手把手教你开发Nginx模块
前面的哪些话
关于Nginx模块开发的博客资料，网上很多，很多。但是，每篇博客都只提要点，无法"stepbystep"照着做，对于初次接触Nginx开发的同学，只能像只盲目的蚂蚁瞎燥急！该篇文章没有太多技术深度，只是一步一步说明白Nginx模块的开发过程。
开发环境搭建
工欲善其事，必先利其器。个人推荐EclipseCDT作为IDE，原因很简单，代码提示与补全功能很全，完胜Codeblock这类...相信与否，试过就知道。
在ubuntu下搭建开发环境：
安装GCC编译器
apt-getinstallbuild-essential
安装pcre/openssl/zlib开发库
apt-getinstalllibpcre3-dev
apt-getinstalllibssl-dev
apt-getinstalllibzip-dev
必需安装nginx核心模块依赖的pcre,openssl,zilib开发库
安装JRE/EclipseCDT
apt-getinstallopenjdk-8-jre
wgethttp://ftp.yz.yamagata-u.ac.jp/pub/eclipse//technology/epp/downloads/release/neon/R/eclipse-cpp-neon-R-linux-gtk-x86_64.tar.gz&&tzr-xzvfeclipse-cpp-neon-R-linux-gtk-x86_64.tar.gz
下载nginx源码
wgethttp://nginx.org/download/nginx-1.10.1.tar.gz&&tar-xzvfnginx-1.10.1.tar.gz
配置CDTBuildEnvironment
添加变量，值Nginxsrc下各模块路径，用冒号分隔，例如：
/root/Workspace/nginx-1.10.1/src/core:/root/Workspace/nginx-1.10.1/src/event:/root/Workspace/nginx-1.10.1/src/http:/root/Workspace/nginx-1.10.1/src/mail:/root/Workspace/nginx-1.10.1/src/stream:/root/Workspace/nginx-1.10.1/src/os/unix
添加环境变量，创建C项目时自动作为-I选项
image
image
Nginx模块编译流程
Nginx使用configure脚本分析环境，自动生成objs结果。哪么configure如何编译第三方模块？答案是--add-module指定第三方模块目录，并将目录存为$ngx_addon_dir环境变量。执行$ngx_addon_dir/config脚本，读取模块配置。在config中的环境变量分为2种：小写的本地环境变量，大写的全局环境变量。例如：
ngx_addon_name=ngx_http_mytest_module
HTTP_MODULES="$HTTP_MODULESngx_http_mytest_module"
NGX_ADDON_SRCS="$NGX_ADDON_SRCS$ngx_addon_dir/ngx_http_mytest_moudle.c"
CORE_LIBS="$CORE_LIBS-lpcre"
HTTP_MODULES中的ngx_http_mytest_module就是NGX_ADDON_SRCS中源码(如果有多个，都要写上)ngx_http_mytest_module.c中定义的ngx_module_t类型的全局变量。
可见，第三方模块的入口点就是ngx_module_t类型全局变量，该变量又关联ngx_http_module_t类型static变量，与ngx_command_t类型static数组。
在ngx_http_module_t中定义上下文配置nginx.conf解析的回调方法。
在ngx_command_t中定义配置项处理的set回调方法。
Nginx的全部操作都是异步的。在上述的方法中根据需要又会使用其他handler方法。
以上可以看成Nginx第三方模块的起式。
Upstream例子源码
config
ngx_addon_name=ngx_http_mytest_module
HTTP_MODULES="$HTTP_MODULESngx_http_mytest_module"
NGX_ADDON_SRCS="$NGX_ADDON_SRCS$ngx_addon_dir/ngx_http_mytest_module.c"
源代码
#include
#include
#include
#include
typedefstruct{
ngx_http_upstream_conf_tupstream;
}mytest_conf_t;
typedefstruct{
ngx_http_status_tstatus;
ngx_str_tbackendServer;
}mytest_ctx_t;
staticvoidmytest_create_loc_conf(ngx_conf_tcf);
staticcharmytest_merge_loc_conf(ngx_conf_tcf,voidparent,voidchild);
staticngx_int_tmytest_upstream_create_request(ngx_http_request_tr);
staticngx_int_tmytest_upstream_process_status_line(ngx_http_request_tr);
staticngx_int_tmytest_upstream_process_header(ngx_http_request_tr);
staticvoidmytest_upstream_finalize_request(ngx_http_request_tr,
ngx_int_trc);
staticngx_int_tmytest_handler(ngx_http_request_tr);
staticcharmytest(ngx_conf_tcf,ngx_command_tcmd,voidconf);
staticngx_http_module_tmytest_ctx={
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
mytest_create_loc_conf,
mytest_merge_loc_conf
};
staticngx_command_tmytest_commands[]={
{
ngx_string("mytest"),
NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_HTTP_LMT_CONF|NGX_CONF_NOARGS,
