[nanny] Regular expression in expected string

Sébastien Bonnet <[email protected]> Thu, 10 Oct 2002 16:20:42 +0200

Newsgroups	gmane.linux.redhat.piranha
Message-ID	<[email protected]>

Hi,

I've been surprised yesterday by nanny's behaviour in regard to the expected
string. The man page doesn't state that expected_string is compared to the
first strlen(received_string) characters of received_string.

This makes impossible to expect something not being the beginning of the
received string. It's quite limitating :(

I've thus enhanced nanny to accept a regular expression as the expected
string. This way, you can look for whatever you want within the first 255
characters of your server's answer.

Quite handy when it comes to check both apache and a module it's running.

Example: I've a PHP page, made of static HTML code and also dynamic content
(say it prints 'MY APP IF FINE').

The expected_string, which formerly could (at most) only be something like
"HTTP/1.1 200 OK" now is "HTTP/1.1 200 OK.*MY APP IF FINE".
I'm thus checking that Apache if OK (HTTP 200) and that my app is working
just fine (replace just print something by a full status check).


For those interested by the enhancement, I've attached the patch against
piranha-0.7.0. Just add -DUSE_REGEX in the CFLAGS (in Makefile), make nanny
and copy it to the right location and you're done.

FYI, if the provided expected string is not a correct regex, no real server
will ever appear. If this is the case, just have a look at your favorite log
files ...

Enjoy :)

-- 
Sébastien Bonnet
  Centre de contacts - Experian France

nanny-regex.diff (text/plain, 1.6 KB)

--- piranha.1/nanny.c	Thu Dec 13 21:30:26 2001
+++ piranha.2/nanny.c	Thu Oct 10 15:53:00 2002
@@ -139,6 +139,11 @@
 #include <math.h>		/* for pow() */
 #include <time.h>
 
+#if defined(USE_REGEX)
+	#include <sys/types.h>
+	#include <regex.h>
+#endif
+
 #include "globals.h"
 #include "util.h"
 #include "nanny.h"
@@ -269,6 +274,25 @@
 	struct iphdr *ip;
 #endif
 
+#if defined(USE_REGEX)
+	static regex_t regExpr;
+	static char regCompiled = 0;
+	char regError[255];
+#endif
+
+#if defined(USE_REGEX)
+	if (!regCompiled) {
+		if ((i = regcomp (&regExpr, expect_str, REG_EXTENDED)) == 0) {
+			regCompiled = 1;
+		} else {
+			regerror (i, &regExpr, regError, sizeof (regError));
+			piranha_log (flags, (char *)
+				     "Error '%s' processing expected regular expression",
+				     regError);
+		}
+	}
+#endif
+
 	if (pingTimeout < 500)
 		pingTimeout = 500;
 
@@ -502,7 +526,11 @@
 			*/
 
 			if (expect_str)
+#if defined(USE_REGEX)
+				read_len = sizeof (read_buf) - 1;
+#else
 				read_len = strlen (expect_str);
+#endif
 			else
 				read_len = 1;	/* for UDP */
 
@@ -555,11 +583,15 @@
 				}
 
 				if ((read_len == 1) && (*expect_str == '*')) {
+					/* Wildcard */
 					read_buf[0] = '*';
 					read_buf[1] = 0;
 					i = 1;
 				}
-				/* Wildcard */
+#if defined(USE_REGEX)
+				if (!regCompiled || regexec (&regExpr, read_buf, 0, NULL, 0))
+					return_status = 1;
+#else
 				if (i >= read_len) {
 					if (strncmp ((const char *) expect_str,
 						     (const char *) read_buf,
@@ -572,6 +604,7 @@
 						     port);
 					return_status = 1;
 				}
+#endif
 			}
 		}
 	}