Apache模块开发学习笔记(一)
先祝大家2009年心想事成,万事如意,工作顺利,心情愉快啊!
最近开始研究Apache模块的开发,在博客里记录一下学习的过程吧,
本来没什么头绪,现在研究下来,
主要学习Apache的基础对象和 API头文件,例如http_头文件里的函数,
APR(Apache Portable Runtime)函数库,请求处理流程,过滤器架构,页面内容生成等等
我是在Fedora10上开发的,现介绍一下环境的搭建:
# yum install httpd-devel # yum install automake autoconf # yum install libtool # yum install ImageMagick # yum install ImageMagick-devel # yum install pcre-devel
现在看一个apache2自带的一个非常简单的filter:
首先创建一个Module工程
cd /usr/local/src mkdir modtest cd modtest apxs -g -n case_filter
自动声称如下文件:
ls -a ./test . .. .deps Makefile case_filter.c modules.mk
修改case_filter.c,代码如下:
#include "httpd.h" #include "http_config.h" #include "apr_buckets.h" #include "apr_general.h" #include "apr_lib.h" #include "util_filter.h" #include "http_request.h" static const char s_szCaseFilterName[] = "CaseFilter"; module AP_MODULE_DECLARE_DATA case_filter_module; typedef struct { int bEnabled; } CaseFilterConfig; static void *CaseFilterCreateServerConfig(apr_pool_t *p, server_rec *s) { CaseFilterConfig *pConfig = apr_pcalloc(p, sizeof *pConfig); pConfig->bEnabled = 0; return pConfig; } static void CaseFilterInsertFilter(request_rec *r) { CaseFilterConfig *pConfig = ap_get_module_config(r->server->module_config, &case_filter_module); if (!pConfig->bEnabled) return; ap_add_output_filter(s_szCaseFilterName, NULL, r, r->connection); } static apr_status_t CaseFilterOutFilter(ap_filter_t *f, apr_bucket_brigade *pbbIn) { request_rec *r = f->r; conn_rec *c = r->connection; apr_bucket *pbktIn; apr_bucket_brigade *pbbOut; pbbOut = apr_brigade_create(r->pool, c->bucket_alloc); for (pbktIn = APR_BRIGADE_FIRST(pbbIn); pbktIn != APR_BRIGADE_SENTINEL(pbbIn); pbktIn = APR_BUCKET_NEXT(pbktIn)) { const char *data; apr_size_t len; char *buf; apr_size_t n; apr_bucket *pbktOut; if (APR_BUCKET_IS_EOS(pbktIn)) { apr_bucket *pbktEOS = apr_bucket_eos_create(c->bucket_alloc); APR_BRIGADE_INSERT_TAIL(pbbOut, pbktEOS); continue; } /* read */ apr_bucket_read(pbktIn, &data, &len, APR_BLOCK_READ); /* write */ buf = apr_bucket_alloc(len, c->bucket_alloc); for (n = 0; n < len; ++n) buf[n] = apr_toupper(data[n]); pbktOut = apr_bucket_heap_create(buf, len, apr_bucket_free, c->bucket_alloc); APR_BRIGADE_INSERT_TAIL(pbbOut, pbktOut); } /* XXX: is there any advantage to passing a brigade for each bucket? */ return ap_pass_brigade(f->next, pbbOut); } static const char *CaseFilterEnable(cmd_parms *cmd, void *dummy, int arg) { CaseFilterConfig *pConfig = ap_get_module_config(cmd->server->module_config, &case_filter_module); pConfig->bEnabled = arg; return NULL; } static const command_rec CaseFilterCmds[] ={ AP_INIT_FLAG("CaseFilter", CaseFilterEnable, NULL, RSRC_CONF,"Run a case filter on this host"), { NULL} }; static void CaseFilterRegisterHooks(apr_pool_t *p) { ap_hook_insert_filter(CaseFilterInsertFilter, NULL, NULL, APR_HOOK_MIDDLE); ap_register_output_filter(s_szCaseFilterName, CaseFilterOutFilter, NULL, AP_FTYPE_RESOURCE); } module AP_MODULE_DECLARE_DATA case_filter_module ={ STANDARD20_MODULE_STUFF, NULL, NULL, CaseFilterCreateServerConfig, NULL, CaseFilterCmds, CaseFilterRegisterHooks };
然后编译:
apxs -c -i mod_case_filter
确认模块安装完毕: