省流总结：

通过修改配置文件以开启分片上传的方式，让藏在cloudflare之后的自建nextcloud绕过cloudflare免费版本身100M大小的上传限制。此方法对网页端和官方客户端上传有效，第三方客户端无效。

具体方法：

1.首先，需要确认自己的源站web服务器默认允许上传的最大限制在合适自己的范围内（可以通过检查相应的php.ini来确认）
2.登录到服务器，找到放置nextcloud站点的根目录，进入 apps/files/js 目录，找到 jquery.fileupload.js 这个文件，并使用文本编辑器打开。
3.跳转到第154行附近，找到 maxChunkSize 这个值，将其修改为其他数值即可

// To upload large files in smaller chunks, set the following option
// to a preferred maximum chunk size. If set to 0, null or undefined,
// or the browser does not support the required Blob API, files will
// be uploaded as a whole.
maxChunkSize: undefined, //就是这个，这是默认情况下的
// When a non-multipart upload or a chunked multipart upload has been
// aborted, this option can be used to resume the upload by setting
// it to the size of the already uploaded bytes. This option is most
// useful when modifying the options object inside of the "add" or
// "send" callbacks, as the options are cloned for each file upload.
uploadedBytes: undefined,

例如我们可以将其修改为 100000000 （约合98MB），然后保存并退出

// To upload large files in smaller chunks, set the following option
// to a preferred maximum chunk size. If set to 0, null or undefined,
// or the browser does not support the required Blob API, files will
// be uploaded as a whole.
maxChunkSize: 100000000, //修改完成之后的数值
// When a non-multipart upload or a chunked multipart upload has been
// aborted, this option can be used to resume the upload by setting
// it to the size of the already uploaded bytes. This option is most
// useful when modifying the options object inside of the "add" or
// "send" callbacks, as the options are cloned for each file upload.
uploadedBytes: undefined,

此时关闭掉原先的浏览器窗口，再打开浏览器就可以上传大于100M的文件了。