[MINOR] http: add pattern extraction method to stick on query string parameter
This is an updated version of my patch for url parameter extraction on
stick table. It adds "url_param(name)" as a possible stick method.
diff --git a/doc/configuration.txt b/doc/configuration.txt
index 699b1c4..cc4ecad 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -7804,6 +7804,13 @@
<lengthoffset> + <lengthsize> else it is absolute.
Ex: see SSL session id example in "stick table" chapter.
+ url_param(name)
+ This extracts the first occurrence of the parameter <name> in
+ the query string of the request and uses the correponding value
+ to match. A typical use is to get sticky session through url (e.g.
+ http://example.com/foo?JESSIONID=some_id with
+ url_param(JSESSIONID)), for cases where cookies cannot be used.
+
The currently available list of transformations include :
lower Convert a string pattern to lower case. This can only be placed
diff --git a/src/proto_http.c b/src/proto_http.c
index bcda01e..ec1e180 100644
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -8258,7 +8258,110 @@
return data->ip.s_addr != 0;
}
+/*
+ * Given a path string and its length, find the position of beginning of the
+ * query string. Returns NULL if no query string is found in the path.
+ *
+ * Example: if path = "/foo/bar/fubar?yo=mama;ye=daddy", and n = 22:
+ *
+ * find_query_string(path, n) points to "yo=mama;ye=daddy" string.
+ */
+static inline char *find_query_string(char *path, size_t path_l)
+{
+ char *p;
+ p = memchr(path, '?', path_l);
+ return p ? p + 1 : NULL;
+}
+
+static inline int is_param_delimiter(char c)
+{
+ return c == '&' || c == ';';
+}
+
+/*
+ * Given a url parameter, find the starting position of the first occurence,
+ * or NULL if the parameter is not found.
+ *
+ * Example: if query_string is "yo=mama;ye=daddy" and url_param_name is "ye",
+ * the function will return query_string+8.
+ */
+static char*
+find_url_param_pos(char* query_string, size_t query_string_l,
+ char* url_param_name, size_t url_param_name_l)
+{
+ char *pos, *last;
+
+ pos = query_string;
+ last = query_string + query_string_l - url_param_name_l - 1;
+
+ while (pos <= last) {
+ if (pos[url_param_name_l] == '=') {
+ if (memcmp(pos, url_param_name, url_param_name_l) == 0)
+ return pos;
+ pos += url_param_name_l + 1;
+ }
+ while (pos <= last && !is_param_delimiter(*pos))
+ pos++;
+ pos++;
+ }
+ return NULL;
+}
+
+/*
+ * Given a url parameter name, returns its value and size into *value and
+ * *value_l respectively, and returns non-zero. If the parameter is not found,
+ * zero is returned and value/value_l are not touched.
+ */
+static int
+find_url_param_value(char* path, size_t path_l,
+ char* url_param_name, size_t url_param_name_l,
+ char** value, size_t* value_l)
+{
+ char *query_string, *qs_end;
+ char *arg_start;
+ char *value_start, *value_end;
+
+ query_string = find_query_string(path, path_l);
+ if (!query_string)
+ return 0;
+
+ qs_end = path + path_l;
+ arg_start = find_url_param_pos(query_string, qs_end - query_string,
+ url_param_name, url_param_name_l);
+ if (!arg_start)
+ return 0;
+
+ value_start = arg_start + url_param_name_l + 1;
+ value_end = value_start;
+
+ while ((value_end < qs_end) && !is_param_delimiter(*value_end))
+ value_end++;
+
+ *value = value_start;
+ *value_l = value_end - value_start;
+ return 1;
+}
+
+static int
+pattern_fetch_url_param(struct proxy *px, struct session *l4, void *l7, int dir,
+ const struct pattern_arg *arg_p, int arg_i, union pattern_data *data)
+{
+ struct http_txn *txn = l7;
+ struct http_msg *msg = &txn->req;
+ char *url_param_value;
+ size_t url_param_value_l;
+
+ if (!find_url_param_value(msg->sol + msg->sl.rq.u, msg->sl.rq.u_l,
+ arg_p->data.str.str, arg_p->data.str.len,
+ &url_param_value, &url_param_value_l))
+ return 0;
+
+ data->str.str = url_param_value;
+ data->str.len = url_param_value_l;
+ return 1;
+}
+
/************************************************************************/
/* All supported keywords must be declared here. */
@@ -8266,6 +8369,7 @@
/* Note: must not be declared <const> as its list will be overwritten */
static struct pattern_fetch_kw_list pattern_fetch_keywords = {{ },{
{ "hdr", pattern_fetch_hdr_ip, pattern_arg_str, PATTERN_TYPE_IP, PATTERN_FETCH_REQ },
+ { "url_param", pattern_fetch_url_param, pattern_arg_str, PATTERN_TYPE_STRING, PATTERN_FETCH_REQ },
{ NULL, NULL, NULL, 0, 0 },
}};