Openresty最佳案例 | 第5篇:http和C_json模块

Openresty没有提供默认的Http客户端,需要下载第三方的http客户端。

下载lua-resty-http到lualib目录下,使用以下的命令下载:

1
2
3
4
5
cd /usr/example/lualib/resty/  
wget https://raw.githubusercontent.com/pintsized/lua-resty-http/master/lib/resty/http_headers.lua

wget https://raw.githubusercontent.com/pintsized/lua-resty-http/master/lib/resty/http.lua

lua-resty-http模块的地址为https://github.com/pintsized/lua-resty-http

安装成功后,通过require(“resty.http”)引入 lua_http模块,它有以下的api方法:

  • syntax: httpc = http.new() 创建一个 http对象
  • syntax: res, err = httpc:request_uri(uri, params)根据参数获取内容,包括:
    • status 状态码
    • headers 响应头
    • body 响应体

vim /usr/example/lua/test_http.lua,写以下代码:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
local http = require("resty.http")  

local httpc = http.new()

local resp, err = httpc:request_uri("http://s.taobao.com", {
method = "GET",
path = "/search?q=hello",
headers = {
["User-Agent"] = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/40.0.2214.111 Safari/537.36"
}
})

if not resp then
ngx.say("request error :", err)
return
end


ngx.status = resp.status


for k, v in pairs(resp.headers) do
if k ~= "Transfer-Encoding" and k ~= "Connection" then
ngx.header[k] = v
end
end

ngx.say(resp.body)

httpc:close()


vim /usr/example/example.conf 加上以下的配置:

1
2
3
4
5
6
location /lua_http {
default_type 'text/html';
lua_code_cache on;
content_by_lua_file /usr/example/lua/test_http.lua;
}

在Nginx的配置文件nginx.conf的http部分,加上以下dns解析:

vim /usr/servers/nginx/conf/nginx.conf

1
2
resolver 8.8.8.8;  

浏览器访问:http://116.196.177.123/lua_http,浏览器会显示淘宝的搜索页。

lua_cjson模块

Json是一种常见的数据交换格式,常用于http通信协议和其他数据传输领域。在openresty默认内嵌了lua_cjson模块,用来序列化数据。

lua_cjson模块的地址:https://www.kyne.com.au/~mark/software/lua-cjson-manual.html

它常用的API如下:

  • local cjson = require “cjson” 获取一个cjson对象
  • local str = cjson.encode(obj) obj转换成string
  • local obj = cjson.decode(str) 将string转obj

vim /usr/example/lua/test_cjson.lua,添加以下内容:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
local cjson = require("cjson")  


local obj = {
id = 1,
name = "zhangsan",
age = nil,
is_male = false,
hobby = {"film", "music", "read"}
}

local str = cjson.encode(obj)
ngx.say(str, "<br/>")


str = '{"hobby":["film","music","read"],"is_male":false,"name":"zhangsan","id":1,"age":null}'
local obj = cjson.decode(str)

ngx.say(obj.age, "<br/>")
ngx.say(obj.age == nil, "<br/>")
ngx.say(obj.age == cjson.null, "<br/>")
ngx.say(obj.hobby[1], "<br/>")


vim /usr/example/example.conf添加以下内容:

1
2
3
4
5
6
location ~ /lua_cjson {  
default_type 'text/html';
lua_code_cache on;
content_by_lua_file /usr/example/lua/test_cjson.lua;
}

在浏览器上访问http://116.196.177.123/lua_cjson,浏览器显示以下内容:

1
2
3
4
5
6
7
{"hobby":["film","music","read"],"is_male":false,"name":"zhangsan","id":1}
null
false
true
film


请我吃🍗