API网关Kong学习笔记（十一）: 自己动手写一个插件

-- kong/plugins/acl/migrations/postgres.lua
return {
  {
    name = "2015-08-25-841841_init_acl",
    up = [[
      CREATE TABLE IF NOT EXISTS acls(
        id uuid,
        consumer_id uuid REFERENCES consumers (id) ON DELETE CASCADE,
        "group" text,
        created_at timestamp without time zone default (CURRENT_TIMESTAMP(0) at time zone 'utc'),
        PRIMARY KEY (id)
      );

      DO $$
      BEGIN
        IF (SELECT to_regclass('acls_group')) IS NULL THEN
          CREATE INDEX acls_group ON acls("group");
        END IF;
        IF (SELECT to_regclass('acls_consumer_id')) IS NULL THEN
          CREATE INDEX acls_consumer_id ON acls(consumer_id);
        END IF;
      END$$;
    ]],
    down = [[
      DROP TABLE acls;
    ]]
  }
}

-- kong/plugins/acl/daos.lua
local singletons = require "kong.singletons"

local function check_unique(group, acl)
   ...
end
...
local SCHEMA = {
  primary_key = {"id"},
  table = "acls",
  cache_key = { "consumer_id" },
  fields = {
    id = { type = "id", dao_insert_value = true },
    created_at = { type = "timestamp", dao_insert_value = true },
    consumer_id = { type = "id", required = true, foreign = "consumers:id" },
    group = { type = "string", required = true, func = check_unique }
  },
}

return {acls = SCHEMA}

-- kong/plugins/acl/schema.lua
local Errors = require "kong.dao.errors"

return {
  no_consumer = true,
  fields = {
    whitelist = { type = "array" },
    blacklist = { type = "array" },
    hide_groups_header = { type = "boolean", default = false },
  },
  self_check = function(schema, plugin_t, dao, is_update)
    if next(plugin_t.whitelist or {}) and next(plugin_t.blacklist or {}) then
      return false, Errors.schema "You cannot set both a whitelist and a blacklist"
    elseif not (next(plugin_t.whitelist or {}) or next(plugin_t.blacklist or {})) then
      return false, Errors.schema "You must set at least a whitelist or blacklist"
    end
    return true
  end
}

--kong/init.lua
local function load_plugins(kong_conf, dao)
...

    local ok, handler = utils.load_module_if_exists("kong.plugins." .. plugin .. ".handler")
    ...
    local ok, schema = utils.load_module_if_exists("kong.plugins." .. plugin .. ".schema")
    ...
    sorted_plugins[#sorted_plugins+1] = {
      name = plugin,
      handler = handler(),
      schema = schema
    }
 ...

-- kong/plugins/acl/handler.lua
...
function ACLHandler:new()
  ACLHandler.super.new(self, "acl")
end

function ACLHandler:access(conf)
  ACLHandler.super.access(self)
...

--kong/runloop/plugins_iterator.lua
local function get_next(self)
   ...
   ctx.plugins_for_request[plugin.name] = plugin_configuration
   ...
return plugin, plugins_for_request[plugin.name]

return {
    {
        name = "2018-11-09_multiple_orgins",
        up = function(db)
            local rows, err = db:query([[
        SELECT * FROM plugins WHERE name = 'http-rewrite'
      ]])
            if err then
                return err
            end
        end,
    }
}

-- kong/plugins/acl/migrations/postgres.lua
return {
  {
    name = "2015-08-25-841841_init_acl",
    up = [[
      CREATE TABLE IF NOT EXISTS acls(
        id uuid,
        consumer_id uuid REFERENCES consumers (id) ON DELETE CASCADE,
        "group" text,
        created_at timestamp without time zone default (CURRENT_TIMESTAMP(0) at time zone 'utc'),
        PRIMARY KEY (id)
      );

      DO $$
      BEGIN
        IF (SELECT to_regclass('acls_group')) IS NULL THEN
          CREATE INDEX acls_group ON acls("group");
        END IF;
        IF (SELECT to_regclass('acls_consumer_id')) IS NULL THEN
          CREATE INDEX acls_consumer_id ON acls(consumer_id);
        END IF;
      END$$;
    ]],
    down = [[
      DROP TABLE acls;
    ]]
  }
}

-- kong/plugins/cors/migrations/postgres.lua
return {
  {
    name = "2017-03-14_multiple_orgins",
    up = function(db)
      local cjson = require "cjson"

      local rows, err = db:query([[
        SELECT * FROM plugins WHERE name = 'cors'
      ]])
      if err then
        return err
      end

      for _, row in ipairs(rows) do
        row.config.origins = { row.config.origin }
        row.config.origin = nil

        local _, err = db:query(string.format([[
          UPDATE plugins SET config = '%s' WHERE id = '%s'
        ]], cjson.encode(row.config), row.id))
        if err then
          return err
        end
      end
    end,
  }
}

local Errors = require "kong.dao.errors"

return {
    no_consumer = true,
    fields = {
        regex = { type = "string" },
        replacement = { type = "string" },
        flag = {type = "string"},
    },
    self_check = function(schema, plugin_t, dao, is_update)
        -- TODO: add check
        return true
    end
}

local BasePlugin = require "kong.plugins.base_plugin"

local RewriteHandler= BasePlugin:extend()


RewriteHandler.PRIORITY = 2000
RewriteHandler.VERSION = "0.1.0"

-- 传入参数conf是这个插件存放在数据库中配置
function RewriteHandler:access(conf)
    RewriteHandler.super.access(self)

    local host = ngx.var.host
    ngx.log(ngx.DEBUG, "http-rewrite plugin, host is: ", host, " ,uri is: ",
            ngx.var.request_uri, " ,config is: ", json.encode(conf))

    local replace,n,err  = ngx.re.sub(ngx.var.request_uri, conf.regex, conf.replacement)
    if replace and n == 0 then
        return
    end

    if err then
        ngx.log(ngx.ERR, "http-rewrite plugin, ngx.re.sub err: ",err, " ,host is: ", host, " ,uri is: ",
                ngx.var.request_uri, " ,config is: ", json.encode(conf))
        return
    end

    ngx.log(ngx.DEBUG, "http-rewrite plugin, replace is: ",replace)
    if conf.flag == "redirect" then
        ngx.redirect(replace,302)
    elseif conf.flag == "permanent" then
        ngx.redirect(replace,301)
    end
end

function RewriteHandler:new()
    RewriteHandler.super.new(self, "http-rewrite")
end

return RewriteHandler