mytest,
NGX_HTTP_LOC_CONF_OFFSET,
0,
NULL
},
ngx_null_command
};
ngx_module_tngx_http_mytest_module={
NGX_MODULE_V1,
&mytest_ctx,
mytest_commands,
NGX_HTTP_MODULE,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
NGX_MODULE_V1_PADDING
};
staticngx_str_tmytest_upstream_hide_headers[]=
{
ngx_string("Date"),
ngx_string("Server"),
ngx_string("X-Pad"),
ngx_string("X-Accel-Expires"),
ngx_string("X-Accel-Redirect"),
ngx_string("X-Accel-Limit-Rate"),
ngx_string("X-Accel-Buffering"),
ngx_string("X-Accel-Charset"),
ngx_null_string
};
staticvoidmytest_create_loc_conf(ngx_conf_tcf){
mytest_conf_tmycf;
mycf=(mytest_conf_t)ngx_pcalloc(cf->pool,sizeof(mytest_conf_t));
if(mycf==NULL){
returnNULL;
}
mycf->upstream.connect_timeout=60000;
mycf->upstream.send_timeout=60000;
mycf->upstream.read_timeout=60000;
mycf->upstream.store_access=0600;
mycf->upstream.buffering=0;
mycf->upstream.bufs.num=8;
mycf->upstream.bufs.size=ngx_pagesize;
mycf->upstream.buffer_size=ngx_pagesize;
mycf->upstream.busy_buffers_size=2ngx_pagesize;
mycf->upstream.temp_file_write_size=2ngx_pagesize;
mycf->upstream.max_temp_file_size=102410241024;
mycf->upstream.hide_headers=NGX_CONF_UNSET_PTR;
mycf->upstream.pass_headers=NGX_CONF_UNSET_PTR;
returnmycf;
}
staticcharmytest_merge_loc_conf(ngx_conf_tcf,voidparent,voidchild){
mytest_conf_tprev=(mytest_conf_t)parent;
mytest_conf_tconf=(mytest_conf_t)child;
ngx_hash_init_thash;
hash.max_size=100;
hash.bucket_size=1024;
hash.name="proxy_headers_hash";
if(ngx_http_upstream_hide_headers_hash(cf,&conf->upstream,&prev->upstream,mytest_upstream_hide_headers,&hash)!=NGX_OK){
returnNGX_CONF_ERROR;
}
returnNGX_CONF_OK;
}
staticngx_int_tmytest_upstream_create_request(ngx_http_request_tr){
staticngx_str_tbackendQueryLine=ngx_string("GET/search?q=%VHTTP/1.1\r\nHost:www.google.com.hk\r\nConnection:close\r\n\r\n");
ngx_int_tqueryLineLen=backendQueryLine.len+r->args.len-2;
ngx_buf_tb=ngx_create_temp_buf(r->pool,queryLineLen);
if(b==NULL)returnNGX_ERROR;
b->last=b->pos+queryLineLen;
ngx_snprintf(b->pos,queryLineLen,(char)backendQueryLine.data,&r->args);
r->upstream->request_bufs=ngx_alloc_chain_link(r->pool);
if(r->upstream->request_bufs==NULL)returnNGX_ERROR;
r->upstream->request_bufs->buf=b;
r->upstream->request_bufs->next=NULL;
r->upstream->request_sent=0;
r->upstream->header_sent=0;
r->header_hash=1;
returnNGX_OK;
}
staticngx_int_tmytest_upstream_process_status_line(ngx_http_request_tr){
size_tlen;
ngx_int_trc;
ngx_http_upstream_tu;
mytest_ctx_tctx=ngx_http_get_module_ctx(r,ngx_http_mytest_module);
if(ctx==NULL)returnNGX_ERROR;
u=r->upstream;
rc=ngx_http_parse_status_line(r,&u->buffer,&ctx->status);
if(rc==NGX_AGAIN)returnrc;
if(rc==NGX_ERROR){
ngx_log_error(NGX_LOG_ERR,r->connection->log,0,"upstreamsenttovalidHTTP/1.0header");
r->http_version=NGX_HTTP_VERSION_9;
u->state->status=NGX_HTTP_OK;
returnNGX_OK;
}
if(u->state){
u->state->status=ctx->status.code;
}
u->headers_in.status_n=ctx->status.code;
len=ctx->status.end-ctx->status.start;
u->headers_in.status_line.len=len;
u->headers_in.status_line.data=ngx_pcalloc(r->pool,len);
if(u->headers_in.status_line.data==NULL)returnNGX_ERROR;
ngx_memcpy(u->headers_in.status_line.data,ctx->status.start,len);
u->process_header=mytest_upstream_process_header;
returnmytest_upstream_process_header(r);
}
staticngx_int_tmytest_upstream_process_header(ngx_http_request_tr){
ngx_int_trc;
ngx_table_elt_th;
ngx_http_upstream_header_thh;
ngx_http_upstream_main_conf_tumcf;
umcf=ngx_http_get_module_main_conf(r,ngx_http_upstream_module);
for(;;){
rc=ngx_http_parse_header_line(r,&r->upstream->buffer,1);
if(rc==NGX_OK){
h=ngx_list_push(&r->upstream->headers_in.headers);
if(h==NULL)returnNGX_ERROR;
h->hash=r->header_hash;
h->key.len=r->header_name_end-r->header_name_start;
h->value.len=r->header_end-r->header_start;
h->key.data=ngx_pcalloc(r->pool,h->key.len+1+h->value.len+1+h->key.len);
if(h->key.data==NULL)returnNGX_ERROR;
h->value.data=h->key.data+h->key.len+1;
h->lowcase_key=h->key.data+h->key.len+1+h->value.len+1;
ngx_memcpy(h->key.data,r->header_name_start,h->key.len);
h->key.data[h->key.len]=''\0'';
ngx_memcpy(h->value.data,r->header_start,h->value.len);
h->value.data[h->value.len]=''\0'';
if(h->key.len==r->lowcase_index){
ngx_memcpy(h->lowcase_key,r->lowcase_header,h->key.len);
}else{
ngx_strlow(h->lowcase_key,h->key.data,h->key.len);
}
hh=ngx_hash_find(&umcf->headers_in_hash,h->hash,h->lowcase_key,h->key.len);
if(hh&&hh->handler(r,h,hh->offset)!=NGX_OK)returnNGX_ERROR;
continue;
}
if(rc==NGX_HTTP_PARSE_HEADER_DONE){
if(r->upstream->headers_in.server==NULL){
h=ngx_list_push(&r->upstream->headers_in.headers);
if(h==NULL)returnNGX_ERROR;
h->hash=ngx_hash(ngx_hash(ngx_hash(ngx_hash(ngx_hash(''s'',''e''),''r''),''v''),''e''),''r'');
ngx_str_set(&h->key,"Server");
ngx_str_null(&h->value);
h->lowcase_key=(u_char)"server";
}
if(r->upstream->headers_in.date==NULL){
h=ngx_list_push(&r->upstream->headers_in.headers);
if(h==NULL)returnNGX_ERROR;
h->hash=ngx_hash(ngx_hash(ngx_hash(''d'',''a''),''t''),''e'');
ngx_str_set(&h->key,"Date");
ngx_str_null(&h->value);
h->lowcase_key=(u_char)"date";
}
returnNGX_OK;
}
if(rc==NGX_AGAIN)returnNGX_AGAIN;
ngx_log_error(NGX_LOG_ERR,r->connection->log,0,"upstreamsentinvalidheader");
returnNGX_HTTP_UPSTREAM_FT_INVALID_HEADER;
}
}
staticvoidmytest_upstream_finalize_request(ngx_http_request_tr,ngx_int_trc){
ngx_log_error(NGX_LOG_DEBUG,r->connection->log,0,"mytest_upstream_finalize_request");
}
staticcharmytest(ngx_conf_tcf,ngx_command_tcmd,voidconf){
ngx_http_core_loc_conf_tclcf;
clcf=ngx_http_conf_get_module_loc_conf(cf,ngx_http_core_module);
clcf->handler=mytest_handler;
returnNGX_CONF_OK;
}
staticngx_int_tmytest_handler(ngx_http_request_tr){
mytest_ctx_tmyctx=ngx_http_get_module_ctx(r,ngx_http_mytest_module);
if(myctx==NULL){
myctx=ngx_pcalloc(r->pool,sizeof(mytest_ctx_t));
if(myctx==NULL)returnNGX_ERROR;
ngx_http_set_ctx(r,myctx,ngx_http_mytest_module);
}
if(ngx_http_upstream_create(r)!=NGX_OK){
ngx_log_error(NGX_LOG_ERR,r->connection->log,0,"ngx_http_upstream_create()failed");
returnNGX_ERROR;
}
mytest_conf_tmycf=(mytest_conf_t)ngx_http_get_module_loc_conf(r,ngx_http_mytest_module);
ngx_http_upstream_tu=r->upstream;
u->conf=&mycf->www.wang027.comupstream;
u->buffering=mycf->upstream.buffering;
u->resolved=(ngx_http_upstream_resolved_t)ngx_pcalloc(r->pool,sizeof(ngx_http_upstream_resolved_t));
if(u->resolved==NULL){
ngx_log_error(NGX_LOG_ERR,r->connection->log,0,"ngx_pcallocresolvederror.%s",strerror(errno));
returnNGX_ERROR;
}
staticstructsockaddr_inbackendSockAddr;
structhostentpHost=gethostbyname((char)"www.google.com.hk");
if(pHost==NULL){
ngx_log_error(NGX_LOG_ERR,r->connection->log,0,"gethostbynamefail.%s",strerror(errno));
returnNGX_ERROR;
}
backendSockAddr.sin_family=AF_INET;
backendSockAddr.sin_port=htons((in_port_t)80);
charpDmsIP=inet_ntoa((structin_addr)(pHost->h_addr_list[0]));
backendSockAddr.sin_addr.s_addr=inet_addr(pDmsIP);
myctx->backendServer.data=(u_char)pDmsIP;
myctx->backendServer.len=strlen(pDmsIP);
u->resolved->sockaddr=(structsockaddr)&backendSockAddr;
u->resolved->port=htons((in_port_t)80);
u->resolved->socklen=sizeof(structsockaddr_in);
u->resolved->naddrs=1;
u->create_request=mytest_upstream_create_request;
u->process_header=mytest_upstream_process_status_line;
u->finalize_request=mytest_upstream_finalize_request;
r->main->count++;
ngx_http_upstream_init(r);
returnNGX_DONE;
}
注意：《Nginx深入解析》的demo少了这句：“u->resolved->port=htons((in_port_t)80);”，否则报错“2016/09/0911:24:18[error]28352#0:1noportinupstream"",client:127.0.0.1,server:localhost,request:"GET/mytest?q=testHTTP/1.1",host:"localhost"”
编译脚本
./configure--prefix=/usr/local/nginx--add-module=/root/Workspace/nginx-modules/ngx_http_mytest_module--with-debug
sudomake
sudomakeinstall
安装后即可到/usr/local/nginx下配置nginx.conf进行测试。
Subrequest例子源码
config
ngx_addon_name=ngx_http_mytest_module
HTTP_MODULES="$HTTP_MODULESngx_http_mytest_module"
NGX_ADDON_SRCS="$NGX_ADDON_SRCS$ngx_addon_dir/ngx_http_mytest_module.c"
源代码
#include
#include
#include
typedefstruct{
ngx_str_tstock[6];
}mytest_ctx_t;
staticngx_int_tmytest_subrequest_post_handler(ngx_http_request_tr,voiddata,ngx_int_trc);
staticvoidmytest_post_handler(ngx_http_request_tr);
staticngx_int_tmytest_handler(ngx_http_request_tr);
staticcharmytest(ngx_conf_tcf,ngx_command_tcmd,voidconf);
staticngx_http_module_tmytest_conf={
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL
};
staticngx_command_tmytest_commands[]={
{
ngx_string("mytest"),
NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_NOARGS,
mytest,
NGX_HTTP_LOC_CONF_OFFSET,
0,
NULL
},
ngx_null_command
};
ngx_module_tngx_http_mytest_module={
NGX_MODULE_V1,
&mytest_conf,
mytest_commands,
NGX_HTTP_MODULE,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
NGX_MODULE_V1_PADDING
};
staticngx_int_tmytest_subrequest_post_handler(ngx_http_request_tr,
voiddata,ngx_int_trc){
ngx_http_request_tpr=r->parent;
mytest_ctx_tmyctx=ngx_http_get_module_ctx(pr,ngx_http_mytest_module);
pr->headers_out.status=r->headers_out.status;
if(r->headers_out.status==NGX_HTTP_OK){
intflag=0;
ngx_buf_tpRecvBuf=&r->upstream->buffer;
for(;pRecvBuf->pos!=pRecvBuf->last;pRecvBuf->pos++){
if(pRecvBuf->pos=='',''||pRecvBuf->pos==''\"''){
if(flag>0){
myctx->stock[flag-1].len=pRecvBuf->pos
-myctx->stock[flag-1].data;
}
flag++;
myctx->stock[flag-1].data=pRecvBuf->pos+1;
}
if(flag>6)
break;
}
}
pr->write_event_handler=mytest_post_handler;
returnNGX_OK;
}
staticvoidmytest_post_handler(ngx_http_request_tr){
if(r->headers_out.status!=NGX_HTTP_OK){
ngx_http_finalize_request(r,r->headers_out.status);
return;
}
mytest_ctx_tmyctx=ngx_http_get_module_ctx(r,ngx_http_mytest_module);
ngx_str_toutput_format=ngx_string("stock[%V],Todaycurrentprice:%V,volumn:%V");
intbodylen=output_format.len+myctx->stock[0].len+myctx->stock[1].len+myctx->stock[4].len-6;
r->headers_out.content_www.baiyuewang.netlength_n=bodylen;
ngx_buf_tb=ngx_create_temp_buf(r->pool,bodylen);
ngx_snprintf(b->pos,bodylen,(char)output_format.data,&myctx->stock[0],&myctx->stock[1],&myctx->stock[4]);
b->last=b->pos+bodylen;
b->last_buf=1;
ngx_chain_tout;
out.buf=b;
out.next=NULL;
staticngx_str_ttype=ngx_string("text/plain;charset=GBK");
r->headers_out.content_type=type;
r->headers_out.status=NGX_HTTP_OK;
r->connection->buffered|=NGX_HTTP_WRITE_BUFFERED;
ngx_int_tret=ngx_http_send_header(r);
ret=ngx_http_output_filter(r,&out);
ngx_http_finalize_request(r,ret);
}
staticngx_int_tmytest_handler(ngx_http_request_tr){
mytest_ctx_tmyctx=ngx_http_get_module_ctx(r,ngx_http_mytest_module);
if(myctx==NULL){
myctx=ngx_pcalloc(r->pool,sizeof(mytest_ctx_t));
if(myctx==NULL)returnNGX_ERROR;
ngx_http_set_ctx(r,myctx,ngx_http_mytest_module);
}
ngx_http_post_subrequest_tpsr=ngx_pcalloc(r->pool,sizeof(ngx_http_post_subrequest_t));
if(psr==NULL)returnNGX_HTTP_INTERNAL_SERVER_ERROR;
psr->handler=mytest_subrequest_post_handler;
psr->data=myctx;
ngx_str_tsub_prefix=ngx_string("/list=");
ngx_str_tsub_location;
sub_location.len=sub_prefix.len+r->args.len;
sub_location.data=ngx_pcalloc(r->pool,sub_location.len);
ngx_snprintf(sub_location.data,sub_location.len,"%V%V",&sub_prefix,&r->args);
ngx_http_request_tsr;
ngx_int_trc=ngx_http_subrequest(r,&sub_location,NULL,&sr,psr,NGX_HTTP_SUBREQUEST_IN_MEMORY);
if(rc!=NGX_OK)returnNGX_ERROR;
returnNGX_DONE;
}
staticcharmytest(ngx_conf_tcf,ngx_command_tcmd,voidconf){
ngx_http_core_loc_conf_tclcf=ngx_http_conf_get_module_loc_conf(cf,ngx_http_core_module);
clcf->handler=mytest_handler;
returnNGX_CONF_OK;
}
编译脚本
./configure--prefix=/usr/local/nginx--add-module=/root/Workspace/nginx-modules/ngx_http_mytest_module2--with-debug
sudomake
sudomakeinstall
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