[webkit-dev] Need advise and code review for use of JSAPI to read and write html values from C++

[Maciej Stachowiak]

On Mar 18, 2008, at 9:51 AM, Richard Bailey wrote:

>
> I looked for but did not find samples for doing this.  If I missed  
> such samples and documentation, please send me links.
>
> The code below is my first draft (compiled and verified) to read and  
> write values from an HTML page.
>
> I appreciate any suggestions you can offer.
>
> Also, is the JS API the best route to use?

It's best to use the native DOM API, if your platform supports it. For  
the Mac port, the Objective-C DOM API would be the way to go. I don't  
know if other ports support this yet, in which case, what you are  
doing is ok. You shouldn't need the newline in your script though.

>
>
> Thanks!
> Richard
>
>
> static JSValueRef myMesssageBox(JSContextRef ctx, JSObjectRef / 
> *function*/, JSObjectRef thisObject, size_t argumentCount, const  
> JSValueRef arguments[], JSValueRef* /*exception*/)
> {
>     JSValueRef undefined = JSValueMakeUndefined(ctx);
>
>     MessageBox( NULL, TEXT("Test"), TEXT("test2"), MB_OK);
>     return undefined;
> }
>
> static JSValueRef myTestReadPageData(JSContextRef ctx, JSObjectRef / 
> *function*/, JSObjectRef thisObject, size_t argumentCount, const  
> JSValueRef arguments[], JSValueRef* /*exception*/)
> {
>     JSValueRef undefined = JSValueMakeUndefined(ctx);
>
>     const char* const script =
>     " document.getElementById('editableText').innerHTML;\
>     ";
>
>     JSStringRef scriptRef = JSStringCreateWithUTF8CString(script);
>
>     JSValueRef exception = 0;
>     JSValueRef resultRef = 0;
>     resultRef = JSEvaluateScript(ctx, scriptRef, 0, 0, 0, &exception);
>     _ASSERT(!exception);
>
>     JSStringRef strResult = JSValueToStringCopy( ctx, resultRef,  
> &exception);
>     _ASSERT(!exception);
>
>         size_t strLen = JSStringGetLength(strResult);
>     const JSChar* jsstr = JSStringGetCharactersPtr( strResult);
>
>
>         TCHAR str[MAX_PATH];
>         wcsncpy( str, jsstr, strLen);
>         str[strLen] = 0;
>
>     MessageBox( NULL, str, TEXT("test2"), MB_OK);
>     return undefined;
> }
>
> static JSValueRef myTestWritePageData(JSContextRef ctx, JSObjectRef / 
> *function*/, JSObjectRef thisObject, size_t argumentCount, const  
> JSValueRef arguments[], JSValueRef* /*exception*/)
> {
>     JSValueRef undefined = JSValueMakeUndefined(ctx);
>
>     const char* const script =
>     " document.getElementById('setableText').innerHTML='Text set  
> from CPP';\
>     ";
>
>     JSStringRef scriptRef = JSStringCreateWithUTF8CString(script);
>
>     JSValueRef exception = 0;
>     JSValueRef resultRef = 0;
>     resultRef = JSEvaluateScript(ctx, scriptRef, 0, 0, 0, &exception);
>     _ASSERT(!exception);
>
>     JSStringRef strResult = JSValueToStringCopy( ctx, resultRef,  
> &exception);
>     _ASSERT(!exception);
>
>         size_t strLen = JSStringGetLength(strResult);
>     const JSChar* jsstr = JSStringGetCharactersPtr( strResult);
>
>
>         TCHAR str[MAX_PATH];
>         wcsncpy( str, jsstr, strLen);
>         str[strLen] = 0;
>
>     MessageBox( NULL, str, TEXT("test2"), MB_OK);
>     return undefined;
> }
>
>
> HRESULT WinPrototypeWebHost::windowScriptObjectAvailable(
>             /* [in] */ IWebView *webView,
>         /* [in] */ JSContextRef context,
>         /* [in] */ JSObjectRef windowScriptObject)
> {
>     if (!m_mainFrame)
>         return S_OK;
>
>     static JSStaticFunction staticFunctions[] = {
>         { "MyMessageBox", myMesssageBox, kJSPropertyAttributeNone },
>         { "TestReadPageData", myTestReadPageData,  
> kJSPropertyAttributeNone },
>         { "TestWritePageData", myTestWritePageData,  
> kJSPropertyAttributeNone },
>         { 0, 0, 0 }
>     };
>
>     JSClassDefinition myControllerDefinition = {
>         0, kJSClassAttributeNone, "MyController", 0, 0,  
> staticFunctions,
>         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
>     };
>
>     JSClassRef controllerClass =  
> JSClassCreate(&myControllerDefinition);
>     _ASSERT(controllerClass);
>
>     m_controllerScriptObject = JSObjectMake(context,  
> controllerClass, reinterpret_cast<void*>(this));
>     _ASSERT(m_controllerScriptObject);
>
>     JSRetainPtr<JSStringRef> controllerObjectString(Adopt,  
> JSStringCreateWithUTF8CString("MyController"));
>     JSObjectSetProperty(context, windowScriptObject,  
> controllerObjectString.get(), m_controllerScriptObject,  
> kJSPropertyAttributeNone, 0);
>
>         return S_OK;
> }
>
>
> _______________________________________________
> webkit-dev mailing list
> webkit-dev at lists.webkit.org
> http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev