Adding namespace prefixes support for xpath

src/lua_xpath.c

@@ -5,6 +5,7 @@
 #define LUA_XPATH_NAME          "xpath"
 #define LUA_XPATH_MT_NAME       "xpath_mt"
 
+#define MAX_XPATH_PREFIX_NUM 20
 
 typedef struct xpath_selector_s {
     struct xpath_selector_s     *root;
@@ -204,11 +205,13 @@ __parse_file(xpath_selector_t *sel, char const *fname)
 
 
 static void **
-__eval_xpath(lua_State *L, xpath_selector_t *sel, char const *xpath)
+__eval_xpath(lua_State *L, xpath_selector_t *sel, char const *xpath, const xmlChar * nsList[])
 {
     int i;
     xmlXPathObject *result = NULL;
     xmlXPathContext *ctxt = NULL; 
+    const xmlChar* prefix = NULL;
+    const xmlChar* href = NULL;
     void **nodes = NULL;
 
 
@@ -223,6 +226,14 @@ __eval_xpath(lua_State *L, xpath_selector_t *sel, char const *xpath)
             break;
         }
 
+        for (i = 0 ; prefix = nsList[i++];) {
+            if ((href = nsList[i])
+                    && (xmlXPathRegisterNs(ctxt, prefix, href) != 0)) {
+                __set_error(sel, NULL, "add namespace to xpath context error");
+                break;
+            }
+        }
+
         /* the current node */
         ctxt->node = sel->node;
 
@@ -460,6 +471,7 @@ xpath_eval_xpath(lua_State *L)
     size_t length;
     void **nodes;
     const char *xpath;
+    const xmlChar* nsList[MAX_XPATH_PREFIX_NUM];
     xpath_selector_t *sel, *node;
 
 
@@ -477,8 +489,29 @@ xpath_eval_xpath(lua_State *L)
         lua_pushstring(L, "xpath pattern needed");
         return 2;
     }
+    {
+        int n, top = lua_gettop(L);
+        i = 1;
+        if (top > 2) { //optionally prefix/href array for xpath
+            if (lua_type(L, 3) != LUA_TTABLE) {
+                lua_pushnil(L);
+                lua_pushstring(L, "prefix/href array is expected");
+                return 2;
+            }
+            if ((n = luaL_getn(L, 3)) > MAX_XPATH_PREFIX_NUM) {
+                lua_pushnil(L);
+                lua_pushstring(L, "too much prefixes");
+                return 2;
+            }
+            for (; i <= n; i++) {
+                lua_rawgeti(L, 3, i);
+                nsList[i - 1] = luaL_optlstring(L, -1, NULL, &length);
+            }
+        }
+        nsList[i - 1] = 0;
+    }
 
-    nodes = (void **) __eval_xpath(L, sel, xpath);
+    nodes = (void **) __eval_xpath(L, sel, xpath, nsList);
     if (nodes == NULL) {
         lua_pushnil(L);
         lua_pushstring(L, __get_error(sel, "eval xpath error"));

src/lua_xpath.h

@@ -7,6 +7,8 @@
 #include <libxml/tree.h>
 #include <libxml/xpath.h>
 #include <libxml/parserInternals.h>
+#include <libxml/xpathInternals.h>
+
 
 #include <stdint.h>
 

tests/api.lua

@@ -1,4 +1,4 @@
-package.cpath = "/home/duhoobo/prj/amateur/lua-xpath/src/?.so;" .. package.cpath
+package.cpath = "/home/akh/local/lua-xpath/src/?.so;" .. package.cpath
 
 local xpath = require("xpath")
 
@@ -12,6 +12,17 @@ xml = [[
     <sex>male</sex>
 </body>
 </html>]]
+xmlns = [[
+<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:message="http://org.mycomp">
+   <soapenv:Header/>
+      <soapenv:Body>
+      <message:SomeMessage>
+        <message:SomeField>4</message:SomeField>
+      </message:SomeMessage>
+   </soapenv:Body>
+</soapenv:Envelope>
+]]
+
 
 
 function test_xpath()
@@ -40,6 +51,33 @@ function test_xpath()
     print "\n--- leave test_xpath ---"
 end
 
+function test_xpath_with_ns()
+    print "--- enter test_xpath_with_ns ---\n"
+
+    local sel, err = xpath.loads(xmlns)
+
+    if not sel then
+        print(sel, err)
+        return
+    end
+
+    print(sel)
+
+    local ls, err = sel:xpath("/soap:Envelope/soap:Body//message:SomeField[text()=4]",
+    {"soap", "http://schemas.xmlsoap.org/soap/envelope/", "message", "http://org.mycomp"})
+
+    if not ls then
+        print(ls, err)
+        return
+    end
+
+    for k, v in pairs(ls) do
+        print(k, v, v:extract())
+    end
+
+    print "\n--- leave test_xpath_with_ns ---"
+end
+
 
 function test_relative_xpath()
     print "--- enter test_relative_xpath ---\n"
@@ -214,6 +252,7 @@ end
 
 
 test_xpath()
+test_xpath_with_ns()
 test_relative_xpath()
 test_re()
 test_css()