imp: readding xpathSelect function

Author: Nagyjano

libxml.cpp

@@ -16,6 +16,7 @@ Napi::Object Libxml::Init(Napi::Env env, Napi::Object exports)
     InstanceMethod("loadXmlFromString", &Libxml::loadXmlFromString),
     InstanceMethod("loadDtds", &Libxml::loadDtds),
     InstanceMethod("validateAgainstDtds", &Libxml::validateAgainstDtds),
+    InstanceMethod("xpathSelect", &Libxml::xpathSelect),
     InstanceMethod("getDtd", &Libxml::getDtd),
     InstanceMethod("freeXml", &Libxml::freeXml),
     InstanceMethod("freeDtds", &Libxml::freeDtds)
@@ -233,6 +234,54 @@ Napi::Value Libxml::validateAgainstDtds(const Napi::CallbackInfo& info) {
   }
 }
 
+Napi::Value Libxml::xpathSelect(const Napi::CallbackInfo& info) {
+  Napi::Env env = info.Env();
+  if (info.Length() < 1){
+    Napi::TypeError::New(env, "xpathSelect requires at least 1 argument").ThrowAsJavaScriptException();
+    return env.Undefined();
+  }
+  Napi::EscapableHandleScope scope(env);
+  Napi::Value res;
+  Napi::String val = info[0].ToString();
+  //Need to keep string in memory and get its const char* casted version for libxml2
+  std::string xpathStr = val.Utf8Value();
+  const char* xpathToGet(xpathStr.c_str());
+  xmlChar * xpathExpr = xmlCharStrdup(xpathToGet);
+  xmlXPathContextPtr xpathCtx;
+  xmlXPathObjectPtr xpathObj;
+  /* Create xpath evaluation context */
+  xpathCtx = xmlXPathNewContext(this->docPtr);
+  if(xpathCtx == nullptr) {
+    Napi::Error::New(env, "Error: unable to create new XPath context").ThrowAsJavaScriptException();
+    return env.Undefined();
+  }
+  /* Evaluate xpath expression */
+  xpathObj = xmlXPathEvalExpression(xpathExpr, xpathCtx);
+  if(xpathObj == nullptr) {
+    xmlXPathFreeContext(xpathCtx);
+    return Napi::Boolean::New(env, false);
+  }
+  else if(xpathObj) {
+    switch (xpathObj->type) {
+    case XPATH_BOOLEAN:
+      res = Napi::Boolean::New(env, xpathObj->boolval);
+      break;
+    case XPATH_NUMBER:
+      res = Napi::Number::New(env, xpathObj->floatval);
+      break;
+    case XPATH_STRING:
+      res = Napi::String::New(env, (const char *)xpathObj->stringval);
+      break;
+    default:
+      res = env.Null();
+      break;
+    }
+  }
+  xmlXPathFreeObject(xpathObj);
+  xmlXPathFreeContext(xpathCtx);
+  return scope.Escape(res);
+}
+
 Napi::Value Libxml::getDtd(const Napi::CallbackInfo& info) {
   Napi::Env env = info.Env();
   Napi::HandleScope scope(env);

libxml.h

@@ -45,7 +45,7 @@ class Libxml : public Napi::ObjectWrap<Libxml>
   // static Napi::Value loadSchemas(const Napi::CallbackInfo& info);
   Napi::Value validateAgainstDtds(const Napi::CallbackInfo& info);
   // static Napi::Value validateAgainstSchemas(const Napi::CallbackInfo& info);
-  // static Napi::Value xpathSelect(const Napi::CallbackInfo& info);
+  Napi::Value xpathSelect(const Napi::CallbackInfo& info);
   Napi::Value getDtd(const Napi::CallbackInfo& info);
   void freeXml(const Napi::CallbackInfo& info);
   Napi::Value freeDtds(const Napi::CallbackInfo& info);

