Re: svn commit: r1884505 - in /httpd/httpd/trunk: changes-entries/pr64339.txt modules/filters/mod_xml2enc.c

[Nick Kew]

On Thu, 17 Dec 2020 17:31:20 +0000
Nick Kew <n...@apache.org> wrote:

> > On 17 Dec 2020, at 16:22, Joe Orton <jor...@redhat.com> wrote:
>  [chop]
> Thanks for prompting me to take a proper look at where this thread
> started.

Further thought: anything hardwired will come up against future
use cases where it acts contrary to expectations and indeed
requirements.  A future-proof solution is to make it configurable.

I attach a patch I've just hacked (untested): if folks are happy
with the approach I'll flesh it out and commit.

-- 
Nick Kew

Index: mod_xml2enc.c
===================================================================
--- mod_xml2enc.c	(revision 1884632)
+++ mod_xml2enc.c	(working copy)
@@ -84,12 +84,19 @@
     apr_bucket_brigade* bbnext;
     apr_bucket_brigade* bbsave;
     const char* encoding;
+    int checkedmime;
 } xml2ctx;
 
 typedef struct {
+  int onoff;
+  const char *ctype;
+} mimetype;
+
+typedef struct {
     const char* default_charset;
     xmlCharEncoding default_encoding;
     apr_array_header_t* skipto;
+    apr_array_header_t* mimetypes;
 } xml2cfg;
 
 typedef struct {
@@ -331,6 +338,7 @@
     int pending_meta = 0;
     char *ctype;
     char *p;
+    xml2cfg *cfg;
 
     if (!ctx || !f->r->content_type) {
         /* log error about configuring this */
@@ -338,15 +346,38 @@
         return ap_pass_brigade(f->next, bb) ;
     }
 
-    ctype = apr_pstrdup(f->r->pool, f->r->content_type);
-    for (p = ctype; *p; ++p)
-        if (isupper(*p))
-            *p = tolower(*p);
+    if (!ctx->checkedmime) {
+        cfg = ap_get_module_config(f->r->per_dir_config, &xml2enc_module);
+        ctype = apr_pstrdup(f->r->pool, f->r->content_type);
+        for (p = ctype; *p; ++p)
+            if (isupper(*p))
+                *p = tolower(*p);
 
-    /* only act if starts-with "text/" or contains "+xml" */
-    if (strncmp(ctype, "text/", 5) && !strstr(ctype, "+xml"))  {
-        ap_remove_output_filter(f);
-        return ap_pass_brigade(f->next, bb) ;
+        /* Check whether we're configured to act on this MIME type */
+        if (cfg->mimetypes != NULL) {
+            mimetype *conftypes = (mimetype*)cfg->mimetypes->elts;
+            int i;
+            for (i = 0; i < cfg->mimetypes->nelts; ++i) {
+                if (!strncmp(conftypes[i].ctype, ctype,
+                    strlen(conftypes[i].ctype))) {
+                    if (conftypes[i].onoff == 0) {
+                        ap_remove_output_filter(f);
+                        return ap_pass_brigade(f->next, bb) ;
+                    }
+                    ctx->checkedmime = 1;
+                    break;
+                }
+            }
+        }
+    
+        /* else only act if starts-with "text/" or contains "xml" */
+        if (!ctx->checkedmime) {
+            if (strncmp(ctype, "text/", 5) && !strstr(ctype, "xml"))  {
+                ap_remove_output_filter(f);
+                return ap_pass_brigade(f->next, bb) ;
+            }
+            ctx->checkedmime = 1;
+        }
     }
 
     if (ctx->bbsave == NULL) {
@@ -637,6 +668,27 @@
     attr->val = arg;
     return NULL;
 }
+static const char* set_mimetype(cmd_parms* cmd, void* CFG, const char* arg)
+{
+    mimetype* type;
+    xml2cfg* cfg = CFG;
+    if (cfg->mimetypes == NULL)
+        cfg->mimetypes = apr_array_make(cmd->pool, 6, sizeof(mimetype));
+    type = apr_array_push(cfg->mimetypes);
+    if (arg[0] == '-') {
+        type->onoff = 0;
+        type->ctype = arg+1;
+    }
+    else if (arg[0] == '+') {
+        type->onoff = 1;
+        type->ctype = arg+1;
+    }
+    else {
+        type->onoff = 1;
+        type->ctype = arg;
+    }
+    return NULL;
+}
 
 static const command_rec xml2enc_cmds[] = {
     AP_INIT_TAKE1("xml2EncDefault", set_default, NULL, OR_ALL,
@@ -645,6 +697,8 @@
                      "EncodingAlias charset alias [more aliases]"),
     AP_INIT_ITERATE("xml2StartParse", set_skipto, NULL, OR_ALL,
                     "Ignore anything in front of the first of these elements"),
+    AP_INIT_ITERATE("xml2MimeType", set_mimetype, NULL, OR_ALL,
+                    "List MIME types to process or leave untouched"),
     { NULL }
 };
 static void* xml2enc_config(apr_pool_t* pool, char* x)
@@ -664,6 +718,7 @@
     ret->default_charset = add->default_charset
                          ? add->default_charset : base->default_charset;
     ret->skipto = add->skipto ? add->skipto : base->skipto;
+    ret->mimetypes = add->mimetypes ? add->mimetypes : base->mimetypes;
     return ret;
 }