1/* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements.  See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License.  You may obtain a copy of the License at
7 *
8 *     http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "httpd.h"
18#include "http_config.h"
19#include "apr_buckets.h"
20#include "apr_general.h"
21#include "apr_lib.h"
22#include "util_filter.h"
23#include "http_request.h"
24
25#include <ctype.h>
26
27static const char s_szCaseFilterName[]="CaseFilter";
28module AP_MODULE_DECLARE_DATA case_filter_module;
29
30typedef struct
31    {
32    int bEnabled;
33    } CaseFilterConfig;
34
35static void *CaseFilterCreateServerConfig(apr_pool_t *p,server_rec *s)
36    {
37    CaseFilterConfig *pConfig=apr_pcalloc(p,sizeof *pConfig);
38
39    pConfig->bEnabled=0;
40
41    return pConfig;
42    }
43
44static void CaseFilterInsertFilter(request_rec *r)
45    {
46    CaseFilterConfig *pConfig=ap_get_module_config(r->server->module_config,
47                                                   &case_filter_module);
48
49    if(!pConfig->bEnabled)
50        return;
51
52    ap_add_output_filter(s_szCaseFilterName,NULL,r,r->connection);
53    }
54
55static apr_status_t CaseFilterOutFilter(ap_filter_t *f,
56                                        apr_bucket_brigade *pbbIn)
57    {
58    request_rec *r = f->r;
59    conn_rec *c = r->connection;
60    apr_bucket *pbktIn;
61    apr_bucket_brigade *pbbOut;
62
63    pbbOut=apr_brigade_create(r->pool, c->bucket_alloc);
64    for (pbktIn = APR_BRIGADE_FIRST(pbbIn);
65         pbktIn != APR_BRIGADE_SENTINEL(pbbIn);
66         pbktIn = APR_BUCKET_NEXT(pbktIn))
67    {
68        const char *data;
69        apr_size_t len;
70        char *buf;
71        apr_size_t n;
72        apr_bucket *pbktOut;
73
74        if(APR_BUCKET_IS_EOS(pbktIn))
75            {
76            apr_bucket *pbktEOS=apr_bucket_eos_create(c->bucket_alloc);
77            APR_BRIGADE_INSERT_TAIL(pbbOut,pbktEOS);
78            continue;
79            }
80
81        /* read */
82        apr_bucket_read(pbktIn,&data,&len,APR_BLOCK_READ);
83
84        /* write */
85        buf = apr_bucket_alloc(len, c->bucket_alloc);
86        for(n=0 ; n < len ; ++n)
87            buf[n] = apr_toupper(data[n]);
88
89        pbktOut = apr_bucket_heap_create(buf, len, apr_bucket_free,
90                                         c->bucket_alloc);
91        APR_BRIGADE_INSERT_TAIL(pbbOut,pbktOut);
92        }
93
94    /* Q: is there any advantage to passing a brigade for each bucket?
95     * A: obviously, it can cut down server resource consumption, if this
96     * experimental module was fed a file of 4MB, it would be using 8MB for
97     * the 'read' buckets and the 'write' buckets.
98     *
99     * Note it is more efficient to consume (destroy) each bucket as it's
100     * processed above than to do a single cleanup down here.  In any case,
101     * don't let our caller pass the same buckets to us, twice;
102     */
103    apr_brigade_cleanup(pbbIn);
104    return ap_pass_brigade(f->next,pbbOut);
105    }
106
107static const char *CaseFilterEnable(cmd_parms *cmd, void *dummy, int arg)
108    {
109    CaseFilterConfig *pConfig=ap_get_module_config(cmd->server->module_config,
110                                                   &case_filter_module);
111    pConfig->bEnabled=arg;
112
113    return NULL;
114    }
115
116static const command_rec CaseFilterCmds[] =
117    {
118    AP_INIT_FLAG("CaseFilter", CaseFilterEnable, NULL, RSRC_CONF,
119                 "Run a case filter on this host"),
120    { NULL }
121    };
122
123static void CaseFilterRegisterHooks(apr_pool_t *p)
124    {
125    ap_hook_insert_filter(CaseFilterInsertFilter,NULL,NULL,APR_HOOK_MIDDLE);
126    ap_register_output_filter(s_szCaseFilterName,CaseFilterOutFilter,NULL,
127                              AP_FTYPE_RESOURCE);
128    }
129
130AP_DECLARE_MODULE(case_filter) =
131{
132    STANDARD20_MODULE_STUFF,
133    NULL,
134    NULL,
135    CaseFilterCreateServerConfig,
136    NULL,
137    CaseFilterCmds,
138    CaseFilterRegisterHooks
139};
140