mirror of
https://github.com/EtherDream/jsproxy
synced 2024-11-22 09:58:46 +00:00
156 lines
3.5 KiB
Lua
156 lines
3.5 KiB
Lua
-- 功能：编码 HTTP 返回头
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-- 阶段：header_filter_by_lua
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-- 备注：
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-- aceh = HTTP 返回头的 access-control-expose-headers 字段
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-- 无论浏览器是否支持，aceh 始终包含 *
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local expose = '*'
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-- 该值为 true 表示浏览器不支持 aceh: *，需返回详细的头部列表
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local detail = ngx.ctx._acehOld
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local function addHdr(k, v)
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ngx.header[k] = v
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if detail then
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expose = expose .. ',' .. k
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end
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end
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local function flushHdr()
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if detail then
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if status ~= 200 then
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expose = expose .. ',--s'
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end
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-- 该字段不在 aceh 中，如果浏览器能读取到，说明支持 * 通配
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ngx.header['--t'] = '1'
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end
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ngx.header['access-control-expose-headers'] = expose
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ngx.header['access-control-allow-origin'] = '*'
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local status = ngx.status
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-- 前端优先使用该字段作为状态码
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if status ~= 200 and status ~= 304 then
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ngx.header['--s'] = status
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end
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-- 保留原始状态码，便于控制台调试
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-- 例如 404 显示红色，如果统一设置成 200 则没有颜色区分
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-- 需要转义 30X 重定向，否则不符合 cors 标准
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if
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status == 301 or
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status == 302 or
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status == 303 or
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status == 307 or
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status == 308
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then
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status = status + 10
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end
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ngx.status = status
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end
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local function nodeSwitched()
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local status = ngx.status
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if status ~= 200 and status ~= 206 then
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return false
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end
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local level = ngx.ctx._level
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if level == nil or level == 0 then
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return false
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end
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if ngx.req.get_method() ~= 'GET' then
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return false
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end
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if ngx.header['set-cookie'] ~= nil then
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return false
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end
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local resLenStr = ngx.header['content-length']
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if resLenStr == nil then
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return false
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end
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-- 小于 400KB 的资源不走加速
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local resLenNum = tonumber(resLenStr)
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if resLenNum == nil or resLenNum < 1000 * 400 then
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return false
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end
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local addr = ngx.var.upstream_addr or ''
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local etag = ngx.header['etag'] or ''
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local last = ngx.header['last-modified'] or ''
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local info = addr .. '|' .. resLenStr .. '|' .. etag .. '|' .. last
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-- clear all res headers
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local h, err = ngx.resp.get_headers()
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for k, v in pairs(h) do
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ngx.header[k] = nil
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end
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addHdr('--raw-info', info)
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addHdr('--switched', '1')
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ngx.header['cache-control'] = 'no-cache'
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ngx.var._switched = resLenStr
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ngx.ctx._switched = true
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flushHdr()
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return true
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end
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-- 节点切换功能，目前还在测试中（demo 中已开启）
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if nodeSwitched() then
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return
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end
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local h, err = ngx.resp.get_headers()
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for k, v in pairs(h) do
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if
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-- 这些头有特殊意义，需要转义 --
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k == 'access-control-allow-origin' or
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k == 'access-control-expose-headers' or
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k == 'location' or
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k == 'set-cookie'
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then
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if type(v) == 'table' then
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-- 重复的字段，例如 Set-Cookie
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-- 转换成 1-Set-Cookie, 2-Set-Cookie, ...
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for i = 1, #v do
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addHdr(i .. '-' .. k, v[i])
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end
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else
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addHdr('--' .. k, v)
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end
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ngx.header[k] = nil
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elseif detail and
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-- 非简单头无法被 fetch 读取，需添加到 aceh 列表 --
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-- https://developer.mozilla.org/en-US/docs/Glossary/Simple_response_header
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k ~= 'cache-control' and
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k ~= 'content-language' and
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k ~= 'content-type' and
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k ~= 'expires' and
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k ~= 'last-modified' and
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k ~= 'pragma'
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then
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expose = expose .. ',' .. k
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end
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end
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-- 不缓存非 GET 请求
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if ngx.req.get_method() ~= 'GET' then
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ngx.header['cache-control'] = 'no-cache'
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end
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flushHdr()
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