根据 JWT 的 key 和 URL 决定是否缓存 HTTP 请求

链接 https://stackoverflow.com/questions/50605544/caching-api-requests-with-jwt-auth/50615736

需求

比如 JWT 里

payload: {
  "iss": "iss",
  "sub": "sub",
  "userGroupID": "{userGroupID}"
}

然后请求 https://myapi.example.com/groups/{groupID}/cars

如果 userGroupID 和 groupID 一样，则缓存，否则不缓存

解决方案

使用 https://github.com/jiangwenyuan/nuster 基于 HAProxy 的高性能缓存服务器

1. Download and build, you will need lua

wget https://github.com/jiangwenyuan/nuster/releases/download/v1.8.8.2/nuster-1.8.8.2.tar.gz

make TARGET=linux2628 USE_ZLIB=1 USE_OPENSSL=1 USE_LUA=1 LUA_LIB=/opt/lua-5.3.1/lib LUA_INC=/opt/lua-5.3.1/include

2. create lua script, say, jwt_group_match.lua

-- base64 FROM http://lua-users.org/wiki/BaseSixtyFour

local b='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'

function dec(data)
    data = string.gsub(data, '[^'..b..'=]', '')
    return (data:gsub('.', function(x)
        if (x == '=') then return '' end
        local r,f='',(b:find(x)-1)
        for i=6,1,-1 do r=r..(f%2^i-f%2^(i-1)>0 and '1' or '0') end
        return r;
    end):gsub('%d%d%d?%d?%d?%d?%d?%d?', function(x)
        if (#x ~= 8) then return '' end
        local c=0
        for i=1,8 do c=c+(x:sub(i,i)=='1' and 2^(8-i) or 0) end
        return string.char(c)
    end))
end

-- end base64


-- json FROM https://gist.github.com/tylerneylon/59f4bcf316be525b30ab
json = {}


function kind_of(obj)
  if type(obj) ~= 'table' then return type(obj) end
  local i = 1
  for _ in pairs(obj) do
    if obj[i] ~= nil then i = i + 1 else return 'table' end
  end
  if i == 1 then return 'table' else return 'array' end
end

function escape_str(s)
  local in_char  = {'\\', '"', '/', '\b', '\f', '\n', '\r', '\t'}
  local out_char = {'\\', '"', '/',  'b',  'f',  'n',  'r',  't'}
  for i, c in ipairs(in_char) do
    s = s:gsub(c, '\\' .. out_char[i])
  end
  return s
end

function skip_delim(str, pos, delim, err_if_missing)
  pos = pos + #str:match('^%s*', pos)
  if str:sub(pos, pos) ~= delim then
    if err_if_missing then
      error('Expected ' .. delim .. ' near position ' .. pos)
    end
    return pos, false
  end
  return pos + 1, true
end

function parse_str_val(str, pos, val)
  val = val or ''
  local early_end_error = 'End of input found while parsing string.'
  if pos > #str then error(early_end_error) end
  local c = str:sub(pos, pos)
  if c == '"'  then return val, pos + 1 end
  if c ~= '\\' then return parse_str_val(str, pos + 1, val .. c) end
  -- We must have a \ character.
  local esc_map = {b = '\b', f = '\f', n = '\n', r = '\r', t = '\t'}
  local nextc = str:sub(pos + 1, pos + 1)
  if not nextc then error(early_end_error) end
  return parse_str_val(str, pos + 2, val .. (esc_map[nextc] or nextc))
end

function parse_num_val(str, pos)
  local num_str = str:match('^-?%d+%.?%d*[eE]?[+-]?%d*', pos)
  local val = tonumber(num_str)
  if not val then error('Error parsing number at position ' .. pos .. '.') end
  return val, pos + #num_str
end

json.null = {}  -- This is a one-off table to represent the null value.

function json.parse(str, pos, end_delim)
  pos = pos or 1
  if pos > #str then error('Reached unexpected end of input.') end
  local pos = pos + #str:match('^%s*', pos)  -- Skip whitespace.
  local first = str:sub(pos, pos)
  if first == '{' then  -- Parse an object.
    local obj, key, delim_found = {}, true, true
    pos = pos + 1
    while true do
      key, pos = json.parse(str, pos, '}')
      if key == nil then return obj, pos end
      if not delim_found then error('Comma missing between object items.') end
      pos = skip_delim(str, pos, ':', true)  -- true -> error if missing.
      obj[key], pos = json.parse(str, pos)
      pos, delim_found = skip_delim(str, pos, ',')
    end
  elseif first == '[' then  -- Parse an array.
    local arr, val, delim_found = {}, true, true
    pos = pos + 1
    while true do
      val, pos = json.parse(str, pos, ']')
      if val == nil then return arr, pos end
      if not delim_found then error('Comma missing between array items.') end
      arr[#arr + 1] = val
      pos, delim_found = skip_delim(str, pos, ',')
    end
  elseif first == '"' then  -- Parse a string.
    return parse_str_val(str, pos + 1)
  elseif first == '-' or first:match('%d') then  -- Parse a number.
    return parse_num_val(str, pos)
  elseif first == end_delim then  -- End of an object or array.
    return nil, pos + 1
  else  -- Parse true, false, or null.
    local literals = {['true'] = true, ['false'] = false, ['null'] = json.null}
    for lit_str, lit_val in pairs(literals) do
      local lit_end = pos + #lit_str - 1
      if str:sub(pos, lit_end) == lit_str then return lit_val, lit_end + 1 end
    end
    local pos_info_str = 'position ' .. pos .. ': ' .. str:sub(pos, pos + 10)
    error('Invalid json syntax starting at ' .. pos_info_str)
  end
end

-- end json






-- nuster jwt


function jwt_group_match(txn)

  local hdr = txn.http:req_get_headers()
  local jwt = hdr["jwt"]
  if jwt == nil then
    return false
  end

  _, payload, _ = jwt[0]:match"([^.]*)%.([^.]*)%.(.*)"
  if payload == nil then
    return false
  end

  local payload_dec = dec(payload)
  local payload_json = json.parse(payload_dec)


  if txn.sf:path() == "/group/" ..  payload_json["userGroupID"] .. "/cars" then
    return true
  end

  return false
end

core.register_fetches("jwt_group_match", jwt_group_match)

3. create conf, say, nuster.conf

global
    nuster cache on dict-size 1m data-size 100m
    debug
    lua-load jwt_group_match.lua

frontend web1
    bind *:8080
    mode http

    default_backend app1

backend app1
    mode http
    http-request set-var(req.jwt_group_match) lua.jwt_group_match

    nuster cache on
    nuster rule group if { var(req.jwt_group_match) -m bool }


    server s1 127.0.0.1:8000
    server s2 127.0.0.1:8001

3. start nuster

./haproxy -f nuster.conf

TEST

payload: {
  "iss": "iss",
  "sub": "sub",
  "userGroupID": "nuster"
}

curl http://127.0.0.1:8080/group/nuster/cars --header "jwt: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJpc3MiLCJzdWIiOiJzdWIiLCJ1c2VyR3JvdXBJRCI6Im51c3RlciJ9.hPpqQS0d4T2BQP90ZDcgxnqJ0AHmwWFqZvdxu65X3FM"

First run

[CACHE] To create

Second run

[CACHE] Hit