XHTTP client: Move x_padding into Referer header

[rPDmYQ]

Move the padding into Referer header, to not bloat the reverse proxy access log.

From browser, the path part of Referer header can be controlled with fetch:

fetch("https://server.example.com/some_path", {referrer: "/?x_padding=000", referrerPolicy: "unsafe-url"})

The actual sent Referer header value would be http://<xray.browser.dialer>/?x_padding=000, and it won't trigger CORS preflight, even if the URL is long (no 128 length limit of "safelisted headers").

Therefore it's fully compatible with browser as dialer without overhead. The only downside would be some browsers may strip the path under privacy-protection mode (I see Firefox doing that, but it can be disabled by user for specific sites).

[Fangliding]

I think this change is acceptable (if others don't think the refer header is too odd)
But we should merge this after making browser dialer capable of processing this padding

[RPRX]

我觉得不用加选项，这项改变应当逐步变成默认的，甚至可以要求服务端及时升级，v25 直接 breaking 也很合理

由于旧服务端会要求 path padding，正好新客户端连不上旧服务端，#4253 修 #4113 (comment) 都方便了

[RPRX]

就是说最近在给 stream-up 加这个 014f5e6 ，从而引入了 x_version，这里 breaking 的话就不需要它了，有点想把它删掉

还有我想要求 xPaddingBytes 不得设为负数，不确定是这个 PR 一起改了还是

[RPRX]

你先这样改一下：

1. 无需加配置，直接改成 Referer，URL 即为以前的完整 URL，新服务端兼容新旧客户端
2. 变量名用 referer
3. 给 browser dialer 加一下，这个其实挺简单的

[rPDmYQ]

变量名用 referer

"Referer" is a misspelling of "referrer". This thing is usually referred as "referrer" in code (e.g. in fetch's parameter), and "referer" is only used when in HTTP header.

[onediram]

😊 сб, 18 янв. 2025 г., 11:07 AM rPDmYQ ***@***.***>:

…

变量名用 referer "Referer" is a misspelling <https://en.wikipedia.org/wiki/HTTP_referer#Etymology> of "referrer". This thing is usually referred as "referrer" in code (e.g. in fetch's parameter), and "referer" is only used when in HTTP header. — Reply to this email directly, view it on GitHub <#4298 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/BORZMM3SAGHIRFOFIF7NSFD2LIDTDAVCNFSM6AAAAABVKCAEYKVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDKOJZGYYDEOJTGY> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[RPRX]

Great

[RPRX]

感谢 @rPDmYQ 的贡献，我觉得把 x_padding 放 Referer 是一个非常好的 idea，且这个 PR 还有一些惊喜：

1. 将 header padding 的 0 改为了 X，说明他仔细研究过 H2 等协议细节
2. 同步修改了 packet-up 相关代码，说明他通读过 XHTTP 的代码
3. 同步修改了 browser dialer 相关代码，我都不太想碰这部分

我打算先合并这个 PR，并发起另一个 PR 完成剩下的修改

[RPRX]

对了，你有空的话可以研究下给 browser dialer 加 stream-up，此前我的研究：#4148 (comment)

到时服务端可能得通过 Referer host 来判断要不要及时响应 stream-up 并发保活包，因为 Chrome 还不支持 bidirectional streaming

[RPRX]

记录一下针对这个 PR 我想改的地方：x_padding 无需设为 const；c.Host 不一定有值；既然 path 没对上可能 query 也别要了