解决Nginx反向代理时URI首斜杠丢失的问题

我们使用Nginx将some.url.com的请求代理到内部服务器的eXist-db应用，要求正确传递域名后的路径作为URI。现有Nginx配置如下：

server {
        server_name     some.url.com www.some.url.com;
        access_log      /var/log/nginx/some.url.com/access.log main;
        #access_log     syslog:server=192.168.19.51,facility=local5,tag=nginx,severity=notice main;
        error_log       /var/log/nginx/some.url.com/error.log;

        location / {
            proxy_set_header Host $host;
            proxy_set_header X-Remote-IP $remote_addr;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
            proxy_set_header nginx-request-uri $request_uri;
            proxy_pass http://172.16.0.4:8080/exist/apps/my_app/;
        }

        location /exist {
            proxy_set_header Host $host;
            proxy_set_header X-Remote-IP $remote_addr;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
            proxy_set_header nginx-request-uri $request_uri;
            proxy_pass http://172.16.0.4:8080/exist;
        }

        location /resources/images {
            proxy_set_header Host $host;
            proxy_set_header X-Remote-IP $remote_addr;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
            proxy_set_header nginx-request-uri $request_uri;
            proxy_pass http://172.16.0.4/images;
        }

        location /resources/files {
            proxy_set_header Host $host;
            proxy_set_header X-Remote-IP $remote_addr;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
            proxy_set_header nginx-request-uri $request_uri;
            proxy_pass http://172.16.0.4/files;
        }
}

正常工作场景 #

• /resources/images和/resources/files路径可正确代理到文件服务器；
• 以some.url.com/exist/开头的请求可通过location /exist正确传递URI；
• 基础URL（some.url.com/或some.url.com）可正常代理到目标应用。

异常场景 #

当请求为some.url.com/archives或some.url.com/documents时，实际传递的URI为/exist/apps/my_apparchives和/exist/apps/my_appdocuments，而非期望的/exist/apps/my_app/archives和/exist/apps/my_app/documents，域名后的首斜杠在拼接时丢失。

解决方法 #

问题根源在于Nginx前缀匹配location /与proxy_pass路径的拼接逻辑。以下两种方法可彻底解决：

方法1：使用rewrite重写URI #

修改location /块，通过rewrite强制将请求路径重写为正确格式，再代理到后端根路径：

location / {
    rewrite ^/(.*)$ /exist/apps/my_app/$1 break;
    proxy_set_header Host $host;
    proxy_set_header X-Remote-IP $remote_addr;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_set_header nginx-request-uri $request_uri;
    proxy_pass http://172.16.0.4:8080;
}

此方法会将所有进入location /的请求，统一重写为/exist/apps/my_app/[原路径]，确保斜杠始终存在。

方法2：调整proxy_pass路径写法 #

保留location /的原有header配置，将proxy_pass修改为包含$uri变量的形式，明确拼接路径：

location / {
    proxy_set_header Host $host;
    proxy_set_header X-Remote-IP $remote_addr;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_set_header nginx-request-uri $request_uri;
    proxy_pass http://172.16.0.4:8080/exist/apps/my_app$uri;
}

$uri变量包含请求的完整路径（如/archives），因此拼接后会形成/exist/apps/my_app/archives，保证路径正确。

内容的提问来源于stack exchange，提问作者jbrehr