Re: svn commit: r1726038 - /httpd/httpd/trunk/modules/proxy/mod_proxy_hcheck.c

[Rainer Jung]

Am 21.01.2016 um 18:55 schrieb Jim Jagielski:
This implies that the kept_body() func added to ap_expr should
be removed, right?

At least it is no longer needed for proxy_hcheck. If we want to provide 
the original kept_body as used by mod_request to expr we can keep it. I 
don't know whether such use is sensible, but maybe best at this point to 
remove it after you can confirm the new approach works for you.

Regards,

Rainer

On Jan 21, 2016, at 12:49 PM, rj...@apache.org wrote:

Author: rjung
Date: Thu Jan 21 17:49:21 2016
New Revision: 1726038

URL: http://svn.apache.org/viewvc?rev=1726038&view=rev
Log:
Implement expr lookup in mod_proxy_hcheck for
variables whose names start with "HC_" and for
the new function hc().

Currently only HC_BODY and hc(body) are supported.
Both return the saved body of the health check
response to be used in an expr that decides about
success of a check.

Modified:
    httpd/httpd/trunk/modules/proxy/mod_proxy_hcheck.c

Modified: httpd/httpd/trunk/modules/proxy/mod_proxy_hcheck.c
URL: 
http://svn.apache.org/viewvc/httpd/httpd/trunk/modules/proxy/mod_proxy_hcheck.c?rev=1726038&r1=1726037&r2=1726038&view=diff
==============================================================================
--- httpd/httpd/trunk/modules/proxy/mod_proxy_hcheck.c (original)
+++ httpd/httpd/trunk/modules/proxy/mod_proxy_hcheck.c Thu Jan 21 17:49:21 2016
@@ -926,6 +926,75 @@ static void hc_show_exprs(request_rec *r
     ap_rputs("</table><hr/>\n", r);
}

+static const char *hc_get_body(request_rec *r)
+{
+    apr_off_t length;
+    apr_size_t len;
+    apr_status_t rv;
+    char *buf;
+
+    if (!r || !r->kept_body)
+        return "";
+
+    rv = apr_brigade_length(r->kept_body, 1, &length);
+    len = (apr_size_t)length;
+    if (rv != APR_SUCCESS || len == 0)
+        return "";
+
+    buf = apr_palloc(r->pool, len + 1);
+    rv = apr_brigade_flatten(r->kept_body, buf, &len);
+    if (rv != APR_SUCCESS)
+        return "";
+    buf[len] = '\0'; /* ensure */
+    return (const char*)buf;
+}
+
+static const char *hc_expr_var_fn(ap_expr_eval_ctx_t *ctx, const void *data)
+{
+    char *var = (char *)data;
+
+    if (var && *var && ctx->r && ap_casecmpstr(var, "BODY") == 0) {
+        return hc_get_body(ctx->r);
+    }
+    return NULL;
+}
+
+static const char *hc_expr_func_fn(ap_expr_eval_ctx_t *ctx, const void *data,
+                                const char *arg)
+{
+    char *var = (char *)arg;
+
+    if (var && *var && ctx->r && ap_casecmpstr(var, "BODY") == 0) {
+        return hc_get_body(ctx->r);
+    }
+    return NULL;
+}
+
+static int hc_expr_lookup(ap_expr_lookup_parms *parms)
+{
+    switch (parms->type) {
+    case AP_EXPR_FUNC_VAR:
+        /* for now, we just handle everything that starts with HC_.
+         */
+        if (strncasecmp(parms->name, "HC_", 3) == 0) {
+            *parms->func = hc_expr_var_fn;
+            *parms->data = parms->name + 4;
+            return OK;
+        }
+        break;
+    case AP_EXPR_FUNC_STRING:
+        /* Function HC() is implemented by us.
+         */
+        if (strcasecmp(parms->name, "HC") == 0) {
+            *parms->func = hc_expr_func_fn;
+            *parms->data = NULL;
+            return OK;
+        }
+        break;
+    }
+    return DECLINED;
+}
+
static const command_rec command_table[] = {
     AP_INIT_RAW_ARGS("ProxyHCTemplate", set_hc_template, NULL, OR_FILEINFO,
                      "Health check template"),
@@ -941,6 +1010,7 @@ static void hc_register_hooks(apr_pool_t
     APR_REGISTER_OPTIONAL_FN(set_worker_hc_param);
     APR_REGISTER_OPTIONAL_FN(hc_show_exprs);
     ap_hook_post_config(hc_post_config, aszPre, aszSucc, APR_HOOK_LAST);
+    ap_hook_expr_lookup(hc_expr_lookup, NULL, NULL, APR_HOOK_MIDDLE);
}

/* the main config structure */