resty_functions/scripts/wx_download.lua

local cjson = require "cjson"
local http = require "resty.http"
local pl = require "pl.pretty"
local httpc = http.new()
local sudoerToken = ngx.req.get_headers().HtySudoerToken
local htyhostHeader = ngx.req.get_headers().HtyHost

local function get_access_token()
    local htyuc = ngx.var.htyuc
    local host = ngx.var.host
    local wx_domain = ngx.var.wx_domain

    ngx.log(ngx.INFO, "HTYUC -> ", htyuc)
    ngx.log(ngx.INFO, "Host -> ", host)
    ngx.log(ngx.INFO, 'HtyHostHeader -> ', htyhostHeader)
    ngx.log(ngx.INFO, 'HtySudoerToken -> ', sudoerToken)

    local remote_url = string.format("%s/api/v1/uc/wx_get_access_token", htyuc)
    ngx.log(ngx.INFO, 'REMOTE URL -> ', remote_url)

    ngx.log(ngx.INFO, "START REQUEST TO GET ACCESS TOKEN -> ", pl.write(sudoerToken))

    local no_exception, resp, resp_err = pcall(httpc.request_uri, httpc, remote_url,
            {
                ssl_verify = false, -- 设置参数 ssl_verify 为false 不校验ssl证书
                pool = nil,
                pool_size = nil,
                method = "GET",
                headers = {
                    ["HtyHost"] = wx_domain,
                    ["HtySudoerToken"] = sudoerToken,
                }
            })

    ngx.log(ngx.INFO, "RESP -> ", pl.write(resp))

    if no_exception == true then
        if 200 ~= resp.status then
            ngx.log(ngx.ERR, "GET ACCESS TOKEN *FAILED*", pl.write(resp_err))
            ngx.status = resp.status
            ngx.say(pl.write(resp_err))
            ngx.exit(resp.status)
        else
            ngx.log(ngx.ERR, "RESP IS OK -> ", pl.write(resp.body))
            return cjson.decode(resp.body).d
        end
    else
        if resp == nil then
            resp = ""
        end
        ngx.log(ngx.ERR, "FAILED TO CONNECT TO *HTYUC*: httpc throws runtime error, please check HTYUC log. / ", pl.write(resp))
        -- 必须先设置ngx.status，否则ngx.say之后就直接被设置为200了，不会再被exit设为401
        -- https://github.com/openresty/lua-resty-redis/issues/15
        ngx.status = 401
        ngx.say(cjson.encode({r = false, d = "HtySudoerTokenErr"}))
        ngx.exit(401)
    end
end

local function get_wx_media(media_id)
    local access_token = get_access_token()
    print("access token: " .. access_token)
    local wx_media_url = string.format("https://api.weixin.qq.com/cgi-bin/media/get?access_token=%s&media_id=%s", access_token, media_id)
    print("wx_media_url: " .. wx_media_url)
    local resp, req_err = httpc:request_uri(wx_media_url, {
        method = 'GET',
        ssl_verify = ssl_verify or false, -- 设置参数 ssl_verify 为false 不校验ssl证书
    })

    if resp == nil then
        ngx.log(ngx.ERR, "FAILED TO CONNECT TO *Weixin*", req_err)
        ngx.status = 500
        ngx.say(req_err)
        ngx.exit(500)
    end

    if 200 ~= resp.status then
        ngx.log(ngx.ERR, 'GET WECHET MEDIA *FAILED*', req_err)
        ngx.status = resp.status
        ngx.say(req_err)
        ngx.exit(resp.status)
    end

    local filename = ngx.re.match(resp.headers['Content-disposition'], [[filename="(.+\.([a-zA-Z0-9]+))"]], "jo")[1]
    local file_dir = ngx.var.tmp_file_dir
    local saved_file = file_dir .. "/" .. filename;
    print('saved file...' .. saved_file);
    local file, err = io.open(saved_file, 'w')
    if file == nil then
        print("Can not open file..." .. err)
    else
        file:write(resp.body)
        file:close()
    end

    return saved_file, filename;
end

return get_wx_media;