Nginx source code analysis - practical part - write a phased module (25)

Old manong Zuli 2020-11-13 04:45:51
nginx source code analysis practical


Catalog

Code instance

Initialization binding phase processing

The callback function writes logs

Compile and debug results


Code instance


HTTP Module article , We talked about Nginx Of HTTP Stage processing 《Nginx Source code analysis - HTTP Module article - HTTP Module phase processing PHASE handler》

Our code is in 《Nginx Source code analysis - Actual combat - Write a custom module 》 On the basis of , Mount a callback function to HTTP On the stage of processing .

#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
static ngx_int_t ngx_http_hello_handler(ngx_http_request_t *r);
static char *
ngx_http_hello(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
static ngx_int_t ngx_http_hello_init(ngx_conf_t *cf);
static ngx_int_t ngx_http_hello_log_handler(ngx_http_request_t *r);
/**
* Handle nginx.conf In the configuration command parsing
* for example :
* location /hello {
* hello
* }
* When the user requests :http://127.0.0.1/hello When , The request will jump to hello In this configuration
* hello Command line parsing callback function :ngx_http_hello
*/
static ngx_command_t ngx_http_hello_commands[] = { {
ngx_string("hello"),
NGX_HTTP_MAIN_CONF | NGX_HTTP_SRV_CONF | NGX_HTTP_LOC_CONF | NGX_HTTP_LMT_CONF
| NGX_CONF_NOARGS, ngx_http_hello,
NGX_HTTP_LOC_CONF_OFFSET, 0, NULL },
ngx_null_command };
/**
* Module context
*/
static ngx_http_module_t ngx_http_hello_module_ctx = { NULL, ngx_http_hello_init, NULL, NULL,
NULL, NULL, NULL, NULL };
/**
* Definition of modules
*/
ngx_module_t ngx_http_hello_module = {
NGX_MODULE_V1, &ngx_http_hello_module_ctx, ngx_http_hello_commands,
NGX_HTTP_MODULE, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
NGX_MODULE_V1_PADDING };
/**
* Command parsing callback function
* In this function , Mainly get loc Configuration of , And set up location The callback function in handler
*/
static char *
ngx_http_hello(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) {
ngx_http_core_loc_conf_t *clcf;
clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
/* Set the callback function . When requested http://127.0.0.1/hello When , This callback function will be called */
clcf->handler = ngx_http_hello_handler;
return NGX_CONF_OK;
}
/**
* Module callback function , Output hello world
*/
static ngx_int_t ngx_http_hello_handler(ngx_http_request_t *r) {
if (!(r->method & (NGX_HTTP_GET | NGX_HTTP_HEAD))) {
return NGX_HTTP_NOT_ALLOWED;
}
ngx_int_t rc = ngx_http_discard_request_body(r);
if (rc != NGX_OK) {
return rc;
}
ngx_str_t type = ngx_string("text/plain");
ngx_str_t response = ngx_string("Hello World");
r->headers_out.status = NGX_HTTP_OK;
r->headers_out.content_length_n = response.len;
r->headers_out.content_type = type;
rc = ngx_http_send_header(r);
if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) {
return rc;
}
ngx_buf_t *b;
b = ngx_create_temp_buf(r->pool, response.len);
if (b == NULL) {
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
ngx_memcpy(b->pos, response.data, response.len);
b->last = b->pos + response.len;
b->last_buf = 1;
ngx_chain_t out;
out.buf = b;
out.next = NULL;
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"hello world ");
return ngx_http_output_filter(r, &out);
}
/**
* initialization
* take ngx_http_hello_log_handler Mount to NGX_HTTP_LOG_PHASE Log processing phase
*/
static ngx_int_t ngx_http_hello_init(ngx_conf_t *cf) {
ngx_http_handler_pt *h;
ngx_http_core_main_conf_t *cmcf;
cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
h = ngx_array_push(&cmcf->phases[NGX_HTTP_LOG_PHASE].handlers);
if (h == NULL) {
return NGX_ERROR;
}
*h = ngx_http_hello_log_handler;
return NGX_OK;
}
/**
* NGX_HTTP_LOG_PHASE The callback function in the log processing phase å
*/
static ngx_int_t ngx_http_hello_log_handler(ngx_http_request_t *r) {
/* Only in the log processing phase , Add a new line of log */
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"hello ==================================> ");
return NGX_DECLINED;
}

Initialization binding phase processing


We define a ngx_http_hello_init Methods , Mainly used to ngx_http_hello_log_handler Function mounted to NGX_HTTP_LOG_PHASE Log processing phase

/**
* initialization
* take ngx_http_hello_log_handler Mount to NGX_HTTP_LOG_PHASE Log processing phase
*/
static ngx_int_t ngx_http_hello_init(ngx_conf_t *cf) {
ngx_http_handler_pt *h;
ngx_http_core_main_conf_t *cmcf;
cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
h = ngx_array_push(&cmcf->phases[NGX_HTTP_LOG_PHASE].handlers);
if (h == NULL) {
return NGX_ERROR;
}
*h = ngx_http_hello_log_handler;
return NGX_OK;
}

among ngx_http_hello_init Method in module context ngx_http_hello_module_ctx The processing phase of is initialized

/**
* Module context
*/
static ngx_http_module_t ngx_http_hello_module_ctx = { NULL, ngx_http_hello_init, NULL, NULL,
NULL, NULL, NULL, NULL };

The callback function writes logs


Callback function ngx_http_hello_log_handler, Mainly write a line error Log

/**
* NGX_HTTP_LOG_PHASE The callback function in the log processing phase å
*/
static ngx_int_t ngx_http_hello_log_handler(ngx_http_request_t *r) {
/* Only in the log processing phase , Add a new line of log */
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"hello ==================================> ");
return NGX_DECLINED;
}

Compile and debug results


Because we are bound to the log processing phase , So every time Nginx Of HTTP request , It's all going back ngx_http_hello_log_hanlder Method

We can see Nginx We found , We have succeeded in


 

版权声明
本文为[Old manong Zuli]所创,转载请带上原文链接,感谢

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