] ======================================
D/mqtt [6.906] connect out: rc=119
D/mqtt [6.910] wait connect, timeout: 29982
D/mqtt [7.224] wait end
E/mqtt [7.228] client W800_29315F, packet_type 1, timeout 29982, pack 0x0
> Seeding the random number generator...
ok
> Loading the CA root certificate ...
ok
> Loading the client cert. and key...
ok (key type: RSA)
> Setting up the SSL/TLS structure...
ok
> Performing the SSL/TLS handshake...
ok
SSLSocket_putdatas: mbedtls_ssl_write rc 245, iov_len 245
D/mqtt [9.730] wait connect, timeout: 27164
D/mqtt [10.024] wait end
E/mqtt [10.028] client W800_29315F, packet_type 1, timeout 27164, pack 0x0
SSLSocket_putdatas: mbedtls_ssl_write rc 33, iov_len 33
D/mqtt [15.034] wait connect ack, timeout: 21860
D/mqtt [15.312] wait end
E/mqtt [15.316] client W800_29315F, packet_type 2, timeout 21860, pack 0x0
D/mqtt [20.312] MQTTClient connected!
I/mqtt example [20.316] mqtt connected
D/mqtt [20.320] mqtt client publish, topic /topic/qos1
SSLSocket_putdatas: mbedtls_ssl_write rc 29, iov_len 29
D/mqtt [20.336] mqtt client publish, token: 1
I/mqtt example [20.342] sent publish successful, msg_id=1
D/mqtt [20.348] mqtt client subscribe, topic /topic/qos0, qos 0
SSLSocket_putdatas: mbedtls_ssl_write rc 24, iov_len 24
D/mqtt [20.362] wait sub ack, timeout: 10000
D/mqtt [20.610] Message with token value 1 delivery confirmed
D/mqtt [20.886] wait end
E/mqtt [20.890] client W800_29315F, packet_type 9, timeout 10000, pack 0x0
I/mqtt example [20.898] sent subscribe successful, msg_id=2
D/mqtt [20.906] mqtt client subscribe, topic /topic/qos1, qos 1
SSLSocket_putdatas: mbedtls_ssl_write rc 24, iov_len 24
D/mqtt [20.922] wait sub ack, timeout: 10000
D/mqtt [21.194] wait end
E/mqtt [21.198] client W800_29315F, packet_type 9, timeout 10000, pack 0x0
I/mqtt example [21.206] sent subscribe successful, msg_id=3
D/mqtt [21.212] mqtt client unsubscribe, topic /topic/qos1
SSLSocket_putdatas: mbedtls_ssl_write rc 23, iov_len 23
D/mqtt [21.228] wait unsub ack, timeout: 10000
D/mqtt [21.506] wait end
E/mqtt [21.510] client W800_29315F, packet_type 11, timeout 10000, pack 0x0
I/mqtt example [21.518] sent unsubscribe successful, msg_id=4
I/mqtt example [21.524] mqtt published, msg_id=1