test/libxml-test.js

@@ -111,36 +111,37 @@ describe('Node-Libxml', function () {
     expect(currentDtd).to.have.property('systemId', 'mydoctype.dtd');
     libxml.freeXml();
   });
-  // it('Shoud return correct xpath values', function () {
-  //   let libxml = new Libxml(),
-  //   xmlfile = libxml.loadXml('test/data/test-default.xml'),
-  //   info = libxml.xpathSelect('string(//infos)'),
-  //   infodust = libxml.xpathSelect('number(//infosdust)'),
-  //   attrib = libxml.xpathSelect('string(//infos/@attrib)'),
-  //   infoExist = libxml.xpathSelect('boolean(//infos)'),
-  //   info23NotExist = libxml.xpathSelect('boolean(//infos23)'),
-  //   xpathToMyExist = libxml.xpathSelect('boolean(/xpath/to/my)'),
-  //   nbElementsInMy = libxml.xpathSelect('count(//my//*)'),
-  //   nbElementsInXpath = libxml.xpathSelect('count(/xpath//*)');
+  it('Should return correct xpath values', function () {
+    let libxml = new Libxml();
+    let xmlfile = libxml.loadXml('test/data/test-default.xml');
+    expect(xmlfile).to.be.true;
+    let info = libxml.xpathSelect('string(//infos)'),
+    infodust = libxml.xpathSelect('number(//infosdust)'),
+    attrib = libxml.xpathSelect('string(//infos/@attrib)'),
+    infoExist = libxml.xpathSelect('boolean(//infos)'),
+    info23NotExist = libxml.xpathSelect('boolean(//infos23)'),
+    xpathToMyExist = libxml.xpathSelect('boolean(/xpath/to/my)'),
+    nbElementsInMy = libxml.xpathSelect('count(//my//*)'),
+    nbElementsInXpath = libxml.xpathSelect('count(/xpath//*)');
 
-  //   expect(info).to.be.a.string;
-  //   expect(info).to.have.string('trezaq');
-  //   expect(infodust).to.be.a('number');
-  //   expect(infodust).to.equal(23);
-  //   expect(attrib).to.be.a.string;
-  //   expect(attrib).to.have.string('example');
-  //   expect(infoExist).to.be.a('boolean');
-  //   expect(infoExist).to.be.true;
-  //   expect(info23NotExist).to.be.a('boolean');
-  //   expect(info23NotExist).to.be.false;
-  //   expect(xpathToMyExist).to.be.a('boolean');
-  //   expect(xpathToMyExist).to.be.true;
-  //   expect(nbElementsInMy).to.be.a('number');
-  //   expect(nbElementsInMy).to.equal(2);
-  //   expect(nbElementsInXpath).to.be.a('number');
-  //   expect(nbElementsInXpath).to.equal(4);
-  //   libxml.freeXml();
-  // });
+    expect(info).to.be.a.string;
+    expect(info).to.have.string('trezaq');
+    expect(infodust).to.be.a('number');
+    expect(infodust).to.equal(23);
+    expect(attrib).to.be.a.string;
+    expect(attrib).to.have.string('example');
+    expect(infoExist).to.be.a('boolean');
+    expect(infoExist).to.be.true;
+    expect(info23NotExist).to.be.a('boolean');
+    expect(info23NotExist).to.be.false;
+    expect(xpathToMyExist).to.be.a('boolean');
+    expect(xpathToMyExist).to.be.true;
+    expect(nbElementsInMy).to.be.a('number');
+    expect(nbElementsInMy).to.equal(2);
+    expect(nbElementsInXpath).to.be.a('number');
+    expect(nbElementsInXpath).to.equal(4);
+    libxml.freeXml();
+  });
   // // // ABOVE IS ALL THE SAME WITH MEMORY MANUAL MANADGEMENT
   it('should free XML memory & infos when asked in manual mod On not wellformed xml', function () {
     let libxml = new Libxml(true);