用header_filter_by_lua设置自定义HTTP头

我会带着你远行 2022-05-17 11:07 218阅读 0赞

**header\_filter\_by\_lua的说明：**

1.  `header_filter_by_lua`
2.   
3.  `syntax: header_filter_by_lua <lua-script-str>`
4.   
5.  `context: http, server, location, location if`
6.   
7.  `phase: output-header-filter`
8.   
9.  `WARNING Since the v0.9.17 release, use of this directive is discouraged; use the new header_filter_by_lua_block directive instead.`
10.  
11. `Uses Lua code specified in <lua-script-str> to define an output header filter.`
12.  
13. `Note that the following API functions are currently disabled within this context:`
14.  
15. `Output API functions (e.g., ngx.say and ngx.send_headers)`
16. `Control API functions (e.g., ngx.redirect and ngx.exec)`
17. `Subrequest API functions (e.g., ngx.location.capture and ngx.location.capture_multi)`
18. `Cosocket API functions (e.g., ngx.socket.tcp and ngx.req.socket).`
19. `Here is an example of overriding a response header (or adding one if absent) in our Lua header filter:`
20.  
21. `location / {`
22. `proxy_pass http://mybackend;`
23. `header_filter_by_lua 'ngx.header.Foo = "blah"';`
24. `}`
25. `This directive was first introduced in the v0.2.1rc20 release.`

官网：[https://github.com/openresty/lua-nginx-module\#header\_filter\_by\_lua][https_github.com_openresty_lua-nginx-module_header_filter_by_lua]

**作用：**

a)新增自定义的HTTP头

b)重新设置upstream返回的HTTP头，也就是起到覆盖作用

**使用示范源码：nginx.conf**

1.  `worker_processes 1;`
2.  `error_log logs/error.log;`
3.  `events {`
4.  `worker_connections 1024;`
5.  `}`
6.   
7.  `http {`
8.   
9.  `log_format main '$msec $status $request $request_time '`
10. `'$http_referer $remote_addr [ $time_local ] '`
11. `'$upstream_response_time $host $bytes_sent '`
12. `'$request_length $upstream_addr';`
13.  
14. `access_log logs/access.log main buffer=32k flush=1s;`
15.  
16. `upstream remote_world {`
17. `server 127.0.0.1:8080;`
18. `}`
19.  
20. `server {`
21. `listen 80;`
22.  
23. `location /exec {`
24. `content_by_lua '`
25. `local cjson = require "cjson"`
26. `local headers = {`
27. `["Etag"] = "663b92165e216225df78fbbd47c9c5ba",`
28. `["Last-Modified"] = "Fri, 12 May 2016 18:53:33 GMT",`
29. `}`
30. `ngx.var.my_headers = cjson.encode(headers)`
31. `ngx.var.my_upstream = "remote_world"`
32. `ngx.var.my_uri = "/world"`
33. `ngx.exec("/upstream")`
34. `';`
35. `}`
36.  
37. `location /upstream {`
38. `internal;`
39.  
40. `set $my_headers $my_headers;`
41. `set $my_upstream $my_upstream;`
42. `set $my_uri $my_uri;`
43. `proxy_pass http://$my_upstream$my_uri;`
44.  
45. `header_filter_by_lua '`
46. `local cjson = require "cjson"`
47. `headers = cjson.decode(ngx.var.my_headers)`
48. `for k, v in pairs(headers) do`
49. `ngx.header[k] = v`
50. `end`
51. `';`
52. `}`
53. `}`
54.  
55.  
56. `server {`
57. `listen 8080;`
58.  
59. `location /world {`
60. `echo "hello world";`
61. `}`
62. `}`
63. `}`

**运行：openresty -p \`pwd\` -c conf/nginx.conf**

**运行结果：**

![SouthEast][]

原文出自：[http://blog.csdn.net/daiyudong2020/article/details/53149242][http_blog.csdn.net_daiyudong2020_article_details_53149242]

[https_github.com_openresty_lua-nginx-module_header_filter_by_lua]: https://github.com/openresty/lua-nginx-module#header_filter_by_lua
[SouthEast]: /images/20220517/692c63b4e6854f22a20316a3c797ff2f.png
[http_blog.csdn.net_daiyudong2020_article_details_53149242]: http://blog.csdn.net/daiyudong2020/article/details/53149242